Example result based on the prefilled values.
Total SMP
£9,112.56
High-Rate Period (weeks 1–6)
£2,700.00
Low-Rate Period
£6,412.56
Unpaid Weeks
0.00
Continue your plan
Useful next calculations
Rates & sources2026/27
2026/27 statutory maternity rates for an employee who qualifies. The tool does not assess service, notice or eligibility conditions.
Source: DWP — Benefit and pension rates 2026 to 2027 — source checked for 2026/27.
When to use this calculator
- Before comparing lenders, brokers, or repayment options.
- When you want to test how a different deposit, rate, or term changes affordability.
- When you need a quick estimate before using a formal quote or agreement in principle.
- When you are stress-testing your budget against a potential rate rise to see the impact on monthly payments.
- When you want to understand the full cost of borrowing — not just the monthly figure — before you commit.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Average Weekly Earnings (£)
25 years
Weeks of Maternity Leave
39
After entering these figures, review total smp, high-rate period (weeks 1–6) and low-rate period together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Total SMP
This is the headline outcome of the calculation, but it is most useful when read alongside the supporting metrics below it rather than in isolation. Try changing one input at a time and watching how this total moves to understand which driver has the biggest impact.
High-Rate Period (weeks 1–6)
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Low-Rate Period
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Unpaid Weeks
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator models 2026/27 Statutory Maternity Pay (SMP) for an eligible employee. The first six weeks are 90% of average weekly earnings with no cap. From week seven to week 39, the rate is the lower of £194.32 a week or 90% of average weekly earnings. Weeks 40–52 of maternity leave are unpaid unless an employer offers contractual pay beyond the statutory period.
The 2026/27 lower earnings limit is £129 a week, and separate service, notice and employment-status rules apply. This calculation does not establish eligibility. Amounts are gross and subject to PAYE deductions.
Common mistakes
- !Mixing up loan amount and property value, which can distort affordability and LTV.
- !Using a headline rate but forgetting fees, insurance, taxes, or repayment type.
- !Testing only one term length instead of comparing the payment and total cost together.
- !Forgetting that a repayment mortgage and an interest-only mortgage produce very different monthly figures and total costs.
- !Not accounting for the impact of a rate revert after an introductory fixed period ends, which can sharply increase payments.
What to do next
- Run a second scenario with a higher rate or shorter term so you can see the downside clearly.
- Compare the result with an affordability or overpayment calculator before applying.
- Use the related guides below to understand trade-offs before you request live quotes.
- Note down the monthly payment and total interest for your two or three strongest scenarios so you have a clear comparison ready when you speak to a broker.
- Check whether making a modest overpayment each month would reduce total interest significantly — run the overpayment calculator next to find out.
Frequently asked
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