UK Tax Code Calculator
Enter an HMRC-issued code to illustrate its effect on steady annual pay. Compare code-based tax with standard annual liability assumptions.
Rule year: 2026/27 · GBP · Sources checked
Annual PAYE-code Income Tax illustration
One steady-pay employment and supported issued code, ordinary income, Category A employee NI, no pensions, student loans, previous-pay reconciliation or tax-code eligibility decision. Emergency/non-cumulative W1/M1/X codes are rejected. Numeric-code allowance is illustrative and differs from HMRC cumulative payroll table rounding.
For informational purposes only. This estimate is not financial advice, a tax return, a payroll calculation or a lender decision. See the supported circumstances and exclusions below.
How this calculator works
HMRC issues a code for each employment or pension. This tool reads a supported numeric code as ten times its number, applies the corresponding regional bands, and shows flat-rate or K-code treatment where appropriate. S selects Scottish bands and C selects Wales; unprefixed codes use England/Northern Ireland rates. It keeps an issued allowance separate from the standard tax-liability allowance and does not automatically correct a code for high income. K codes add income, with a 50% deduction cap under the constant-pay illustration. Actual PAYE includes cumulative tax-free-pay tables, payroll rounding, code changes and previous pay; this is an annual illustration, not a payslip reproduction.
Formula and rules
Numeric code allowance illustration = code number × £10. Tax = regional band tax(max(0, annual pay − encoded allowance)). Flat codes use their specified rate. K-code addition = number × £10, with the steady-pay 50% deduction cap.
Assumptions and limitations
One steady-pay employment and supported issued code, ordinary income, Category A employee NI, no pensions, student loans, previous-pay reconciliation or tax-code eligibility decision. Emergency/non-cumulative W1/M1/X codes are rejected. Numeric-code allowance is illustrative and differs from HMRC cumulative payroll table rounding.
Worked example
At £30,000 annual pay, 1257L encodes an illustrative £12,570 allowance. £17,430 at 20% gives £3,486 annual code tax (£290.50 a month). BR taxes the same £30,000 at 20%, giving £6,000; actual payroll or final liability can differ.
- Annual PAYE-code Income Tax illustration
- £3,486.00
- Monthly Income Tax equivalent
- £290.50
- Difference from standard annual tax-liability model
- £0.00
- Annual cash after code tax and ordinary employee NI
- £25,119.60
Official sources and review
Reviewed against the sources below on 2026-10-07. Rates are held in versioned rule modules. Versioned rules, official source review and year-specific calculation tests.
- GOV.UK: employee tax-code letters ↗
Numeric allowances, UK/Scottish flat-rate codes, K-code adjustments and the 50% pay-period limit. W1/M1 codes are non-cumulative.
- GOV.UK: what tax-code numbers mean ↗
Multiply numeric code by ten to illustrate the tax-free amount; HMRC calculates and issues codes based on personal circumstances.
- HMRC: Rates and thresholds 2026 to 2027 ↗
Regional PAYE bands, Category A NI, student-loan plans and current minimum wage.
Common questions
Will this tell me which code HMRC should issue?
No. It interprets a supplied supported code. Benefits, other jobs, underpayments and eligibility affect the correct code; check HMRC's service for your own code.
Why reject emergency codes?
W1/M1/X treatment depends on each pay period rather than a full-year cumulative allowance. Exact previous pay and tax data are needed for a reliable payroll result.
Why can code tax differ from annual liability?
A code can collect earlier underpayments or reflect other income and benefits. It is a collection instruction, while final liability is reconciled using the complete tax position.