2026 Quarterly Estimated Tax Calculator for Freelancers - Form 1040-ES Safe Harbor, Due Dates and Payment Tracker, Offline

Work out your 2026 quarterly estimated tax payments as a freelancer or self-employed person - offline, in one file that opens in your browser.

What you get

• One HTML file (works offline, nothing is sent anywhere, no account).
• Follows the IRS 2026 Form 1040-ES worksheets line by line: self-employment tax (92.35% of profit; 2.9% Medicare; 12.4% Social Security up to $184,500 minus your wages), the deduction for half of it, the 2026 tax rate schedules and standard deduction for all four filing statuses.
• Safe harbor: required annual payment = the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if your 2025 AGI was over $150,000), minus withholding; the $1,000 test.
• The amount to pay on each 2026 due date: April 15, June 15, Sept. 15, 2026 and Jan. 15, 2027.
• A payment tracker that remembers what you have paid (saved only in your browser).

Checked: the calculator was compared with a separate implementation of the IRS tables in 1,729 test cases, with 0 differences.

Not covered: qualified dividends and capital gains rates, alternative minimum tax, the QBI deduction calculation (you can type your own estimate), farming/fishing and fiscal-year rules, the annualized income method, state taxes.

Estimates for planning, not tax advice. Not affiliated with the IRS.

Refunds: if the file does not open or does not calculate as described, a fixed version or a full refund within 30 days. Contact sungje5575@gmail.com.