Compute your effective tax rate by dividing total tax by taxable income, and compare to marginal rate (the tax on the next dollar). Enter income, deductions, and credits to see how changes affect overall liability. Useful for planning withholding, avoiding underpayment penalties, and evaluating the benefit of tax‑advantaged accounts.
Frequently Asked Questions
Effective vs marginal rate?
Effective is average across all income; marginal is the rate on your next dollar.
Planning often focuses on marginal impacts.
Why is my effective rate lower than marginal?
Progressive brackets and deductions reduce your average rate below the top bracket you reach.
Do credits reduce the rate?
Yes—credits lower tax dollar‑for‑dollar, reducing the effective rate more than equivalent deductions.
Should I adjust withholding?
If your effective rate changes due to life events, adjust W‑4 to avoid large balances due or over‑withholding.
How to estimate next year?
Project income and deductions using conservative assumptions; consider bracket creep and sunset provisions for 2026 and beyond.
State taxes included?
This tool focuses on federal.
Include state liabilities separately to estimate all‑in effective rate.
About This Page
Editorial & Updates
- Author: SuperCalc Editorial Team
- Reviewed: SuperCalc Editors (clarity & accuracy)
- Last updated: 2026-01-13
We maintain this page to improve clarity, accuracy, and usability. If you see an issue, please contact hello@supercalc.dev.
Financial/Tax Disclaimer
This tool does not provide financial, investment, or tax advice. Calculations are estimates and may not reflect your specific situation. Consider consulting a licensed professional before making decisions.