Fifty two nights. That is the number that decides whether a paying parent's figure drops by a seventh or does not move at all, and almost nobody arguing about child maintenance at the kitchen table knows it.
Child maintenance is one of the few parts of separating that runs on a published formula rather than on negotiation. The Child Maintenance Service does not weigh up who was at fault, who left, or who is being reasonable. It takes a gross income figure from HMRC, applies a percentage, and adjusts for overnight stays. Understanding the formula is the difference between a fight and a calculation.
Here is how it actually works, from the Child Maintenance Service's own step by step guide.
The Five Rates
Everything starts with the paying parent's gross weekly income: pay before tax and National Insurance, after pension contributions are taken off. HMRC supplies the figure, which is why disputing it rarely goes anywhere.
That number drops into one of five rates.
| Rate | Gross weekly income | What is paid |
|---|---|---|
| Nil | Under £7, or certain circumstances such as being a student or in prison | £0 |
| Flat | £7 to £100, or on certain benefits | £7 a week |
| Reduced | £100.01 to £199.99 | £7 plus a percentage of the income above £100 |
| Basic | £200 to £800 | A straight percentage of gross weekly income |
| Basic plus | £800.01 to £3,000 | Basic percentages on the first £800, lower percentages above it |
Above £3,000 a week the CMS stops. A receiving parent who wants more than the formula gives at that level has to apply to court for a top up order, which is a different process with different costs.
The Percentages
For the basic rate, which covers most working parents, the figure is simply a share of gross weekly income.
| Number of children | Basic rate, £200 to £800 | Basic plus, portion above £800 |
|---|---|---|
| One | 12% | 9% |
| Two | 16% | 12% |
| Three or more | 19% | 15% |
The reduced rate works differently. It is £7 plus 17% of the income above £100 for one child, 25% for two, and 31% for three or more.
A worked example
A paying parent earning £1,000 gross a week with two children:
- 16% of the first £800 is £128
- 12% of the remaining £200 is £24
- Total before any shared care reduction: £152 a week
The two band structure is the part people miss. They take 16% of £1,000, get £160, and then cannot work out why the statement says something else.
The 52 Night Cliff Edge
If the child stays overnight with the paying parent, the figure comes down. But only once the nights cross a threshold, and the reductions arrive in steps rather than gradually.
| Overnight stays a year | Reduction |
|---|---|
| Fewer than 52 | None |
| 52 to 103 | One seventh |
| 104 to 155 | Two sevenths |
| 156 to 174 | Three sevenths |
| 175 or more | Half, plus a further £7 a week for each child |
Fifty two nights is one night a week. One hundred and seventy five nights is very close to an even split. Between those two points, four nights a year can move a family from one band to the next and change the payment permanently.
This is where coaching work and legal work part company. A solicitor will tell you what the bands are. The harder question is whether a parent is asking for more nights because they want the time, or because they have worked out what the nights are worth. Those two motives produce the same request and need completely different responses.
What Parents Get Wrong
Treating maintenance as a lever. Maintenance and contact are separate in law. Withholding one because of the other does not work and is noticed.
Assuming a private agreement is safe. A family based arrangement is perfectly legal and costs nothing, and it has no enforcement behind it whatsoever. If the paying parent stops, the receiving parent starts from scratch with the CMS.
Not telling the CMS about a change. Income changes of 25% or more trigger a recalculation. Sitting on a pay rise builds an arrears problem rather than avoiding one.
Confusing maintenance with the rest of the settlement. Child maintenance is not spousal maintenance, it is not a share of the house, and it does not touch pensions. Those are separate questions, decided separately. How the family home is actually decided and how pensions are split run on entirely different logic.
Arguing about the formula instead of the relationship. The percentages are not negotiable. The way two parents talk to each other for the next decade is. That is the part worth spending energy on, and it is what co-parenting after divorce is really about.
Where to Get the Actual Number
The government's child maintenance calculatorgives an estimate in a couple of minutes. It is the right first stop, because it replaces a guess with a figure, and a figure is much easier to discuss than a suspicion.
If you are already in family court proceedings about your children, you may also be referred to the Cafcass course. That is a separate process with its own deadline, explained in Planning Together for Children.
Frequently Asked Questions
Does child maintenance stop at 16?
No. It continues while the child is under 16, or under 20 if they are in approved full time education up to and including A level, or on approved training.
Does a new partner's income count?
No. The CMS looks at the paying parent's gross income only. A new partner's earnings are not part of the calculation, however much that feels wrong to the other household.
What if the paying parent is self employed?
The CMS still uses HMRC data, which for a self employed parent means the figures from their tax return. Where income is genuinely unclear, the CMS can apply the default rate of £38 a week for one child, £51 for two and £64 for three or more until it has a proper figure.
Can we agree a different amount between ourselves?
Yes. A family based arrangement can be any amount you both accept, and many work well for years. It has no legal force, so it depends entirely on the relationship holding up.
Does the formula change if the children live in different households?
The percentages are applied across all the children the paying parent is liable for, then divided between the receiving parents in proportion to the number of children in each household.
The Part the Formula Does Not Cover
The calculation takes a minute. Accepting it takes much longer, because the number always means something beyond the money: whether the other parent is being fair, whether the time with the children is being valued properly, whether any of this is going to settle down.
That is coaching territory rather than legal territory. If the figure has landed and the conversation around it has stalled, book a free call and we will work on the conversation rather than the arithmetic.
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