We Switch Payroll
The exact engine, made visible

Every payslip, worked out in the open.

Enter a wage for the period you actually run — weekly, monthly or yearly — and see the full 2026/27 calculation, line by line: income tax bands, National Insurance thresholds, student loan, pension, net pay and the true cost to the employer. The same engine that runs real payroll, checked against 612 HMRC-verified test vectors. Nothing hidden.

The employee & the pay period

Pay period matches a weekly payroll run
£
Off
Yes

One free calculation per company. Give us a company number and a work email and you get the same engine that runs real payroll — every band, threshold and rounding step shown. Your company number, work email, phone number and name, and the figures you type in, are sent to our server and stored against your company — what we do with them.

Take-home this week
£499.68
£25,983 a year
Total deductions
£100.32
16.7% of gross
Cost to employer
£675.58
£35,130 a year

The working — how every figure is calculated LIVE

The other calculators

Auto-enrolmentWho must be enrolled, and for how much CIS deductions20%, 30% or gross
612
HMRC-verified test vectors, all green — tax, NI, statutory pay, auto-enrolment, year-end
9
tax-code families: L/M/N, BR, D0, D1, 0T, K, NT + Scottish S-codes
weekly
monthly, 4-weekly, yearly — real per-period thresholds, not an annual guess
gov.uk
rates sourced to "Rates and thresholds for employers 2026 to 2027"

How to read this. Every deduction shows its full working from the 2026/27 rate tables — the free pay for the period, the tax bands the taxable pay falls into, the NI thresholds, the loan and pension bands — so a payroll professional can reconcile it line for line against their own run. Figures use the standard non-cumulative (period) basis for a steady wage.  Scope. Mid-year starters with year-to-date figures, company directors (annual-earnings basis), benefits beyond the tax code, and live RTI submission to HMRC are handled by the full We Switch Payroll application. This is a calculation tool, not tax advice — edge cases go to a qualified accountant.  Why it's different. Most calculators give a number. This one shows the arithmetic and the employer's true cost — because it's the same engine built to run the payroll.

This is one payslip. What about the whole run?

The engine above is the same one that runs real payroll — it just stops at a single period. The full application carries the bits a calculator can't: year-to-date figures, directors on the annual-earnings basis, auto-enrolment assessment, payslips, and RTI.

Run it yourself → We Switch Payroll Have someone run it → We Switch Payroll

The calculator is free, but it is not anonymous and it is not local. It has no engine in your browser: pressing Calculate sends the figures you typed to our server, and you are asked for your company number, work email, phone number and name before it will run. Those details and your figures are stored against your company, and the free-run meter is keyed on your email address across every one of our calculators. How we handle that.