TurboTax tax calculator vs our AI estimator

What TurboTax is, and what this is

TurboTax sells tax filing software. TaxCaster is its free estimator, and the estimator exists to introduce you to the product — which is a perfectly ordinary way to run a business and worth knowing before you read the output.

That shapes what the free tool is optimised for. It is built to be finished, because a finished estimate is a warm lead, and it is built to hand off cleanly into the paid product. Neither of those is a criticism; both explain design decisions that would otherwise look arbitrary, like why the flow is a wizard rather than a single screen.

This site sells nothing. There is no filing product to upsell, no adviser network, no deposit account, and no account to create — which is worth stating plainly because it is the structural difference between the two, and structure predicts behaviour better than intentions do.

What it is instead: a deterministic calculator over verified rate data. On $85,000 single it puts federal income tax at $9,870 and FICA at $6,503, then adds your state and, where one exists, your city. The arithmetic is fixed; the language model on these pages explains a number it was given and never computes one.

What goes into each calculation

We opened both tools on 2026-08-28 and compared what each one actually puts into the calculation. That is the only comparison worth publishing: we are not going to show you a screenshot of someone else's output and ask you to trust our transcription of it.

TurboTax's free calculator covers federal tax. It does not compute state income tax, which on $85,000 ranges from nothing in 9 states to $6,604 in Oregon — a number too large to leave out of anything described as what you will take home.

Nor local income tax, which eleven states permit and which we model for 3,672 jurisdictions across 7 states. In several of those places the city takes more from a modest salary than the state does, so its absence is not a rounding difference.

The property side is the other difference, and nothing in this category joins it up. The tax on a salary and the tax on a house are what actually decide whether a move works, they are set by different authorities, and comparing either alone regularly produces the opposite of the right answer. Every one of the 3,143 US counties has a page here.

The same salary, run here

Take $85,000, single, standard deduction. Federal income tax is $9,870 — an effective 11.61% against a marginal bracket of 22.00%, which is the gap that makes people think their calculator is broken. FICA adds $6,503, flat from the first dollar with no deduction at all.

That much is the same wherever you run it, because federal tax does not care where you live. What changes the answer is the next line: state tax on the same salary runs from $0 to $6,604, and then local tax on top in eleven states.

A federal-only tool stops before that line. It is not wrong about the part it computes — it is answering a narrower question than the one most people are asking, and the difference between the two answers is up to $6,604 a year.

Run the same figures in both and compare the line items rather than the total. If the totals differ, the useful question is which line differs and why — a different standard deduction means one of the two is using last year's, and a missing state or local line means one is answering a different question.

The word "free", and what usually ends it

Free tiers in filing software are real, and they are also bounded — normally by the complexity of the return rather than by income. The boundary is what to check before starting, because the point at which a return stops qualifying tends to arrive after the data is already entered.

The usual triggers are predictable: itemising rather than taking the standard deduction, self-employment or 1099 income, a rental, investment sales, and in many products the state return as a separate charge even when the federal one is free. None of those is hidden, but all of them are discovered part-way through, when the switching cost is highest.

The genuinely free route that fewest people use is IRS Free File, a partnership between the tax authority and several software providers, open below an income threshold that covers a large share of filers. It is worth checking eligibility before paying for anything, and it is not marketed with anything like the same budget.

An estimator has no such boundary because it produces no return. What this site computes on any salary — federal, FICA, state and local — costs nothing at any complexity, for the simple reason that there is no paid tier for it to be the top of.

The honest caveat runs the other way too: because there is no paid tier, there is also nobody here to take over when the return turns out to be complicated. That handoff is exactly what a filing product is for, and it is a real advantage of one.

The part nobody checks: whether the numbers are current

Every calculator in this category applies the same arithmetic. What separates them is whether the rates going in are this year's, and that is checked far less often than you would expect — including by tools that are otherwise carefully built.

When we audited the category in August 2026 we found sites ranking on the first page for "income tax calculator 2026" that were serving the previous year's figures: a standard deduction of $15,200 single instead of $16,100, and a first bracket ending at $11,925 instead of $12,400. Several linked to the correct IRS page from the same screen.

State data goes stale faster still, because states legislate on their own calendars and backdate. Of the 37 states we checked against their own department of revenue, 12 carried a wrong rate, threshold or credit in the compiled sources everyone uses. Ohio's bill was overstated by 43% because a source treated a flat rate as flat from the first dollar. Georgia cut its rate in May with effect from 1 January, so a table published in April was correct when written and wrong by summer.

So every figure here carries the document it came from and the date it was verified, and the log is published rather than kept internally. Where a state has not yet been read off a primary source, the page says so instead of implying it has — "we have not looked" and "it does not exist" are different claims, and treating them as the same is how a calculator confidently tells someone a relief they qualify for is not available.

This is the one comparison we would ask you to actually run. Take any tool, including this one, find the standard deduction it is using, and check it against the IRS revenue procedure. It takes two minutes and it tells you more about a calculator than any feature list.

If two calculators disagree, here is how to find out which is wrong

Work down the lines rather than arguing about the total. Almost every discrepancy in this category comes from one of five places, and each has a tell you can check in under a minute.

The standard deduction. Find the figure each tool used. For 2026 it is $16,100 single and $32,200 joint. If one is using $15,200 or $30,400, it is serving last year's numbers, and everything downstream of that is wrong by the difference times your marginal rate.

Whether FICA is included. A tool showing federal income tax of $9,870 on $85,000 and a tool showing $16,373 are not disagreeing — one is reporting income tax and the other total federal tax. Both are correct about different things, and the labels are frequently ambiguous.

Whether state tax is in there at all. This is the largest single cause of a big gap, because a federal-only tool is simply answering a narrower question. Check whether the tool ever asked you what state you live in; if it did not, it cannot have included it.

Gross versus net input. Some tools ask for gross pay and some for taxable wages after pre-tax deductions. Feeding a gross figure into a field expecting net, or the reverse, moves the answer by the size of your 401(k) and health premiums — which is thousands, not rounding.

Marginal versus effective rate. A tool reporting 22.00% and one reporting 11.61% on the same salary are both right: the first is the rate on your next dollar, the second the average across everything you earned. Comparing one against the other is the commonest reason people conclude a calculator is broken when it is not.

If all five line up and the totals still differ, one of the two has a stale state rate — and that is the case where checking against the state's own department of revenue publication is the only way to settle it.

Where TurboTax is the better choice

El asistente de cuatro pasos es probablemente la mejor experiencia de uso de la categoría.

Si vas a declarar con ellos, la estimación se convierte en la declaración sin volver a teclear nada.

And the obvious one: this site cannot file your return. If you are going to file with TurboTax anyway, running the estimate anywhere else is duplicated typing. Use theirs.

We publish this section because a comparison that finds its own product better at everything is not a comparison, it is an advertisement — and readers can tell the difference immediately. The credibility of everything else here depends on this paragraph being true.

What each one does with what you type

Tax figures are among the more revealing things a person enters into a web form: salary, marital status, dependants, where you live, sometimes what you own. It is worth knowing where they go before you type them.

A free estimator attached to a paid product is, among other things, a lead capture. That is the normal arrangement and it is not hidden — but it means the natural end of the flow is an account, an email address, or a prompt to continue into the paid product, and the figures you entered are how the offer that follows gets targeted. Read whatever privacy terms apply to the free tool specifically; they are not always the same as the ones covering the paid product.

This site asks for no account, no email and no name. The calculation runs in your browser, the figures are not stored against an identity, and there is no product to route you into afterwards. That is not a virtue so much as a consequence of the business model: there is nothing here that a profile of you would make more valuable.

The AI explanation is the one place data leaves the browser, and it is worth being precise about it. What gets sent is the computed figures — income, tax amounts, rates, state — so the model can describe them in plain English. It is not sent a name, an email or anything identifying, and it never computes a number: the arithmetic is settled before the model sees anything, which is the only arrangement in which a language model belongs near a tax figure.

Which one for which question

Filing a return: TurboTax, or any filing product. This is a planning tool and not a filing tool, and no calculator on any site is a substitute for one.

Comparing two job offers in two states, or two cities: here. That is the question this was built for, and it needs the state and local lines that a federal-only tool does not compute.

Setting or fixing your W-4: neither, strictly. The IRS Tax Withholding Estimator is the authoritative tool for that specific job, it is free, and its output maps onto the form's numbered steps. We say so on its own comparison page too.

Deciding whether a move is worth it: this, but using both halves. Income tax on one side and county property tax on the other, because states trade the two against each other and every comparison built on one alone is unreliable in a predictable direction.

Checking whether a number you were given is plausible: any of them, twice. Two independent tools agreeing is weak evidence and two disagreeing is strong evidence that one of them is out of date — which is worth finding out before you make a decision on it.

What this page does not claim

We have no affiliation with TurboTax, no partnership, and no relationship of any kind. We do not use their logo or their branding, and nothing here should be read as their statement or as endorsed by them. TurboTax is their name, used to identify what is being compared, which is what a comparison requires.

Everything asserted above about their tool comes from opening it on 2026-08-28 and looking. Products change, and something described here may have changed since — if you find that it has, the correction page on this site exists for exactly that, and we would rather be told than be wrong.

We are not making claims about their accuracy. We did not find errors in TurboTax's figures and we are not implying any — the data section above describes what we found across the category and names the specific pattern, which is stale figures on sites that publish no verification date at all.

And we are not a filing service, a tax adviser or a substitute for one. This is a planning calculator. Where a situation needs professional judgement, it needs a professional, and several of the products compared on this page supply one.

Questions

Is this a good alternative to TurboTax?

For working out what a salary is worth in a particular state and city, yes — it computes federal, FICA, state and local income tax together and it is free with no account. For filing a return it is not an alternative to anything: it does not file. And TurboTax answers a narrower question, which is fine when that is your question.

Is it free? What is the catch?

Free, no account, nothing stored. There is no filing product to sell you, no adviser network and no deposit account. The site is funded by advertising and by a paid API for businesses, neither of which changes the number you are shown — which is the only guarantee that matters here.

Which is more accurate?

Accuracy in this category is almost never about the arithmetic — everyone applies the same brackets correctly. It is about whether the rates going in are current. Of 37 states we checked against their own department of revenue, 12 carried a wrong figure in the compiled sources. Every number here shows the document it came from and the date it was checked, so you can verify rather than trust.

Does it include state and city taxes?

Yes. All 51 jurisdictions for state income tax, each read off the state's own publication, plus 3,672 local jurisdictions across 7 states — every Pennsylvania municipality, every Ohio municipality and school district, all 92 Indiana counties, Maryland's counties, Michigan's cities and New York City. Local income tax is the layer most national calculators omit entirely.

What does it calculate on $85,000?

Federal income tax of $9,870 and FICA of $6,503 for a single filer taking the standard deduction, then your state's own tax and any local tax on top. It shows two effective rates — one on income tax alone, which compares to your marginal bracket, and one including FICA, which is what actually leaves your pay.

Are you affiliated with TurboTax?

No. No affiliation, no partnership, no sponsorship. We do not use their logo or branding. Their name appears here to identify what is being compared, and the page includes a section on where their product is the better choice — because a comparison that finds its own side better at everything is not a comparison.