If you're in a salary sacrifice scheme — childcare vouchers, additional pension contributions, cycle to work, or buying extra annual leave — it can quietly reduce your maternity pay, sometimes by more than people expect. But how it does that is widely misunderstood, and there's one protection in the rules that most calculators never mention.
For your own figures, enter your salary sacrifice amount into the NHS Maternity Pay Calculator, and it will show you the exact reduction.
Salary sacrifice is a contractual arrangement where you voluntarily give up part of your cash salary in return for a benefit from your employer. Common NHS examples include childcare vouchers, additional voluntary pension contributions (AVCs), cycle to work, and buying additional annual leave.
Because you're giving up salary rather than just having a deduction taken afterwards, your gross pay for tax and national insurance is genuinely lower while the arrangement runs. That lower gross figure is the root of how salary sacrifice affects your maternity pay.
Salary sacrifice reduces your SMP by reducing your Average Weekly Earnings (AWE), the figure your SMP is calculated from. Because the arrangement lowers the gross pay that counts for National Insurance, the AWE worked out from your payslips comes out lower, and a lower AWE means lower SMP.
This matters most in the first 6 weeks of SMP, which are paid at 90% of your AWE with no upper limit, so any reduction in AWE feeds straight through. From week 7 onward, SMP is the lower of the flat rate (£194.32 for 2026/27) or 90% of AWE. Most NHS salaries sit comfortably above the crossover point, so the flat rate still applies and those weeks usually aren't affected — unless your sacrifice is large enough to pull your AWE right down.
Here's the part that gives you some control: only salary sacrifice running during the AWE calculation window affects your SMP. That window is the reference period used to work out your earnings; for monthly-paid NHS staff, it's the last two monthly payslips before the end of your qualifying week (the 15th week before your due date).
In practice, this means:
Planning ahead: pausing a salary sacrifice arrangement before your AWE reference period begins can protect your SMP. This is worth raising with payroll early, because the window falls months before your leave actually starts. Always confirm your own dates and scheme rules with payroll before making changes.
Sacrifice can't be deducted once SMP is being paid. This is the protection almost no calculator explains. Once your SMP is in payment, your employer cannot use a salary sacrifice arrangement to further reduce it. Your SMP must be paid to you in full.
In other words, salary sacrifice affects your SMP only through the AWE calculation described above, by lowering the rate you qualify for. It cannot then be taken a second time as a deduction from the SMP payments themselves during your maternity pay period.
Your employer can still make the normal deductions from your SMP — income tax, National Insurance, pension contributions and things like trade union subscriptions. What they can't do is keep clawing back a salary sacrifice amount out of your SMP. If your payslips during leave look as though a sacrifice is still being deducted straight from your SMP, that's worth querying with payroll.
There's a more serious scenario worth knowing about. To qualify for SMP at all, your AWE must be at least the Lower Earnings Limit — £129 a week for 2026/27. If salary sacrifice pulls your AWE below that threshold, you may lose SMP eligibility altogether, not just receive a lower amount.
If that happens, you may instead be able to claim Maternity Allowance through the Department for Work and Pensions. For who qualifies and how the two interact, see our NHS Maternity Pay Eligibility & Repayment Rules guide, and check gov.uk for current Maternity Allowance rules.
Salary sacrifice's clearest, best-established effect is on the SMP element through AWE. Your contractual NHS occupational pay — the full pay and half pay phases — is worked out from your normal pay rate rather than from the AWE figure, so it isn't reduced in the same automatic way.
That said, exactly how your Trust treats a continuing sacrifice during leave, and how it defines "full pay" for OMP, can vary — so if you have an ongoing arrangement it's worth asking payroll specifically how it's handled across each phase rather than assuming. The calculator's salary sacrifice field models the SMP impact; for anything scheme-specific, payroll is the authority.
Additional voluntary pension contributions are themselves a form of salary sacrifice, and the interaction with maternity leave can get confusing, because your pension contributions during leave are based on the actual pay you receive in each phase, while your pension still builds on your full notional pay.
This is genuinely one of the more tangled areas, so it has its own guide: see NHS Maternity Pay and Your Pension for how contributions step down across the four phases and what happens during the unpaid weeks.
The same principle applies if you're claiming maternity allowance rather than SMP. Maternity Allowance is assessed on your lower, post-sacrifice contractual earnings; no account is taken of the salary you gave up or the value of the benefit you received instead. So salary sacrifice can reduce your maternity allowance or affect whether you qualify, in much the same way it affects SMP.
Yes, but only through one route. Salary sacrifice lowers your Average Weekly Earnings, which reduces the SMP rate you qualify for, most noticeably in the first 6 weeks paid at 90% of AWE. Your contractual full and half pay phases are worked out from your normal pay rate, not from AWE.
Only salary sacrifice running during your AWE calculation window affects your SMP. For monthly-paid staff that's the last two payslips before the end of your qualifying week, the 15th week before your due date. Sacrifice you pause before that window, or start after it, doesn't reduce your SMP rate.
No. Once your SMP is in payment, it must be paid in full and cannot be further reduced by a salary sacrifice arrangement. Normal deductions like tax, National Insurance, and pension can still come off your SMP, but a sacrifice amount cannot be clawed back from it.
Yes. If salary sacrifice pulls your average weekly earnings below the £129 lower earnings limit for 2026/27, you may not qualify for SMP at all. You may instead be able to claim maternity allowance through the Department for Work and Pensions.
It can help protect your SMP if you pause it before your AWE reference period, which falls months before your leave starts. Whether it's worth it depends on the benefit you'd be giving up, so confirm your exact dates and weigh it up with payroll before making any change.
Yes. Maternity Allowance is assessed on your lower post-sacrifice earnings, with no account taken of the salary given up, so it can reduce your Maternity Allowance or affect whether you qualify, in the same way it affects SMP.