§ StatuteRates

IRS Underpayment Interest Rate (§6621)

United States  What the IRS charges on unpaid federal tax.

Current rate
7% per year, effective July 1, 2026
Published value

The IRS underpayment rate is the interest the IRS charges individuals and businesses on tax they paid late or underpaid. Under Internal Revenue Code §6621 it equals the federal short-term rate plus 3 percentage points, and it is reset every calendar quarter — so a figure that was right last quarter is often wrong today. This page tracks the published value each quarter with its effective date.

→ Calculate interest at this rate

Effective-date history

39 data points on record. Full history in the JSON API.
Effective dateRateBasis
July 1, 2026 7% Published
April 1, 2026 6% Published
January 1, 2026 7% Published
October 1, 2025 7% Published
July 1, 2025 7% Published
April 1, 2025 7% Published
January 1, 2025 7% Published
October 1, 2024 8% Published
July 1, 2024 8% Published
April 1, 2024 8% Published
January 1, 2024 8% Published
October 1, 2023 8% Published
July 1, 2023 7% Published
April 1, 2023 7% Published
January 1, 2023 7% Published
October 1, 2022 6% Published
July 1, 2022 5% Published
April 1, 2022 4% Published
January 1, 2022 3% Published
October 1, 2021 3% Published
July 1, 2021 3% Published
April 1, 2021 3% Published
January 1, 2021 3% Published
October 1, 2020 3% Published
July 1, 2020 3% Published
April 1, 2020 5% Published
January 1, 2020 5% Published
October 1, 2019 5% Published
July 1, 2019 5% Published
April 1, 2019 6% Published
January 1, 2019 6% Published
October 1, 2018 5% Published
July 1, 2018 5% Published
April 1, 2018 5% Published
January 1, 2018 4% Published
October 1, 2017 4% Published
July 1, 2017 4% Published
April 1, 2017 4% Published
January 1, 2017 4% Published

Source & provenance

Latest value retrieved July 11, 2026 (11:51 UTC) from the official source:
https://www.irs.gov/payments/quarterly-interest-rates

Reference data only — not legal, tax, or financial advice. Always confirm the controlling value against the official source and, where applicable, the governing statute or court before relying on it.