There is no sign-up form on this page. That is deliberate.

Who this is for, and who it is not

A business office with a question, not a school without a payroll provider.

It fits a finance officer or business manager who already has payroll running somewhere and wants an independent way to check it — particularly one who has been handed a figure and told it is correct without being shown why. It fits a team building around a finance system that needs one calculation rather than a whole suite. And it fits an organisation whose auditor has asked about segregation of duties and change evidence, provided they read the scope bounds on those controls carefully.

It does not fit a school without a payroll provider. We do not disburse, we do not file, and we ship no statutory tax tables, so we cannot be the thing that pays your staff on Friday. If that is the requirement, buy from a full-service provider — the first three rows of our own comparison table go to them outright for exactly this reason.

It also does not fit an organisation with nobody who can sign for a tax table. The registry ships empty by design, and an unsigned table withholds zero. That is the right behaviour, and it is only useful if there is somebody whose job it is to sign.

And there is a case we would talk you out of: adopting this as a system of record. It is not one. The payroll surfaces persist nothing, five payroll tables exist with no producer, and the module that would create a run has no production caller. Everything here is arithmetic and access control, both of which are real, and none of it is storage.

What step three actually looks like

One pay period, four calls, and a number you already know.

The verification use is the one most business offices should try first, and it is worth describing concretely rather than as a bullet, because the shape of it is unusual: you already know the right answer before you start. That is what makes it cheap.

Take a pay period you have already run and already reconciled. Send the earnings and the deductions for one employee to the taxable-basis endpoint with a signed exemption mask and you get back a basis per authority, each with the amount that reduced it. Compare those to the basis figures on the stub you were sent. If they differ, the difference is almost always a deduction class treated as pre-tax for the wrong authority, and it will be the same on every period since the deduction was set up.

Send the federal basis and a signed bracket table to the federal withholding endpoint and you get the worksheet worked step by step, with the per-period division floored and the dropped sub-cent fraction returned rather than rounded away. Send the FICA basis and the year-to-date wages to the FICA endpoint and you get the employee and employer sides separately, with Social Security capped, Medicare uncapped, and Additional Medicare employee-only.

Then compose the same inputs through the gross-to-net stub endpoint. It uses the same primitives the three individual endpoints expose, so the composed statement and the individual answers cannot disagree — there is no second arithmetic path for the stub version of a number.

Nothing is installed and nothing is migrated for any of this, because the engines hold no state: values arrive on the request and a typed result comes back. The route module says in its own header that there is no persistence, in those words. If the figures agree with your provider, you have an independent check you can repeat at year end. If they do not, you have a specific disagreement on a specific authority, which is a far better thing to take to a provider than a feeling that the number looks wrong.

The operating boundary

A wages engine is not a payroll service, and the difference controls every screen.

Wages.software is being built around calculation and validation boundaries. It can take a deliberately scoped set of wage facts, apply a signed and dated ruleset, and return an explainable result in integer cents. It is not the system that moves money, submits a filing, enrolls a worker, chooses a tax treatment, or declares that a payroll is legally complete. Those duties need different authority, different evidence, and different operational controls. Keeping them outside this product is a product decision rather than a missing footnote.

The arithmetic begins with gross wages and an explicit exemption mask. Each authority receives its own taxable basis because a deduction may reduce federal income-tax wages while leaving Social Security or Medicare wages unchanged. A single field called taxable wages would conceal that distinction. The engine therefore returns separate bases, carries the reason for each exclusion, and refuses an unsigned mask. It never guesses a classification from an employee name, job title, school, or employer.

Money is represented as integer cents. Rates that cannot be represented safely as a decimal are evaluated as integer ratios, with rounding performed at the named boundary. Net is floored at zero and over-deduction is flagged; that return does not recover the shortage from a later check. A W-2, W-3, and Form 941 comparison is a reconciliation result, not a filing. A NACHA-shaped output is checked structurally, but the raw bank file remains withheld. These distinctions matter because an attractive page can otherwise turn a calculation claim into a claim that funds moved.

Rules are data with provenance. Wages.software ships no statutory tables today. The registry starts empty, and an unsigned or out-of-period table cannot silently become active. An operator must be able to identify the authority, effective dates, source artifact, signature, and exact version used for a calculation. A future update process must preserve the prior version so a historical result can be explained with the rules that existed when it was made.

The employee-facing seams follow the same narrow posture. A W-4, direct-deposit change, or address change may be validated, masked, and audited by the relevant module, but the marketing surface does not persist it and does not imply that a production workflow consumes it. The built modules and their test gates are named on this site precisely because several have no production caller. A module can exist, compile, and pass focused tests while remaining intentionally unreachable.