Quarterly Estimated Tax
Safe-harbor required annual payment, per-quarter installment, and IRS 1040-ES due dates.
Example
You enter
- Projected current-year tax (USD) 20000
- Prior-year total tax (USD) 18000
- Current-year withholding to date (USD) 4000
- Prior-year safe harbor 1
- Tax year 2025
You get
- Safe harbor 90pct current 18000
- Safe harbor prior year 18000
- Required annual payment $18000
- After withholding 14000
- Per-quarter installment $3500
Checked against published worked examples from: IRS Form 1040-ES + Pub 505 estimated-tax safe-harbor rules.
Details, formula, and sources
Formula or tableRequired annual payment = min(0.90 * projected_current_tax, multiplier * prior_year_tax). multiplier = 1.10 if prior-year AGI > $150k else 1.00. After-withholding = required - withholding. Per-quarter = after-withholding / 4.
Source and editionIRC 6654 (failure-to-pay-estimated-tax safe harbors). IRS Form 1040-ES quarterly schedule.
Free accessFree at irs.gov/forms-pubs/about-form-1040-es. Due dates bundled per year in ESTIMATED_TAX_DUE_DATES.
What governsEstimate only. Tax law changes. Confirm with the current IRS publication or a licensed CPA before filing.
API field namesprojected_current_tax, prior_year_tax, current_withholding, prior_year_multiplier, tax_year, safe_harbor_90pct_current, safe_harbor_prior_year, required_annual_payment, after_withholding, per_quarter
- Safe harbor smaller of 90% current-year or 100% / 110% prior-year taxIRC 6654(d)(1)(B)
- Equal installments even quarterly split (the annualized-income alternative is not modeled)user choice; Form 2210 covers the alternative