Key facts (2026): Child maintenance under the Child Maintenance Service (CMS) is calculated as a percentage of the paying parent's gross weekly income: 12% for one child, 16% for two children, and 19% for three or more. Income is based on HMRC gross income data. Reductions apply for overnight stays with the paying parent.
Child maintenance — the financial support paid by a non-resident parent toward the costs of raising a child — is one of the most practically important financial matters for separated families in the UK. Understanding how the calculation works helps both parents budget accurately and ensures children receive appropriate support.
CMS Calculation Rates 2026
The basic rate calculation (for gross weekly income between £200 and £3,000) is: 12% for 1 child; 16% for 2 children; 19% for 3 or more children. For gross weekly income over £3,000, a reduced rate applies on the excess. For income below £200/week, a flat rate of £7/week applies. For income below £100/week or certain benefit recipients, the rate is £0 (nil rate).
Overnight Stay Reductions
The calculated amount is reduced if the child stays overnight with the paying parent: 1–52 nights per year: no reduction; 53–103 nights: 1/7 reduction; 104–155 nights: 2/7 reduction; 156–174 nights: 3/7 reduction; 175+ nights (roughly equal shared care): 50% reduction. These reductions recognise that the paying parent bears direct costs during overnight stays.
Family-Based Arrangements vs CMS
Parents can agree child maintenance privately without using the CMS — this is called a family-based arrangement. If both parents agree on an amount, no CMS involvement is needed. The CMS charges an application fee (currently £20) and takes a percentage of payments when it collects and pays the money (4% from the paying parent, 4% from the receiving parent). Direct pay arrangements (paying privately but CMS-calculated) avoid these collection charges.
Our Verdict
The CMS calculation is transparent and straightforward if you know the paying parent's gross income. For most families, a private arrangement based on the CMS formula — but paid directly without CMS involvement — saves both parties the collection fees and avoids the adversarial dynamic of formal CMS involvement. Always document private arrangements in writing.
Frequently Asked Questions
How is child maintenance calculated UK 2026?
12% of gross weekly income for 1 child, 16% for 2, 19% for 3+ (basic rate). Reductions apply for overnight stays with the paying parent.
What if the paying parent refuses to pay?
The CMS can enforce payment through deduction from earnings orders, deduction orders from bank accounts, and ultimately charging orders on property.
Can we agree child maintenance privately?
Yes — family-based arrangements without CMS involvement are entirely valid and save both parties the CMS collection fees.
Disclaimer: For informational purposes only. Verify with gov.uk or qualified professionals before making decisions.
Last updated: April 2026 · Author: Chandraketu Tripathi
