The basics: gross income is used
The CMS calculates child maintenance based on the paying parent's gross annual income. That is, income before income tax and National Insurance are deducted. The CMS gets this figure directly from HMRC, so it reflects your actual earnings.
This is why many paying parents feel the CMS calculation seems high. It is worked out on your gross pay, not your take-home pay. Our net pay calculator can show you what the payments would look like based on what you actually take home each month.
The five rate bands
The CMS uses five different rate bands depending on the paying parent's gross weekly income:
1. Nil Rate (£0–£7 per week gross)
No child maintenance is payable. This also applies if the paying parent is on certain benefits or in prison.
2. Flat Rate (£7–£100 per week gross)
A fixed amount of £7 per week is payable regardless of how many children are involved.
3. Reduced Rate (£100.01–£200 per week gross)
The amount is calculated using a formula:
| Number of children | Formula |
|---|---|
| 1 child | £7 + 17% of income above £100 |
| 2 children | £7 + 25% of income above £100 |
| 3+ children | £7 + 31% of income above £100 |
4. Basic Rate (£200.01–£800 per week gross)
This is the most common band, and where the well-known percentages come from. The paying parent pays a percentage of their gross weekly income:
| Number of children | % of gross weekly income |
|---|---|
| 1 child | 12% |
| 2 children | 16% |
| 3+ children | 19% |
5. Basic Rate Plus (£800.01–£3,000 per week gross)
Higher earners pay the basic rate on the first £800 a week, then a lower percentage on everything above it: 9% for one child, 12% for two, 15% for three or more. Gross weekly income above £3,000, which is £156,000 a year, is ignored completely. Past that point the receiving parent has to apply to the courts for a top-up order.
What percentage is child maintenance in the UK?
12% for one child, 16% for two and 19% for three or more, on gross weekly income between £200 and £800. Those three figures are what people usually mean by the child maintenance percentage. They are not applied to take-home pay, they are not charged per child, and they are not the only rates in the system, as the five bands above show.
How much child maintenance for 1 child?
For one child at the basic rate, you pay 12% of gross weekly income. On £500 a week gross that is £60 a week, or £260 a month. On a £30,000 salary it is £69.23 a week, which is £300 a month. Use our calculator to work this out from your take-home pay.
How much child maintenance for 2 children?
For two children, the rate is 16% of gross weekly income. On £500 a week gross that is £80 a week, or £347 a month. On a £30,000 salary it is £92.31 a week.
How much child maintenance for 3 children?
For three children the rate is 19% of gross weekly income, and it stops rising there. A fourth or fifth child in the same case adds nothing. On £500 a week gross, 19% is £95 a week, or £412 a month.
This is the part that surprises people on both sides. The second child adds 4% of income and the third adds 3%, so the amount per child falls each time. The percentage covers the case, not the individual children.
How does shared care affect the amount?
If the paying parent has the children to stay overnight, the CMS will reduce the maintenance amount. See our full guide: How shared care affects child maintenance.