Understanding how your pay changes when you work fewer hours is important before accepting a part-time role or changing your schedule. A pro rata salary shows the amount you earn compared with the full-time salary for the same position. The calculation is based on your contracted hours or days and the full-time working pattern. You can use a pro rata salary calculator
to check your expected pay quickly.
What Is a Pro Rata Salary?
A pro rata salary is the amount paid to an employee who works fewer hours or days than a full-time employee. It is calculated as a proportion of the full-time salary.
For example, if a full-time employee earns £40,000 per year for 40 hours per week and you work 20 hours, you work half of the full-time schedule.
The calculation is:
£40,000 × 20 ÷ 40 = £20,000
Your annual salary would be £20,000 before tax and other deductions.
The same principle can be used when your working pattern is based on days instead of hours.
How Does a Pro Rata Salary Calculator Work?
A Pro Rata Salary Calculator uses the full-time salary and working hours to estimate your part-time earnings.
The basic formula is:
Pro Rata Salary = Full-Time Salary × Part-Time Hours ÷ Full-Time Hours
For example, assume:
- Full-time salary: £35,000
- Full-time hours: 35 hours per week
- Your hours: 21 hours per week
The calculation is:
£35,000 × 21 ÷ 35 = £21,000
Your estimated annual salary would be £21,000.
This calculation works when your pay is directly proportional to your contracted working hours.
How to Calculate Pro Rata Salary
To calculate your salary manually, you only need a few figures.
First, find the annual full-time salary. Next, check the number of hours a full-time employee works each week. Then identify your own contracted hours.
For example, a full-time role pays £42,000 for 40 hours per week. You work 30 hours.
Calculate the percentage:
30 ÷ 40 × 100 = 75%
You work 75% of the full-time schedule.
Now calculate your salary:
£42,000 × 75% = £31,500
Your annual gross salary is £31,500.
This method gives you a direct answer without requiring a complicated calculation.
Pro Rata Salary Based on Working Days
Some employees work a fixed number of days instead of using weekly hours. In this situation, you can calculate your salary using the number of working days.
Suppose the full-time salary is £30,000 and the full-time schedule is five days per week. If you work three days, your working proportion is 60%.
The calculation is:
£30,000 × 3 ÷ 5 = £18,000
Your estimated annual salary is £18,000.
Use the working pattern stated in your employment contract. If your daily hours are different, calculating by hours may give a more accurate result.
How to Calculate Monthly Pro Rata Pay
After finding your annual salary, you can estimate your monthly gross pay by dividing the annual amount by 12.
For example:
Annual salary: £24,000
£24,000 ÷ 12 = £2,000
Your estimated monthly gross salary is £2,000.
This amount is before deductions. Your actual take-home pay can be lower because of Income Tax, National Insurance, pension contributions, student loan payments, or other deductions that apply to you.
A monthly calculation is useful when comparing your expected salary with your regular household income.
What Is Full-Time Equivalent Salary?
Full-Time Equivalent, usually called FTE, is the salary or working arrangement used as the full-time reference.
For example, if a company lists a role as £40,000 for 40 hours per week, £40,000 is the full-time equivalent salary.
If you work 20 hours, your working level is 0.5 FTE.
If you work 30 hours, it is 0.75 FTE.
If you work 32 hours, it is 0.8 FTE.
Using FTE makes it easier to compare salaries when employees have different working schedules.
Pro Rata Salary for Part-Time Employees
Part-time employees generally receive salary based on their proportion of full-time work. The exact amount depends on the full-time salary and the hours or days included in the contract.
For example, a full-time employee earns £36,000 for 36 hours per week. A part-time employee works 18 hours.
Because 18 hours is half of 36 hours, the salary is:
£36,000 × 18 ÷ 36 = £18,000
The employee would receive an estimated annual gross salary of £18,000.
If the employee changes from 18 to 27 hours, the proportion becomes 75%.
The salary would then be:
£36,000 × 27 ÷ 36 = £27,000
This shows how changing contracted hours can change gross annual pay.
Pro Rata Salary UK
When calculating a pro rata salary UK figure, check the full-time salary and contractual working pattern first. You can use proratacalculators to quickly check your figures and compare different working arrangements.
For example, a UK employer advertises a position with a full-time salary of £32,000 for 40 hours per week. You agree to work 24 hours.
Your working percentage is:
24 ÷ 40 × 100 = 60%
Your annual salary is:
£32,000 × 60% = £19,200
Your estimated monthly gross pay is:
£19,200 ÷ 12 = £1,600
This calculation gives you the gross salary. It does not calculate your final take-home pay.
Does Pro Rata Salary Include Holiday?
Salary and holiday entitlement are separate calculations, although both can be affected by your working pattern.
Part-time employees are generally entitled to paid holiday. The way entitlement is calculated depends on whether you work regular hours, irregular hours, or part of the year.
For a regular part-time employee, holiday entitlement is usually related to the number of days or hours worked.
For example, someone working three days per week may have holiday entitlement based on those three working days rather than the five days worked by a full-time employee.
Do not use your salary percentage alone to calculate holiday entitlement unless the relevant calculation method supports it.
What Is a Part-Month Salary?
A part-month salary is pay for only part of a monthly payroll period. This can happen when you start a new job after the month has begun or leave before the month ends.
For example, if your monthly salary is £2,400 and you work only part of your first month, your employer needs to calculate the amount payable for that period.
The exact calculation can depend on the employer’s payroll method, contract, working days, or hours.
Therefore, working for half a month does not always mean you will automatically receive exactly half of your monthly salary.
When Should You Use a Pro Rata Salary Calculator?
A calculator can help when you need to compare different working arrangements or check an advertised salary.
You may use it when:
- Moving from full-time to part-time work
- Comparing part-time job offers
- Changing your weekly hours
- Working fewer days per week
- Estimating annual gross salary
- Estimating monthly gross salary
For a simple fixed-hours contract, you normally need the full-time salary, full-time hours, and your own contracted hours.
Example: Calculate Your Part-Time Salary
Suppose a full-time role pays £45,000 for 37.5 hours per week. You work 25 hours.
First calculate your working proportion:
25 ÷ 37.5 = 0.6667
You work approximately 66.67% of the full-time schedule.
Now calculate your salary:
£45,000 × 0.6667 = approximately £30,000
Your estimated annual gross salary is £30,000.
To estimate monthly gross pay:
£30,000 ÷ 12 = £2,500
This example assumes that the salary is directly proportional to contracted hours.
What Information Do You Need?
To calculate a pro rata salary, collect these details:
- Full-time annual salary
- Full-time weekly hours
- Your weekly hours
- Full-time working days, if relevant
- Your working days, if relevant
Once you have these figures, the calculation is usually straightforward.
If your contract includes overtime, bonuses, allowances, commission, or irregular working hours, your final earnings may require a separate calculation.
Final Thoughts
A pro rata salary shows how much you earn compared with the full-time salary for the same role. The simplest calculation is based on your contracted hours and the standard full-time hours.
Use this formula:
Full-Time Salary × Part-Time Hours ÷ Full-Time Hours
For example, £40,000 at 20 hours compared with 40 full-time hours gives an annual salary of £20,000.
A Pro Rata Salary Calculator can make these calculations faster and help you compare different working schedules. Remember that the result is normally gross pay, so your actual take-home amount may be lower after applicable deductions.
1. What does pro rata salary mean?
It means your salary is calculated in proportion to the full-time salary based on your working hours or days.
2. How do I calculate pro rata salary?
Multiply the full-time salary by your contracted hours and divide by the full-time hours.
3. Can I calculate salary by days?
Yes. Compare your working days with the full-time working days and apply that percentage to the full-time salary.
4. Is pro rata salary the same as take-home pay?
No. Pro rata salary is normally the gross amount before tax and other payroll deductions.
5. Can I calculate monthly pro rata pay?
Yes. Calculate your annual salary first, then divide it by 12 to estimate monthly gross pay.
