hmrc maternity calculator

How this HMRC maternity calculator works

In the UK, Statutory Maternity Pay (SMP) is usually paid for up to 39 weeks. The first 6 weeks are paid at 90% of average weekly earnings, and the next 33 weeks are paid at the lower of:

• the current SMP standard weekly rate, or
• 90% of average weekly earnings.

This calculator follows that HMRC structure so you can quickly estimate your gross maternity pay schedule. It is useful for budgeting, cash-flow planning, and understanding your expected income before discussing details with payroll or HR.

Quick guide to eligibility for Statutory Maternity Pay

You will typically need to meet key conditions, including:

• You are classed as an employee (not self-employed for SMP purposes).
• You have been continuously employed by your employer for at least 26 weeks into the qualifying week.
• Your earnings are at or above the Lower Earnings Limit in the relevant period.
• You give proper notice and evidence of pregnancy (for example, MATB1 form) when requested.

If you do not meet SMP conditions, you may still be able to claim Maternity Allowance. This page is focused on SMP estimation only.

Input fields explained

Average weekly earnings

Enter your gross average weekly earnings for the relevant calculation period. This figure drives both the 90% rate in weeks 1 to 6 and the cap comparison in weeks 7 to 39.

Maternity leave start date

Add a date if you want a week-by-week schedule with calendar ranges. If you leave it blank, the calculator still gives totals, but without dates.

Standard SMP rate and lower earnings limit

Rates can change each tax year. This tool lets you edit values, so you can update it quickly when HMRC rates change. If you are not sure, check your payroll team or the official government guidance.

Worked example

Suppose your average weekly earnings are £500 and your leave begins on 1 April. The calculator applies:

• Weeks 1 to 6: 90% of £500 = £450 per week
• Weeks 7 to 39: lower of £450 and standard rate (for example £184.03) = £184.03 per week

This produces a much higher amount in the first six weeks, then a lower fixed amount for the remaining statutory period. Many people use this insight to plan savings before leave starts.

Common planning mistakes to avoid

• Ignoring tax and NI: this calculator estimates gross SMP, not your net take-home pay.
• Forgetting enhanced employer schemes: some employers top up maternity pay above statutory minimums.
• Missing timing effects: payroll cut-off dates can shift when payments land in your bank account.
• Using outdated rates: annual updates matter, especially near a tax year boundary.

What this calculator does not cover

This estimate is intentionally simple. It does not automatically model:

• enhanced contractual maternity pay policies,
• tax code changes and pension deductions,
• benefits-in-kind impacts,
• shared parental pay transitions, or
• complex employment history across multiple employers.

For an exact figure, use this estimate as a starting point and confirm with payroll, HR, or a qualified adviser.

FAQ

Is this an official HMRC calculator?

No. This is an independent estimator based on standard SMP rules.

Can I use monthly salary instead of weekly earnings?

You should use average weekly earnings for best accuracy. If needed, convert monthly gross pay to weekly before entering.

Can SMP be less than the standard weekly rate?

Yes. For weeks 7 to 39, the amount is the lower of the standard rate or 90% of your average weekly earnings.

What if I am not eligible for SMP?

You may be eligible for Maternity Allowance instead. Check current government guidance for the relevant criteria.