Our mission
SalaryGrid exists because UK PAYE math is more subtle than the dominant free calculators let on — and because most of those calculators ship third-party trackers before they ship correct numbers. We set out to build a fast, honest, dark-themed grid for the people whose payslip math is being shaped by the 2026/27 ruleset: salaried PAYE employees, hourly-paid workers with overtime, outside-IR35 contractors, and the growing slice of UK professionals stuck inside the £100,000 personal allowance taper.
Every figure on every page is computed in your browser using integer pence arithmetic against the same statutory thresholds HMRC and Revenue Scotland use. We never see your numbers; nor does anyone else. The calculator is the product — not the data you put into it.
What we are
- A static Astro v6 site rendered to plain HTML and shipped via the Cloudflare edge — no origin server is ever asked to compute your take-home pay.
-
A small Preact island per page (hydrated with
client:load) that runs the calculation engine entirely in your browser using@preact/signalsfor sub-millisecond reactivity. - A shared TypeScript engine — every monetary value modelled as integer pence so that £100.10 + £200.20 isn't quietly off by 0.00000000000001.
- A design system anchored on Slate 950, Slate 800 borders, a single Emerald accent, JetBrains Mono for figures and Inter for prose. That's it — no Material, no Tailwind component library, no UI kit.
What we are not
- Not regulated financial advice. SalaryGrid produces estimates. For Self-Assessment filings, complex personal allowances or non-PAYE income, see a qualified UK accountant.
- Not a data-collection funnel. No accounts, no logins, no email gates, no "free PDF in exchange for your scenario".
- Not a JavaScript-everywhere SPA. Each page is a static HTML document with one focused interactive island; navigation between calculators is a full document load, deliberately. The result is faster cold loads and zero JavaScript on content pages like this one.
Why client-side?
A salary calculator is a small, self-contained mathematical function — every threshold and rate is public, frozen for the year, and fits comfortably in a few kilobytes of TypeScript. The instant you send the user's gross salary to a server, you have created an obligation: encryption-in-transit, encryption-at-rest, retention policies, breach notification, GDPR data-subject access requests. None of that is necessary when the math runs in the same browser tab that asked the question. That's the architectural decision the rest of the project flows from.
How we keep ourselves honest
- One ruleset, locked. The 2026/27 thresholds — Personal Allowance £12,570, basic-rate threshold £50,270, NI primary threshold £12,570, UEL £50,270, employer NI 15%, Scottish bands 19/20/21/42/45/48% — are stored as constants and never read from remote configuration. What you see in the calculator today is what you would see if you re-opened it tomorrow with no connection.
- Penny-accurate by construction. Every monetary input
is parsed to integer pence at the I/O boundary; every multiplication
wraps in
Math.round(); every period scaling (÷ 12, ÷ 52) rounds. We will never claim "approximately £X" when HMRC is willing to compute it to the penny. - Symmetric URL state. Anything you tweak in the calculator can be captured into a single shareable link — your scenario travels with the URL, not through us.
How we pay for it
SalaryGrid is free at the point of use and we intend to keep it that way. The site shows a small number of clearly-labelled Google AdSense placements with fixed dimensions (300×250, 728×90, 300×600) so that the layout never shifts when an ad loads — a deliberate respect for your attention. We disclose the ads in our Privacy Policy and you can ask Google to stop personalising them at any time via your Ad Settings.
Get involved
Found a band edge we round the wrong way? Spotted a guide that needs a Scotland counterpart? Want a calculator for dividend-vs-salary modelling, a Capital Gains tool, or a Self-Assessment dry-run? We read every issue. The project is small, opinionated and friendly — and the codebase is deliberately readable enough that you can audit our PAYE math in a single sitting.
For general enquiries, bug reports or feedback, please email us at [email protected].