US Estimated Tax Calculator
Compare federal estimated-payment safe harbors using your established tax estimates, prior-year AGI and expected withholding.
Rule year: 2026 · USD · Sources checked
Annual estimated-payment target after withholding
Prior-year return covers 12 months and the general safe-harbor method applies. Supplied tax totals already include the applicable federal taxes and credits. No penalty calculation, installment timing, annualized-income method, $1,000 balance-due exception or special farming/fishing rules.
For informational purposes only. This estimate is not financial advice, a tax return, a payroll calculation or a lender decision. See the supported circumstances and exclusions below.
How this calculator works
The general federal safe harbor compares 90% of current-year tax with 100% of the prior-year tax shown on a full 12-month return. For prior-year AGI above $150,000, or $75,000 if married filing separately, the prior-year percentage becomes 110%. Expected withholding offsets the annual target; payments already made reduce the remaining annual amount. Dividing the annual target by four illustrates equal installments, but an annual amount alone cannot establish that each payment arrived on time.
Formula and rules
General annual target = min(90% × current-year tax, prior-year tax × 100% or 110%). Estimated-payment target = max(0, annual target − expected withholding).
Assumptions and limitations
Prior-year return covers 12 months and the general safe-harbor method applies. Supplied tax totals already include the applicable federal taxes and credits. No penalty calculation, installment timing, annualized-income method, $1,000 balance-due exception or special farming/fishing rules.
Worked example
Projected tax $15,000, prior tax $12,000 and prior AGI $100,000 give targets of $13,500 and $12,000. After $4,000 withholding, the annual payment target is $8,000, or $2,000 per equal installment.
- Annual estimated-payment target after withholding
- $8,000.00
- Equal-installment illustration
- $2,000.00
- Remaining annual target after payments entered
- $6,000.00
- 90% current-year tax reference
- $13,500.00
Official sources and review
Reviewed against the sources below on 2026-10-07. Rates are held in versioned rule modules. Versioned rules, official source review and year-specific calculation tests.
- IRS: estimated-tax underpayment rules ↗
90% current-year or 100%/110% prior-year safe-harbor rules; payment timing and special exceptions remain relevant.
- IRS Publication 505 (2026) ↗
2026 ordinary-income rate schedules, standard deductions and capital-gain worksheet thresholds.
Common questions
Does meeting the annual target eliminate every penalty?
Payment timing matters. A late estimated payment can still leave an underpaid installment even if the year-end total meets a safe harbor.
Is the remaining amount my next quarterly payment?
It is the remaining annual target. Earlier installment requirements and due dates must be checked separately.
Why enter prior-year AGI?
It determines whether the general prior-year safe harbor uses 100% or 110%. This uses the prior year, not your projected current-year income.