Estimated annual pro-rata gross salary
£0.00
Enter your full-time salary and weekly hours to calculate.
Breakdown
Monthly gross pay:
Weekly gross pay:
Equivalent hourly gross rate:
Percentage of full-time hours:
Annual pay difference from full-time:
Compare weekly hours
Annual gross pay by weekly hours
iThe graph could not load. Your figures are available in the table below.
| Arrangement | Hours/week | Full-time hours (%) | Annual gross pay | Monthly gross pay | Equivalent hourly gross rate |
|---|
Estimates proportional gross pay for regular weekly hours throughout a full year. Monthly pay assumes 12 equal payments. Weekly pay uses annual pay divided by 52. The equivalent hourly gross rate uses the full-time annual salary divided by 52 and then by full-time weekly hours. Excludes tax, National Insurance, pensions and other deductions.
How pro-rata salary is calculated
A part-time job advert may show a full-time annual salary followed by “pro rata”. Your actual salary depends on the proportion of the full-time hours you will work.
This calculator divides your weekly hours by the full-time weekly hours, then multiplies the full-time annual gross salary by that proportion. Gross pay means pay before deductions.
Enter the full-time salary, the weekly hours that salary covers, and your proposed weekly hours. Use the full-time hours stated in the advert or contract rather than assuming every employer uses the same working week.
Actual annual salary = full-time annual salary × your weekly hours ÷ full-time weekly hours.
Worked example: £36,000 full-time salary at 25 hours
Suppose an advert quotes £36,000 a year for a 37.5-hour full-time week, and you plan to work 25 hours each week.
Your hours represent 25 ÷ 37.5 of the full-time week. Multiplying £36,000 by that fraction gives an actual annual gross salary of £24,000.
| Full-time annual gross salary | £36,000 |
|---|---|
| Full-time hours per week | 37.5 |
| Your hours per week | 25 |
| Percentage of full-time hours | 66.67% |
| Actual annual gross salary | £24,000 |
| Monthly gross pay | £2,000 |
| Weekly gross pay | £461.54 |
| Equivalent hourly gross rate | £18.46 |
| Annual pay difference from full-time | £12,000 less |
The calculation uses the hours ratio before rounding. The displayed percentage is rounded for readability; the annual pay is not calculated from the rounded percentage.
Full-time equivalent, pro-rata pay and actual salary
Full-time equivalent salary
The full-time equivalent salary is the annual gross salary for the role’s full-time working hours. It provides the reference figure from which a proportional part-time salary can be calculated.
Pro-rata pay
Pro rata means in proportion. For this calculator, that proportion is your weekly hours divided by the full-time weekly hours. Working half the full-time hours produces half the full-time annual salary, assuming the same pay rate.
Actual annual salary
Your actual annual salary is the amount you would receive before deductions for your agreed working arrangement over a full year. Once you know this figure, the Salary Calculator can convert it into other pay-period and hourly equivalents.
What does “£36,000 pro rata” mean?
It does not mean every part-time employee receives £36,000. If £36,000 is the full-time equivalent salary, the amount payable is adjusted to reflect the agreed hours.
With a 37.5-hour full-time week, 18.75 hours would produce £18,000 a year, while 30 hours would produce £28,800. Both calculations use the same £36,000 full-time reference.
Check whether the advert quotes a full-time equivalent salary or an actual part-time salary. If the salary has already been adjusted for your hours, applying the pro-rata calculation again would reduce it incorrectly.
Comparing different weekly hours
Use the two + buttons to add up to two alternative weekly-hours arrangements. Every arrangement uses the same full-time salary and full-time weekly hours.
The horizontal graph includes a full-time reference alongside your hours and valid comparisons. Each bar shows annual gross pay from a zero baseline. Hover or tap a bar to see its weekly hours, percentage of full-time hours, annual and monthly gross pay, and equivalent hourly gross rate.
The table below the graph provides the exact displayed figures. An incomplete or invalid comparison stays available to edit but is excluded from the graph and table.
Gross pay and take-home pay
Pro-rata gross salary is calculated before Income Tax, National Insurance, pension contributions and other deductions. The monthly gross figure is therefore not the amount you should expect in your bank account.
Use your calculated actual annual gross salary in the Take Home Pay Calculator to estimate pay after applicable deductions. The Income Tax Calculator can help you explore Income Tax separately.
For household planning, use an appropriate take-home income figure in the Budget Calculator.
Assumptions and limits
This calculator assumes the same regular weekly hours and proportional pay rate throughout a full year. Monthly gross pay assumes the annual salary is divided into 12 equal payments.
Weekly gross pay is annual gross pay divided by 52. The equivalent hourly gross rate is the full-time annual salary divided by 52 and by full-time weekly hours. It remains the same across arrangements, including when your proposed hours are zero.
- Use weekly hours measured on the same basis for every arrangement.
- Exclude unpaid breaks consistently from the hours you enter.
- Decimal hours are supported: 37 hours 30 minutes is 37.5 hours.
- Zero salary and zero proposed hours produce mathematically valid zero-pay results.
- Full-time weekly hours must be greater than zero.
- Negative figures and weekly hours above 168 are not accepted.
You can enter proposed hours above the full-time baseline. The estimate then assumes every additional hour is paid at the same proportional rate. It does not calculate overtime premiums or establish what your employer must pay.
The 168-hour input ceiling is a mathematical limit based on the number of hours in a week. It is not guidance on permitted or suitable working hours.
The calculator does not calculate term-time salaries, partial-year earnings, irregular-hours pay, furlough pay, bonuses, allowances, holiday entitlement or deductions. Those arrangements may require additional information and a different calculation.
Important note
This tool provides a proportional gross-pay estimate for comparison. Confirm the full-time reference, contracted hours and actual salary with the employer before relying on the result. It does not check minimum-wage compliance or provide employment, tax or financial advice.
Frequently Asked Questions
How do I calculate a pro-rata salary?
Multiply the full-time annual gross salary by your weekly hours, then divide by the full-time weekly hours. For example, £36,000 × 25 ÷ 37.5 = £24,000 a year before deductions.
What does 60% of full-time hours mean?
It means you work 60% of the full-time working week. If full-time hours are 37.5 per week, this is 22.5 hours. At a £36,000 full-time salary, the proportional annual gross salary would be £21,600.
Is pro-rata salary my take-home pay?
No. This calculator shows gross pay before deductions. Use the Take Home Pay Calculator with your actual annual gross salary to estimate take-home pay.
Should I enter the advertised salary or my actual part-time salary?
Enter the salary for the full-time hours. If an advert already gives the actual salary for your part-time hours, do not reduce it again. Confirm unclear wording with the employer.
Can I compare working three days with four days?
Yes. Convert each arrangement into weekly paid hours and add a comparison. Use hours rather than days because working days can have different lengths.
Can I enter decimal hours?
Yes. Enter hours as decimal numbers rather than hours and minutes. For example, 22 hours 45 minutes is 22.75 hours.
Why is monthly gross pay annual salary divided by 12?
The monthly estimate assumes 12 equal salary payments. It does not represent a four-weekly payment or calculate an individual payslip. Your employer’s pay schedule and rounding may produce differences.
Can I calculate a term-time or part-year salary?
No. This tool adjusts for weekly hours only. Term-time and part-year arrangements may also depend on paid weeks, holiday pay and contract terms. Do not treat this full-year estimate as your actual earnings for those arrangements.
What happens if I enter more hours than the full-time baseline?
The calculator shows a proportional estimate above 100% of full-time pay and clearly states the same-rate assumption. Overtime premiums, allowances and contractual rules are not included.
Sources and review
The proportional-pay method and supporting information were reviewed in October 2026.
Official guidance explaining part-time work and proportional pay is available from:
- GOV.UK — Part-time workers’ rights
- Acas — Part-time workers’ rights and pro-rata pay
- nidirect — Part-time work in Northern Ireland
These references provide employment context. Your estimate uses the salary and hours you enter; the calculator does not determine contractual entitlements.