About MyTaxQuarter

MyTaxQuarter is a planning tool for US freelancers, independent contractors, consultants, creators, and other 1099 workers who need to estimate quarterly tax payments. It focuses on the questions that matter during the year: how much tax might I owe, how much should I set aside, and how do safe harbor rules compare with my current income pace?

How the calculator works

The calculator starts with net self-employment income, then estimates self-employment tax, federal income tax, and state income tax. For self-employment tax, it models the Social Security wage base cap, the Medicare portion, Additional Medicare Tax thresholds, and the deduction for the employer-equivalent share of self-employment tax. For federal income tax, it applies 2026 filing-status brackets and standard deductions. It then compares a current-year annualized estimate with the safe harbor method based on prior-year tax and prior-year AGI.

Data sources and updates

Federal tax figures are maintained as static TypeScript constants based on IRS annual inflation-adjustment guidance, including the revenue procedure that publishes bracket and standard deduction amounts for the tax year. Self-employment tax concepts are based on IRS guidance for Social Security, Medicare, Additional Medicare Tax, and estimated taxes. State rates are maintained separately and should be verified against each state revenue department before payment.

Tax data is updated annually each October when the IRS publishes new inflation-adjusted figures for the coming tax year. State data is reviewed alongside those updates and whenever major state tax changes are announced.

Accuracy disclaimer

This tool provides estimates only. Consult a tax professional for advice specific to your situation. MyTaxQuarter does not model every credit, deduction, local tax, alternative calculation, phaseout, state adjustment, or special taxpayer rule.