Last updated: August 2026
by Jess Knauf, Director of Client Strategy at Mediate UK. Reviewed by Belinda Atkins, Managing Director, Family Legal Ltd. Written in accordance with our editorial standards. Information is current as of 31 August 2026.
Key Takeaways
- The Child Maintenance Service works out payments from the paying parent’s gross weekly income, taken straight from HMRC records, not from what either parent says they earn (see the Family Law Wiki reference entry on child maintenance).
- At the basic rate, the headline percentages are 12% for one child, 16% for two and 19% for three or more, before any reductions.
- Two things reduce the figure: other children living with the paying parent, and the number of nights the children stay overnight.
- There is no longer an application fee to use the CMS. It was removed on 26 February 2024. Collect and Pay still costs 20% on top for the paying parent and 4% off the top for the receiving parent.
- The formula is a blunt instrument. It does not touch school fees, childcare, university costs or a parent whose income swings, which is why many separated parents agree their own figure instead.
How is child maintenance calculated
Child maintenance is calculated as a percentage of the paying parent’s gross weekly income, using a six step formula set by the Child Maintenance Service. At the basic rate, that is 12% of gross weekly income for one child, 16% for two children and 19% for three or more. The figure is then reduced for any other children living in the paying parent’s household, and reduced again for each band of overnight stays the children have with them.
If you want to know how child maintenance is calculated, the honest answer is that the sum itself is simpler than most people expect, and the arguments around it are harder. The Child Maintenance Service applies a fixed formula to one number, the paying parent’s gross weekly income, and everything else is an adjustment to that starting point.
This guide walks through the formula step by step, with the 2026 rates and worked examples, so you can work out roughly what the CMS would say in your situation. It also covers the parts the formula deliberately ignores, such as school fees and childcare, and what you can do about those. Whether you are the parent paying or the parent receiving, the aim is that you finish this page knowing the number and knowing your options.
Our family mediator walks through how child maintenance works in the UK, and where parents most often get stuck.
What Is Child Maintenance, and Who Has to Pay It?
Child maintenance is regular financial support towards a child’s everyday living costs, paid by the parent the child does not mainly live with. In the CMS system that parent is called the paying parent, and the parent the child mainly lives with is the receiving parent.
A few points catch people out:
- It is not linked to contact: a parent must still pay even if they are not seeing the children, and a parent must still allow contact even if maintenance is not being paid. The two are separate in law.
- It is paid to the parent, not the child: the money goes to the receiving parent to spend on the child’s costs.
- Either parent can be the payer: the formula is about where the child mainly lives and who earns what, not about which parent is the mother or the father.
- It covers everyday costs: housing, food, clothes, and the general cost of raising a child. It is not designed to cover school fees or one off extras.
Child maintenance is also a separate question from where the children live and how much time they spend with each parent. If that is unresolved too, our complete guide to child arrangement orders covers that side of things.
How Do You Arrange Child Maintenance in the UK?
There are three routes, and most families are free to pick whichever suits them:
- A family based arrangement: the two of you agree an amount and pay it between yourselves. Free, flexible, and not legally enforceable.
- The Child Maintenance Service: the CMS calculates the amount using the statutory formula and can collect and enforce it.
- A court order: only available in a limited set of situations, covered further down this page.
Most parents start with the formula as a reference point even if they never contact the CMS, because it gives a neutral figure that neither of them invented. That is a sensible instinct. The number below is the number the state would arrive at, so it is a fair place to begin the conversation.
What stands out in the national picture is how many families never get there at all. Reporting to the House of Lords Public Services Committee found that of the 2.4 million separated families in Great Britain, 35% had no financial child maintenance arrangement of any kind, on figures for the financial year ending 2025. The formula is not the hard part. Agreeing to use it is.
The CMS calculator gives you a figure, but not the answer on school fees, clubs, uniform or who pays for the extras. Our accredited family mediators help you agree the whole picture, and put it in writing so it is not revisited every month.
How Does the Child Maintenance Service Calculate the Amount?
The CMS follows the same six steps in every case. Working through them in order is the quickest way to see where your own figure comes from.
| 1 | Work out the gross weekly incomeThe CMS takes the paying parent’s gross annual income from HMRC records for the most recent tax year, then divides it by 365 and multiplies by 7. Gross means before tax and National Insurance, but after pension contributions. |
| 2 | Check for things that change that figureEither parent can ask the CMS to look again if the income on file is out of date or incomplete. This is where variations come in, covered further down. |
| 3 | Take off for other children in the householdIf the paying parent has other children living with them, the gross weekly income is reduced before any percentage is applied: by 11% for one other child, 14% for two, and 16% for three or more. This is how it works at the basic and basic plus rates. The reduced rate uses its own percentage table instead. |
| 4 | Apply the right rateThe adjusted income decides which of the six rates applies, and the percentage is applied to it. The full rate table is in the next section. |
| 5 | Reduce it for shared careCount the nights a year the children stay overnight with the paying parent, and cut the figure by the matching fraction. |
| 6 | Divide between the childrenWhere the children live in different households, the weekly amount is split between them. Where they all live together, this step makes no difference. |
The official calculation is set out in the GOV.UK guide, how the Child Maintenance Service works out child maintenance, which also carries the government’s own calculator.
What Are the Child Maintenance Rates in 2026?
There are six child maintenance rates, and which one applies depends entirely on the paying parent’s gross weekly income after the step 3 adjustment.
| Rate | Gross weekly income | What is paid |
| Default | Not known or not provided | £39 a week for one child, £51 for two, £64 for three or more |
| Nil | Below £7 | Nothing. Also applies to certain paying parents whatever their income, including prisoners and 16 to 19 year olds in full time non advanced education |
| Flat | £7 to £100, or on certain benefits | £7 a week, whatever the number of children |
| Reduced | £100.01 to £199.99 | £7 a week, plus 17% of income above £100 for one child, 25% for two, 31% for three or more |
| Basic | £200 to £800 | 12% for one child, 16% for two, 19% for three or more |
| Basic plus | £800.01 to £3,000 | The basic rate on the first £800, plus 9% for one child, 12% for two and 15% for three or more on the rest |
These are the statutory figures as of August 2026, taken from the GOV.UK step by step guide, how we work out child maintenance.
Gross weekly income is capped at £3,000. Above that the CMS simply stops counting, and the receiving parent has to apply to the family court for a top up order if they want more. That cap has not moved since 2012, so it now bites on a good many more households than it once did.
How Much Is Child Maintenance for One, Two or Three Children?
The quickest way to see how much child maintenance works out at is to follow three real shaped examples through the formula.
Example 1: one child, £500 gross a week, 60 nights a year
- No other children in the household, so the income stays at £500.
- £500 is in the basic band, so the rate is 12% for one child: £60 a week.
- 60 nights falls in the 52 to 103 band, so cut it by one seventh: £60 less £8.57.
- Result: about £51 a week.
Example 2: two children, £900 gross a week, one child at home, 104 nights a year
- One other child living with the paying parent, so take 11% off the income first: £900 becomes £801.
- £801 crosses into basic plus, so the sum is 16% of the first £800 (£128) plus 12% of the remaining £1.
- 104 nights falls in the 104 to 155 band, so cut it by two sevenths.
- Result: about £92 a week for both children, roughly £46 each.
Example 3: three children, £90 gross a week
- £90 is inside the flat rate band, so the number of children makes no difference at all.
- Result: £7 a week in total, not £7 per child.
Example 2 shows something parents often miss. A second family in the paying parent’s home reduces what the first family receives, and the reduction is applied to the income before any percentage is worked out, so it compounds. That is one of the points most likely to cause a row, and it is written into the regulations rather than being anyone’s decision.
Does Shared Care Reduce Child Maintenance?
Yes. Shared care reduces the amount, and it is counted in overnight stays across a year, not in hours or in daytime contact.
| Nights a year with the paying parent | Reduction |
| 52 to 103 (about one night a week) | One seventh off |
| 104 to 155 (about two nights a week) | Two sevenths off |
| 156 to 174 (about three nights a week) | Three sevenths off |
| 175 or more (roughly half the year) | Half off, plus a further £7 a week reduction for each child in this band |
Two things about this table cause more disputes than anything else in the formula. The bands are wide, so one extra night a week can move a family from one band to the next and change the payment sharply, which gives both parents a financial reason to argue about a single night. And even a genuine 50:50 arrangement does not usually take the payment to zero, because half off is still half on.
The House of Lords Public Services Committee looked at exactly this in its October 2025 report on reforming the Child Maintenance Service, and concluded that the formula was neither fair nor transparent and did not properly reflect shared care or modern family life. The government has not changed the calculation in response.
“We see the same argument again and again, and it is almost never really about the money. It is about one night a week, because one night a week moves you into a different band. When parents work the figure out together in a session, with the formula in front of them as a reference rather than a weapon, that argument tends to disappear within an hour. They stop negotiating against the bands and start talking about what the children actually need.”
Jess Knauf, Director of Client Strategy, Mediate UK
Stuck on the number?
A mediator can put the calculation in front of both of you and help you agree a figure that works, including the things the formula leaves out. The first step is a MIAM, a private meeting with a mediator to talk through your options.
Does the CMS Charge a Fee to Use It?
There is no application fee. The £20 charge that used to apply was removed on 26 February 2024 by the Child Support (Management of Payments and Arrears and Fees) (Amendment) Regulations 2024. A good deal of advice online still quotes it, so if you have been told to budget £20 to open a case, that advice is out of date.
What can still cost money is the way the payments are collected. The CMS offers two options:
- Direct Pay: the CMS works out the amount and the parents move the money between themselves. There are no collection fees.
- Collect and Pay: the CMS takes the money and passes it on. The paying parent pays 20% on top of the assessment, and the receiving parent gets 4% less than the assessed figure.
On a £100 a week assessment, that means the paying parent hands over £120 and the receiving parent gets £96. Nearly a quarter of the money disappears in charges, which is a strong argument for sorting the payment method out between yourselves if you possibly can.
This is due to change, but it has not changed yet. In June 2025 the government confirmed it intends to abolish Direct Pay, move everyone onto a single collection service, and cut fees to 2% for paying parents who pay on time and to 2% for receiving parents, while keeping the 20% charge for paying parents who do not. Implementation is planned for 2027 to 2028, so as of August 2026 Direct Pay still exists and the 2% figure does not yet apply to anyone. The House of Commons Library keeps a current summary in its briefing on what fees are charged when arranging child maintenance.
What Income Does the CMS Count, and What Happens if It Is Hidden?
The starting figure is taxable income reported to HMRC: employment income, self employment profits, and certain pensions, before tax and National Insurance but after pension contributions. That is deliberately mechanical, because the old Child Support Agency relied on parents declaring their own net income and it went badly.
The weakness of using an HMRC figure is that it can be a year or more out of date, and it does not see money that never appears on a tax return. If you think the calculation is based on the wrong picture, you can ask the CMS for a variation. Either parent can apply, and the grounds include:
- Unearned income: rental income, dividends, savings interest and similar, above a threshold.
- Diversion of income: where a parent controls a company and pays themselves a small salary while the money stays in the business.
- Assets: in some cases, capital held rather than income received.
- Special expenses: applied for by the paying parent, covering things like contact travel costs, or supporting a child with a disability.
The income used is also refreshed automatically once a year on the case anniversary. In between, 25% is the threshold at which the CMS will look again: a paying parent must report an income increase of 25% or more, and may report a fall of 25% or more, though they are not obliged to. A drop of 20% changes nothing at all until the annual review, which catches out plenty of paying parents whose hours have been cut.
Can You Challenge or Change a Child Maintenance Calculation?
Yes, and there is an order to it. Going straight to a complaint or straight to a tribunal is the most common mistake.
- Ask for a mandatory reconsideration: normally within 30 days of the date on the decision letter. The CMS looks at the decision again. You cannot appeal until this step is done.
- Appeal to the First tier Tribunal: normally within one month of the mandatory reconsideration notice.
- Report a change of circumstances: a different route entirely, for when the facts have changed rather than the decision being wrong.
- Apply for a variation: where the income figure does not reflect reality, as set out above.
Enforcement runs the other way. Where a paying parent on Collect and Pay does not pay, the CMS can take the money from wages or from a bank account, and in the more serious cases apply for a liability order, use bailiffs, or ask a court to remove a driving licence or a passport. The scale of the problem is significant: DWP figures published on 30 June 2026 show £791.2 million of unpaid maintenance has built up since the service began in 2012, and that 23% of paying parents on Collect and Pay paid nothing at all in the quarter to March 2026.
When Does a Court Decide Child Maintenance Instead of the CMS?
The CMS has the job in most cases, and the family court cannot simply take it over. There are exceptions, and they matter to a small but significant group of families:
- A top up order: where gross income is above the £3,000 a week cap, the court can order more on top of the maximum CMS assessment.
- School fees: the CMS formula does not cover them, so a school fees order is a court matter.
- A child with a disability: the court can order payments towards costs connected with the disability.
- Stepchildren: the CMS deals with biological and adoptive parents, so maintenance for a stepchild is dealt with by the court.
- A paying parent living abroad: usually outside CMS jurisdiction. There are real exceptions, though, including the Civil Service, the Diplomatic Service, the armed forces, the NHS, a UK local authority, and a company registered and based in the UK.
- By consent: the court can make an order in the terms both parents have agreed.
That last one comes with a rule worth understanding before you rely on it. If child maintenance is written into a consent order, it binds both of you, but after twelve months either parent can apply to the CMS anyway. If they do, the CMS calculation takes over and the child maintenance provisions in the order stop having effect. The rest of the order is unaffected, so spousal maintenance, capital terms and a clean break all stand, and any arrears built up before that point stay enforceable. So a consent order gives you a firm arrangement for a year, and after that it holds only for as long as you both want it to. That is the reality behind the twelve month rule, and it is a good reason to build an arrangement you both genuinely accept rather than one that was won.
Need the agreement made legally binding?
Our sister service, Family Law Service, drafts consent orders on a fixed fee, so a financial agreement reached in mediation can be turned into a court approved order without open ended solicitor costs. The online clean break consent order is £499.
What Can You Agree in Mediation That the CMS Formula Cannot?
This is the part most guides skip, and it is where the real money usually sits. The CMS produces one weekly number for everyday costs. It has nothing to say about the items separated parents actually fall out over:
- School fees, uniforms and trips: outside the formula entirely.
- Childcare and wraparound care: often the single biggest cost in the early years, and not counted.
- Clubs, music lessons, sport and equipment: not counted.
- University and the years after 20: CMS maintenance has stopped by then.
- A parent whose income moves: the annual review suits a salaried employee and suits nobody else.
- Care that does not fit the bands: a 50:50 week about week arrangement, or a pattern that changes in the holidays.
In family mediation you can deal with all of it in one conversation: a base figure, who pays for what on top, how it is reviewed, and what happens when someone’s circumstances change. You can agree a percentage split of extras rather than a fixed sum, or agree to revisit the figure each September. The formula cannot do any of that, because it was never designed to.
A mediated agreement of this kind is usually written up as a parenting plan or, where finances are involved, folded into a wider settlement. Our guide to whether a parenting plan is legally binding explains where it stands, and the complete guide to a financial consent order covers turning a financial agreement into a court approved order. Legal aid for family mediation is means tested, so if you meet the financial criteria your MIAM and mediation sessions are free, and you can check with our legal aid eligibility checker in about two minutes.
When Does Child Maintenance Stop?
In short, payments run until the child turns 16, or until they turn 20 if they stay in approved full time education or training up to A level or equivalent, whichever comes first. University does not count, and arrears survive the end date.
There is more to it than that, including what happens if the child moves in with the paying parent, starts work, or leaves a course part way through. Our full guide covers those in detail: read when do I stop paying child maintenance for the ages, dates and exceptions.
Summary
Child maintenance is calculated from the paying parent’s gross weekly income using a six step formula. Find the income, reduce it for any other children in that parent’s home, apply the rate for the number of children, then reduce the result for overnight stays. At the basic rate the percentages are 12%, 16% and 19% for one, two and three or more children, and the income counted is capped at £3,000 a week.
There is no fee to apply to the CMS. Collect and Pay costs 20% on top for the paying parent and 4% off the top for the receiving parent, and Direct Pay remains free and still available, whatever you may have read about the 2027 to 2028 reforms.
The formula is a floor, not a full answer. It says nothing about school fees, childcare, clubs or university, and its shared care bands are wide enough to turn a single overnight into an argument. Parents who agree their own arrangement, using the formula as a reference, usually end up with something that fits their family better and lasts longer.
Frequently Asked Questions
How much child maintenance should I pay for one child?
At the basic rate, 12% of your gross weekly income for one child, before any reductions. On £500 a week that is £60, falling to about £51 if the child stays with you 60 nights a year. If your gross weekly income is between £7 and £100, or you receive certain benefits, you pay the flat rate of £7 a week instead.
Is child maintenance based on gross or net income?
Gross. The CMS uses gross income taken from HMRC records, before tax and National Insurance but after pension contributions. The old Child Support Agency used net income that parents declared themselves, which is one of the reasons it was replaced.
Does 50/50 shared care mean no child maintenance?
Usually not. Where care is shared, the CMS treats whoever is registered with HMRC for Child Benefit as the receiving parent, and the other as the paying parent. At 175 nights a year or more the payment is halved and reduced by a further £7 a week for each child, but half of the assessment is still payable. It only reaches zero if the reduced figure works out at nothing, or if the two of you agree between yourselves that no payment is needed.
Do I have to use the Child Maintenance Service?
No. A family based arrangement between the two of you is perfectly valid and costs nothing. It is not legally enforceable, so either of you can go to the CMS later if it breaks down, but most parents who can agree find it cheaper, quicker and far less adversarial.
Does the CMS charge a fee to open a case?
No. The £20 application fee was removed on 26 February 2024 and applying is now free. Charges only arise if you use Collect and Pay, where the paying parent pays 20% on top and the receiving parent gets 4% less.
Can my ex refuse to pay child maintenance?
They can refuse, but the CMS has real powers to collect. It can take payments directly from wages or a bank account, and in serious cases apply for a liability order, instruct bailiffs, or ask a court to remove a driving licence or passport. Withholding payment because contact is being blocked is not a defence, as the two issues are legally separate.
Does having a new partner affect child maintenance?
A new partner’s income is never counted. What does change the figure is a new child living in the paying parent’s household, which reduces their gross weekly income by 11% for one, 14% for two and 16% for three or more before the rate is applied.
Is child maintenance the same as spousal maintenance?
No. Child maintenance supports the children and is worked out by the CMS formula. Spousal maintenance supports an ex husband or ex wife, is decided by agreement or by the court, and only arises where the couple were married or in a civil partnership. The two can run alongside each other in the same settlement.
Is child maintenance paid to the child or the other parent?
Almost always to the other parent. There is no rule in law about what the money must be spent on, because it is accepted that feeding, heating and clothing a child costs money. Some parents agree to pay it straight into an older child’s own account, which can work well where the child manages their own expenses, but that is a private agreement rather than the standard route.
Can a mother pay child maintenance?
Yes. The rules do not depend on gender at all. What decides who pays is which parent the children mainly live with, so a mother is the paying parent whenever the children mainly live with their father.
Do I have to pay child maintenance if my ex will not let me see the child?
Yes. Contact and maintenance are separate areas of law and one is never a condition of the other. If you later apply to court for a child arrangements order, the court may well ask whether you kept up your payments, and why not if you did not.
What happens to child maintenance if I am self-employed or have a variable income?
The CMS still starts from HMRC records, and for self employed parents that means the profit figure from the most recent tax return, which can be well out of date. It can include dividends and bonuses, and it can average income over a period. If the figure on file does not reflect what is actually coming in, a variation application is the route to get it looked at again.
Do I need to pay child maintenance for a step-child?
The CMS deals with biological and adoptive parents, so it will look to locate the child’s other biological parent rather than a step-parent. Maintenance for a step-child is a matter for the court, not the CMS, and it does not arise automatically.
Do I pay child maintenance if my ex re-marries?
Yes. Child maintenance carries on regardless of whether either parent remarries, and a new partner’s income is never counted. Remarriage affects spousal maintenance, which is a different thing entirely.
What happens if my circumstances change or I cannot afford to pay?
Report it. The annual review picks up changes on the case anniversary, and in between, 25% is the point at which the CMS will recalculate: an increase of 25% or more must be reported, and a fall of 25% or more can be. Talk to the other parent first if you can. Child maintenance is a legal liability and it survives bankruptcy, so leaving it unpaid builds arrears rather than clearing them.
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Agree the Figure Without the Fight
Our mediators help separated parents settle child maintenance alongside everything else, including the school fees, childcare and extras the CMS formula ignores. Start with a MIAM, a private meeting with a mediator, and see what is possible.
