IRS Penalty & Interest Calculator

Federal (IRS) only — state taxes are not included

Estimate IRS failure-to-file, failure-to-pay, estimated tax penalties, and quarterly interest. Everything runs privately in your browser.

Step 1 · Scenario

What's your situation?

Select one to configure

I filed or paid late§6651(a)

A return was filed after the deadline, or federal tax remains unpaid.

Return & Dates

Entity type

Choose tax classification

Tax year

Calendar year only

Tax shown on the return

After withholding/credits, before payments below

Date the return was filed

Leave blank if not yet filed

Compute as of

Penalties and interest accrue through this date

Filed an extension?

Extends time to file, but not time to pay.

Payments

Payments reduce penalties and interest on the portion covered from their credit date.

Installment agreement periods (individuals only)

The 0.25%/month failure-to-pay rate (§6651(h)) only applies to individuals who filed on time. Enter the date range(s) the agreement was in effect.

IRS notice & levy dates

Did the IRS send a bill? (notice date)

Date printed on the notice (CP14 etc.). Interest on failure-to-pay and §6698/§6699 penalties runs from this date if still unpaid after 21 days.

Notice of intent to levy date (optional)

CP504 / LT11 / Letter 1058 — raises the failure-to-pay rate to 1%/month after 10 days

Total owed as of Oct 22, 2026

$13,028.14

Growing by $14.27 per day

Of which penalties & interest

$2,949.50

29% of the unpaid tax

Unpaid tax

$10,000.00

Interest

$349.50

Failure to file

$2,250.00

Failure to pay

$350.00

How it accrues over time

By category

Statutory Dates Used (§7503 weekend/holiday rolled)

Return Due2026-04-15

Tax Due2026-04-15

Filing Deadline2026-04-15

Extended Due2026-10-15

⚠️ IRS Calculation Notices

Return not filed: the IRS may file a substitute return (SFR) and assess on its own figures; failure-to-pay is estimated here on the tax amount you entered.

How this was calculated (assumptions & citations)

Minimum FTF penalty is applied as a floor on the FTF addition AFTER the FTP reduction. Confirm this interaction with a CPA.
No IRS notice and demand date entered, so NO interest is charged on failure-to-pay or §6698/§6699 penalties yet.
Payments are applied to tax first. Interest is compounded daily at the quarterly rate (rate ÷ 365, or ÷ 366 in leap years). Results can differ from an IRS transcript by a few cents due to IRS rounding.
Calendar-year filers only. Accuracy-related (§6662), fraud, failure-to-deposit and large-corporate "hot interest" are not modeled.