Tax Calculators

Tax basics

Federal income tax is based on taxable income after deductions and credits. Payroll withholding and estimated payments are payments toward tax; they are not the same thing as final tax liability.

Self-employment tax

Self-employed workers often estimate both self-employment tax and income tax. Self-employment tax covers Social Security and Medicare, while federal income tax is calculated through progressive brackets.

Estimated taxes

People with income not fully covered by withholding may make estimated tax payments during the year. A quarterly estimate and a monthly reserve target can make the obligation easier to plan.

Tax brackets

US federal brackets are progressive. Marginal rate is the rate on the next dollar of taxable income. Effective rate is total tax divided by income.

Withholding

W-4 withholding controls how much federal tax is taken from paychecks. A refund usually means payments exceeded final tax, while an amount owed means payments were short.

Frequently asked questions

Do these tools include state taxes?

No. This sprint is focused on federal tax calculators. State tax requires separate state-specific rules.

Are these calculators tax advice?

No. They are educational estimates based on published federal rules and user-entered assumptions.

Which tool should I use first?

Use 1099 for contractor tax planning, Self-Employment Tax for SE tax only, Quarterly Estimated Tax for payment planning, Tax Bracket for marginal/effective rate, Refund Estimator near filing time and W-4 for paycheck withholding.