About this site
A free, independently built calculator for freelancers and 1099 contractors trying to figure out what they actually owe.
Who built this
QuarterlyVoucher is built and maintained by an independent software developer, not a tax firm or financial institution. It isn't reviewed by a CPA or Enrolled Agent — that's a real limitation, disclosed here rather than glossed over, and it's why every page on this site says clearly that it's an estimate, not advice. What it does bring is engineering rigor applied to tax math: every calculation in the engine is covered by an automated test suite checked against known Schedule SE, QBI, and safe-harbor worked examples, so the numbers you see can't silently drift from what the code actually computes.
This site exists because most free self-employment tax calculators stop short of what freelancers actually need: they skip state income tax, ignore the QBI deduction, or don't help you work out a safe-harbor quarterly payment amount. This one computes self-employment tax, federal income tax, state income tax, and quarterly estimated payments together, for all 50 states, plus dedicated tools for S-corp elections and self-employed retirement contributions, and a set of plain-language guides on the rules behind the numbers.
Methodology — what's modeled and what isn't
Every tax-year constant — federal brackets, the standard deduction, Social Security and Medicare thresholds, the standard mileage rate, retirement contribution limits, and each state's income tax structure — is sourced from official IRS, SSA, and state department of revenue publications for tax year 2026 (see Sources below). Where an official source wasn't reachable or hadn't yet published a figure at the time of writing, that's flagged directly in the code and, for several states, in the page copy itself.
Deliberately not modeled in this version: multi-state income allocation, itemized deductions (the calculator assumes the standard deduction), the QBI phase-out for specified service trades and high earners, and several states' local/county-level taxes (called out on the specific state pages where they apply — New York City, Maryland's county piggyback tax, Indiana's county tax, and Oregon's Portland-area local taxes, among others). The S-corp tool doesn't model state-level S-corp entity taxes. These are real gaps, not oversights, and they're the reason every result is framed as an estimate rather than a filing-ready number.
Tax rules change — sometimes mid-year — so figures are reviewed and updated at least annually.
Sources
The primary government sources behind this site's 2026 figures:
- IRS Rev. Proc. 2025-32 — 2026 federal tax brackets & standard deduction
- IRS — Self-Employment Tax (Social Security and Medicare Taxes)
- SSA — 2026 Social Security COLA Fact Sheet (wage base)
- IRS — Qualified Business Income Deduction
- IRS — Estimated Taxes (safe harbor rules, Form 1040-ES)
- IRS Newsroom — 2026 standard mileage rates
- IRS Publication 587 — Business Use of Your Home
- IRS Publication 463 — Travel, Gift, and Car Expenses
- IRS Form 2210 — Underpayment of Estimated Tax
- IRS Newsroom — 2026 retirement plan contribution limits
- IRS — COLA increases for dollar limitations on benefits and contributions
- IRS Form 1120-S — U.S. Income Tax Return for an S Corporation
- IRS Form 2553 — Election by a Small Business Corporation
- IRS Schedule SE — Self-Employment Tax instructions
What this site is not
This site is not affiliated with the IRS, the Social Security Administration, any state department of revenue, or any other government agency. It doesn't prepare or file tax returns, and it isn't a substitute for advice from a qualified tax professional — it's a planning tool to help you understand roughly what you owe and set money aside accordingly.
Contact
Found an error, have a question, or want to suggest a state or feature? Reach out at contact@quarterlyvoucher.com.