Are these comparisons impartial?

We have an obvious interest, and saying otherwise would be silly. What we can do is make them checkable: we compare scope rather than reproducing anyone's output, we say when we audited a tool and when we have not, and every page names where the competitor is better.

Are you affiliated with any of these companies?

No. No affiliation, no partnership, no sponsorship, and we do not use their logos or branding. Their names appear to identify what is being compared.

Which calculator is actually the most accurate?

Accuracy in this category is rarely about arithmetic — everyone applies brackets correctly. It is about whether the rates going in are current, and whether the tool models the layer you need. Both are checkable, and each comparison page shows how.

Do you compare against the IRS tool?

Yes, and it is the one comparison where we recommend the other tool for its own job. For setting a W-4 the IRS Tax Withholding Estimator is authoritative, free and better than this — it handles year-to-date figures for a mid-year change, which we do not.

2026 · 6 comparisons · No affiliation

Comparisons

Side-by-sides with the other calculators people actually use, written on the principle that a comparison finding its own side better at everything is an advertisement rather than a comparison.

Written and edited by Pablo Ruiz QuinteroSources checked September 1, 2026Competitor audit 2026-08-28

Every comparison

IRS Tax Withholding EstimatorThe authoritative tool for setting a W-4 — and better than this one for that job.TurboTaxAudited 2026-08-28. Federal only in its free calculator.SmartAssetAudited 2026-08-28. Covers the state layer too — the difference is data currency.H&R BlockA tax preparation business. We have not audited its calculator and the page says so.NerdWalletAudited 2026-08-28. Federal only in its free calculator.Jackson HewittA tax preparation business. We have not audited its calculator and the page says so.

How these comparisons are written

We compare scope — what each tool actually puts into the calculation — because that is checkable by opening both. We do not reproduce anyone else's output and ask you to trust our transcription of it.

Where we have audited a competitor's tool, the page says when. Where we have not, the page says that instead of describing it from general impression. That is the same distinction applied throughout this site between "we checked" and "we have not looked".

Every page includes a section on where the other tool is the better choice, and it is not a token paragraph. For filing a return, filing software wins. For setting a W-4, the IRS estimator wins. For a situation with real judgement in it, a preparer wins.

What this site adds is the state and local layer — 3,672 local jurisdictions across 7 states — and per-figure sourcing with dates. Those are the two things the audit found nobody else doing together.

None of these companies is affiliated with us, sponsors us, or has endorsed anything here. Their names appear to identify what is being compared, which is what a comparison requires.

What the audit actually found

We opened the major calculators in August and compared what each puts into the calculation. Three patterns came out of it, and they shape every page in this section.

Federal-only is common. Several widely used free calculators, including ones attached to well-known filing products, compute federal tax and stop. That is complete about a narrower question, and the missing state line is worth thousands a year at ordinary salaries.

Local income tax is almost universally absent. Eleven states permit a city, county or school district to levy one, and in several of those places it exceeds what the state takes from a modest salary. We found nobody modelling it at scale.

Dates are missing. Very few pages in this category attach a verification date to their tax figures, and the ones serving the previous year's standard deduction were all in that group. Its absence is the strongest available signal about a calculator.

None of which makes any of these tools bad. They are built for particular jobs and mostly do those jobs well, which is why each comparison page names where the other side wins.

Where to go next

Are tax estimators accurate?What we found auditing the whole category.Income tax calculatorThe tool being compared.How the figures are verifiedWhy data currency is the real difference.SourcesEvery figure with its document and date.

Questions

Are these comparisons impartial?: We have an obvious interest, and saying otherwise would be silly. What we can do is make them checkable: we compare scope rather than reproducing anyone's output, we say when we audited a tool and when we have not, and every page names where the competitor is better.
Are you affiliated with any of these companies?: No. No affiliation, no partnership, no sponsorship, and we do not use their logos or branding. Their names appear to identify what is being compared.
Which calculator is actually the most accurate?: Accuracy in this category is rarely about arithmetic — everyone applies brackets correctly. It is about whether the rates going in are current, and whether the tool models the layer you need. Both are checkable, and each comparison page shows how.
Do you compare against the IRS tool?: Yes, and it is the one comparison where we recommend the other tool for its own job. For setting a W-4 the IRS Tax Withholding Estimator is authoritative, free and better than this — it handles year-to-date figures for a mid-year change, which we do not.