Question 1

How is pro-rata salary calculated?

Accepted Answer

Pro-rata salary = full-time salary multiplied by actual hours or days divided by full-time hours or days. A £45,000 FTE salary at 4 days per week (out of 5) = £36,000 pro-rata gross.

Question 2

Is take-home pay proportional to hours worked?

Accepted Answer

Not exactly. Income tax and NI thresholds are fixed amounts, not pro-rated for part-time hours. This means part-time workers keep a higher proportion of their salary. A 4-day week worker keeps a larger percentage of gross pay than the equivalent full-time worker.

Question 3

What is pro-rata salary?

Accepted Answer

Pro-rata salary is the portion of a full-time salary paid for part-time hours. If a full-time salary is £45,000 for 37.5 hours per week, a 30-hour week is paid at £45,000 x (30/37.5) = £36,000 pro-rata.

Question 4

Do part-time workers get the same pension contributions?

Accepted Answer

Pension auto-enrolment applies to all eligible workers earning above £10,000 per year. Contribution percentages are the same for part-time as full-time — applied to your actual earnings. Employer contributions are also the same percentage, just on lower earnings.

Question 5

How does the 4-day week affect take-home pay?

Accepted Answer

A 4-day week on £45,000 FTE gives pro-rata salary of £36,000. Take-home on £36,000 (5% pension) is approximately £27,220/year. This compares to £34,120 on the full £45,000 — a reduction of £6,900/year in take-home for a 20% reduction in hours.

Part-Time Salary Calculator 2026-27

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