Calculator
RSU withholding gap calculator
Will the flat withholding on an RSU vest cover the federal income tax the vest adds?
Calculators · tax year 2026
Tax calculators that show their work.
Estimates for education, worked out in your browser from checked and dated federal figures. Each one shows every step and every figure it uses.
The calculators
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Roth conversion bracket room calculator
How much income fits before you cross into the next tax bracket, and the federal tax on a conversion.
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S-corp salary vs. distributions: payroll tax
How much payroll tax a lower S-corp salary avoids, compared with taking everything as salary.
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HSA, 401(k) and IRA contribution room calculator
How much room is left this year in an HSA, a 401(k), 403(b) or TSP, and an IRA, including the Roth income range.
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Is my Social Security taxable? Calculator
The provisional income test, step by step: how much of your Social Security benefits is taxable.
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Estimated tax safe harbor calculator
The smallest total of withholding and estimated payments that avoids the underpayment penalty, split into the four due dates.
How these work
- Every tax figure comes from the same verified library as the rest of this site, and each page lists the figures it uses with their sources and review dates.
- The arithmetic runs in your browser. Nothing you type is sent anywhere, and nothing is saved unless you tick Remember my entries.
- Results are estimates for learning how a rule works, not a return and not advice. Each page says what it leaves out.