Form 2210 Underpayment Calculator
Check the current-year and prior-year safe harbors, allocate withholding, and estimate each quarterly underpayment separately.
Form 1040 line 22 plus the other taxes on Form 2210 line 2, minus the refundable credits on line 3. Before withholding.
W-2 + 1099 withholding (treated as paid evenly).
Prior year tax as figured for Form 2210 line 8, after refundable credits. Used for the 100%/110% safe harbor.
If > $150k, safe harbor rises to 110% of prior year tax.
Estimated Payments Made
Each box counts as paid on its due date. Paid on another date, or more than once in a period? Add each payment with the date you made it.
| Period | Due Date | Required Cum. | Paid Cum. | Underpaid | Days | Penalty |
|---|---|---|---|---|---|---|
| Q1 | 2025-04-15 | $5,000 | $2,500 | $2,500 | 61 | $29.25 |
| Q2 | 2025-06-15 | $10,000 | $5,000 | $5,000 | 214 | $146.71 |
| Q3 | 2025-09-15 | $15,000 | $7,500 | $7,500 | 212 | $201.23 |
| Q4 | 2026-01-15 | $20,000 | $10,000 | $10,000 | 90 | $84.25 |
| Total Penalty | $461.44 | |||||
What this tool covers
Calculation scope
- Tests the $1,000 balance-due exception.
- Applies the 100% or 110% prior-year safe harbor.
- Computes underpayment exposure separately for each installment.
Frequently asked questions
Does the IRS always require me to file Form 2210?
No. The IRS generally figures the penalty. Filing is required in specific situations described in Part II, including certain waiver and withholding allocation cases.
Can a later payment erase an earlier underpayment?
Not automatically. Form 2210 computes the penalty separately for each required installment, so a later catch-up payment does not undo the time the earlier installment was unpaid.
What if my income was uneven during the year?
Schedule AI’s annualized income installment method can reduce or eliminate a penalty when income was earned unevenly. This calculator models the regular installment method.
Sources
Related Calculators
Estimated Tax Penalty
Form 2210 safe harbor, 90%/100% prior-year test, 7% rate
Quarterly Estimated Tax
Four installments (4/15, 6/15, 9/15, 1/15), safe harbor 90%/100%
2026 Estimated Tax Due Dates
Form 1040-ES Q1 through Q4 payment dates, covered income periods, and quarter-specific planning guides
IRS Interest Rates
Current and historical quarterly IRS underpayment and overpayment interest rates, updated each Revenue Ruling
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