How UK Benefits in Kind affect your tax code

By PaySlipCheck Editorial · Reviewed by PaySlipCheck Editorial Standards Team · 14 June 2026 · 5 min read

UK Benefits in Kind (BiK) are collected via a tax-code adjustment. If your annual BiK total is £1,200 (e.g., private medical insurance), HMRC reduces your personal allowance from £12,570 to £11,370, and your tax code drops from 1257L to 1137L. This means slightly more Income Tax is deducted from each monthly payslip, spreading the £480 higher-rate tax across the year. This guide explains the mechanics + how to verify your code is correct.

Verified against 7 official sources · Last reviewed 14 June 2026
On this page
  1. The mechanic
  2. Common BiK-adjusted tax codes
  3. Confirming your BiK amount
  4. What if BiK changes mid-year
  5. The end-of-year reconciliation
  6. Payrolled benefits eliminate the code adjustment
  7. In short

The mechanic

  1. Employer reports total BiK on P11D (or payrolled real-time)
  2. HMRC calculates equivalent cash value
  3. Personal allowance reduced by that amount
  4. Tax code numeric portion drops

Common BiK-adjusted tax codes

For a basic 1257L starting code:

BiK total New allowance New tax code
£600 (basic PMI) £11,970 1197L
£1,200 (PMI + gym) £11,370 1137L
£2,400 (PMI + company car small EV) £10,170 1017L
£12,600 (petrol car) £0 (starts at 0T) 0T

Confirming your BiK amount

Check your tax code: - Payslip: shows current code - Online: gov.uk/personal-tax-account - Compare to your latest P11D or expected BiK

If the code doesn't match expected BiK: - Verify P11D figures are correct - Contact employer to fix any errors - Contact HMRC to correct if HMRC's estimate is wrong

What if BiK changes mid-year

  • Bought/sold company car during year: HMRC updates tax code
  • Started/stopped PMI: HMRC updates code
  • Employer notifies HMRC of changes; you should also confirm

The end-of-year reconciliation

  • After each tax year, HMRC reconciles actual BiK vs code
  • If under-taxed: bill for the difference (or spread across next year)
  • If over-taxed: refund

Payrolled benefits eliminate the code adjustment

  • Employer takes BiK tax at source via PAYE
  • No tax-code adjustment needed
  • Cleaner but requires employer setup

In short

UK BiK adjusts your tax code by reducing your personal allowance by the BiK cash value. Check your code against expected BiK — errors are common. Payrolled benefits eliminate the code adjustment.

Frequently asked questions

How does BiK reduce my tax code?

HMRC subtracts the BiK cash value from your personal allowance. £1,200 BiK → allowance drops by £1,200 → tax code drops by 120.

What if my tax code is wrong?

Contact HMRC via personal tax account. Employer can also correct if P11D was submitted with wrong values.

Does BiK affect my NI?

Employees no — you don't pay NI on BiK. Employers pay Class 1A NI at 13.8%.

Can BiK make me pay more than 40% tax on some of my income?

Yes — a large company car BiK on a mid-earner can push slice into higher rate. Watch band boundary.

What's the difference between P11D and payrolled benefits?

P11D reports BiK annually + adjusts tax code retrospectively. Payrolled benefits take tax through PAYE in real-time. Payrolled is cleaner.

Related calculators

Related guides

  • Tax code with BiK — Benefits in kind (company car, private medical, beneficial loans,
  • How to read a payslip — A UK payslip has up to 20+ separate lines, each with a specific
  • Tax code 1257L — Tax code 1257L is the standard UK tax code for 2026/27. The 1257
  • Salary sacrifice — Salary sacrifice is the most tax-efficient UK pension contribution
  • Is sacrifice worth it? — Salary sacrifice is typically a strong win for higher-rate
  • What is a P11D — The UK P11D form is submitted annually by employers to HMRC reporting all Benefits in Kind provided to employees. You get a copy showing your total BiK for the tax year. HMRC uses this to adjust your tax code and collect BiK tax.
  • UK tax codes — A complete UK tax code reference for 2026/27. Covers every letter and
  • No payslip — Missing payslip = breach of Employment Rights Act 1996 s8. Remedies: informal → grievance → ACAS → tribunal.

More on related topics

  • Childcare vouchers — UK childcare vouchers closed to new joiners in October 2018 — existing users can continue. Tax-Free Childcare replaced it (£2,000/child/year government top-up). This guide covers both + which is better for your situation.
  • Company car tax — UK company car BiK tax is calculated as list price × emission-band % × your marginal Income Tax rate. Electric cars sit at 3% BiK for 2026/27 (rising 1% per year), making them exceptionally tax-efficient. This guide covers the maths + when a company car beats a car allowance.
  • Company car vs allowance — UK company car is better than cash car allowance for electric vehicles (3% BiK) at higher-rate tax. Cash allowance is better for petrol/diesel cars at higher-rate. This guide covers the specific numbers.

Related salary breakdowns

Glossary terms used on this page

Quick definitions for the key terms above.

  • Personal allowance — The amount you can earn each tax year before paying any UK Income Tax — £12,570 in 2026/27, frozen until April 2031.

Sources

All figures on this page are sourced from official UK government publications. We don't cite secondary commentary or other calculator sites.

  1. GOV.UK — Employer-provided benefits (Expenses and benefits)
  2. GOV.UK — P11D form
  3. GOV.UK — Income Tax rates
  4. MoneyHelper — Employee benefits
  5. HMRC — CWG2 employer's guide to PAYE and NICs
  6. GOV.UK — Understanding your payslip
  7. HMRC — Income Tax rates and allowances

All tax figures on this page use the same configuration that powers our calculators — see our editorial standards for the review process.

Last reviewed: 14 June 2026. Next review due 14 December 2026.

Disclaimer: This page provides general information based on published HMRC and gov.scot figures. It is not personal tax or financial advice. For your specific situation, please consult a qualified accountant or contact HMRC directly.