National Minimum Wage Underpayment Calculator UK 2026/27 — Claim Back Pay from Your Employer
From April 2025, the National Living Wage is £12.71 per hour for workers aged 21 and over. If you are being paid less, your employer is breaking the law. HMRC enforces NMW and can order back pay for up to 6 years plus a penalty of up to 200% of arrears. This calculator works out exactly how much you are owed and how to claim it.
NMW rates April 2025: £12.71 (21+), £10.00 (18–20), £7.55 (16–17 & apprentice). Report to HMRC: 0300 123 1100 or gov.uk/national-minimum-wage-enquiries. HMRC investigates confidentially. Employment tribunal: 3-month time limit (ACAS early conciliation first). County court: 6-year limit. Tips don’t count toward NMW from April 2009.
NMW Rates 2026/27 — April 2025 Onwards
| Worker category | Hourly rate from April 2025 | Increase |
|---|---|---|
| National Living Wage (age 21+) | £12.71 | +6.7% from £11.44 |
| 18–20 year rate | £10.00 | +16.3% from £8.60 |
| 16–17 year rate | £7.55 | +18.0% from £6.40 |
| Apprentice rate | £7.55 | +18.0% from £6.40 |
The apprentice rate applies to apprentices aged under 19, or those in the first year of their apprenticeship. Once an apprentice is 19 or older AND past their first year, they move to the standard rate for their age.
Common Ways Employers Underpay NMW
- Salary sacrifice — if salary sacrifice schemes reduce pay below NMW, the employer must top up
- Uniform and equipment deductions — if the employer requires you to buy a uniform or tools for the job and the deduction takes you below NMW, it is unlawful
- Sleep-in shifts — the law on sleep-ins is complex; where workers are required to be at the workplace overnight, NMW may apply to the whole shift
- Unpaid training — mandatory training during working hours counts as working time
- Travel time — travel between work assignments (not commuting) counts as working time
- Sham self-employment — being labelled “self-employed” does not remove NMW entitlement if you are actually a worker
HMRC Enforcement — What Happens
HMRC’s National Minimum Wage team investigates underpayment complaints. Investigations are confidential — HMRC will not tell your employer who made the complaint. If HMRC finds underpayment, they can: issue a Notice of Underpayment requiring payment of arrears; impose a penalty of up to 200% of the arrears (minimum £100, maximum £20,000 per worker); and name and shame the employer publicly. HMRC also conducts proactive investigations of certain sectors known for NMW non-compliance.
How to Report Underpayment to HMRC
You can report suspected NMW underpayment to HMRC confidentially through the online complaint form on gov.uk, or by calling the ACAS helpline, who pass details on to HMRC on your behalf if you'd rather not contact HMRC directly yourself. You don't need to still be working for the employer to report — you can complain about underpayment from a previous job, and HMRC can pursue arrears going back as far as the underpayment occurred, since there's no time limit on HMRC enforcement action for NMW arrears (unlike bringing your own tribunal claim, which does have time limits). It's worth gathering as much evidence as you can before reporting — payslips, contracts, rotas, and any record of actual hours worked — since this speeds up HMRC's investigation and strengthens the case, though HMRC can also compel employers to produce their own records once an investigation begins.
Recovering Arrears Yourself Through a Tribunal Claim
As an alternative or addition to an HMRC complaint, you can bring your own claim to the employment tribunal for unlawful deduction from wages, or in some cases breach of contract, to recover NMW arrears directly. This route has a strict time limit — normally three months less one day from the underpayment (or the last in a series of underpayments), so it's much tighter than HMRC's unlimited enforcement window. Bringing your own tribunal claim can be faster than waiting for an HMRC investigation to conclude, particularly if HMRC's enforcement team has a significant backlog, but it does require you to actively prepare and present the case yourself (or with representation), rather than relying on HMRC to investigate and act on your behalf.
Frequently Asked Questions
Dismissal or detriment for asserting your NMW rights is automatically unfair from day one of employment (no 2-year qualifying period). This includes: dismissal for complaining about underpayment; being denied a pay rise because you complained; or being treated less favourably in any way. You can bring an automatically unfair dismissal claim to the employment tribunal regardless of how long you have worked for the employer. HMRC complaints are also confidential.
Yes. If you are salaried, HMRC divides your annual salary by your total working hours to calculate your effective hourly rate. If that rate falls below NMW for any pay reference period (usually monthly or weekly), your employer must pay the difference. Salaried workers who routinely work beyond their contracted hours can find their effective hourly rate falls below NMW if their salary is at the lower end. Use a time and pay diary to record all hours worked.
Apprentices are entitled to the specific Apprentice Rate (lower than the standard age-based rates) for the first year of their apprenticeship, or while they're under 19, whichever is longer — after that, they must receive the appropriate rate for their age. Unpaid internships are only lawful in narrow circumstances, such as genuine work shadowing with no set hours or duties, or specific student placements that are a required part of a course; if an intern is doing real work with set hours and responsibilities, they generally count as a "worker" and are entitled to at least NMW, regardless of whether their role is labelled an "internship."
Yes, but only if the deduction doesn't take your pay below NMW for that pay period. This is a common way employers unintentionally (or sometimes deliberately) fall foul of NMW rules — a deduction for a uniform, tools, or training costs that seems reasonable on paper can push an already low-paid worker's effective hourly rate below the legal minimum once accounted for, which is exactly the kind of "common way employers underpay" scenario HMRC actively investigates.