Pro-Rata Salary Calculator

Working part-time? Calculate your pro-rata salary based on the number of days you work compared to full-time.

Full-time equivalent salary

The salary for the role at full-time hours

Full-time days per week

Your days per week

Pro-rata result

Full-time gross

£30,000

Pro-rata gross

£18,000

Full-time net

£25,119.6

Pro-rata net

£16,479.6

Working 3 out of 5 days (60% FTE)

Your take-home pay

£16,480

per year

Income Tax£1,086

National Insurance£434

Take-Home£16,480

Gross salary£18,000

Income tax−£1,086

National Insurance−£434

Net take-home£16,480

Effective rate

8.4%

Marginal rate

28.0%

Pro rata means in proportion to the hours worked. A £40,000 full-time role at 37.5 hours a week becomes £24,000 for someone working three days, and the tax follows the lower figure rather than the headline one. That matters more than it sounds: the personal allowance is an annual amount per person, so a part-time salary below £12,570 pays no income tax at all and the effective rate on part-time work is lower than on the full-time equivalent. Holiday is pro-rated too, at 5.6 weeks of your own working week, which is 16.8 days for a three-day week rather than 28. Bank holidays count inside that entitlement unless the contract says otherwise, which is a common source of disagreement between employer and employee.

Written by Radif Partners

Publisher of calculators and practical guides · Finance Enthusiast

Updated for 2026/27 tax year

What Does Pro Rata Mean?

Pro rata is a Latin term meaning "in proportion." In the context of UK employment, a pro rata salary is the full-time equivalent salary adjusted for the number of hours you actually work. If a job is advertised as "£30,000 pro rata" for 3 days per week, your actual salary would be £18,000, three-fifths of the full-time amount.

Pro rata calculations apply to anyone working fewer hours than the full-time equivalent: part-time employees, job-sharers, term-time workers, and people who start or leave a job partway through the year. Understanding your pro rata salary helps you compare part-time roles with full-time opportunities and ensure you're being paid fairly for the hours you work.

How Pro Rata Salary Is Calculated

The formula is:

Pro rata salary = Full-time salary × (Part-time hours ÷ Full-time hours)

For example, if the full-time salary is £35,000 based on 37.5 hours per week, and you work 22.5 hours:

£35,000 × (22.5 ÷ 37.5) = £35,000 × 0.6 = £21,000

This is your actual gross annual salary. Tax, NI, and other deductions are then calculated on this figure, not on the full-time equivalent.

Worked Examples

Example 1: 3 Days Per Week at £28,000 FTE

Full-time salary	£28,000
Full-time hours	37.5 hrs/week
Part-time hours	22.5 hrs/week (3 days)
Pro rata salary	£16,800
Income tax	£846
National Insurance	£338
Take-home pay	£15,616
Monthly take-home	£1,301

Example 2: 4 Days Per Week at £45,000 FTE

Full-time salary	£45,000
Full-time hours	37.5 hrs/week
Part-time hours	30 hrs/week (4 days)
Pro rata salary	£36,000
Income tax	£4,686
National Insurance	£1,874
Take-home pay	£29,440
Monthly take-home	£2,453

By working 4 days instead of 5, you earn 80% of the salary but keep a higher proportion due to the progressive tax system. Your effective tax rate drops from 19.2% (at £45,000) to 18.2% (at £36,000).

Example 3: Term-Time Worker at £32,000 FTE

Term-time workers (common in schools) work during school terms only, typically 39 weeks per year plus 5.6 weeks holiday entitlement:

Full-time salary	£32,000
Weeks worked (term-time + holiday)	44.6 weeks
Full-time weeks	52 weeks
Pro rata salary	£27,446
Monthly take-home	£1,929

Term-time workers typically receive their salary spread across 12 months, even though they only work during term time. This makes budgeting easier but means the monthly figure is lower than it would be if paid only during working months.

Pro Rata and Tax Bands

One benefit of working part-time is that your pro rata salary may fall into a lower tax band than the full-time equivalent. This means you keep a higher percentage of each pound you earn:

FTE Salary	FTE Effective Rate	0.6 Pro Rata	Pro Rata Effective Rate	Saving
£30,000	16.3%	£18,000	8.8%	7.5pp
£50,000	21.0%	£30,000	16.3%	4.7pp
£80,000	28.8%	£48,000	20.5%	8.3pp
£110,000	34.0%	£66,000	25.7%	8.3pp

The savings are particularly significant when the pro rata salary drops below key thresholds like £50,270 (avoiding the 40% higher rate) or £100,000 (avoiding the personal allowance taper).

Part-Time vs Full-Time: Financial Comparison

When deciding between full-time and part-time work, the financial picture is more nuanced than the headline salary suggests:

Lower effective tax rate: As shown above, you keep a higher proportion of each pound earned.
Reduced childcare costs: If you're working part-time to reduce childcare, the savings can be substantial. Full-time nursery costs average £14,000–£20,000 per year. Working 3 days instead of 5 could save £5,600–£8,000.
Commuting costs: Fewer working days means fewer commutes. If your daily commute costs £15, working 3 days instead of 5 saves £1,560/year.
Pension impact: Your pension contributions and employer contributions are based on your actual (pro rata) salary, not the FTE. Going from £40,000 to £24,000 reduces employer pension contributions by £480/year (at 3%).
State Pension: As long as you earn above the Lower Earnings Limit (£6,708/year), your year still counts as a qualifying year for State Pension purposes.

Pro Rata Holiday Entitlement

UK employees are entitled to a minimum of 5.6 weeks of paid holiday per year (28 days for a 5-day worker). Part-time workers receive the same 5.6 weeks, but calculated on their working pattern:

Working Pattern	Holiday Days	Holiday Hours (7.5hrs/day)
5 days/week	28 days	210 hours
4 days/week	22.4 days	168 hours
3 days/week	16.8 days	126 hours
2.5 days/week	14 days	105 hours

Bank holidays are included in the statutory minimum. Your employer can choose to include or exclude them from your allocation. If your employer gives full-time staff 28 days plus bank holidays, your pro rata entitlement should include the same proportional bank holiday allowance.

Common Questions About Pro Rata Pay

Is the advertised salary always the full-time equivalent?

Usually, yes. When a job advert says "£35,000 pro rata," the £35,000 is the full-time salary. However, some adverts state the actual part-time salary. Check the job description carefully; it should specify the working hours and whether the figure is FTE or actual.

Do I get the same hourly rate as full-time colleagues?

Under the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000, you have the right to the same hourly rate as a comparable full-time worker doing the same job. You also have equal access to training, promotion, and benefits (on a pro rata basis).

How does pro rata work for mid-year starters?

If you start a full-time job partway through the tax year, your first year's pay is calculated pro rata based on the number of days or months worked. Your personal allowance still applies in full; it isn't pro-rated. This means your effective tax rate in a partial year is lower than in a full year, and you may receive a tax rebate.

Sources and Official References

For a complete overview of all tax rates this year, see our UK Tax Year 2026/27 guide.

A worked example: three days a week on a £40,000 role

A full-time role advertised at £40,000 for 37.5 hours a week is £20.51 an hour. Someone working three days of 7.5 hours works 22.5 hours a week, which is 60 per cent of full time, so the pro-rata salary is £24,000. Income tax and National Insurance are then charged on £24,000, not on £40,000, which leaves roughly £20,500 a year in hand in England.

The proportion matters more than the percentage suggests, because the personal allowance is a fixed annual amount. On £24,000 only £11,430 is taxable, so the effective tax rate is far lower than on the full-time salary. That is why two half-time jobs can leave more in hand than one full-time job of the same total, provided each stays above the National Insurance threshold and below the point where the allowance is exhausted.

Holiday follows the same logic. Statutory leave is 5.6 weeks of your own working week, so three days a week gives 16.8 days rather than 28, and bank holidays count inside that entitlement unless the contract says otherwise. Where hours vary week to week, entitlement is now accrued at 12.07 per cent of hours worked instead of a fixed number of days.

What part-time work does to pensions and benefits

Auto-enrolment into a workplace pension is triggered by earnings above a threshold in a single job, so two part-time jobs each below it enrol you in neither, even when the combined income would qualify comfortably. You can usually ask to join voluntarily, and where earnings are above the lower earnings limit the employer must contribute, which is worth the request.

The National Insurance record works the same way. A qualifying year towards the state pension requires earnings above the lower earnings limit in one employment, so fragmented part-time work can leave gaps in a record without the worker noticing for years. Checking the record on GOV.UK once a year, and filling gaps with voluntary contributions where it is worthwhile, is the safeguard.

Checking a pro-rata offer before accepting it

Three questions settle whether a part-time offer is fair. First, is the full-time equivalent stated, and does the pro-rata figure match the hours exactly? Second, does the holiday entitlement follow the same proportion, including bank holidays? Third, are benefits pro-rated or granted in full: private medical cover and life assurance are usually given in full, while bonuses and allowances are normally scaled.

Frequently Asked Questions

What does pro-rata mean?

Pro-rata means "in proportion". If a full-time salary is £30,000 for 5 days a week and you work 3 days, your pro-rata salary is £18,000 (3/5 of £30,000). It means in proportion: a part-time salary expressed as the full-time equivalent scaled to the hours worked. A £40,000 full-time role at three days a week is £24,000 pro rata, and the tax follows the lower figure.

How do I calculate pro-rata salary?

Multiply the full-time salary by (your days ÷ full-time days). For example: £40,000 × (3 ÷ 5) = £24,000. Divide the full-time salary by the full-time hours, then multiply by your own hours. For a £40,000 role at 37.5 hours, three days of 7.5 hours gives 22.5 hours and a pro-rata salary of £24,000.

Does pro-rata affect my tax?

Your pro-rata salary is taxed the same way as any other salary. You still get the full personal allowance. Your overall tax bill will be lower because you earn less. Only through the lower gross figure. The personal allowance and the bands are the same for everyone, so a part-time salary below £12,570 pays no income tax at all, and one just above it pays 20 per cent on the excess.

Do part-time workers get the same personal allowance?

Yes. The personal allowance is an annual figure per person, not per hour, so a part-time salary below £12,570 pays no income tax at all. That makes the effective tax rate on part-time work lower than on the full-time equivalent.

How is holiday calculated pro rata?

Statutory leave is 5.6 weeks of your normal working week, so someone working three days a week is entitled to 16.8 days rather than 28. Bank holidays are included in that figure unless the contract says otherwise. Where hours vary week to week, the entitlement is now worked out as 12.07 per cent of hours actually worked rather than as a fixed number of days.

Does part-time work affect my pension and NI record?

It can. Auto-enrolment applies above an earnings trigger, and National Insurance credits towards the state pension require earnings above the lower earnings limit, so a very small part-time salary may build neither unless you check. Two part-time jobs are assessed separately for both, so someone below the threshold in each can build neither entitlement despite a reasonable combined income.