If you’re paid by the hour but want to know what that works out to over a year, working out your pro rata salary from hourly rate is simpler than it looks. Plenty of part-time workers in the UK are paid an hourly figure — retail assistants, care workers, cleaners, hospitality staff — yet job adverts, mortgage applications and benefit calculations usually talk in annual salaries. This guide walks you through the exact formula, with worked examples in pounds, so you can convert any hourly rate into its annual pro-rata equivalent with confidence.
The basic formula
The calculation has three moving parts: your hourly rate, the number of hours you work each week, and the number of paid weeks in the year. The formula is:
Annual pro rata salary = hourly rate × hours per week × paid weeks per year
In the UK, most salaried calculations assume 52 paid weeks per year, because statutory holiday entitlement is paid — you’re paid for your holidays, so they count. If you’re on a term-time-only contract or an arrangement with unpaid weeks, you’d use a lower figure (more on that later).
So the whole job is multiplication. The only place people tend to slip up is forgetting the “paid weeks” part and multiplying by 52 when they actually have unpaid time off, or vice versa. Get those three numbers right and the answer follows.
If you’d rather skip the maths, our free pro rata salary calculator does this conversion instantly — but it’s worth understanding the method so you can sanity-check any figure an employer gives you.
Worked example 1: £12.50 per hour, 22.5 hours a week
Let’s take a realistic example. Priya works as a healthcare assistant in Manchester. She’s paid £12.50 per hour and works three days a week, 7.5 hours a day — 22.5 hours in total. Her contract includes paid holidays, so we use 52 weeks.
Step by step:
- Weekly pay: £12.50 × 22.5 hours = £281.25 per week
- Annual salary: £281.25 × 52 weeks = £14,625 per year
So Priya’s pro rata salary is £14,625 a year. Notice how this compares with a full-time colleague on the same hourly rate working 37.5 hours: £12.50 × 37.5 × 52 = £24,375. Priya works 60% of full-time hours (22.5 ÷ 37.5), and £14,625 is exactly 60% of £24,375. That’s the whole idea of pro rata — “in proportion”.
A useful cross-check: divide your weekly hours by full-time weekly hours to get your proportion, then apply it to the full-time annual figure. If both routes give the same answer, your maths is right.
Worked example 2: £15.80 per hour, 30 hours a week
Now a slightly different pattern. Daniel works in a warehouse outside Birmingham, paid £15.80 an hour including a small shift premium. He works 30 hours a week across four days.
- Weekly pay: £15.80 × 30 = £474.00 per week
- Annual salary: £474.00 × 52 = £24,648 per year
Daniel’s full-time equivalent on the same rate would be £15.80 × 37.5 × 52 = £30,810. He works 80% of full-time hours, and £24,648 is 80% of £30,810. Again, the proportion holds.
One thing to watch: if your hourly rate already includes extras like shift premiums or location allowances, the annual figure you calculate is your total — don’t add the premium on top again. Always check your payslip or contract to see what’s baked into the hourly figure.
Quick-reference table: common hourly rates
The table below shows annual pro rata salaries for popular hourly rates at common part-time patterns, assuming 52 paid weeks. Find your rate and hours for a fast estimate — though for an exact figure tailored to your situation, the free pro rata salary calculator on our homepage handles any combination.
| Hourly rate | 16 hrs/week | 22.5 hrs/week | 30 hrs/week | 37.5 hrs/week (full-time) |
|---|---|---|---|---|
| £11.44 (NMW 21+) | £9,519 | £13,395 | £17,860 | £22,308 |
| £12.50 | £10,400 | £14,625 | £19,500 | £24,375 |
| £13.00 | £10,816 | £15,210 | £20,280 | £25,350 |
| £15.00 | £12,480 | £17,550 | £23,400 | £29,250 |
| £18.00 | £14,976 | £21,060 | £28,080 | £35,100 |
| £20.00 | £16,640 | £23,400 | £31,200 | £39,000 |
NMW = National Minimum Wage rate shown for reference; rates change each April, so check the current figure.
What if you have unpaid weeks?
Not everyone is paid for 52 weeks. Term-time-only school staff, for example, are typically paid for around 39–44 weeks depending on how their employer structures it. Seasonal workers may have unpaid gaps too.
The formula doesn’t change — you just swap 52 for your actual paid weeks:
Annual salary = hourly rate × hours per week × your paid weeks
Example: a lunchtime supervisor paid £12.00 an hour, working 10 hours a week during 39 term-time weeks: £12.00 × 10 × 39 = £4,680 per year. Many schools then spread that evenly across 12 monthly payments (£390 a month), so don’t be confused if your monthly payslip doesn’t match a simple weekly × 4.33 calculation — the annual total is what matters.
If you’re unsure how many paid weeks your contract covers, ask your employer or check your written statement of employment particulars. It’s one of the most common sources of pay confusion for term-time staff.
Common mistakes to avoid
Mixing up gross and net. The figure you calculate is gross — before Income Tax, National Insurance, pension contributions and student loan deductions. Your take-home pay will be lower. Never compare a gross annual figure with your bank balance and assume an error.
Using 52 weeks when you have unpaid leave. As above, term-time and seasonal workers must use their actual paid weeks.
Forgetting the hourly rate might change. If you get a pay rise mid-year, your annual figure is a blend: months at the old rate plus months at the new rate. Don’t just multiply the new rate by 52 and assume that’s what you’ll receive this year.
Comparing hourly rates without checking what’s included. One employer’s £13.50 an hour might include holiday pay rolled up (common for zero-hours contracts), while another’s £12.80 might be plus separate paid holidays. The rolled-up rate looks higher but may not be — always compare like with like.
Rounding too early. Keep the pence in your intermediate steps and round only the final answer. Rounding weekly pay to the nearest pound before multiplying by 52 can throw the annual figure off by £50 or more.
How job adverts use pro rata figures
You’ll often see part-time roles advertised with a pro rata salary rather than an hourly rate — for example, “£26,000 pro rata, 25 hours per week”. To work out what you’d actually earn, reverse the calculation: divide the advertised figure by full-time hours, then multiply by your hours.
Take that £26,000 example, assuming full-time is 37.5 hours and you’d work 25:
- Hourly equivalent: £26,000 ÷ 52 weeks ÷ 37.5 hours = £13.33 per hour
- Your annual pay: £13.33 × 25 hours × 52 weeks = £17,333 per year
Or more directly: £26,000 × (25 ÷ 37.5) = £17,333. Same answer, fewer steps.
Watch out for adverts that say “£26,000 (pro rata)” without stating the full-time hours — a £26,000 pro rata figure means very different take-home pay against a 35-hour full-time week versus a 40-hour one. If the advert doesn’t say, ask before you apply. It’s also worth confirming whether the quoted figure is the full-time equivalent or the actual part-time pay; reputable employers state “pro rata” explicitly when it’s the full-time figure, but not all do, and the distinction is worth tens of thousands over a year.
Frequently asked questions
How do I convert my hourly wage to a pro rata annual salary?
Multiply your hourly rate by your weekly hours, then multiply that weekly figure by your number of paid weeks per year (usually 52 in the UK). For example, £12.50 × 22.5 hours × 52 weeks = £14,625 per year. That’s your gross pro rata salary.
Is pro rata salary the same as part-time salary?
Essentially, yes — “pro rata” is the method, “part-time” is the working pattern. A pro rata salary is a full-time salary scaled down in proportion to the hours you work. If someone says a role pays “£24,000 pro rata”, they mean £24,000 is the full-time figure and you’ll get the proportion matching your hours.
Do I use 52 weeks if I’m paid monthly?
Yes, in most cases. Being paid monthly is just how the annual total is divided up (annual ÷ 12). The 52 weeks represents that your holidays are paid. Only use fewer weeks if your contract genuinely has unpaid weeks, such as term-time-only arrangements.
Why does my employer’s figure differ slightly from my calculation?
Small differences usually come from rounding, or from the employer using 52.14 or 52.18 weeks (365 ÷ 7) instead of exactly 52 for extra precision. Larger gaps are worth querying — ask for a breakdown showing the hourly rate, weekly hours and weeks used.
Check your figure in seconds
Now you know the method, but for speed — or to double-check an employer’s number — try our free pro rata salary calculator. Enter your hourly rate and weekly hours and it works out your annual, monthly, weekly and daily equivalents instantly, with the full working shown so you can see exactly how the figure was reached.