How to Calculate Part Time Salary in the UK 2026

What Counts as Part-Time Work in the UK?

Let’s start with the basics. In the UK, there’s no legal definition specifying exactly what makes someone a part-time worker. The distinction is surprisingly simple: if you work fewer hours than someone in a comparable full-time position, you’re part-time.

Typically, full-time workers in the UK work between 35-40 hours per week. Anything below this range usually qualifies as part-time work, but the exact threshold can vary by employer and industry.

Common Part-Time Working Patterns

Part-time work comes in many forms, and understanding your specific pattern is crucial for calculating your salary accurately:

• Regular reduced hours: Working fewer days per week (e.g., three days instead of five)
• Shorter daily hours: Working full days but fewer hours each day (e.g., 9am-2pm instead of 9am-5pm)
• Term-time only: Common in education, working during school terms but not holidays
• Job share arrangements: Two people splitting one full-time role
• Variable hours: Hours that change week to week based on business needs

Part-Time vs. Zero-Hours Contracts

It’s worth clarifying the difference. Part-time workers typically have a set number of contracted hours each week or month. Zero-hours contract workers have no guaranteed hours, though they may work regularly. The salary calculation methods differ significantly between these arrangements.

Basic Part-Time Salary Calculation

Calculating part-time salary follows a straightforward principle: you’re paid proportionally to the hours you work compared to a full-time equivalent position. Here’s how it works in practice.

The Standard Formula

If you know the full-time salary for an equivalent role and the hours both positions work, the calculation is simple:

Breaking Down to Monthly and Weekly Pay

Once you have your annual part-time salary, you can calculate your monthly and weekly pay:

Period	Calculation	Example (£20,000 annual)
Monthly	Annual Salary ÷ 12	£20,000 ÷ 12 = £1,666.67
Weekly	Annual Salary ÷ 52	£20,000 ÷ 52 = £384.62
Daily	Weekly Pay ÷ Days Worked	£384.62 ÷ 5 = £76.92

When You Don’t Know the Full-Time Equivalent

Sometimes employers advertise part-time roles without specifying the full-time equivalent salary. In this case, you’ll need to calculate based on your hourly rate:

For example, if you’re offered £15 per hour for 20 hours per week: £15 × 20 × 52 = £15,600 per year.

Understanding Pro Rata Salary

You’ll often hear the term “pro rata” when discussing part-time pay. This Latin phrase means “in proportion” and it’s the principle that ensures part-time workers are treated fairly relative to full-time colleagues.

What Pro Rata Really Means

Pro rata ensures that part-time workers receive the same hourly rate as equivalent full-time workers. It’s not about paying part-timers less per hour, it’s about paying them proportionally for the hours they actually work.

Pro Rata Benefits

Pro rata doesn’t just apply to salary. Your benefits should also be calculated proportionally:

• Holiday entitlement: If full-timers get 28 days, someone working 3 days per week gets 16.8 days (3 ÷ 5 × 28)
• Bonuses: A £1,000 full-time bonus becomes £500 for someone working half-time
• Pension contributions: Based on your actual salary, not the full-time equivalent
• Sick pay: Calculated on your contracted hours, not full-time hours

Pro Rata Mid-Year Starters

If you start a job mid-way through the financial or holiday year, your entitlements for that first partial year are also calculated pro rata:

Converting Annual Salary to Hourly Rate

Whether you’re comparing job offers or checking if your pay is correct, knowing how to convert between annual salary and hourly rate is invaluable.

The Standard Conversion Method

To find your hourly rate from an annual salary:

Reverse Calculation: Hourly to Annual

Going the other way is equally straightforward:

Watch Out for Unpaid Breaks

When calculating hourly rates, remember that unpaid lunch breaks don’t count as working hours. If you work 8am-5pm with an hour unpaid lunch, your working hours are 8, not 9.

Tax and National Insurance for Part-Time Workers

Part-time workers pay exactly the same tax and National Insurance rates as full-time workers. Your liability depends on your total income, not how many hours you work.

Income Tax Basics 2026

Everyone in the UK gets a Personal Allowance of £12,570 for the 2026/27 tax year. You only pay tax on earnings above this amount:

Income Band	Tax Rate	Annual Earnings
Personal Allowance	0%	Up to £12,570
Basic Rate	20%	£12,571 to £50,270
Higher Rate	40%	£50,271 to £125,140
Additional Rate	45%	Over £125,140

National Insurance Contributions

National Insurance is calculated differently from income tax. For 2026/27, you pay NI if you earn over £242 per week (£1,048 per month or £12,570 per year):

• Earnings between £12,570-£50,270: You pay 8% NI
• Earnings above £50,270: You pay 2% NI

For Emma earning £20,000, her National Insurance is: (£20,000 – £12,570) × 8% = £594.40 per year, or £49.53 per month.

Take-Home Pay Calculation

Your take-home (net) pay is your gross salary minus tax and National Insurance:

Part-Time Benefits and Holiday Pay

Part-time workers are entitled to the same benefits as full-time colleagues, calculated proportionally. Let’s break down the key entitlements.

Holiday Entitlement

Every UK worker, regardless of hours, is entitled to 5.6 weeks of paid holiday per year. For part-time workers, this is calculated based on your working days:

Crucially, when you take a day’s holiday, it counts as one day of your entitlement, regardless of how many hours you would have worked that day.

Pension Rights

Part-time workers have the same automatic enrollment rights as full-time workers. If you earn over £10,000 per year and are aged 22 or over, your employer must enroll you in a workplace pension.

Minimum contributions for 2026:

• Employer contribution: At least 3% of qualifying earnings
• Your contribution: At least 5% of qualifying earnings
• Total: 8% minimum combined contribution

Statutory Benefits

Part-time workers qualify for all statutory payments, calculated based on your average weekly earnings:

Benefit	Weekly Rate 2026	Eligibility
Statutory Sick Pay	£116.75	Earn £123+ per week
Statutory Maternity Pay	90% then £194.32	26 weeks continuous employment
Statutory Paternity Pay	£194.32	26 weeks continuous employment

National Minimum Wage Requirements 2026

Every part-time worker must be paid at least the National Minimum Wage. These rates increased in April 2025 and remain in effect for 2026:

Age Category	Hourly Rate	Annual Full-Time Equivalent (37.5 hrs/week)
21 and over (National Living Wage)	£12.21	£23,789
18-20 years	£10.00	£19,500
16-17 years	£7.55	£14,723
Apprentice	£7.55	£14,723

What Counts Toward Minimum Wage

Your minimum wage calculation includes:

• Basic pay
• Shift premiums and allowances
• Bonuses (but not tips from customers)

It excludes:

• Overtime premium (the extra on top of basic rate)
• Benefits in kind (like company cars)
• Loans and advances
• Pension contributions

Your Rights as a Part-Time Worker

Part-time workers have strong legal protections in the UK. Here’s what you’re entitled to.

Equal Treatment

Your employer cannot treat you less favorably than comparable full-time workers regarding:

• Pay rates (same hourly rate for same work)
• Access to company pension schemes
• Training and development opportunities
• Promotion opportunities
• Selection for redundancy (can’t target part-timers)
• Contractual sick pay and maternity pay

Employment Rights from Day One (2026)

Thanks to the Employment Rights Act 2025, which came into force in phases during 2026, part-time workers now have enhanced protections from day one of employment:

• Paternity leave: Right to request from day one
• Unpaid parental leave: Available immediately (previously after 1 year)
• Flexible working: Right to request from day one, with employers required to provide reasonable justifications for refusal

Requesting More Hours

If you regularly work more hours than your contract states, new 2026 regulations give you the right to request guaranteed hours that reflect your actual working pattern. Employers must consider these requests reasonably.

Common Salary Calculation Mistakes

Even experienced HR departments get part-time salary calculations wrong sometimes. Here are the most common errors to watch for.

1. Incorrect Pro Rata Calculation

Some employers miscalculate the proportion. Always verify the math yourself:

2. Not Including Regular Overtime in Holiday Pay

If you regularly work overtime as part of your normal working pattern, this must be included when calculating your holiday pay rate. Many employers forget this.

3. Reducing Benefits More Than Pro Rata

Some employers give part-time workers disproportionately lower benefits. For example, giving part-timers working 50% hours only 30% of the bonus full-timers receive. This is likely unlawful discrimination.

4. Confusing Calendar Days with Working Days

Holiday entitlement is based on working days, not calendar days. A part-timer working 3 days per week gets 16.8 days holiday, which represents the same amount of time off (5.6 weeks) as a full-timer with 28 days.

Frequently Asked Questions