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.
Frequently Asked Questions
Can I just withhold more?
Yes. Submit new W-4 to employer. Withhold extra. Treated as evenly distributed across year. Avoids estimated tax filing entirely.
What if income drops?
Use annualized income method (Form 2210AI). Calculates penalty based on actual quarterly income. Often eliminates penalty.
State estimated tax?
Most income-tax states require separate. Different safe-harbor rules per state. Check your state DOR.