How Is Child Maintenance Calculated? UK 2026 CMS Guide

If you are separating or already parenting apart, one of the first practical questions is money: how much should be paid to support the children, and how is that figure worked out? In England and Wales, most child maintenance is calculated using a fixed government formula run by the Child Maintenance Service (CMS). This guide explains, in plain English, exactly how the calculation works in 2026, the five payment rates, how shared care and other children change the figure, what the CMS charges, and when you may need a court or a solicitor instead.

The rules come from the Child Support Act 1991 and the Child Support Maintenance Calculation Regulations 2012. The percentages in the formula are set in that legislation and are relatively stable, but the cash thresholds, flat-rate amount, application fee and collection charges are reviewed periodically. Wherever a figure can change, we say so and point you to gov.uk for the current number before you rely on it.

What is child maintenance?

Child maintenance is regular financial support towards a child's everyday living costs, paid by the parent who does not have main day-to-day care (the paying parent) to the parent or person who does (the receiving parent). It is separate from any division of property, pensions or spousal maintenance on divorce. It normally continues until the child is 16, or up to 20 if they remain in approved full-time, non-advanced education (for example A-levels) or approved training.

The parent who receives maintenance does not have to be a mother, and the paying parent does not have to be a father. What matters is who provides the main home for the child and who is the non-resident parent. Grandparents and other guardians with main care can also receive maintenance.

Three ways child maintenance can be arranged

Before looking at the formula, it helps to know that the CMS is not the only route. There are three main options.

A family-based arrangement. Parents agree an amount privately between themselves. It is flexible and free, with no CMS fees, but it is not legally binding and cannot be enforced if payments stop. Many parents still use the CMS online calculator as a starting point for a fair figure.
The Child Maintenance Service (CMS). A government service that works out the amount using the statutory formula and can arrange or enforce payment. This is the route most people mean when they ask how maintenance is "calculated".
A court order. The family court's powers over ordinary maintenance are limited because the CMS has primary jurisdiction, but courts can deal with specific situations such as "top-up" maintenance for very high earners, school fees, maintenance for a child with a disability, or maintenance for a stepchild.

Since 2014 there has usually been a requirement to consider or attempt a family-based arrangement, often via the Child Maintenance Options service, before the CMS will open a case. Check gov.uk for the current process.

How the CMS calculates child maintenance: the six-step formula

The CMS follows the same broad sequence in every case. Understanding these steps lets you sanity-check any figure you are given.

Work out the paying parent's gross income. The CMS normally takes the paying parent's gross annual income (before tax and National Insurance, but usually after pension contributions) from information supplied by HM Revenue & Customs, typically for the latest available tax year. This is converted to a weekly figure.
Check for things that change the income figure. The CMS looks at whether the paying parent has other children living with them and whether any pension contributions or other adjustments apply.
Decide which of the five rates applies. The gross weekly income is matched to one of five rates (explained below): nil, flat, reduced, basic or basic plus.
Apply the correct percentage for the number of children. The percentage depends on how many children the paying parent must support.
Adjust for shared care. The amount is reduced according to how many nights a year the child stays overnight with the paying parent.
Produce the weekly amount. The result is the weekly maintenance figure, which the CMS can review and update over time.

The five child maintenance rates explained

Which rate applies depends on the paying parent's gross weekly income. The income bands and the flat-rate cash amount can change, so treat the figures below as an illustration of how the bands work and confirm the current numbers on gov.uk.

1. Nil rate

No maintenance is payable under the formula. This typically applies where the paying parent has very low gross weekly income (below the flat-rate threshold), or is a student, a prisoner, aged 16 or 17, or living in a care home and receiving certain help with fees. The exact qualifying categories are set in the regulations.

2. Flat rate

A fixed weekly amount is payable regardless of the number of children. The flat rate usually applies where the paying parent's gross weekly income is below the lower band, or where they (or their partner) receive certain benefits such as some state pensions or income-related benefits. The flat-rate figure is a single set amount per week; it is reviewed from time to time, so check gov.uk for the current amount.

3. Reduced rate

This applies where gross weekly income sits between the flat-rate threshold and the start of the basic rate band. The maintenance is the flat-rate amount plus a percentage of income above the lower threshold, calculated on a sliding scale so that payments increase gradually rather than jumping straight to the basic rate.

4. Basic rate

The basic rate is the one most working parents fall under. It applies to gross weekly income from the lower basic-rate threshold up to a set ceiling (historically the band has run to £800 gross per week). A straight percentage of gross weekly income is applied according to the number of children the paying parent is responsible for:

One child: 12% of gross weekly income
Two children: 16% of gross weekly income
Three or more children: 19% of gross weekly income

5. Basic plus rate

For higher earners, income above the basic-rate ceiling (historically £800 gross per week) up to the statutory cap is charged at a lower additional percentage, on top of the basic-rate percentage applied to the first band:

One child: 9% on income in the upper band
Two children: 12% on income in the upper band
Three or more children: 15% on income in the upper band

The CMS formula only considers gross income up to a weekly cap (historically £3,000 gross per week, roughly £156,000 a year). Income above the cap is ignored by the CMS calculation, which is where court "top-up" orders can become relevant for wealthy paying parents. Check gov.uk for the current cap.

How other children reduce the calculation

Before applying the percentages, the CMS reduces the paying parent's gross income to reflect other children they support, whether living with them or supported through another maintenance arrangement. The income figure is reduced by a set percentage depending on how many other children are involved:

One other child: reduce income by 11%
Two other children: reduce income by 14%
Three or more other children: reduce income by 16%

The percentages for the maintenance calculation are then applied to this reduced income, which lowers the amount payable for the children in the current case.

How shared care reduces child maintenance

If the child regularly stays overnight with the paying parent, the calculated amount is reduced. The reduction is based on the average number of nights per year the child stays with the paying parent:

52 to 103 nights a year: reduce the weekly amount by one-seventh
104 to 155 nights a year: reduce by two-sevenths
156 to 174 nights a year: reduce by three-sevenths
175 nights or more a year: reduce by one-half, plus a further set weekly reduction per child

Where care is genuinely equal, or where the child stays overnight for 175 nights or more, the maintenance can reduce substantially and in some cases to nil. Disputes about the true number of overnights are one of the most common reasons parents challenge a CMS calculation, so keeping an accurate record of overnight stays is worthwhile.

A worked example

Imagine a paying parent with a gross weekly income of £600, two children in the current case, no other children, and the children staying overnight with them for about 60 nights a year. The steps would be:

Gross weekly income is £600, which falls in the basic-rate band.
No other children, so no income reduction applies.
Two children means the basic rate of 16% applies: 16% of £600 = £96 per week.
Shared care of 60 nights falls in the 52 to 103 band, so reduce by one-seventh: £96 minus about £13.71 = roughly £82 per week.

This is illustrative only. Your actual figure depends on your precise income, the current thresholds and the exact overnight pattern. The free calculator on gov.uk is the best way to get a current estimate.

What counts as income, and what if it is hidden?

The CMS normally uses gross taxable income reported to HMRC, which captures most employed and self-employed earnings. Certain unearned income (such as significant income from property, savings, investments or dividends) is not automatically included, but the receiving parent can ask the CMS to take it into account through a variation. Variations can also be requested where a paying parent appears to be diverting income, living off assets, or artificially reducing their declared earnings.

If you suspect a paying parent is understating their income, hiding money through a company, or arranging their affairs to reduce maintenance, this is exactly the kind of situation where legal advice pays for itself. We can advise on variation applications and on court routes where the CMS formula does not reach the full picture.

CMS fees and Direct Pay v Collect & Pay

Using the CMS is not always free. There is usually a one-off application fee to set up a case, with exemptions for applicants under a certain age and for victims of domestic abuse. Once an amount is set, there are two ways to pay:

Direct Pay: the CMS works out the amount, but the parents arrange payment between themselves directly. There are no ongoing collection charges.
Collect & Pay: the CMS collects the money from the paying parent and passes it to the receiving parent. This attracts collection fees: historically an amount is added on top of the maintenance for the paying parent and a percentage is deducted from the amount the receiving parent gets. Collect & Pay is generally used where direct payment has broken down or there is a history of non-payment.

The application fee and the collection percentages are set by government and have been the subject of reform proposals, so confirm the current fees on gov.uk before deciding which service to use.

What if the paying parent does not pay?

If a paying parent falls into arrears on a CMS case, the CMS has strong enforcement powers. These can include taking payments directly from wages through a deduction from earnings order, taking money directly from a bank or building society account, and applying to court for enforcement. In serious cases the courts can, on application, remove a driving licence or passport, or in the most extreme cases impose a prison sentence. Enforcement is generally only available where the CMS is managing collection, which is one reason receiving parents move to Collect & Pay when payments stop.

When the court, not the CMS, decides maintenance

The CMS handles the great majority of cases, but the family court retains a role in specific situations:

Top-up maintenance where the paying parent's income exceeds the CMS gross-income cap, so the receiving parent seeks additional support above the maximum CMS figure.
School fees orders to cover private education costs, which fall outside the CMS formula.
Maintenance for a child with a disability, to meet expenses connected to the disability.
Maintenance for a stepchild or a child who is not the paying parent's biological or adopted child, where the CMS has no jurisdiction.
Where both parents agree a maintenance figure and want it recorded in a consent order, for example as part of an overall financial settlement on divorce. Note that after 12 months either parent can usually apply to the CMS to override such an order.

Can you challenge or change a CMS calculation?

Yes. If you think the CMS has made a mistake, for example using the wrong income figure or the wrong number of overnights, you can ask for a mandatory reconsideration, and if still dissatisfied you can appeal to an independent tribunal. Separately, either parent can report a change of circumstances, such as a significant change in income, a new child, or a change in shared care, and the CMS will review the calculation. The CMS also carries out periodic reviews using updated HMRC income data. Strict time limits apply to reconsiderations and appeals, so act quickly and take advice if you are unsure.

How MCR Solicitors can help

The CMS formula looks simple on paper, but real cases are rarely simple. Disputes over the true level of income, self-employment and company earnings, hidden assets, the correct number of overnight stays, high-earner top-up claims, school fees and cross-border issues all sit outside a basic calculation. Getting the right advice early can make a substantial difference to the amount paid or received over many years.

At MCR Solicitors in Manchester, our family law team advises parents across England and Wales on child maintenance, variations, court top-up and school fees applications, enforcement and how maintenance fits into a wider divorce or financial settlement. Call MCR Solicitors today on 0161 466 1280 for clear, practical advice on your situation.

Frequently asked questions

How much child maintenance should I pay for one child in the UK?

Under the CMS basic rate, maintenance for one child is broadly 12% of the paying parent's gross weekly income, before any reductions for shared care or other children. The precise figure depends on your income band and overnight arrangements. Use the free calculator on gov.uk for a current estimate based on your actual income.

Is child maintenance based on gross or net income?

The CMS uses gross income, meaning income before tax and National Insurance are taken off, though usually after pension contributions. It normally comes from the paying parent's HMRC records for the latest available tax year, converted into a weekly figure.

Does 50/50 shared care mean no child maintenance is payable?

Not automatically. Where the child stays overnight for 175 nights or more a year, the calculation is reduced by half plus a further per-child reduction, which can bring it to nil, but the outcome also depends on each parent's income. Equal overnights do not guarantee zero maintenance, and the parent treated as the main carer can still be entitled to a payment.

Do I have to use the Child Maintenance Service?

No. Many parents use a private family-based arrangement, which is free and flexible but not legally enforceable. The CMS is there when parents cannot agree or when payments are not being made reliably. You can move from a private arrangement to the CMS at any time.

Does child maintenance stop at 16?

It can continue beyond 16. Maintenance is usually payable until the child turns 16, or up to their 20th birthday if they remain in approved full-time, non-advanced education such as A-levels, or in approved training. It generally stops once they leave qualifying education or training.

Can child maintenance be increased for a high earner?

The CMS formula only counts gross income up to a weekly cap. If the paying parent earns above that cap, the receiving parent can apply to the family court for a top-up order in addition to the maximum CMS amount. The court can also deal with school fees and disability-related costs that the CMS formula does not cover.

How is Child Maintenance Calculated UK? Complete Guide 2026