Child Maintenance Calculator UK 2026

Calculate child maintenance payments using the Child Maintenance Service (CMS) standard rate for 2026. Includes shared care reductions and adjustments for other children in the paying parent's household.

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Enter the paying parent's details
Fill in the income, number of children and any shared care arrangement on the left to calculate the child maintenance amount.

Child Maintenance Calculator FAQs

How does the CMS calculate child maintenance?
The Child Maintenance Service (CMS) uses the paying parent's gross weekly income as the basis for the calculation. For the standard rate (income between £200 and £3,000 per week), the percentage applied depends on the number of children: 12% for 1 child, 16% for 2 children and 19% for 3 or more children. If the paying parent earns less than £100 per week, a flat rate of £7 per week applies. If they receive certain qualifying benefits, a nil rate applies. For income above £3,000 per week, the standard rate is calculated on £3,000 and the remaining income above that figure can be considered via a variation.
What is the shared care reduction?
When the paying parent has the child or children staying with them overnight, the maintenance amount is reduced to reflect that shared care. The reduction is based on the average number of nights per week: 1 night per week reduces maintenance by 1/7 (approximately 14%), 2 nights by 2/7 (approximately 29%) and 3 nights by 3/7 (approximately 43%). At 4 or more nights per week, the arrangement is considered substantial shared care and a 50% reduction is applied first, followed by an additional weekly discount. If the paying parent has the child for 4 nights a week on average (roughly 175 nights per year) the maintenance is reduced significantly as both parents are providing accommodation for the child.
What if the paying parent earns over £3,000 per week?
The CMS standard rate calculation is capped at £3,000 gross weekly income (£156,000 per year). Above this level, the standard amount is calculated on £3,000 per week as normal, and the receiving parent (or the paying parent) can apply for a variation if they believe additional income should be taken into account. Variations can cover income from property, investments, assets or income that has been deliberately reduced. The CMS considers these on a case-by-case basis and any additional maintenance is set separately.
Related calculators: Child Benefit Calculator Budget Planner Universal Credit Calculator

Estimates only · Not financial advice · CMS rates and rules shown are based on current CMS standard rate guidance · Actual assessments by CMS may differ based on individual circumstances · Visit gov.uk/child-maintenance for official guidance