About Calc365

What Calc365 offers today

The site currently covers United States tax estimation for the 2026 tax year: federal income tax, take-home pay, payroll tax, self-employment tax, capital gains, sales tax, and the estate and gift tax that share one unified exclusion. Each one runs in your browser and needs no account.

The longer-term aim is broader — everyday money questions as well as tax ones. Several tools covering property tax and retirement contributions are drafted but unpublished, because the figures they depend on have not been confirmed against an official source yet. You can see exactly which, and why, on the calculators page.

The name reflects the intent of a tool you can reach for whenever a question comes up. It is not a claim that anything is updated daily or guaranteed year-round; every page carries the date its figures were last reviewed so you can judge for yourself.

Who this is for

People handling their own money decisions in the United States: employees comparing an offer, freelancers sizing a quarterly payment, investors checking what is left after a sale, small employers working out the true cost of a hire, and anyone who wants to understand a number before acting on it.

It is aimed at people who want to see how a figure was reached, not just what it is.

Why the arithmetic is on the page

Most calculators hand you a number and stop. You cannot see which bracket did what, which deduction applied, or where the underlying rates came from. When two calculators disagree — and they often do — there is no way to tell which one is wrong.

Every tool here shows its intermediate steps. On the federal calculator that means gross income, adjustments, adjusted gross income, the deduction applied, taxable income, the tax charged in each rate band, credits, and payments. If you disagree with the result, you can point at the line you disagree with.

What gets published, and what gets held back

A figure appears in a calculator only if it traces to a primary government publication. Not a news article, not another calculator site, not a plausible extrapolation from last year.

That rule has visible consequences. There is no state income tax calculator, because 2026 state rate schedules were not confirmed against each state's revenue department. The federal calculator leaves out the refundable portion of the child tax credit and applies no cap to the state and local tax deduction, because neither 2026 figure could be confirmed. Several tools remain unpublished rather than shipping with placeholder rates.

A calculator that looks authoritative while being wrong is worse than one that admits what it does not know. Where an omission affects your result, the results panel tells you directly instead of burying it in a footnote.

How the calculations are built and checked

Calculation logic is kept entirely separate from the interface. The functions take plain numbers and return plain numbers; they never read the page or write to it. That separation is what makes the arithmetic directly testable, and it is tested — a few hundred assertions run against the engine.

The bracket tests are the ones worth mentioning. Rev. Proc. 2025-32 publishes each rate band as a cumulative dollar amount plus a marginal rate, so the tests compare our output against the IRS's own arithmetic at every bracket edge, for every filing status. The expected values were transcribed from the published tables, not produced by running our code and copying the answer.

Money is handled as integer cents throughout. Binary floating point cannot represent most decimal money values exactly, and progressive brackets multiply that error by every band they cross.

The methodology page sets out the full process, and sources lists every publication behind the figures.

Your figures stay with you

Calculations happen in your browser. Nothing you type is sent to a server, stored in a database, or included in analytics, and no calculator here asks for your name, address, Social Security number, or account details. The privacy policy explains the detail, including what a shareable result link contains.

Independence

Calc365 is not affiliated with, endorsed by, or approved by the Internal Revenue Service, the Social Security Administration, any state revenue department, or any other government agency. We link to official publications so you can check our work, not to suggest any relationship with the bodies that produce them.

The site is supported by advertising. Ad placements stay out of the input form and away from the results so they cannot be mistaken for part of a calculation, and each slot reserves its space in advance so a loading advert never shifts the page under you.

What this site is not

These are estimation tools for planning and understanding. They are not tax preparation software, they file nothing, and they do not replace professional advice. Outcomes depend on the full picture of your circumstances, and much of that picture is not something a calculator can see. The disclaimer sets out the limits.

Telling us something is wrong

Corrections are welcome and are the most useful thing you can send. If a figure looks wrong, say which calculator, what it shows, what you believe it should show, and the official publication you are working from. Corrections backed by a primary source get acted on quickly. The contact page has the details.