Child maintenance — how the CMS calculates, charges and enforces

REVIEWED BY: Sean McNamara on 2026-08-29

What the CMS is

The Child Maintenance Service (CMS) is the government agency that arranges child maintenance when parents separate. It replaced the old CSA. It can calculate what the paying parent should contribute, collect the money, and pass it to the receiving parent.

The calculation formula

Based on the paying parent's gross annual income:

| Gross income | Rate | Example (2 children) | |---|---|---| | Up to £800/week | 12% (1 child), 16% (2), 19% (3+) | £100/week → £16/wk for 2 | | £800.01–£3,000/week | 9% (1 child), 12% (2), 15% (3+) | £1,000/week → £120/wk for 2 | | £3,200+/week | Capped at £3,200 income for calculation | Maximum applies |

Reductions for other children living with the paying parent:

1 other child: reduce by 11.11%
2 other children: reduce by 14.29%
3+ other children: reduce by 16.67%

Reductions for overnight stays with the paying parent:

52–103 nights/year: reduce by 1/7th
104–155 nights/year: reduce by 2/7ths
156–174 nights/year: reduce by 3/7ths
175+ nights/year: reduce by 50% + £7/week

Collection types

| Type | How it works | Fees | |------|-------------|------| | Direct Pay | Payer pays receiver directly; CMS monitors only | Free | | Collect and Pay | CMS collects from payer and passes to receiver | 20% payer + 4% receiver |

Enforcement powers (if the payer doesn't pay)

Deduction from earnings order — taken directly from wages
Deduction from earnings request — for armed forces personnel
Regular deduction order — taken from bank account
Lump sum deduction order — one-off bank account deduction
Liability order — court order enabling bailiffs/charging orders
Disqualification from driving — for persistent non-payment
Committal to prison — for very serious non-payment

Variation grounds (when the standard calculation is wrong)

The payer has unearned income ≥ £2,500/year (dividends, rent, investments)
The payer has notional assets ≥ £31,250 (assets they could sell for income)
The payer's earned income ≥ £100/week while claiming benefits
Diversion of income (being paid in goods instead of money to avoid the calculation)
Hardship for either party

Domestic abuse and the CMS

If there's a non-molestation order, the CMS must offer Collect and Pay with no collection fees for the receiving parent
Safety concerns about meeting the other parent are taken into account
See our DA support pages for safety planning

How to apply

1. Apply online: https://www.gov.uk/apply-child-maintenance 2. Application fee: £20 (waived for under-19s and some circumstances) 3. CMS contacts both parents, gathers income data, calculates 4. You choose Direct Pay or Collect and Pay

Official links

CMS: https://www.gov.uk/child-maintenance
Apply: https://www.gov.uk/apply-child-maintenance
Calculator: https://www.gov.uk/calculate-child-maintenance

This page is general information, not legal advice. Fees and rates change — always verify at gov.uk. YourFamilyCase.co.uk is an independent directory and is not affiliated with the CMS or gov.uk.

Content verified against the official HMCTS court directory, gov.uk forms and fees pages, and the professional body registers (SRA, FMC, Bar Council). Last reviewed September 2026.