About CalcPaid

What this is for

Most online calculators answer a question you did not ask. You want to know what will be in your account on Friday; they give you a figure derived from an average tax rate, with no indication of how it was reached or which of your circumstances it ignored.

CalcPaid is built the other way round. Every result comes with a breakdown of where each dollar went and a plain-English explanation of the arithmetic, using your own figures. If you disagree with the number, you can see exactly which step you disagree with.

How the calculations work

The tax rules live in a calculation engine that is completely separate from the interface. It knows nothing about buttons or colors; it takes a description of your situation and returns a result. That separation is what makes the numbers testable, and it is why the paycheck, hourly, pay stub and bonus calculators — and the raise calculator's take-home estimate — share exactly the same logic rather than each reimplementing it slightly differently.

Three things the engine is careful about, because they are commonly got wrong:

• Three separate wage bases. Social Security and Medicare, federal income tax, and state income tax are each charged on a different figure. A traditional 401(k) reduces the second but not the first, and whether it reduces the third depends on the state.
• Progressive brackets, not average rates. Federal tax — and state tax in most states — is charged in bands. The calculator shows which band each part of your income fell into.
• Pay frequency is arithmetic, not a label. Biweekly is 26 paychecks, semimonthly is 24. Everything is worked out annually and divided at the very end, so the two genuinely differ.

Where the tax data comes from

Rates, brackets, standard deductions and thresholds are taken from the Internal Revenue Service and from each state's own revenue or taxation department. Every figure in the codebase is stored alongside a note saying which authority it came from, which tax year it applies to, and when it was last checked.

Where a state has announced a rate for the coming year but has not yet published final inflation-adjusted brackets, the previous year's brackets are carried forward and flagged as such rather than guessed at. Tax data for each year is stored separately, so adding a new year never disturbs the last one.

What it deliberately does not do

It does not ask who you are. There is no account, no email capture and no newsletter. Everything is calculated by JavaScript running on your own device — your salary never travels anywhere, because there is nowhere for it to travel to. The site counts visits with Google Analytics and may show Google ads, and neither of those ever sees the figures you enter. See the privacy page for the detail.

It also does not claim to be your payslip. It is an estimate built from published rules, and the disclaimer explains precisely which factors can make your real paycheck differ.

What is coming

Ten tools are live today: the paycheck, hourly paycheck, pay stub, bonus, pay raise, salary to hourly, overtime, time card and work hours calculators, and the salary after tax tables. Tax, tip, loan and mortgage calculators are planned, each built on the same engine and the same component system. They will be published when they are finished and tested, not as placeholders.