Child maintenance after separation: private arrangements, CMS and what to record

What child maintenance is

GOV.UK explains child maintenance as a financial arrangement for a child’s living costs when one parent does not live with the child. Both parents remain responsible for the cost of raising their children, even if one parent does not see them.

Maintenance is not the same as contact. A parent should not stop paying because they are unhappy about contact, and a parent should not withhold time with a child because maintenance is disputed. The issues may be connected emotionally, but they are separate legally and practically.

Private arrangements

Parents can agree child maintenance privately if both are able to do so safely and reliably. A private arrangement can be flexible: monthly payments, direct payments for agreed costs, school uniform, childcare, travel or a mix of these.

The weakness is enforcement. A private arrangement depends on cooperation. If payments become late, inconsistent or disputed, the receiving parent may need to consider the Child Maintenance Service.

Put the arrangement in writing. Include the amount, payment date, bank details, what the payment covers, how extras are dealt with, and when the arrangement will be reviewed. Avoid vague phrases like “help out where possible” if the relationship is strained.

Child Maintenance Service

The Child Maintenance Service can calculate maintenance, arrange payments and take action if a parent does not pay. GOV.UK says maintenance can be arranged privately or through the CMS.

Using the CMS can be useful where income is disputed, payments have stopped, one parent will not engage, or direct communication is unsafe. GOV.UK also notes that parents can tell the CMS if it is not safe for the other parent to know their location or changed name.

How it is calculated

The CMS usually starts with the paying parent’s gross yearly income using HMRC information, then considers factors such as benefits, pension contributions, other children the paying parent supports and the number of nights the child stays with them.

The GOV.UK calculator gives an estimate. It is useful for negotiation, but it is not a binding decision and the final CMS calculation can differ.

Changes and variations

Maintenance may need reviewing if income changes, care arrangements change, a child leaves education, a parent loses work, or there are relevant additional costs. If using the CMS, either parent may be able to ask for certain matters to be considered through a variation.

Keep evidence of the change. A short written explanation, payslips, benefit letters, childcare invoices, school records or a revised overnight pattern can make the issue easier to understand.

If payments stop

If payments stop under a private arrangement, start by checking whether there is a practical explanation. If there is no good reason or the pattern repeats, move quickly to written records: dates missed, amounts due, messages sent and any response.

For CMS cases, use the CMS process. Do not rely only on informal messages if there is already a formal arrangement in place. If the issue sits alongside child arrangements, keep the maintenance records separate from contact arguments so the factual picture stays clear.

The short version

Child maintenance should be specific, recorded and reviewed when circumstances change. Private arrangements can work well where trust remains. The CMS is there where calculation, payment or enforcement needs a formal route.

Nothing in this guide is legal advice for your specific situation.

Related guides

• Child arrangements after separation
• Divorce process: first steps and timings
• GOV.UK: Child Maintenance Service

All resources