Child Maintenance in the UK: How the CMS Basic Rate Is Worked Out

Child Maintenance in the UK

After a separation, the parent who does not live with the children usually pays child maintenance. Parents can agree the amount themselves, which is often best, or use the Child Maintenance Service (CMS), which works out a figure by formula. Knowing the formula helps in both cases. The Child Maintenance (CMS) Estimate Calculator gives an estimate.

The basic rule

The CMS uses the paying parent's gross weekly income, taken from HMRC records. For income up to £800 a week the basic rate is 12 percent for one child, 16 percent for two and 19 percent for three or more. For the part of income between £800 and £3,000 a week, the percentages are lower: 9, 12 and 15. Income above £3,000 a week is ignored. Pensions, benefits and some other income are treated by special rules not covered here.

Low incomes

If gross weekly income is less than £7, the amount is nil. From £7 to £100 a week, a flat rate of £8 applies. From £100 to £200 a week a reduced rate applies, which the tool approximates. People on certain benefits also pay the flat rate.

Other children in the household

If the paying parent supports other children who live with them, part of their income is disregarded in the calculation: 11 percent for one other child, 14 percent for two and 16 percent for three or more. Enter the number of such children in the calculator.

Shared care

Child maintenance falls if the children stay overnight with the paying parent. The amount is reduced by one seventh for 52 to 103 nights a year, two sevenths for 104 to 155 nights and three sevenths for 156 to 174 nights. If the children stay 175 nights or more, the reduction is one half, and a further £7 a week per child is taken off. These numbers are editable in the table.

Using the calculator

Enter the paying parent's gross weekly income, the number of children the maintenance is for, the nights a year they stay with the paying parent and the number of other children in the paying parent's household. The tool shows the income used, the rate that applies, the weekly amount before and after shared care, and the monthly and yearly amounts.

Examples

A parent earning £650 a week with two children pays 16 percent, £104 a week. With 52 nights of overnight care a year, the amount falls by one seventh to about £89.14 a week, or about £386 a month. A parent with £1,000 a week and one child pays 12 percent of the first £800 and 9 percent of the next £200: £96 plus £18, which is £114 a week.

Family-based arrangements and the CMS

You can reach a family-based arrangement without using the service, which is free and flexible. If you cannot agree, you can apply to the CMS. Using the CMS for a Direct Pay arrangement, the paying parent pays the other parent directly. Collect and Pay, where the service collects and passes on the money, has fees for both parents.

Limits

The CMS uses more detailed rules and the latest figures from HMRC. This tool applies a simplified version and is an estimate only. It is not legal advice; Gingerbread and Citizens Advice offer free guidance.

Quick answers

Can I agree a different amount? Yes. A family-based arrangement is voluntary and can be more or less than the formula.

Does the other parent's income matter? Not in the formula: only the paying parent's income is used.

What if the paying parent is self-employed? The service uses HMRC figures from the tax return, which can lag behind real income.