Child Maintenance and Overnight Stays: How the CMS Decides Shared Care

If you pay or receive child maintenance through the Child Maintenance Service (CMS), the number of nights your children spend with each of you can change the amount. When you both agree on that number, it is usually simple. When you don't, it can turn into a long back-and-forth about who had the children when.

On 19 October 2026 a government minister set out how the CMS handles those disagreements, in an answer to a written parliamentary question. Here is what she said, what the official guidance adds, and the simple habit that makes all of this easier: keeping a clear, shared record of which home the children slept in each night.

What the minister said

Andrew Snowden MP asked the Department for Work and Pensions what evidence the CMS accepts when parents dispute how many nights a child spends with each of them. Lilian Greenwood, the DWP minister, answered on 19 October 2026 (full text also on Westminster Brief). In summary:

• The paying parent's maintenance can be reduced if they have the child overnight for at least 52 nights a year, which is one night a week on average. The reduction goes up in set bands as the number of nights rises.
• The CMS cannot tell parents what shared care should happen. Its job is to work out what shared care is happening, based on the evidence, and reflect that in the calculation.
• The most reliable sources carry the most weight. The answer names court orders, formal or informal agreements between parents, and evidence of an established pattern of care.
• What actually happens can count. If the care really happening is different from a formal arrangement, the CMS may take account of the care provided in practice, as long as there is enough evidence.
• No side is favoured. When parents disagree, caseworkers must consider all the relevant evidence from both parents and must not make assumptions in favour of either.

How the CMS counts overnight stays

The GOV.UK guidance on telling the CMS about living arrangements explains the counting in more detail.

• Only nights count. Daytime visits on their own cannot be used for shared care reductions.
• It is about who is responsible that night. A night still counts if the child sleeps somewhere else, such as a sleepover, as long as the paying parent is responsible for them that night and would be the one contacted in an emergency.
• It is a yearly average. The CMS adds up the overnight stays in a year and divides by 52. Two nights every fortnight is 52 nights, an average of one a week. Six weeks every summer plus two weeks at Christmas is 56 nights, which also averages one a week.
• Equal nights don't automatically mean nothing to pay. If the children spend about the same number of nights with each of you, the CMS also looks at who provides most of the day-to-day care.

For paying parents on an eligible rate, the guidance sets out these bands:

Not everyone is affected the same way. Changes in overnight stays don't change payments for someone on the Nil rate, or on the Flat rate because their income is £100 a week or less. A Reduced or Basic rate payment can't go below £7 a week. For a rough idea of your own figure, try our child maintenance calculator.

What evidence the CMS can accept

This is the part many parents find surprising. If you report a change to overnight stays, or dispute a change the other parent has reported, GOV.UK says the CMS can only accept these as supporting evidence:

• a current court order
• a formal agreement, for example one drawn up by a solicitor
• another official document, such as a Cafcass or social services report

It also says the CMS cannot accept messages that are only between you and the other parent, photos of your child, screenshots of social media, or calendar entries.

Two other points from the guidance matter here:

• If you both agree on the change, the CMS may not need to look at supporting evidence at all.
• You can report a change without evidence. The CMS will review the information it has and tell you its decision.

Why a clear record of nights still matters

GOV.UK itself says it is important to keep a record of how many nights your child stays with you, because a change in the yearly total could change the weekly average and the calculation. A clear record helps in a few practical ways:

• You can both agree on the number. Most disputes start with two different memories of the same year. If you both look at the same record, there is less to argue about, and agreement is the route where the CMS may not need any evidence.
• You notice when the average changes. Extra weekends, a new school-term pattern or a long summer can move the yearly total into a different band. The CMS wants changes reported as soon as possible after they happen, even if you think they are temporary, and it can't take a report before the change happens.
• You know when it's time to formalise. If the real pattern has drifted from your court order or agreement and you can't agree on it, that's a sign to talk to a mediator or solicitor about putting the current arrangement in writing.
• Holidays and swaps are easier to count. Christmas, half-term and one-off swaps are the nights people forget. Our school holiday planner helps you map those out in advance.

What a useful record looks like

• Which home each child slept in, night by night
• Any one-off changes and swaps, and that you both agreed to them
• Nights a child spent elsewhere, such as at a grandparent's or on a school trip, and which parent was responsible
• A running total for the year, so you can see the weekly average at a glance

If you are building a regular pattern from scratch, our guides to 50/50 schedules and co-parenting calendars are a good place to start. For how records are treated in the family court, which is a separate system from the CMS, see co-parenting records in UK family court.

If you disagree with a CMS decision

You can ask the CMS to look at a decision again. This is called a mandatory reconsideration, and your decision letter explains how to ask for one. According to GOV.UK, a different outcome is more likely if there is updated information or new supporting evidence the CMS hasn't seen before. If you are paying, keep making your regular payments until the CMS responds to a change you've reported. Any change to payments is backdated to the date the change happened.

Separately, the CMS is going through other changes this year. Our guide to Child Maintenance Service changes in 2026 covers those.

Where Larkling fits

Larkling gives both homes one shared calendar that you can both see, so there is a single picture of where the children are each night rather than two versions. When you agree a swap or a change to the usual pattern, there is a record of what was agreed, so the year's nights are easier to tally when you need to. Larkling is a way to stay organised and on the same page, not a substitute for the evidence the CMS asks for. It is always free for both parents, and it works for every family shape, with Solo Mode if your co-parent doesn't sign up.

This page is general information as published on 26 October 2026, not legal advice. It is based on the written answer to parliamentary question 32153 (19 October 2026) and the GOV.UK guidance linked above, which may change. Contact the Child Maintenance Service, or speak to a family solicitor or mediator, about your own situation.