Guide · Updated 07/07/2026

How the Child Maintenance Service works, start to finish

The CMS is the statutory scheme for child maintenance in England, Wales and Scotland, run by the Department for Work and Pensions. This guide walks the whole journey — from application to enforcement — and flags the points where cases most often go wrong.

Before the CMS: family-based arrangements

Nobody is required to use the CMS. Parents can agree maintenance privately (a "family-based arrangement"), which costs nothing, can be as flexible as you like, and can be replaced by a statutory application at any time if it breaks down. GOV.UK's child maintenance guidance and the CMS online calculator let you baseline what the statutory figure would be — a sensible anchor for any private agreement.

A court order for maintenance (a "Segal order" aside) generally only blocks a CMS application for the first 12 months after it is made; after that, either parent can apply to the CMS and displace it.

The statutory journey

1. Application

   Either the parent with main day-to-day care (the "receiving parent") or the "paying parent" can apply, as can a grandparent or guardian with care. Since February 2024 there is no application fee. Before applying you must normally speak to the Get Help Arranging Child Maintenance service.

2. Initial contact and the effective date

   The CMS contacts the paying parent. The date the CMS notifies the paying parent of the application (usually by phone, or two days after posting the notification letter) becomes the initial effective date — liability runs from this date, not from when the calculation is finally worked out. Delays in processing can therefore create instant "arrears" that are nobody's fault. Check this date on your first letters.

3. The calculation

   The CMS takes the paying parent's gross annual income from HMRC (normally the latest completed tax year), converts it to a weekly figure, adjusts for pension contributions, other children the paying parent supports, and shared care, then applies the formula percentages. See the calculation explained and how income really works. If the CMS cannot get income information it can impose a default maintenance decision (£39/£51/£64 a week for 1/2/3+ children) until real figures arrive.

4. Payment arrangement

   Direct Pay: the CMS sets the figure; you pay each other directly with no fees. Collect & Pay: the CMS collects and passes payments on — the paying parent pays 20% on top and the receiving parent gives up 4%. The CMS decides which applies; a paying parent showing an "unlikely to pay" history can be forced onto Collect & Pay. Note: the Government plans to abolish Direct Pay around 2027-28 — see the reform tracker.

5. Life of the case: reviews and changes

   Every case has an annual review against fresh HMRC data. In between, either parent can report a change of circumstances; an in-year income change generally only alters the figure if income has moved by 25% or more from the figure in use. Either parent can also seek a variation — for special expenses, or to bring in unearned or diverted income.

6. If payments are missed

   On Collect & Pay the CMS should act within days of a missed payment. Its enforcement powers escalate from deductions from earnings, through deductions direct from bank accounts, to liability orders, bailiffs, charging orders, and ultimately disqualification from driving or holding a passport, or committal to prison. Arrears figures should always be checked before you accept them — they are frequently built on flawed underlying decisions.

7. If a decision is wrong — or the service fails

   Two separate tracks. Wrong decision: request a mandatory reconsideration within one month, then appeal to the independent First-tier Tribunal. Poor service (delay, errors, misinformation): use the complaints ladder — CMS, then Independent Case Examiner, then the Parliamentary Ombudsman via your MP — which can lead to compensation.

8. End of liability

   Maintenance normally runs until a child turns 16, or 20 if they remain in approved full-time non-advanced education or training (A-levels or equivalent — not university), or until Child Benefit stops being payable for them. Cases also end on the death of either parent, reconciliation of the parents, or the child ceasing to live with the receiving parent.

Where cases most often go wrong