Methodology & sources

Each series below shows its authority, how the value is obtained, and its confidence.

The rate series

IRS §6621 rates

The IRS sets its interest rates each quarter as the federal short-term rate plus a fixed spread that depends on the category: +3 points for underpayments and non-corporate overpayments, +2 for corporate overpayments, +5 for large corporate underpayments, and +0.5 for the GATT portion of large corporate overpayments. We read the published quarterly figures directly from the IRS and record each with its effective quarter — these are published values.

The separate Form 1040 penalty and interest calculator uses committed, reviewable rules rather than scraping live prose into a formula. Each weekly refresh rechecks five official IRS pages covering failure to file, failure to pay, penalty interest, administrative relief, and the indexed minimum schedule. If a calculation-critical statement changes, validation stops publication until the rule and its boundary tests are reviewed. The interest engine likewise refuses to carry the latest rate into an unpublished quarter.

The federal post-judgment rate (28 U.S.C. §1961)

Federal law defines this rate as the weekly average 1-year Treasury constant maturity yield for the calendar week preceding the date of judgment. The U.S. Courts publish that rule but not the number. We compute it from the Federal Reserve's official H.15 1-year Treasury series (daily), averaged by week, and label it a derived value with medium confidence. Always confirm the exact applicable week against your district court's own published table before relying on it.

UK statutory late-payment interest (Late Payment Act 1998)

UK statutory interest on late commercial (B2B) debts is the Bank of England base rate plus 8 percentage points — but it is fixed for six-month periods using the base rate in force on the reference date: 31 December (for debts falling due Jan–Jun) or 30 June (for Jul–Dec). We track the Bank of England base rate directly (published) and compute the semi-annual statutory rate from it (derived), applying the correct reference date for each period.

EU Directive ECB minimum-framework benchmark (2011/7/EU)

We track the ECB main refinancing rate in force on the first calendar day of each half-year (1 January / 1 July) and preserve it as a derived benchmark. Adding eight points provides a transparent illustration of the Directive's minimum framework, not a member-state statutory rate. National implementations can use different reference bases or more creditor-favourable rules. Use the official EU country-rate table and the governing national law for a country-specific figure.

Data sources

• Alaska Court System (official) — Alaska pre- and post-judgment interest rate table (ADM-505). https://public.courts.alaska.gov/web/forms/docs/adm-505.pdf. Government edict — not subject to copyright.
• Alaska Court System (official) — Alaska pre- and post-judgment interest rate table (ADM-505). https://public.courts.alaska.gov/web/forms/docs/adm-505.pdf. Government edict — not subject to copyright.
• Alabama — alison.legislature.state.al.us — Alabama judgment interest (Ala. Code § 8-8-10(a)). https://alison.legislature.state.al.us/code-of-alabama?section=8-8-10. Government edict — not subject to copyright.
• Alabama — alison.legislature.state.al.us — Alabama prejudgment interest (Ala. Code § 8-8-1). https://alison.legislature.state.al.us/code-of-alabama?section=8-8-1. Government edict — not subject to copyright.
• Arkansas — federalreserve.gov — Arkansas judgment interest (Ark. Code Ann. § 16-65-114(a)). https://www.federalreserve.gov/releases/h15/. Government edict — not subject to copyright.
• Arkansas General Assembly (official enacted act) — Arkansas Act 995 of 2019 (§ 16-65-114). https://www.arkleg.state.ar.us/Home/FTPDocument?path=%2FACTS%2F2019R%2FPublic%2FACT995.pdf. Government edict — not subject to copyright.
• Arizona State Legislature (official) — Arizona judgment interest (A.R.S. §44-1201). https://www.azleg.gov/ars/44/01201.htm. Government edict — not subject to copyright.
• Arizona — azleg.gov — Arizona prejudgment interest (A.R.S. § 44-1201(A), &). https://www.azleg.gov/ars/44/01201.htm. Government edict — not subject to copyright.
• Bank of England — Bank of England — Bank Rate (IUDBEDR). https://www.bankofengland.co.uk/boeapps/database/Bank-Rate.asp. Bank of England statistical data, free to reuse with attribution.
• California Legislative Information and Attorney General (official) — California judgment-interest statutes and official transition authority. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CCP&sectionNum=685.010. Government edict — not subject to copyright.
• California — leginfo.legislature.ca.gov — California prejudgment interest (Cal. Civ. Code sec. 3287). https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=3289.&lawCode=CIV. Government edict — not subject to copyright.
• Colorado General Assembly — Office of Legislative Legal Services (official) — Colorado Revised Statutes, Titles 5 and 13. https://content.leg.colorado.gov/agencies/office-legislative-legal-services/2025-crs-titles-download. Government edict — not subject to copyright.
• Colorado Secretary of State (official rate certification) — Colorado judgment interest (C.R.S. §5-12-102 / §13-21-101). https://www.coloradosos.gov/pubs/info_center/files/interest_rates.pdf. Government edict — not subject to copyright.
• Connecticut General Assembly (official) — Connecticut judgment interest branches (§§37-3a–37-3c). https://www.cga.ct.gov/current/pub/chap_673.htm. Government edict — not subject to copyright.
• Connecticut General Assembly (official) — Connecticut prejudgment interest (§37-3a). https://www.cga.ct.gov/current/pub/chap_673.htm. Government edict — not subject to copyright.
• District of Columbia — code.dccouncil.gov — District of Columbia judgment interest (D.C. Code § 28-3302(c)). https://code.dccouncil.gov/us/dc/council/code/sections/28-3302. Government edict — not subject to copyright.
• D.C. — code.dccouncil.gov — D.C. prejudgment interest (D.C. Code § 15-108). https://code.dccouncil.gov/us/dc/council/code/sections/15-108. Government edict — not subject to copyright.
• Delaware — delcode.delaware.gov — Delaware judgment interest (6 Del. C. § 2301). https://delcode.delaware.gov/title6/c023/. Government edict — not subject to copyright.
• Delaware — delcode.delaware.gov — Delaware prejudgment interest (6 Del. C. § 2301(a)). https://delcode.delaware.gov/title6/c023/. Government edict — not subject to copyright.
• European Central Bank — ECB — Main Refinancing Operations fixed rate (MRR). https://data.ecb.europa.eu/data/datasets/FM/FM.B.U2.EUR.4F.KR.MRR_FR.LEV. ECB statistical data, free to reuse with attribution.
• Board of Governors of the Federal Reserve System via FRED — Federal Reserve H.15 — 1-Year Treasury Constant Maturity (FRED DGS1/WGS1YR). https://fred.stlouisfed.org/series/DGS1. U.S. federal government work — public domain. FRED requests source attribution.
• Florida Department of Financial Services, Chief Financial Officer (official) — Florida judgment interest current and historical rates. https://myfloridacfo.com/division/aa/audits-reports/judgment-interest-rates. Government edict — not subject to copyright.
• Florida Department of Financial Services, Chief Financial Officer (official) — Florida prejudgment-interest rate schedule (Fla. Stat. § 55.03). https://myfloridacfo.com/division/aa/audits-reports/judgment-interest-rates. Government edict — not subject to copyright.
• Georgia General Assembly-authorized Code portal (LexisNexis); Federal Reserve prime benchmark via FRED — Georgia judgment interest (O.C.G.A. §7-4-12). https://www.lexisnexis.com/hottopics/gacode. Georgia statutory text is a government edict; the FRED PRIME series requests citation to its Federal Reserve source.
• Georgia General Assembly-authorized Code portal (LexisNexis); Federal Reserve prime benchmark via FRED — Georgia prejudgment-interest rules and Federal Reserve prime benchmark. https://www.lexisnexis.com/hottopics/gacode. Government edict — not subject to copyright.
• Hawaii — capitol.hawaii.gov — Hawaii judgment interest (Haw. Rev. Stat. 478-3. Related: 478-2). https://www.capitol.hawaii.gov/hrscurrent/Vol11_Ch0476-0490/HRS0478/HRS_0478-0003.htm. Government edict — not subject to copyright.
• Hawaii — data.capitol.hawaii.gov — Hawaii prejudgment interest (HRS 636-16). https://data.capitol.hawaii.gov/sessions/session2017/HRS-Chapter-PDF's/HRS_0478.pdf. Government edict — not subject to copyright.
• Iowa Judicial Branch (official) — Iowa §668.13 post-judgment interest table. https://www.iowacourts.gov/iowa-courts/district-court/post-judgment-interest-table/. Government edict — not subject to copyright.
• Idaho State Treasurer (official) — Idaho judgment interest official fiscal-year table. https://sto.idaho.gov/Banking/Legal-Rate-of-Interest. Government edict — not subject to copyright.
• Idaho — legislature.idaho.gov — Idaho prejudgment interest (Idaho Code 28-22-104(1)). https://legislature.idaho.gov/statutesrules/idstat/title28/t28ch22/sect28-22-104/. Government edict — not subject to copyright.
• Illinois General Assembly (official) — Illinois judgment interest (735 ILCS 5/2-1303). https://www.ilga.gov/legislation/ilcs/fulltext?DocName=073500050K2-1303. Government edict — not subject to copyright.
• Illinois — ilga.gov — Illinois prejudgment interest (735 ILCS 5/2-1303(c)). https://ilga.gov/documents/legislation/ilcs/documents/081502050K2.htm. Government edict — not subject to copyright.
• Indiana General Assembly (official) — Indiana money-judgment interest statute. https://iga.in.gov/laws/current/ic/titles/24#24-4.6-1-101. Government edict — not subject to copyright.
• Indiana — iga.in.gov — Indiana prejudgment interest (Contract/liquidated: IC 24-4.6-1-103). https://iga.in.gov/laws/2024/ic/titles/24#24-4.6-1-103. Government edict — not subject to copyright.
• U.S. Internal Revenue Service — IRS quarterly interest rates (§6621). https://www.irs.gov/payments/quarterly-interest-rates. U.S. federal government work — not subject to copyright (public domain).
• U.S. Internal Revenue Service — IRS Form 1040 failure-to-file, failure-to-pay, interest, and penalty-relief rules. https://www.irs.gov/payments/failure-to-file-penalty. U.S. federal government work — not subject to copyright (public domain).
• Kansas — sos.ks.gov — Kansas judgment interest (Kan. Stat. Ann. 16-204). https://sos.ks.gov/general-services/finance-rates.html. Government edict — not subject to copyright.
• Kansas — ksrevisor.gov — Kansas prejudgment interest (K.S.A. 16-201). https://ksrevisor.gov/statutes/chapters/ch16/016_002_0001.html. Government edict — not subject to copyright.
• Kentucky General Assembly (official) — Kentucky judgment interest history (KRS 360.040 and 2017 Ky. Acts ch. 17). https://apps.legislature.ky.gov/law/acts/17RS/documents/0017.pdf. Government edict — not subject to copyright.
• Kentucky General Assembly and Kentucky Court of Appeals (official) — Kentucky legal rate and official appellate prejudgment-interest authority. https://apps.legislature.ky.gov/law/statutes/statute.aspx?id=47989. Government edict — not subject to copyright.
• Louisiana Office of Financial Institutions (official) — Louisiana official judicial-interest schedule. https://ofi.la.gov/legal/statutes-rules-policies-opinions/judicial-interest-rates/. Government edict — not subject to copyright.
• Louisiana Legislature and Office of Financial Institutions (official) — Louisiana prejudgment interest branches. https://ofi.la.gov/legal/statutes-rules-policies-opinions/judicial-interest-rates/. Government edict — not subject to copyright.
• Massachusetts Legislature (official) — Massachusetts G.L. c.231 §§6B–6C. https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section6B. Government edict — not subject to copyright.
• Massachusetts — malegislature.gov — Massachusetts prejudgment interest (M.G.L. c. 231, § 6B). https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section6B. Government edict — not subject to copyright.
• Maryland — mgaleg.maryland.gov — Maryland judgment interest (Md. Code, Courts & Judicial Proceedings Section 11-107(a)). https://mgaleg.maryland.gov/mgawebsite/laws/StatuteText?article=gcj&section=11-107. Government edict — not subject to copyright.
• Maryland — mgaleg.maryland.gov — Maryland prejudgment interest (Md. Const. Art. III, sec. 57). https://mgaleg.maryland.gov/Pubs/LegisLegal/2025-constitution-maryland-us.pdf. Government edict — not subject to copyright.
• Federal Reserve Board and Maine Legislature (official inputs) — Maine annual judgment-interest provisional H.15 calculation. https://www.federalreserve.gov/datadownload/Download.aspx?rel=H15&series=bf17364827e38702b42a58cf8eaa3f78&filetype=csv&label=include&layout=seriescolumn. U.S. government publication and government edict.
• Maine Judicial Branch (official) — Maine post-judgment interest official annual chart (OTH-156). https://mjbportal.courts.maine.gov/CourtForms/FormsLists/DownloadForm?strFormNumber=OTH-156. Government edict — not subject to copyright.
• Maine Judicial Branch (official) — Maine prejudgment interest official annual chart (OTH-155). https://mjbportal.courts.maine.gov/CourtForms/FormsLists/DownloadForm?strFormNumber=OTH-155. Government edict — not subject to copyright.
• Michigan Legislature (official) — Michigan judgment interest (MCL §600.6013). https://www.legislature.mi.gov/Laws/MCL?objectName=mcl-600-6013. Government edict — not subject to copyright.
• Michigan Department of Treasury and Legislature (official) — Michigan official money-judgment interest benchmark history and MCL 600.6013. https://www.michigan.gov/taxes/interest-rates-for-money-judgments. Government edict — not subject to copyright.
• Michigan Department of Treasury (official) — Michigan official money-judgment interest benchmark history. https://www.michigan.gov/taxes/interest-rates-for-money-judgments. Government edict — not subject to copyright.
• Minnesota Judicial Branch and Revisor of Statutes (official) — Minnesota official judgment-interest branches and history. https://www.revisor.mn.gov/court_rules/rule/msinte/. Government edict — not subject to copyright.
• Minnesota — revisor.mn.gov — Minnesota prejudgment interest (Minn. Stat. § 549.09, subd. 1(b)). https://www.revisor.mn.gov/statutes/cite/549.09. Government edict — not subject to copyright.
• Missouri — revisor.mo.gov — Missouri judgment interest (Mo. Rev. Stat. §408.040). https://revisor.mo.gov/main/OneSection.aspx?section=408.040. Government edict — not subject to copyright.
• Missouri — revisor.mo.gov — Missouri prejudgment interest (Mo. Rev. Stat. § 408.040). https://revisor.mo.gov/main/OneSection.aspx?section=408.040. Government edict — not subject to copyright.
• Mississippi Legislature-authorized Code portal (LexisNexis) — Mississippi judgment and prejudgment interest rules (Miss. Code Ann. §§75-17-7 and 75-17-1). https://www.lexisnexis.com/hottopics/mscode/. Government edict — not subject to copyright.
• Montana — mca.legmt.gov — Montana judgment interest (Mont. Code Ann. § 25-9-205). https://mca.legmt.gov/bills/mca/title_0250/chapter_0090/part_0020/section_0050/0250-0090-0020-0050.html. Government edict — not subject to copyright.
• Montana — mca.legmt.gov — Montana prejudgment interest (MCA 27-1-211). https://mca.legmt.gov/bills/mca/title_0270/chapter_0010/part_0020/section_0110/0270-0010-0020-0110.html. Government edict — not subject to copyright.
• North Carolina General Assembly (official) — North Carolina judgment interest (N.C.G.S. §24-5 / §24-1). https://www.ncleg.gov/EnactedLegislation/Statutes/HTML/BySection/Chapter_24/GS_24-5.html. Government edict — not subject to copyright.
• North Carolina — ncleg.net — North Carolina prejudgment interest (N.C. Gen. Stat. 24-5). https://www.ncleg.net/EnactedLegislation/Statutes/PDF/BySection/Chapter_24/GS_24-5.pdf. Government edict — not subject to copyright.
• North Dakota Courts (official) — North Dakota official judgment-interest table. https://www.ndcourts.gov/state-court-administration/interest-rate-on-judgments. Government edict — not subject to copyright.
• North Dakota — ndlegis.gov — North Dakota prejudgment interest (N.D.C.C. § 32-03-04). https://ndlegis.gov/cencode/t32c03.pdf. Government edict — not subject to copyright.
• Nebraska Judicial Branch (official) — Nebraska judgment interest rate (Neb. Rev. Stat. §45-103). https://nebraskajudicial.gov/rules/administrative-policies-schedules/judgment-interest-rate. Nebraska government publication - not subject to copyright.
• Nebraska Legislature (official) — Nebraska prejudgment interest statutes (§§45-103.02–45-104). https://nebraskalegislature.gov/laws/laws-index/chap45-full.html. Government edict — not subject to copyright.
• New Hampshire Judicial Branch (official) — New Hampshire civil interest rates. https://www.courts.nh.gov/our-courts/superior-court/civil/civil-interest-rates. Government edict — not subject to copyright.
• New Hampshire — courts.nh.gov — New Hampshire prejudgment interest (RSA 336:1, II). https://www.courts.nh.gov/our-courts/superior-court/civil/civil-interest-rates. Government edict — not subject to copyright.
• New Jersey Courts (official) — New Jersey official post- and prejudgment interest schedule. https://www.njcourts.gov/notices/notice-post-judgment-interest-rate-calendar-year-2026-rule-442-11. Government edict — not subject to copyright.
• New Jersey Courts (official) — New Jersey official pre- and postjudgment interest schedule. https://www.njcourts.gov/sites/default/files/courts/civil/postprejudgmentrates.pdf. Government edict — not subject to copyright.
• New Mexico Compilation Commission — NMOneSource (official) — New Mexico judgment interest (N.M. Stat. Ann. § 56-8-4). https://nmonesource.com/nmos/nmsa/en/item/4418/index.do. Government edict — not subject to copyright.
• New Mexico Compilation Commission — NMOneSource (official) — New Mexico prejudgment interest (NMSA 1978 §§ 56-8-3, 56-8-4). https://nmonesource.com/nmos/nmsa/en/item/4418/index.do. Government edict — not subject to copyright.
• Nevada Financial Institutions Division (official) — Nevada FID prime-rate and NRS 17.130 judgment-rate history. https://fid.nv.gov/uploadedFiles/fidnvgov/content/Resources/Prime%20Interest%20Rate%20July%201%2C%202026.pdf. Government edict — not subject to copyright.
• Nevada — leg.state.nv.us — Nevada prejudgment interest (NRS 99.040). https://www.leg.state.nv.us/NRS/NRS-099.html. Government edict — not subject to copyright.
• New York State Law Reporting Bureau (official court opinion) — Matter of HSBC Bank USA — 9% rate effective June 15, 1981. https://www.nycourts.gov/REPORTER/3dseries/2012/2012_04954.htm. Official judicial opinion.
• New York — nysenate.gov — New York prejudgment interest (N.Y. C.P.L.R. 5004). https://www.nysenate.gov/legislation/laws/CVP/5004. Government edict — not subject to copyright.
• New York State Senate (official statute and enacted bill text) — New York CPLR 5001–5004 and Fair Consumer Judgment Interest Act. https://www.nysenate.gov/legislation/laws/CVP/5004. Government edict — not subject to copyright.
• Ohio — codes.ohio.gov — Ohio prejudgment interest (Ohio Rev. Code 1343.03). https://codes.ohio.gov/ohio-revised-code/section-1343.03. Government edict — not subject to copyright.
• Ohio Department of Taxation (official) — Ohio judgment interest (R.C. §1343.03 / §5703.47). https://dam.assets.ohio.gov/image/upload/tax.ohio.gov/individual/2026_Interest_Rates.pdf. Government edict — not subject to copyright.
• Oklahoma State Courts Network (official judicial publication) — Oklahoma Administrative Director-certified judgment-interest history. https://www.oscn.net/applications/oscn/DeliverDocument.asp?CiteID=551111. Government edict — not subject to copyright.
• Oklahoma — oscn.net — Oklahoma prejudgment interest (12 O.S. Sec. 727.1). https://www.oscn.net/applications/oscn/DeliverDocument.asp?CiteID=551111. Government edict — not subject to copyright.
• Oregon Legislative Assembly (official) — Oregon judgment interest (ORS 82.010(2)). https://www.oregonlegislature.gov/bills_laws/ors/ors082.html. Government edict — not subject to copyright.
• Oregon Legislature (official) — Oregon prejudgment interest (ORS 82.010). https://www.oregonlegislature.gov/bills_laws/ors/ors082.html. Government edict — not subject to copyright.
• Pennsylvania — pacodeandbulletin.gov — Pennsylvania prejudgment interest (41 P.S. Sec. 202). https://www.pacodeandbulletin.gov/secure/pacode/data/231/chapter200/s238.html. Government edict — not subject to copyright.
• Pennsylvania General Assembly (official) — Pennsylvania judgment interest (42 Pa.C.S. §8101; 41 P.S. §202). https://www.legis.state.pa.us/WU01/LI/LI/CT/HTM/42/00.081.001.000..HTM. Government edict — not subject to copyright.
• Rhode Island — webserver.rilegislature.gov — Rhode Island judgment interest (R.I. Gen. Laws § 9-21-10). https://webserver.rilegislature.gov/Statutes/TITLE9/9-21/9-21-10.HTM. Government edict — not subject to copyright.
• Rhode Island — webserver.rilegislature.gov — Rhode Island prejudgment interest (R.I. Gen. Laws § 9-21-10). https://webserver.rilegislature.gov/Statutes/TITLE9/9-21/9-21-10.HTM. Government edict — not subject to copyright.
• South Carolina — scstatehouse.gov — South Carolina judgment interest (S.C. Code Ann. § 34-31-20(B)). https://www.scstatehouse.gov/code/t34c031.php. Government edict — not subject to copyright.
• South Carolina — scstatehouse.gov — South Carolina prejudgment interest (S.C. Code Ann. § 34-31-20(A)). https://www.scstatehouse.gov/code/t34c031.php. Government edict — not subject to copyright.
• South Dakota — sdlegislature.gov — South Dakota judgment interest (SDCL § 54-3-5.1). https://sdlegislature.gov/Statutes/54-3-5.1. Government edict — not subject to copyright.
• South Dakota — sdlegislature.gov — South Dakota prejudgment interest (SDCL 21-1-13.1). https://sdlegislature.gov/Statutes/21-1-13.1. Government edict — not subject to copyright.
• Tennessee Courts / Dept. of Financial Institutions (official) — Tennessee post-judgment interest (Tenn. Code §47-14-121). https://www.tncourts.gov/tennessee-judgment-interest-rates. Government edict — not subject to copyright.
• Tennessee Courts (official judicial source) — Tennessee prejudgment interest (§ 47-14-123, discussed by Tennessee Court of Appeals). https://www.tncourts.gov/sites/default/files/OPINIONS/TCA/PDF/014/willselectric.pdf. Government edict — not subject to copyright.
• Texas Office of Consumer Credit Commissioner (official) — Texas postjudgment interest rate (Finance Code §304.003). https://occc.texas.gov/publications/interest-rates/. Texas government publication — not subject to copyright.
• Texas Legislature and Office of Consumer Credit Commissioner (official) — Texas prejudgment interest (Finance Code Chapter 304 + OCCC rate). https://statutes.capitol.texas.gov/Docs/FI/pdf/FI.304.pdf. Government edict — not subject to copyright.
• Utah State Courts (official) — Utah post-judgment interest current and historical tables. https://www.utcourts.gov/en/court-records-publications/resources/interest-rates/interestrates.html. Government edict — not subject to copyright.
• Utah — le.utah.gov — Utah prejudgment interest (Utah Code Ann. 15-1-1(2)). https://le.utah.gov/xcode/Title15/Chapter1/15-1-S1.html. Government edict — not subject to copyright.
• Virginia General Assembly (official) — Virginia judgment interest (Va. Code §6.2-302). https://law.lis.virginia.gov/vacode/title6.2/chapter3/section6.2-302/. Government edict — not subject to copyright.
• Virginia — law.lis.virginia.gov — Virginia prejudgment interest (Va. Code Ann. § 8.01-382). https://law.lis.virginia.gov/vacode/title8.01/chapter13/section8.01-382/. Government edict — not subject to copyright.
• Vermont — legislature.vermont.gov — Vermont judgment interest (9 V.S.A. § 41a(a)). https://legislature.vermont.gov/statutes/section/09/004/00041a. Government edict — not subject to copyright.
• Vermont — legislature.vermont.gov — Vermont prejudgment interest (9 V.S.A. § 41a(a)). https://legislature.vermont.gov/statutes/section/09/004/00041a. Government edict — not subject to copyright.
• Washington — app.leg.wa.gov — Washington prejudgment interest (RCW 19.52.010(1)). https://app.leg.wa.gov/rcw/default.aspx?cite=19.52.010. Government edict — not subject to copyright.
• Washington State Legislature (official) — Washington post-judgment interest (RCW 4.56.110). https://app.leg.wa.gov/rcw/default.aspx?cite=4.56.110. Government edict — not subject to copyright.
• Wisconsin Court System and Legislature (official) — Wisconsin official judgment-interest half-year history. https://www.wicourts.gov/services/public/selfhelp/docs/interestrate.pdf. Government edict — not subject to copyright.
• Wisconsin — docs.legis.wisconsin.gov — Wisconsin prejudgment interest (Wis. Stat. 138.04). https://docs.legis.wisconsin.gov/statutes/statutes/138/04. Government edict — not subject to copyright.
• Supreme Court of Appeals of West Virginia (official) — West Virginia annual judgment-interest orders. https://www.courtswv.gov/legal-community/court-rules. Government edict — not subject to copyright.
• West Virginia — code.wvlegislature.gov — West Virginia prejudgment interest (W. Va. Code § 56-6-31(b)). https://code.wvlegislature.gov/56-6-31/. Government edict — not subject to copyright.
• Wyoming — wyoleg.gov — Wyoming judgment interest (Wyo. Stat. Ann. 1-16-102). https://wyoleg.gov/statutes/compress/title01.pdf. Government edict — not subject to copyright.
• Wyoming — wyoleg.gov — Wyoming prejudgment interest (Wyo. Stat. Ann. Sec. 40-14-106(e)). https://wyoleg.gov/statutes/compress/title40.pdf. Government edict — not subject to copyright.

US state judgment rates

State entries are curated references. Fixed rates are written into law; variable rates come from a statutory formula, court rule, or agency table. Each record cites its current source and carries a source-check time. Primary government sources are preferred and secondary mirrors are identified. A current value alone does not establish a complete historical series or make a calculator safe.

US state prejudgment rates

Prejudgment interest — the interest that accrues before judgment, compensating for the time between the loss or breach and the judgment — is tracked as a separate metric from post-judgment interest, for all 50 states and D.C. (browse the table). It is treated differently for a reason: unlike the post-judgment rate, prejudgment interest usually turns on claim type. Most states allow it only on liquidated or readily ascertainable amounts and bar it on unliquidated damages (pain and suffering, most general tort damages); several make it discretionary; a few apply the same rate as post-judgment. Each state's page states the recorded rate, cited rule, accrual date, compounding method, and known carve-outs. These pages remain reference material while their rule branches and historical coverage move through the calculator-ready audit.

Coverage & roadmap

The dataset covers U.S. federal statutory, judgment, and tax interest rates; U.S. state judgment rates (49 states + D.C. — every jurisdiction except Mississippi, which sets judgment interest case by case rather than by a fixed statutory default); U.S. state prejudgment interest rates (all 50 states + D.C.); U.K. statutory late-commercial-payment interest and the Bank of England base rate; and a non-country-specific EU Directive benchmark built from the ECB main refinancing rate. Federal, IRS, UK, and EU benchmark calculators remain available. State calculators are withheld until each included rule passes the calculator-safety contract. Planned expansion: calculator-ready state histories and primary-source, per-country EU late-payment models.