Rota Calculator
Calculate salary for shift patterns and rota-based schedules
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Rota Calculator: Pro Rata Pay for Shift Workers
This rota calculator computes earnings for UK workers on rotating shift patterns. Whether you work a 4-on-4-off, continental, or 3-shift rotation, the calculator determines your average weekly hours and converts them to an equivalent annual salary for comparison with 9-to-5 roles.
Shift workers face unique pay calculation challenges: their weekly hours fluctuate, they may receive shift premiums for unsocial hours, and their holiday entitlement needs to be calculated differently from standard day workers.
Common UK Shift Patterns
| Pattern | Cycle Length | Avg Hours/Week | Annual Hrs |
|---|---|---|---|
| 4 on, 4 off (12h shifts) | 8 days | 42 | 2,184 |
| Continental (3-shift) | 28 days | 42 | 2,184 |
| 3 on, 3 off (12h shifts) | 6 days | 42 | 2,184 |
| 5 days, 2 off (8h shifts) | 7 days | 40 | 2,080 |
| Panama (2-2-3) | 28 days | 42 | 2,184 |
Shift Pay and Pro Rata Adjustments
Many shift workers receive a shift premium (typically 15-33% extra for nights, 25-50% for weekends). This premium is separate from the base hourly rate and should be considered when comparing job offers. An apparently lower base salary with generous shift premiums may actually pay more than a higher base without premiums.
For converting your rota earnings to an equivalent standard pro rata salary, use the pro rata calculator. For overtime on top of your shift pattern, try our overtime calculator. To check your rota meets Working Time Regulations (including 11-hour daily rest and 48-hour weekly average), verify your FTE equivalent.
How to Use the Rota Calculator
Using our rota calculator is straightforward. Follow these steps to get accurate results for your situation:
- Enter your full-time salary — This is the annual salary for the equivalent full-time role, before any deductions. You'll find this on the job advert or your contract.
- Set the full-time hours — The standard working week for the role. Most UK employers use 37.5 or 40 hours per week.
- Enter your actual hours — Your contracted weekly hours. This is the number you actually work.
- Click Calculate — The rota calculator displays your results instantly, with annual, monthly, weekly, daily, and hourly breakdowns.
Worked Example: Rota-Based Pro Rata
A security guard on a 4-on-4-off rota pattern works 12-hour shifts. Full-time equivalent is 37.5 hours across 52 weeks, and the FTE salary is £26,000.
Average weekly hours: (4 × 12) ÷ 8 days × 7 = 42 hours — but spread across a rolling pattern
Annualised hours: 4 shifts × 12 hours × (365 ÷ 8) = 2,190 hours per year
FTE comparison: 37.5 × 52 = 1,950 hours — so the rota worker does 2,190 ÷ 1,950 = 1.123 FTE
This means the rota worker should earn £26,000 × 1.123 = £29,198 to maintain pay parity. Use the rota calculator above to check your own rota pattern.
Tips for Using This Calculator
- Always use gross salary: Enter the salary before tax and deductions — the rota calculator works with gross figures.
- Check your contract: Your employment contract should state your full-time equivalent hours. Common UK standards are 35, 37, 37.5, and 40 hours per week.
- Know your rights: Under the Part-time Workers Regulations 2000, part-time employees must receive the same hourly rate, holiday entitlement (pro rata), and benefits as full-time colleagues.
- Tax personal allowance: For 2025/26, the first £12,570 of earnings is tax-free. If your pro rata salary falls below this, you pay no income tax at all.
- National Insurance: Employee NI is 8% on earnings between £12,570 and £50,270 (2025/26 rates). Check HMRC NI rates for the latest figures.
Pro Rata Holiday Entitlement
Under the Working Time Regulations 1998, all UK workers are entitled to a minimum of 5.6 weeks' paid holiday per year (28 days for full-time). If you work part-time, your entitlement is calculated pro rata based on your actual hours or days worked.
| Days Worked/Week | FTE Ratio | Statutory Days/Year | Bank Holidays (pro rata) |
|---|---|---|---|
| 5 days (full-time) | 1.0 | 28 days | 8 days |
| 4 days/week | 0.8 | 22.4 days | 6.4 days |
| 3 days/week | 0.6 | 16.8 days | 4.8 days |
| 2.5 days/week | 0.5 | 14 days | 4 days |
| 2 days/week | 0.4 | 11.2 days | 3.2 days |
Holiday entitlement is always rounded up — never down — when the result is not a whole number, per ACAS guidance on holiday entitlement. Bank holidays may be included in or added on top of your statutory 28 days, depending on your contract.
All calculations on this page follow ACAS pro rata pay guidelines and are consistent with the UK Employment Rights Act 1996. Tax figures use HMRC 2025/26 rates. The April 2025 National Living Wage of £12.21/hour is applied where relevant.
Related Salary Calculators
Our rota calculator is just one of the tools available on ProRataCalculator. You may also find these useful: pro rata calculator, term-time salary calculator, overtime calculator.
Last updated: February 2026. Verified against HMRC 2025/26 tax rates and April 2025 National Living Wage (£12.21/hour).
Frequently Asked Questions
To calculate rota-based salary, determine the average hours worked per week across the full rota cycle, then calculate pro rata from the full-time equivalent salary using those average hours.
A 4-on-4-off pattern means 4 days working followed by 4 days off. Over a year, this averages approximately 182 working days, compared to 260 for a standard 5-day week.
Holiday is calculated based on average hours/shifts worked. For rota workers, this is often calculated in hours rather than days to ensure accurate entitlement.
Not necessarily. Many rota workers are contracted for full-time or even above-average hours. The key difference is the pattern of work, not the total hours.