UK SMP across 39 weeks.
Total SMP over 39 weeks
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Weeks 1-6 (90% AWE)
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Weeks 7-39 (lower)
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Your breakdown
Updates live as you type| Phase | Weekly | Phase total |
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How statutory maternity pay is built
Statutory Maternity Pay runs for up to 39 weeks and comes in two distinct phases. For the first 6 weeks you receive 90% of your average weekly earnings with no cap. For the next 33 weeks you receive the lower of that same 90% figure or the flat statutory rate, set here at £184.03 a week. There is no payment for the final 13 weeks of the 52-week leave entitlement, so many parents plan for an unpaid stretch at the end or return early. This tool turns your average weekly earnings into the full 39-week total and splits it across the two phases.
A full calculation on £800 a week
Using the default average weekly earnings of £800, the first 6 weeks pay 90% of £800, which is £720 a week. The next 33 weeks compare £720 against the £184.03 flat rate and pay the lower one, so £184.03 a week. The arithmetic looks like this.
The visual gap between the two phases is the point worth absorbing. The first six weeks are generous, then income drops sharply to the flat rate for the long middle stretch. Budgeting for that cliff is the single most useful thing this calculator can show you.
The earnings level where the cap stops biting
For most employees the 90% figure is far above the flat rate, so the second phase pays exactly £184.03 a week. But there is a crossover. The cap only bites when 90% of your average weekly earnings is above £184.03, which happens at average weekly earnings of roughly £204.50. Below that, a part-time or lower-paid worker receives 90% throughout all 39 weeks and never touches the flat rate. If you earn under that threshold, change the average weekly earnings field and watch the second-phase weekly drop below £184.03. There is also a lower gate: you must earn at least £125 a week on average to qualify for SMP at all, and below that you would look at Maternity Allowance from the DWP instead.
Tax, top-ups, and a planning tip
SMP is treated as earnings, so Income Tax and National Insurance still apply through PAYE if the amounts cross the thresholds. Many people pay little or no tax during leave simply because the flat rate is low, and some are owed a small refund at year end because their personal allowance was spread across months of higher pay that never arrived. A practical tip for couples: since April 2015 you can convert most of the maternity entitlement into Shared Parental Leave and split it with a partner, which can be worth modelling if one of you has stronger enhanced pay than the other. Always check your contract first, because a generous employer scheme can dwarf the statutory floor this tool calculates.
Two common queries
When does the 90% pay actually start?
SMP can begin from 11 weeks before your due date at the earliest. It starts automatically if the baby arrives early or if you are off work with a pregnancy-related illness in the final four weeks before the due date. Otherwise it usually begins the day after your last working day, so the timing of when you finish work directly sets when the first six weeks of higher pay land.
Do I have to pay any SMP back if I do not return?
No. Statutory Maternity Pay is never repayable even if you decide not to go back to your job. That protection is statutory. Enhanced or contractual maternity pay is different: many employer schemes require you to return for a set period or repay the top-up portion, so read the small print on any pay above the statutory amount.