§ StatuteRates

Interest calculators and benchmarks

Law-specific tools apply their audited statutory method and cite the controlling source. The general tool performs transparent arithmetic using a rate you verify, while the EU mode is explicitly a non-country-specific benchmark illustration. All use the same versioned foundation behind our free API.

Choose a calculator

Florida judgment interest

8.06%
The audited §55.03 method: CFO rate at entry, annual January 1 adjustments, daily simple interest, and a transparent period schedule.

Verified historical rate lookup

20 state series
Search 20 reviewed state series for the recorded value on a past date—with branch warnings, official source, and CSV history.

Judgment interest & per diem

Enter your rate
Enter a verified rate to calculate simple or annually compounded interest, total payoff, accrual days, and per diem.

Federal post-judgment interest

4%
The §1961 method: H.15 weekly rate for the week before judgment, daily accrual, compounded annually.

IRS penalty & interest (Form 1040)

Form 1040
Estimate failure-to-file and failure-to-pay penalties, partial payments, and daily interest—with the important exclusions shown.

IRS interest (underpayment & refund)

7%
Quarterly §6621 rates compounded daily per §6622, across every rate change since 2017.

Late payment interest (UK & EU)

11.75%
UK Late Payment Act 1998 (base + 8pp, fixed at overdue date) plus a clearly labeled EU Directive minimum-benchmark illustration.

Why these are different

Most online calculators hardcode a rate that quietly goes stale. The law-specific tools use versioned observations from scheduled primary-source fetches: daily compounding for the IRS, annual compounding for federal judgments, and a fixed-at-overdue-date rate for qualifying UK late payments. The general calculator and EU benchmark keep their narrower scope visible instead of implying a statutory entitlement.