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How our maternity pay calculator works


Gross Pay
When calculating your maternity pay we assume:
  • Your average weekly earnings are your salary divided by 52 (weeks).
  • We use the HMRC rates for SMP, lower earnings limit threshold etc. at the time of the maternity leave period – where HMRC have not yet published future rates we use the current rates.
  • We apply the lower earnings limit to calculate SMP, if you are on occupational maternity pay then we assume that the LEL threshold is not applied to non-SMP components of that scheme.
  • We assume that you have checked that your are eligible for SMP – eligibility checkers are available elsewhere.
  • We assume that maternity pay (whether SMP or Occupational) is calculated weekly and pro-rated to the number of days in the month and as such will fluctuate on a monthly basis depending on the number of days in the month.
  • We do not yet cater for Maternity Allowance
  • We do not yet cater for Shared Parental Leave
  • We do not yet cater for taking Keep In Touch days.
When calculating gross pay we assume:
  • You are paid monthly (rather than four-weekly or weekly)
  • The working days of the month are Monday to Friday.
  • You are paid on the last day of the month
When calculating your pension we assume:
  • Your pension is taken from your gross pay before tax. This is what is (confusingly) called a Net Pay arrangement.
  • We do not yet cater for Relief at Source pension arrangements
  • We do not yet cater for Salary Sacrifice pension arrangements
Student Loans
  • We support Plan 1 (started studying pre 1st Sept 2012) and plan 2 (after 1st Sept 2012) student loans, we do not yet support post graduate loan programmes.
Take Home Pay

Take home pay is calculated net of national insurance and income tax, pension contributions, student loan repayments.

When you have Maternity Allowance:

We present Maternity Allowance as though it is "Pay" from your employer. Maternity Alowance is actually paid to you by the Job Centre, and not by your employer.

There is no income tax, national insurance, pension or student loan repayments due on Maternity Allowance, the calculator correctly takes this into account.

When calculating income tax we assume:
  • Unlike other online pay calculators our calculator is not a simple “month 1” calculation, this means your personal tax allowance is used correctly throughout the financial year, and means that if your income reduces (like when you go on maternity leave) your effective tax rate is reduced or you may even be due a refund.
  • We test our calculator to match the HMRC PAYE calculator here: http://payecalculator.hmrc.gov.uk/PAYE0.aspx
  • You have the standard personal allowance and “L” tax code (although we do adjust for high earners who have their personal allowance reduced)
  • You pay English tax rates.
  • We use the rates applicable for the relevant tax year, where tax rates for future years have not yet been published we use current rates.
When calculating National Insurance we assume:
  • You are on category letter A
  • We (correctly) calculate NI on per pay cycle basis rather than on an annual basis. This is important when your pay fluctuates.
Return To Work
When calculating how much holiday you have available
  • We assume you have no holiday accrued or owed when you start your maternity leave. E.g. if you get 20 days holiday and 8 bank holidays, and you start maternity leave exactly half way through the year we assume that you have taken 14 days holiday before your maternity leave starts.
  • Holiday is accrued both during your maternity leave and in your “use up holiday” period.
Return to work options

If you take holiday at the end of maternity (either to stay off work for longer, or to return part time while getting paid full time) then this uses all accrued holiday (including that accrued during this period) such that you have no accrued or owed holiday when you return to a normal work pattern.