SelfQuarter computes your US self-employment quarterly tax payments using the official 2026 Schedule SE rates, federal brackets, and the safe-harbour 110% rule. Enter your year-to-date 1099 income and SelfQuarter calculates your quarterly federal tax estimates, plus state add-on for the top 10 states. Light and dark themes. WHAT IT CALCULATES - Schedule SE (self-employment tax): 12.4% Social Security + 2.9% Medicare - Additional 0.9% Medicare tax for high earners - Federal income tax at marginal rate (2026 brackets) - State income tax for CA, NY, TX, FL, IL, PA, OH, GA, NC, MI - Safe-harbour 110% rule (prior year x 110% to avoid penalty) - Quarterly payment amounts and IRS due dates WHY SELFQUARTER - Built for the 1099 freelancer / contractor / consultant - Works 100% offline. No account, no sign-up, no cloud - No subscription, no ads, no tracking. Pay once, keep it - Save quarter-over-quarter, share clean breakdowns SelfQuarter is an estimate for self-employed individuals and does not replace professional tax advice. Always consult a CPA for your final filing.
