U.S. Estimated Tax

Estimated Tax Safe Harbor Calculator 2026

Estimate a simplified federal annual-payment target for 2026 using the common IRS safe-harbor comparison: 90% of expected current-year tax versus 100% or 110% of prior-year tax.

General safe-harbor rules modeled

Current-year method: 90% of expected 2026 tax.
Prior-year method: generally 100% of tax shown on the 2025 return.
Higher-income prior-year method: use 110% instead of 100% if 2025 AGI was over $150,000, or over $75,000 if married filing separately.
The simplified annual target is the smaller of the applicable current-year and prior-year amounts.
Expected withholding and estimated payments already made reduce the remaining amount shown by this tool.

This is a planning estimator, not a penalty guarantee. The IRS generally also looks at whether you expect to owe at least $1,000 after withholding and refundable credits. This calculator does not model refundable credits, annualized-income installments, unequal payment timing, underpayment interest, farmers/fishers rules, nonresident rules, household-employer exceptions, a prior return covering less than 12 months or other special situations. Withholding timing can receive different treatment from estimated payments.

Worked example

If expected 2026 tax is $30,000, 2025 tax was $20,000, prior AGI was $100,000, expected 2026 withholding is $10,000, and $2,000 of estimated tax has already been paid, the simplified safe-harbor target is $20,000. That leaves $8,000 still needed through estimated payments, or about $4,000 across two remaining installments.

Primary sources

Methodology & verification

Tax year: 2026.
Current-year safe harbor: 90% of expected 2026 tax.
Prior-year safe harbor: 100% of 2025 tax, or 110% above the applicable prior-AGI threshold.
Scope: Simplified federal annual-payment planning; special installment and penalty rules excluded.
Last reviewed: 2026-09-17.

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