Free tools built to a high standard — no sign-up, no tracking, no fluff. A UK take-home pay calculator that does the maths properly, and a QR-code scavenger hunt builder that just works.
Built to do one thing well. No accounts, no tracking, instant results.
Enter your salary — annual, monthly, daily, or hourly. See a full breakdown of income tax, National Insurance, pension, and student loan by every pay period. Supports Scottish income tax, all student loan plans, and tax years back to 2023/24.
Convert between day rate and equivalent salary — accounting for holiday allowance, pension, and employer NI. Built for the 2M+ UK contractors trying to make apples-to-apples comparisons against PAYE offers.
Work out monthly repayments, total interest, and affordability bounds from your take-home. Switch between repayment and interest-only. See an amortisation schedule for the full term.
See how much interest you save by overpaying your mortgage each month. Enter your remaining balance, rate, and term — then drag the overpayment slider to watch the savings stack up.
Build QR-code scavenger hunts in minutes. Add clues, set answers, and arrange them in a drag-and-drop editor. Each clue gets a printable QR code. Watch participants race through your trail on a live dashboard.
One codebase. Web and native. Typed end-to-end.
React Native + Web from a single codebase. The same screen renders in a browser or on iOS/Android without modification.
Every calculation is pure TypeScript with no UI dependencies — easily testable, portable, and correct.
Bun handles package management, test running, and bundling. Faster cold starts, no config overhead.
Tax logic lives in a self-contained module — tested independently from the UI. Tax year tables are updated each April.
Every tax scenario is compared against a golden snapshot. If HMRC numbers change, a test breaks — not a silent regression.
Hosted on the web for instant access. Android APK available for offline use. iOS support in progress.
export function calculateTakeHome(params: TakeHomeParams): TakeHomeResult {
const { grossAnnual, taxYear, region, pension, studentLoan } = params;
// Personal allowance tapers above £100k
const allowance = getPersonalAllowance(grossAnnual, taxYear);
const taxable = Math.max(0, grossAnnual - allowance);
const incomeTax = calcIncomeTax(taxable, taxYear, region);
const ni = calcNI(grossAnnual, taxYear);
const pensionDed = grossAnnual * (pension / 100);
const slrDed = calcStudentLoan(grossAnnual, studentLoan, taxYear);
const netAnnual = grossAnnual - incomeTax - ni - pensionDed - slrDed;
return toAllPeriods(netAnnual, incomeTax, ni, pensionDed, slrDed);
}No analytics, no tracking, no data sent anywhere. Everything runs in your browser or on your device.
Every edge case — tapering personal allowances, Scottish rate bands, Plan 4 student loans — is tested against HMRC figures.
Expo Router means web, iOS, and Android share the same screens and the same calculation engine. No drift.
Every calculator state encodes into a URL. Send a link and the recipient sees your exact numbers — no account required.