http://www.direct.gov.uk/en/MoneyTaxAnd ... G_10018869
Says:
How much do you get?
Maternity Allowance pays a standard weekly rate of £117.18 or 90 per cent of your average gross weekly earnings (before tax), whichever is the smaller.
In case your situation is trickier to work out,
http://www.dwp.gov.uk/advisers/ni17a/ma/index.asp#intro
says:
Earnings rule
To get MA your earnings, on average, must be at least equal to the Maternity Allowance Threshold (MAT) in force at the beginning of your test period. The MAT is £30 a week so you must earn on average at least £30 a week. If you have more than one employer, all earnings will count when working out the average.
If you are an employee the earnings rule is based on your gross earnings during your test period. Gross earnings are your earnings before any deductions and may include:
* Statutory Adoption Pay
* Statutory Maternity Pay
* Statutory Paternity Pay, or
* Statutory Sick Pay
If you are a student in receipt of a bursary, your bursary is not treated as earnings for MA purposes.
If you are part of a salary sacrifice scheme this will mean that you have voluntarily given up the right to some of your earnings in return for benefits from your employer e.g. childcare vouchers. MA will be assessed on those lower earnings that is, no account will be taken of the salary you have given up or the value of the benefit you receive in its place. This may reduce your entitlement to MA or may mean that you will not be entitled to MA as your earnings are below the MAT.
If you are self-employed and do not have a small earnings exception certificate, for any week covered by a Class 2 NI contribution you will be treated as having enough earnings to result in the standard rate of MA, payable at the end of the week covered by a class 2 NI contribution. This means that:
* From 10 April 2006 treated as earning £120.95
* From 9 April 2007 treated as earning £125.28
* From 7 April 2008 treated as earning £130.20
If you are self-employed and hold a small earnings exception certificate, you will be treated as having earnings equal to the MAT at the end of any week covered by your certificate. This applies even if you pay a class 2 contribution for a week which is also covered by the certificate.
If you are employed and self-employed, earnings from your employment and earnings you are treated as having from self-employment can be added together to help you get more MA.
Period for calculating average weekly earnings
Your earnings are averaged over any 13 weeks in your test period. The 13 weeks do not have to be in a row and you may choose the weeks with the most earnings to help you get more MA. Earnings from all your jobs (if you have more than one) and earnings you are treated as having from self-employment will be used to work out your average weekly earnings. If your average is at least equal to £30 a week you will get MA.
I hope this helps.