About ContractMath

ContractMath (contractmath.com) publishes free calculators that compare W-2 employment with 1099 contract work and estimate freelance taxes for tax year 2026. It is independent and not affiliated with the IRS, SSA or any government agency.

How the numbers are sourced

• Every federal figure comes from a primary source: IRS Rev. Proc. 2025-32 (brackets, standard deduction, QBI), the SSA contribution and benefit base ($184,500), the 2026 Form 1040-ES (due dates) and IRS Notice 2025-67 (retirement limits).
• State rates come from the Tax Foundation 2026 table, with Georgia and Utah taken from state law because both changed rates after January 1.
• The tax engine is covered by automated tests that check brackets, wage-base caps, QBI phase-outs and break-even math. Formulas are published on the methodology page.
• Pages show the date they were last reviewed (October 2026). When the IRS or SSA publishes new figures, they are updated.

Limits

Results are estimates for planning, not tax, legal or financial advice. Local taxes, credits and itemized deductions are not modeled.

Contact

Corrections and questions: [email protected].