How we calculate and verify our numbers

Tax numbers affect real decisions, so we want you to be able to check ours. This page explains where every figure comes from, what our calculators assume, and how we catch mistakes.

1. Official sources only

Every rate, limit and date comes from a primary source: IRS revenue procedures, notices, forms and instructions, and the Social Security Administration. Each calculator lists its sources at the bottom of the page. We do not copy figures from other calculators or blogs.

2. One place for each year's numbers

All figures for a tax year live in a single data file, each one next to the link to its source. When the IRS publishes new numbers, we update that file and every calculator and guide changes at once. Current tax year:2026, last reviewed on 2026-09-22.

3. Tested against the IRS

The math behind our calculators is covered by automated tests. For example, our federal income tax function must reproduce, to the cent, every amount in the IRS tax rate tables for all four filing statuses, and our self-employment tax function must follow the steps of Schedule SE. If a test fails, the site does not update.

4. What our calculators assume

Our results are estimates. Unless a calculator says otherwise, it assumes:

• Federal taxes only. State and local taxes are not included.
• The standard deduction, not itemized deductions.
• No tax credits (such as the Child Tax Credit or the Earned Income Tax Credit), which can lower your tax.
• For the qualified business income (QBI) deduction: one business in which you materially participate, with no employees on payroll and no significant business property. This is typical for freelancers and gig workers.
• No capital gains, and no income from other businesses or partnerships.

We keep cents in the math and round only what we show you. The IRS lets you round to whole dollars on your return, so your forms may differ by a few dollars.

5. Your privacy

Calculators run entirely in your browser. The numbers you type are not sent to us or stored anywhere. If you use the "copy link" button, your numbers are saved only in that link, so share it only with people you trust.

6. Corrections

If you think a number is wrong, please tell us at hola@netacalc.com. We review every report, fix confirmed errors quickly, and update the "last updated" date on the page.

7. What NetaCalc is not

NetaCalc is an educational resource, not a tax preparer or an advisor. We explain the rules and do the math; we do not tell you what to do in your specific situation. For decisions with real consequences, talk to a tax professional such as a CPA or an Enrolled Agent.