Estimated Tax Safe-Harbor 2027 Calculator
Calculate estimated tax safe-harbor 2027 — 100% of prior year tax (110% if AGI > $150k) or 90% of current year. Avoid underpayment penalty.
Safe-Harbor Rules
Pay LESSER of: 100% of prior year tax (110% if prior AGI > $150k) OR 90% of current year. Avoids underpayment penalty regardless of actual tax.
Underpayment Penalty
IRS short-term rate + 3% (about 8% in 2027). Per-quarter penalty on underpaid amount. Form 2210 to calculate.
Annualized Income Method
If income varies (seasonal, capital gains), annualized method may reduce penalty. Compute estimated tax based on income earned through each quarter.
W-2 Withholding Counts
Withholding from wages counts as paid evenly through year. Increase withholding late in year to avoid penalty (better than late estimated).
Source: irs.gov Form 2210 underpayment penalty, Form 1040-ES. Last updated: May 2026.