Statutory maternity pay is income paid to employed women in the United Kingdom who are about to give birth or have recently done so. Statutory maternity pay is a government-mandated program that allows women in the UK to take time off from work for childbirth without sacrificing a paycheck. The amount of pay is determined by the average weekly earnings of the employee before qualifying for statutory maternity pay, according to the website DirectGov.

Determine the qualifying week by counting back 15 weeks before the baby's due date. Add together all gross earnings paid to the employee during the qualifying week and the seven weeks prior. For example, £100 each week added over eight consecutive weeks equals £800. Divide the result by 8 to get the average weekly earnings. So £800 divided by 8 equals £100.

Multiply the result by .9 to obtain 90 per cent of the average weekly earnings. So £100 times .9 equals £90. This is the rate that is paid for the first six weeks of statutory maternity pay.

Compare the rate paid for the first six weeks of statutory maternity pay to the weekly standard rate (which changes annually). The lower of the two amounts is paid for the remaining 33 weeks of statutory maternity pay. If the weekly standard rate is £123, the average weekly earnings rate of £90 would be paid.