Proving your hours : calculate what you are owed

• Employers must keep sufficient records to show NMW was paid for every pay reference period, and (from records created or still required from 1 April 2021) keep them for at least 6 years.
• If you have reasonable grounds to believe you were underpaid, you can make a written request to see your NMW records. The employer must usually produce them within 14 days (or an agreed later date). Refusal can lead to a tribunal award of 80 × the hourly NMW rate.
• Payslips must be given on or before payday and must show hours when pay varies with time worked. Rotas, messages, till logs and your own diary fill holes when the slip is thin.
• In a civil NMW claim the employer must prove payment; you still win more easily with a dated pack that matches pay reference periods.
• Route: check figures, raise with employer, then Acas (and Early Conciliation before most tribunal claims). For the same NMW underpayment you generally choose HMRC or tribunal, not both.
• Dual tribunal limits: 3 months minus 1 day as at September 2026; 6 months minus 1 day if the limitation clock starts on or after 1 October 2026.

GOV.UK enforcing the minimum wage is blunt: you (the employer) are legally required to keep sufficient records to show you are meeting minimum wage requirements. Records can be paper or digital, but the employer must be able to produce the picture for an individual worker and pay reference period in a single document on request.

There is no fixed checklist labelled "sufficient" for every business. GOV.UK recommends clear breakdowns of working time and pay rates across each period. Practical items it flags include:

• total pay paid
• hours actually worked, broken down where needed (contact time, travel between appointments, waiting time)
• overtime and enhanced rates
• allowances, tips treatment, accommodation offsets
• absences (rest breaks, sick leave, holidays)
• travel or training during work hours
• contracts, agreements, dates of birth
• deductions and payments connected with the employment

Failing to keep or preserve NMW records, falsifying them, or obstructing HMRC officers can be a criminal offence. Separately, weak records leave the employer exposed in any civil dispute because they carry the burden of proof.

Retention: from 1 April 2021, employers must keep NMW records for a minimum of 6 years after the end of the pay reference period following the one the records cover. Older three-year rules were replaced for records still required at that date. Civil claims can reach back years; thin archives hurt the employer more than the worker.

If you reasonably believe you may not have been paid NMW, you can request access in writing to the employer's records relating to you. GOV.UK:

• production within 14 days of the request, or within a longer period you agree
• you may inspect, examine and copy them, and bring someone with you if you said so in the request
• records must be produced at the place of work or another place you can reasonably attend (or that is agreed)

If the employer refuses or fails to produce the records, you can complain to an employment tribunal. If the tribunal upholds the complaint it will award 80 times the hourly rate of the minimum wage. From April 2026, for a worker aged 21+, that illustrative award unit is 80 × £12.71 = £1,016.80 (plus the underlying underpayment claim if you bring one). For under 18, 80 × £8.00 = £640.

Keep a dated copy of your request and any reply. Email is enough; a recorded delivery letter helps if relations are hostile.

GOV.UK payslips: employers must give employees and workers a payslip on or before payday (with limited exceptions such as some police and share fishermen). The slip must show:

• earnings before and after deductions
• variable deductions (for example tax and National Insurance)
• the number of hours you worked if your pay varies depending on time worked

Fixed deductions can be explained on the slip or in a separate written statement issued before the first payslip and updated yearly.

Acas unpaid-wages guidance tells you to check the payslip, the written statement / contract, how you are paid, the period covered, how many hours you worked, any timesheet approval rules, and whether rates change for overtime or nights. If the slip shows 18 hours and your rota plus messages show 22, that mismatch is exhibit A.

GBP example: You are 32. Weekly time work. Slip shows 35 hours × £12.80 = £448. Your diary and closing texts show 38 hours actually worked. £448 ÷ 38 ≈ £11.79, below £12.71. Floor on 38 hours: 38 × £12.71 = £482.98. Shortfall ≈ £34.98 that week. The slip's hour figure is useful precisely because it is wrong: it proves what payroll paid for, while your pack proves what was worked.

Aim for one folder (digital is fine) ordered by pay reference period:

1. Contract / written statement stating pay, hours and payday.
2. All payslips for the disputed months (PDF exports or clear photos).
3. Rotas and every amended rota (screenshot before the app deletes history).
4. Clock or timesheet exports, including rejected overtime lines.
5. Contemporaneous diary: start, finish, unpaid tasks, who told you to stay.
6. Messages: "can you close?", "come in early for delivery", shift-swap chats.
7. Corroboration: till Z-reads, alarm logs, delivery notes, door-entry stamps, colleague statements if they are willing.
8. Holiday and absence records so nobody claims you were off when you were in.
9. GOV.UK minimum wage calculator printouts or screenshots for each period.
10. Running spreadsheet: date, hours claimed by employer, hours you say, pay received, shortfall vs £12.71 / £10.85 / £8.00 as applicable.

Do not alter originals. If you annotate, keep a clean copy. HMRC and tribunals care about contemporaneous detail more than perfect prose.

GOV.UK: NMW can be enforced by HMRC compliance officers or by you in a tribunal or court. If you take your own tribunal claim for the underpayment, HMRC will no longer investigate or act on your behalf for that same issue. Choose deliberately.

HMRC officers can require production of records, enter premises at reasonable times, interview, and remove records for copying. They may issue a notice of underpayment requiring arrears and a penalty (up to 200% of arrears, capped per worker, with a possible 50% reduction for fast compliance). You can also complain about suspected underpayment via Acas (0300 123 1100) or online routes pointed to from GOV.UK pay-and-work-rights pages.

Arrears HMRC calculates can use a formula that uplifts historical underpayments by reference to current rates for the age band that applied at the time. That is separate from how a tribunal awards unpaid wages. Get advice if the pattern spans years.

Acas: by law employers must pay wages on the agreed payday. If pay is missing or wrong, work out what you are owed, check the payslip and written statement, then raise the issue with the employer. Practical ladder:

1. Informal written query with your pack attached (or summarised).
2. Formal grievance if needed. Grievance does not pause tribunal time limits.
3. Notify Acas for Early Conciliation before most employment tribunal claims.
4. Issue the claim in time after the Early Conciliation certificate.

Dual regime: most unpaid-wages / similar claims use 3 months minus 1 day as at September 2026. From 1 October 2026, most become 6 months minus 1 day if the limitation clock starts on or after that date. For a series of deductions, presentation time is usually counted from the most recent wrong deduction (ERA 1996 section 23 / Acas framing), subject to that dual length rule. Notify Acas inside the limit so the clock can pause through conciliation.

GBP timing sketch: Wrong payday Friday 4 September 2026. Under the current-length rule, 3 months minus 1 day points to notifying Acas by about 3 December 2026 (check the exact calendar day; weekends and bank holidays need care). If instead the claim's clock starts on or after 1 October 2026, the longer 6 months minus 1 day length applies. Do not gamble on memory: diary the deadline the day you spot the shortfall.

• "They will have CCTV so I do not need notes." Footage is often overwritten. Your diary and messages survive.
• "Verbal promise to fix next month." Get it in writing. Time limits keep running.
• "I deleted the rota app screenshots." Export early. Apps tidy history.
• "HMRC and tribunal at once for the same NMW pot." GOV.UK says choosing your own tribunal route means HMRC stops acting on that underpayment for you.
• "I'll wait until the busy season ends." Dual tribunal limits do not wait for trading patterns.

Evidence packs fail when hours and pounds are fuzzy. Paye Mes Heures helps you turn rotas, diaries and payslip hour totals into a period-by-period shortfall against £12.71 (or the correct youth rate) before you write to payroll or start Acas Early Conciliation. Use it to prepare figures. It is not a substitute for official advice or a ruling.

• https://www.gov.uk/guidance/calculating-the-minimum-wage/enforcing-the-minimum-wage
• https://www.gov.uk/payslips
• https://www.acas.org.uk/if-your-wages-are-not-paid
• https://www.gov.uk/national-minimum-wage-rates
• https://www.acas.org.uk/early-conciliation
• https://www.acas.org.uk/employment-tribunal-time-limits
• https://www.gov.uk/pay-and-work-rights