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What Is a Pro Rata Salary?
A pro rata salary is a full-time salary scaled down to reflect the hours or weeks you actually work. The term comes from Latin, meaning in proportion. If a role pays £35,000 full-time and you work three days out of five, your pro rata salary is £21,000 — exactly 60% of the full-time figure.
The same principle applies in every country. Whether you are on a part-time contract in the UK, a reduced-hours role in the US, a term-time position in a school, or a job that started mid-year, the calculation works the same way: your pay reflects your actual working time as a proportion of the full-time standard.
Where people go wrong is when two ratios apply at once — reduced hours and a partial year. Both adjustments multiply together, not add. This calculator handles both automatically.
How to Use This Calculator
Step 1 — Select Your Currency
GBP is set by default. Switch to USD, EUR, AUD, CAD, NZD or ZAR using the currency buttons above the calculator.
Step 2 — Enter Your FTE Annual Salary
This is the full-time equivalent salary — the figure your contract or offer letter states before any pro rata adjustment. It is the benchmark for the calculation.
Step 3 — Enter Standard Full-Time Hours
This is where most calculation errors happen. Do not assume a standard figure:
- UK office and professional roles: typically 37 or 37.5 hours per week
- NHS and public sector: usually 37.5
- US roles: most commonly 40 hours per week
- Education and some public sector roles: sometimes expressed differently — check your contract
Using the wrong denominator changes every figure in the result. When in doubt, ask your HR department to confirm.
Step 4 — Choose Hours or Days Mode
If your contract specifies hours per week, use Hours mode. If it specifies days per week — common in education, some government roles, and flexible working arrangements — switch to Days mode.
Step 5 — Enter Your Actual Hours or Days
Your contracted hours or days per week. Not what you sometimes work — what your contract specifies.
Step 6 — Add Part-Year Details (If Applicable)
Enable the Part-Year / Term-Time toggle if you work fewer than 52 weeks per year. Enter your working weeks and the total weeks in the year (almost always 52). This covers:
- School and university support staff on term-time contracts
- Seasonal workers
- Employees who started partway through the employer’s leave year
- Anyone returning from a career break mid-year
Step 7 — Calculate
Your pro rata annual salary appears immediately, along with a full breakdown by month, week, day, and hour — plus the exact calculation used so you can verify it.
The Pro Rata Formula Explained
Hours-Based Calculation
Pro Rata Salary = FTE Salary × (Your Hours per Week ÷ Standard Full-Time Hours)
Example — UK part-time office worker:
FTE salary £40,000 · Standard hours 37.5 · Your hours 25
25 ÷ 37.5 = 0.667 → £40,000 × 0.667 = £26,667 pro rata annual salary
Example — US part-time employee:
FTE salary $75,000 · Standard hours 40 · Your hours 30
30 ÷ 40 = 0.75 → $75,000 × 0.75 = $56,250 pro rata annual salary
Days-Based Calculation
Pro Rata Salary = FTE Salary × (Your Days per Week ÷ Standard Full-Time Days)
Working 3 days out of 5 on a £45,000 FTE salary:
3 ÷ 5 = 0.60 → £45,000 × 0.60 = £27,000 pro rata annual salary
Adding a Part-Year Adjustment
Pro Rata Salary = FTE Salary × (Your Hours ÷ FTE Hours) × (Your Working Weeks ÷ 52)
Example — UK term-time teaching assistant:
FTE salary £28,000 · Full-time hours 37.5 · Your hours 37.5 · Term weeks 39
Hours ratio: 1.0 · Year ratio: 39 ÷ 52 = 0.75
£28,000 × 1.0 × 0.75 = £21,000 pro rata annual salary
Example — US employee starting mid-year:
FTE salary $90,000 · Starting 1 July · 26 weeks remaining in calendar year
Year ratio: 26 ÷ 52 = 0.50
$90,000 × 1.0 × 0.50 = $45,000 first-year pro rata salary
Pro Rata Pay — Country-Specific Notes
United Kingdom
UK employment law gives part-time workers the right to pay and benefits on a pro rata basis relative to comparable full-time colleagues. This covers basic salary, annual leave, pension contributions, and contractual sick pay. The UK Government’s guidance on part-time worker rights confirms that less favourable treatment without objective justification is unlawful.
Annual leave for UK part-time workers is based on the statutory minimum of 5.6 weeks, pro rated to actual working days. A worker doing 3 days per week is entitled to 5.6 × 3 = 16.8 days per year.
United States
In the US, pro rata salary calculations follow the same mathematical principle. The key variable is the employer’s defined full-time standard — most commonly 40 hours per week, though some organisations use 37.5. Select USD from the currency bar and enter 40 (or your employer’s standard) in the full-time hours field.
US employers are not federally required to provide pro rata benefits to part-time workers at the same level as full-time staff, though many do. Salary, however, should always reflect actual hours worked against the defined full-time standard.
Australia, Canada, and Other Countries
The same formula applies. Select your currency, enter the full-time hours standard for your employer and country, and the calculator produces the correct result. For Australian awards and enterprise agreements, full-time hours vary by sector — check the relevant Modern Award or your contract.
What Pro Rata Pay Covers Beyond Basic Salary
Annual Leave
Part-time workers receive pro rata annual leave. In the UK, the 5.6-week statutory minimum is calculated against actual working days. In the US, employer-provided leave policies typically pro rate accrual based on hours worked. Use our pro rata holiday calculator to work out your exact entitlement.
Pension Contributions
Employer pension contributions calculated as a percentage of salary scale automatically with your pro rata pay. If your employer contributes 5% of salary, that 5% applies to your pro rata figure — not the FTE amount. Use our pro rata take home pay calculator to estimate net pay after deductions.
Sick Pay
Statutory Sick Pay in the UK applies equally to part-time workers meeting the earnings threshold. Contractual sick pay should be pro rated to match the proportion of full-time work.
Bonus and Profit Share
Contractual bonuses and profit-sharing arrangements should be pro rated. Discretionary bonuses may not be — always check the wording of your contract. A contract that says “up to X% of salary” typically means the pro rata salary, not the FTE figure.
Common Mistakes and How to Avoid Them
Assuming 40 Hours as the UK Standard
Using 40 hours as the denominator for a UK role where the standard is 37.5 understates your entitlement. On a £42,000 FTE salary at 25 actual hours, the difference between a 37.5-hour and 40-hour denominator is over £1,750 per year. Always confirm the figure in your contract.
Using Calendar Days for Partial-Year Calculations
Partial-year calculations should use working weeks or working days — not calendar days. Dividing by 365 significantly reduces the ratio and understates your entitlement. Use 52 weeks or 260 working days (Mon–Fri) as the annual baseline unless your contract specifies otherwise.
Treating Two Adjustments as Additive
A part-time employee who starts mid-year faces two adjustments: a reduced-hours ratio and a partial-year ratio. Adding them produces a different result from multiplying them. The correct approach is multiplication — both ratios compound. This calculator applies the correct method automatically.
Not Checking the Contract Before Accepting a Salary
If an offer letter states £50,000 FTE and you will work 3 days per week term-time only, your actual annual pay may be considerably lower than the headline figure suggests. Always run the calculation before accepting.
Frequently Asked Questions
What does pro rata salary mean?
Pro rata salary means your pay is scaled proportionally to the hours or weeks you actually work compared to the full-time full-year standard. It is not a reduction in hourly rate — the hourly value stays the same. It is simply the correct annual total for your actual working time. See our pro rata calculator for a full explanation.
How do I calculate my pro rata salary manually?
Divide your actual hours per week by the full-time standard hours to get a ratio, then multiply the FTE salary by that ratio. If you also work part of the year, multiply by a second ratio: your working weeks divided by 52. Full formula: FTE Salary × (Actual Hours ÷ FTE Hours) × (Working Weeks ÷ 52).
What is the standard full-time hours figure to use?
It depends on your employer and country. UK office roles: typically 37 or 37.5. NHS: 37.5. US: most commonly 40. Retail and hospitality: sometimes 39 or 40. Your employment contract is the only authoritative source.
Is pro rata the same as part-time pay?
Essentially yes. Part-time pay is one application of the pro rata principle. The same calculation also covers mid-year starts, term-time contracts, and any other scenario where total working time falls below the full-time full-year baseline.
Can I use this for a UK pro rata salary?
Yes. GBP is the default currency. Enter 37 or 37.5 as the full-time hours standard (check your contract). The calculator applies UK-standard calculations including the part-year adjustment for term-time workers.
Can I use this for a US pro rata salary?
Yes. Select USD from the currency bar and enter 40 as the standard full-time hours (or your employer’s defined standard). The formula is identical regardless of country — only the currency symbol and full-time hours figure change.
How is term-time salary calculated?
FTE Salary × (Term Weeks ÷ 52). A school support worker on £26,000 FTE working 39 term-time weeks receives £26,000 × (39 ÷ 52) = £19,500. If the role is also part-time during term, the hours ratio applies first. Use the Part-Year toggle in this calculator to handle both adjustments automatically. See also our dedicated pro rata term-time salary calculator.
Does pro rata salary include holiday entitlement?
The salary figure itself does not include a separate holiday element — annual leave entitlement is calculated separately on a pro rata basis. For UK workers, the statutory minimum is 5.6 weeks pro rated to actual working days. Use our pro rata holiday calculator to work out the exact figure.
What is the difference between pro rata salary and hourly rate?
Pro rata salary is your adjusted annual pay for part-time or part-year working. Hourly rate is the amount earned per hour. Dividing your pro rata annual salary by your total annual hours gives your effective hourly rate. Use our pro rata hourly rate calculator to convert between the two.
My employer calculated a different figure — what should I do?
Ask HR to provide the exact formula used. Common reasons for discrepancies include different full-time hours denominators, different annual working-week or working-day baselines, and different treatment of bank holidays. If the difference is significant, the Acas guidance on pay calculations is a useful reference for UK workers.