Overtime rates on invoices: time and a quarter, time and a half, double time
Enhanced rates for overtime and weekends are common in construction, logistics, events and agency work. Here's what the terms mean, how to calculate them from your day or hourly rate, and how to show them clearly on an invoice.
On this page
What the terms mean
| Term | Multiplier | On a £20 base hourly rate |
|---|---|---|
| Flat / standard time | × 1.00 | £20.00 |
| Time and a quarter | × 1.25 | £25.00 |
| Time and a third | × 1.333… | £26.67 |
| Time and a half | × 1.50 | £30.00 |
| Double time | × 2.00 | £40.00 |
A common pattern is weekday overtime and Saturdays at time and a quarter, Sundays at time and a half, and bank holidays at double time. But there's no single UK standard.
Is there a legal right to an overtime rate?
For employees, GOV.UK says there's no legal right to be paid for overtime at a higher rate. Overtime pay depends on the employment contract, as long as average pay doesn't fall below the National Minimum Wage. For the self-employed and limited company contractors, overtime and weekend rates are purely commercial: they're whatever you agree with your client or agency. So:
- Get the enhanced rates in writing before you start: in the contract, the agency's assignment schedule, or an email confirmation.
- Agree what counts as overtime. Is it hours over 8 a day, over 40 a week, or any time after 5pm?
- Agree how weekends are treated. Is every Saturday hour enhanced, or only hours over a threshold?
Working it out from a day rate
Most trades and contractors think in day rates. To get enhanced rates, convert the day rate to an hourly rate first (see day rate to hourly rate), then apply the multiplier:
- Hourly rate = day rate ÷ standard hours per day
- Overtime rate = hourly rate × overtime multiplier
Example: a £165 day rate for an 8-hour day.
| Calculation | Exact | Shown on invoice | |
|---|---|---|---|
| Hourly | £165 ÷ 8 | £20.625 | £20.63 |
| Overtime / Saturday (× 1.25) | £20.625 × 1.25 | £25.78125 | £25.78 |
| Sunday (× 1.5) | £20.625 × 1.5 | £30.9375 | £30.94 |
The rounding trap (and how to avoid it)
The example above shows why rounding matters. If you round £20.625 to £20.63 first and then multiply by 8, you get £165.04, which is 4p more than your agreed day rate. Do this on every line of a monthly invoice and the client's accounts team may query it. Round the hourly rate down to £20.62 and you're underpaid. The fix is simple:
- Calculate amounts from the exact rate (£20.625 × 8 = £165.00 exactly).
- Show the unit rate rounded to 2 decimal places for readability.
- Round only the line total to the penny.
Two overtime hours at £25.78125 come to £51.5625, which rounds to £51.56. If you'd rounded the rate first (£25.78 × 2), you'd also get £51.56 here, but over many lines the differences add up. Agree with your client which method you'll use if they have a preference.
Showing overtime clearly on the invoice
There are two tidy ways to lay it out.
Option A: one row per day, with an overtime column, which works well for weekly timesheets:
| Day & date | Rate | Hours | OT hrs | Amount |
|---|---|---|---|---|
| Monday 5th October | £20.63 | 8 | 2 | £216.56 |
| Saturday 10th October | £25.78 | 6 | – | £154.69 |
| Sunday 11th October | £30.94 | 3 | – | £92.81 |
Then add a note under the table stating the overtime rate, e.g. "Overtime charged at £25.78/hr (time and a quarter)".
Option B: separate overtime lines, one for normal hours and one for overtime per day (e.g. "Monday – normal 8 hrs @ £20.63" and "Monday – overtime 2 hrs @ £25.78"). It's longer, but some agencies' systems expect it.
Whichever you choose, the hours must match the approved timesheet, and the rates must match what you agreed.
Weekend rates vs weekday overtime
On Saturdays and Sundays the enhanced rate usually applies to all hours worked that day, not just hours beyond a threshold. So a 6-hour Saturday at time and a quarter is 6 × £25.78125 = £154.69, and a 3-hour Sunday at time and a half is 3 × £30.9375 = £92.81. If your agreement says weekend hours are only enhanced after a certain number, show the split explicitly.
Bank holidays and nights
Bank holiday and night-shift rates follow the same logic: base hourly rate × agreed multiplier. Because they're less common, add a short description on the line ("Bank holiday – double time") so whoever checks the invoice doesn't have to guess.
Quick checklist
- Rates agreed in writing, including what triggers overtime.
- Hourly rate derived from your day rate using the agreed standard hours.
- Amounts calculated from exact rates; only line totals rounded.
- Overtime and weekend lines clearly labelled.
- Hours match the approved timesheet.
Frequently asked questions
What is time and a quarter?
Your normal hourly rate multiplied by 1.25. On £20 an hour, that's £25 an hour.
What is time and a half?
Your normal hourly rate multiplied by 1.5. On £20 an hour, that's £30 an hour.
Am I legally entitled to overtime pay?
GOV.UK says employees have no legal right to an enhanced overtime rate; it depends on the contract (and pay can't fall below the National Minimum Wage). For the self-employed, overtime rates are whatever you agree with the client.
How do I work out overtime from a day rate?
Divide the day rate by your standard hours to get the hourly rate, then multiply by the overtime multiplier. For example, £165 ÷ 8 × 1.25 = £25.78 per hour (rounded).
Why doesn't 8 × £20.63 equal my £165 day rate?
Because £20.63 is a rounded figure. Calculate from the exact hourly rate (£20.625) and only round the final line amount.
Sources
This guide is general information, not legal, tax or financial advice. Rules and rates change, so check the linked GOV.UK pages for the current position.