The 2025 underpayment penalty on this example is $5.37. Required annual payment is the smaller of 90 percent of this year's tax and 100 percent of last year's tax, here $8,000. A $500 shortfall from April 15 to June 10 is 56 days at the 7 percent rate.
Penalty
$5.37
The penalty is $5.37.
Shortfall × days ÷ 365 × the quarter's rate. June 15, 2025 was a Sunday, so the due date is June 16.
| Required annual payment | $8,000.00 |
|---|---|
| Installment 1 | $2,000.00 |
| Installment 2 | $2,000.00 |
| Installment 3 | $2,000.00 |
| Installment 4 | $2,000.00 |
| Shortfall after installment 1 | $500.00 |
| Shortfall after installment 2 | $0.00 |
| Shortfall after installment 3 | $0.00 |
| Shortfall after installment 4 | $0.00 |
| Penalty | $5.37 |
| Days with no published rate | 0 days |
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Penalty = shortfall × days ÷ 365 × the published underpayment rate for each quarter. The required annual payment is the lesser of 90% of current-year tax and 100% or 110% of prior-year tax.
The required annual payment is the smaller of 90% of the tax you type for this year and 100% of last year's tax. Last year's tax is multiplied by 110% when prior AGI is over $150,000, or over $75,000 if you file married filing separately. If the tax after withholding is under $1,000, or last year's full-year tax was zero, the penalty is zero.
That required amount is split into four installments, before withholding. Withholding is credited in four equal parts on the due dates, not on the day it was withheld. Estimated tax is credited on the date you enter and is applied to the oldest shortfall first. For 2025 the dates are April 15, June 16 (June 15 was a Sunday), September 15, and January 15, 2026. For 2026 they are April 15, June 15, September 15, and January 15, 2027.
The penalty is shortfall times days divided by 365 times the rate, which is the Form 2210 worksheet. It is not daily-compounded interest. Published rates: 2025 Q1 7%, Q2 7%, Q3 7%, Q4 7%. 2026 Q1 7%, Q2 6%, Q3 7%, Q4 7%. The first quarter of 2027 is not published. Days in an unpublished quarter are counted and left out of the dollar penalty.
| Required annual payment | $8,000.00 |
|---|---|
| Penalty | $5.37 |
| Penalty | $30.74 |
|---|---|
| Days with no published rate | 0 |
It is the smaller of 90% of the current-year tax you enter and 100% of last year's tax. Use 110% of last year's tax when prior AGI was over $150,000, or over $75,000 if you file married filing separately. Withholding is subtracted when the four installments are set, and the $1,000 rule can zero the penalty.
Each day uses the IRS rate published for that calendar quarter. 2025 is 7% all year. 2026 is 7%, then 6% for April through June, then 7% again. The first quarter of 2027 is not published, so those days add nothing to the penalty and the result says it is incomplete.
No. The newsroom releases describe statutory interest as compounded daily. Form 2210's regular-method worksheet uses simple interest: underpayment times the number of days divided by 365 times the rate. This calculator follows the worksheet, not the compounding sentence.