The amount of Maternity Allowance you get is either £139.58 a week or 90% of your average weekly earnings (whichever is less) for up to 39 weeks or £27.00 a week for up to 14 weeks (if your baby us due on or after 15 July 2015). Maternity Allowance is paid every 2 or 4 weeks.tatutory Maternity Pay is paid: 1  for the first six weeks at 90 per cent of your average gross weekly earnings with no upper limit and. 2  for the remaining 33 weeks at the lower of either the standard rate of £139.58 (from April 2015), or 90 per cent of your average gross weekly earnings.