Calculating child maintenance
Child maintenance can be arranged voluntarily between parents, or calculated (and, if necessary, collected) under the Child Maintenance Service (CMS), or determined by court order.
How do I calculate child maintenance?
- If the payer’s income is less than £156,000 gross per annum (after deduction of pension contributions), apply the CMS standard formula. The calculation can be done on the CMS calculator: Calculate your child maintenance – GOV.UK (www.gov.uk).
- If the payer’s income is £156,000 – £650,000 gross per annum, the 2023 High Court child maintenance case of James v Seymour sets out the following formula for one, two or three children:
- Identify the payer’s gross income (disclosed in their most recent P60 or tax return);
- Reduce the payer’s gross income by the number of children living with them: 11% for one child, 14% for two children and 16% for three or more children;
- Deduct current pension contributions;
- Gross up school fees and extras paid by the payer by the amount of income tax paid; this will give the ‘Exigible Income’;
- To the first £156,000 of the Exigible income apply the CMS formula:
- The first £800 per month: 12% for one child, 16% for two children, 19% for three children;
- For the balance over £800 up to £12,200 per month: 9% for one child, 12% for two children, 15% for three children
6. To the income over £156,000 multiply by 2.4% for a single child and 3% for each of two or three children.
7. Reduce for the number of nights the child spends with the payer each year:
- Less than 52 nights: no reduction;
- 52 – 103 nights: 1/7 reduction;
- 104-155 nights: 2/7 reduction;
- 156-175 nights: 3/7 reduction;
- 176 – 183: equal.
This formula is not used where there are more than three children, where the payer’s gross income exceeds £650,000 or is largely unearned, where the payer lives on capital or for a variation of an existing child maintenance order. For variations, the maintenance should be as set out in the order and adjusted by the higher of CPI or RPI.
- If the payer’s income exceeds £650,000 gross per annum there is discretion and we will advise client on potential claims with reference to relevant case law.