Why use this calculator
Unpaid wages is the most common employment claim in the United Kingdom and the one most often abandoned, usually because the worker is unsure how much they are owed, unsure whether it is worth pursuing, and completely unaware that a hard three-month deadline is running.
Employment tribunal claims for unlawful deduction from wages carry no fee, do not require a solicitor, and are frequently settled by the employer as soon as the claim form arrives. The obstacle is nearly always quantification. This calculator produces the total figure broken into the three heads a tribunal recognises, flags whether the rate itself breaches the minimum wage, which opens a second and quite separate route through HMRC, and tells you how much of the deadline remains.
How to use it
- Enter your gross hourly rate before tax as it appears on your contract or payslip.
- Add up the basic hours you worked but were not paid for across every affected pay period and enter the total, then do the same for unpaid overtime and set the multiplier your contract specifies.
- Enter any accrued holiday that was never taken and never paid out, along with the number of hours in your normal working day so each of those days can be valued.
- Finally, enter how many weeks have passed since the most recent payday on which you were underpaid, because that date rather than the first underpayment starts the three-month claim clock.
What each result means
- Total owed
- The gross sum to claim as an unlawful deduction from wages. Put this exact figure in the claim form and in any letter before action.
- Shortfall against the minimum wage
- How far your hourly rate falls below the National Minimum Wage for workers aged 21 and over. Every hour worked at a lower rate is owed the difference, separately from the unpaid hours, and HMRC can enforce it.
- Unpaid basic pay
- Contracted hours worked but never paid. This is the strongest part of most claims because the hours are usually evidenced by rotas or clock-in records.
- Unpaid overtime
- Extra hours at the contractual premium. If your contract is silent on the rate, overtime is usually payable at the plain hourly rate rather than a premium.
- Untaken holiday pay
- Accrued leave that was never taken. It must be paid on termination, and refusing to pay it is itself an unlawful deduction.
- Total hours unpaid
- Basic and overtime hours combined. Tribunals expect you to evidence these, so keep rotas, timesheets, messages and clock-in records.
- Time left to start Acas conciliation
- How long remains of the three-month limit, counted from the most recent underpayment. Once this expires the claim is usually lost however strong it is.
- Rate against the minimum wage
- Whether your hourly rate breaches the National Minimum Wage. If it does, HMRC can recover arrears for you and fine the employer, with no time limit of this kind.
The formula
Unpaid basic pay = unpaid hours x gross hourly rate
Unpaid overtime = overtime hours x hourly rate x the contractual multiplier
Untaken holiday pay = days owed x hours in a normal day x hourly rate
Total owed is the three added together. The claim deadline is three months less one day from the most recent underpayment, treated here as 13.04 weeks, and a series of linked deductions can be claimed back as one, subject to a two-year backstop. The rate is compared against the National Minimum Wage of £12.71 an hour for workers aged 21 and over.
How this number is used in practice
There are two independent routes and most workers only know about one. An unlawful deduction from wages claim goes to the employment tribunal, is free to bring, and must be started through Acas early conciliation within three months less one day of the last underpayment.
Separately, if the shortfall takes your effective hourly rate below the National Minimum Wage, you can report the employer to HMRC, which investigates, orders repayment of arrears at current rates, and can impose a penalty of up to two hundred per cent of the underpayment.
The HMRC route has no three-month cut-off and costs you nothing, so where the rate itself is unlawful it is often worth using both.
Where the underpayments form a series, you can claim the whole series as one, with time running from the most recent deduction rather than the first. That is what lets a worker recover months of small shortfalls in a single claim. Since the deduction from wages rules were amended, however, a series claim cannot reach back more than two years from the date of the claim, so very long-running underpayments are partly lost.
A gap of more than three months between deductions can also break the series, leaving the earlier ones out of time.
Holiday pay deserves separate attention because it is so commonly calculated wrongly rather than simply withheld. Workers with variable hours or regular overtime should have holiday pay based on average earnings over the previous fifty-two paid weeks, not on basic contractual hours, so anyone who regularly works overtime and is paid only their basic rate while on leave has been underpaid every time they took a holiday. That shortfall is recoverable through exactly the same unlawful deduction route.
Worked examples
60 unpaid hours at £14, 12 overtime hours at time and a half, and 4 untaken holiday days
Total of £1,540 made up of £840 basic, £252 overtime and £448 holiday pay
A worker paid £11.50 an hour for 100 hours with no holiday owed
£1,150 owed, and the rate is flagged as below the £12.71 minimum wage, which is a separate HMRC matter
The same claim where the last underpayment was 20 weeks ago
The result shows the deadline has passed, since three months is roughly 13 weeks
When people use it
- Quantifying a claim before contacting Acas about unpaid wages
- Checking a final payslip after leaving a job for missing holiday pay
- Workers on variable hours checking whether their rate has fallen below the minimum wage
- Preparing a letter before action to an employer that has missed a payroll run
- Employers auditing payroll after a systems error to work out what to repay
Tips
- The three-month clock runs from the most recent underpayment, not the first, so a continuing series buys you time on the earlier shortfalls.
- Employment tribunal claims for unpaid wages are free and need no solicitor. Many employers settle as soon as the claim form lands.
- If your effective rate is below the minimum wage, report it to HMRC as well. That route has no three-month deadline and carries penalties for the employer.
- Keep rotas, timesheets, clock-in records and any messages about shifts. Without evidence of hours worked the claim becomes your word against theirs.
- Holiday pay for anyone with regular overtime should use a 52-week average of actual earnings, not basic pay, so check past holidays too.
- It is unlawful for an employer to punish you for claiming unpaid wages. Dismissal for asserting a statutory right is automatically unfair with no qualifying service.
What it assumes, and where it stops being accurate
- Figures are gross, before income tax and National Insurance, which is how a tribunal award is expressed.
- Assumes the contractual overtime multiplier you enter is correct. There is no statutory right to a premium rate for overtime in the UK.
- Holiday is valued at basic hourly pay. Workers with regular overtime or commission are entitled to holiday pay based on a 52-week average, which is higher.
- The three-month limit is approximated as 13.04 weeks from the most recent underpayment; the precise rule is three months less one day.
- A series of deductions is assumed to be unbroken. A gap of more than three months between underpayments can break the series and put earlier ones out of time.
- Series claims cannot reach back more than 2 years from the date the claim is presented.
Terms used on this page
- Unlawful deduction from wages
- Any shortfall between wages properly payable and wages paid, without legal or written contractual authority.
- Series of deductions
- Linked underpayments claimable together, with time running from the most recent one.
- National Minimum Wage
- The legal hourly floor, £12.71 for workers aged 21 and over from April 2026.
- Acas early conciliation
- The free, mandatory step before filing a tribunal claim, which also pauses the time limit.
- Holiday pay reference period
- The 52 paid weeks averaged to set holiday pay for workers with variable earnings.
Questions people ask
- What is an unlawful deduction from wages?
- Any shortfall between the wages properly payable to you and what you actually received, unless the deduction is required by law, permitted by your contract in writing, or agreed in advance. Simply failing to pay for hours worked is the commonest form, and it is dealt with by the employment tribunal.
- How long do I have to claim unpaid wages?
- You must start Acas early conciliation within three months less one day of the last underpayment. Where deductions form an unbroken series, time runs from the most recent one, though a series claim cannot reach back further than two years from the date of the claim.
- Does it cost anything to bring a claim?
- No. There are no employment tribunal fees, and unpaid wages claims are straightforward enough that many people bring them without a solicitor. Acas early conciliation is free and often resolves the matter without a hearing, since the employer can see the sum is owed.
- What if I was paid below the minimum wage?
- That is a separate breach with its own enforcement route. Report it to HMRC, which can investigate, order the employer to repay arrears calculated at current rates, and impose a penalty of up to two hundred per cent of the underpayment. This route has no three-month deadline.
- Am I entitled to overtime pay?
- There is no statutory right to a premium rate for overtime in the UK. What you are owed depends on your contract, so if it promises time and a half then that is enforceable. Your average pay across all hours must still not fall below the National Minimum Wage.
- Can I be dismissed for claiming unpaid wages?
- Dismissing or penalising a worker for asserting a statutory right such as the right to be paid is automatically unfair, and it needs no qualifying period of service. If it happens you gain a second and considerably more valuable claim alongside the wages claim itself.
Use this with
Unpaid Wages Claim Calculator answers one part of the question. These pick up where it stops: Notice Period Pay Calculator, Unfair Dismissal Compensation Calculator, Statutory Redundancy Pay Calculator and Employment Tribunal Cost Estimator.
Where these figures come from
Figures and rules on this page follow United Kingdom law.
- GOV.UK: Redundancy: your rights. Week's pay cap of £751 and the £22,530 maximum
- Acas: Dismissals. Fair procedure, the Acas Code of Practice and the 25% uplift
- Employment Rights Act 1996, Part X and XI. Statutory basis for unfair dismissal, redundancy pay and notice
- GOV.UK: National Minimum Wage and National Living Wage rates. Current hourly rates by age band and how to report an underpayment
- Acas: Holiday pay. Accrual, the 52-week reference period and payment on termination
Unpaid Wages Claim Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.