Child maintenance calculator: income and shared care

This guide explains the Child Maintenance Service calculation in Great Britain. Northern Ireland has a separate service; use the appropriate official calculator and guidance.

In this article, we’ll answer your big questions:

• How is child support worked out in the UK?
• How can you use a child support calculator?
• Who has to pay child support in 50-50 custody (UK)?
• What can you do if child support is not paid?

Child maintenance is separate from the overall cost of a divorce. A historic divorce-cost average does not predict your maintenance liability.

Don’t worry! We’re ready to guide you, giving you the best advice to keep your money safe.

Before we get started, feel free to use the resource below to find out how much you’ll need to pay in child maintenance or to calculate how much you’ll receive.

Calculate your child support

Use the official government calculator for an estimate. Any calculator on this page is guidance, not a CMS decision or an order to pay.

Child Maintenance Calculator

Gross Weekly Income

£

This is before tax and deductions

Children

1 2 3 or more

How many to be covered by child maintenance

Children from other parent(s)

0 1 2 3 or more

Those living with or covered by child maintenance

Nights per week with children

None Up to 1 night a week 1 to 2 nights a week 2 to 3 nights a week More than 3 nights a week – but not half the time Half the time

Averaged out over a year

This is a guidance tool only and not an assessment. For accurate child maintenance assessment, contact the Child Maintenance Service. Do not rely solely on this calculator’s results.

The government calculator gives an estimate from the information entered. CMS can reach a different figure after applying its rules to verified circumstances. See related guidance.

You can use this child maintenance calculator if you’re the paying parent or if you’re not and want to see how much you are entitled to receive.

How often are payments reviewed?

CMS will automatically review your case each year.

Report relevant changes promptly. CMS has specific rules for changes between annual reviews, including income thresholds and permitted variations; not every expense or income movement changes the amount immediately.

For example, if the child stays overnight with them more often. You should report a change as soon as it happens.

How is it calculated in the UK?

Child support payments can be negotiated and arranged by both parents on their own.

These arrangements are called family-based arrangements. You can use my free Child Maintenance Calculator earlier in this post to get a rough idea of how much it will cost.

The alternative option is to get the Child Maintenance Service (CMS) to calculate the required child support payments. 

The CMS can even help you enforce payments if needed.

Even when you use a family-based arrangement, it’s worth using the free UK child support calculator first – and it’s always worth speaking to the CMS for support. 

CMS uses a six-step calculation. Key factors include:

1. The paying parent’s gross weekly income
2. The number of children they need to contribute for
3. The number of nights they spend caring for the child(ren)
4. Other qualifying children, pension contributions and permitted adjustments to income, as well as relevant family-based maintenance arrangements

These factors enter the calculation at different stages. Payments for other children are not simply a fixed percentage discount from a new award.

We have elaborated on each of these below…

1. Gross weekly income

CMS applies income bands and rules to the adjusted gross weekly income. The table is an outline, not a complete calculation:

Weekly income (gross)	Category/Rate	Child support payment
Income information unavailable	Default decision	CMS determines the applicable default amount or uses other available evidence; check the decision and current guidance
Less than £7	Nil	£0
Between £7 and £100 or receiving benefits	Flat	£7
Between £100.01 and £199.99	Reduced	Calculated using a formula
£200 to £3,000	Basic and Basic Plus	Basic percentages up to £800; lower Basic Plus percentages on the portion above £800
More than £3,000	CMS income cap	The receiving parent may apply to court for additional maintenance

The calculation also depends on the children included and any relevant adjustments.

2. Number of children

At the Basic rate, the number of qualifying children determines the percentage applied to adjusted gross weekly income.

For income up to £800 a week, the Basic percentages are 12% for one child, 16% for two and 19% for three or more. For the portion above £800, up to £3,000, the Basic Plus percentages are 9%, 12% and 15% respectively.

Shared care and other qualifying children can affect the result under the applicable rules.

3. Nights spent caring for the child(ren)

Overnight shared care can reduce liability under specific rules. Equal day-to-day care is a separate question and may mean no maintenance is payable.

The table summarises the overnight reductions for relevant Basic, Basic Plus and Reduced-rate cases. Minimum-payment and other rules can apply; flat-rate benefit cases have different rules.

Nights spent in the paying parent’s care per year	Reduction applied to child support payments
52 to 103 nights	1/7th per child
104 to 155 nights	2/7ths per child
156 to 174 nights	3/7ths per child
175 nights +	50% + £7 reduction per child

4. Other children and existing arrangements

A paying parent may already have children from a previous relationship.

CMS may reduce the income used where the paying parent or their partner receives Child Benefit for other children they support. The detailed guidance says these children may or may not live with them.

For qualifying Basic or Basic Plus cases, the income reductions are 11%, 14% or 16% for one, two or three or more such children. Maintenance paid under other family-based arrangements is taken into account differently; it is not the same automatic reduction.

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Do you still pay with 50-50 care?

Not necessarily. If CMS establishes equal day-to-day care, no maintenance is payable for that child. Equal overnight stays alone do not always establish equal day-to-day care.

Divorce Costs

While child support is certainly a key component of divorce proceedings, it’s just one piece of the financial puzzle.

It’s important to keep in mind that divorce involves a range of expenses beyond supporting children. To offer a complete picture, I’ve included a table below outlining various costs associated with divorce.

Category	Costs
Court Fees	Filing for Divorce: £628 application fee in England and Wales, according to GOV.UK checked 4 October 2026. Fee help may be available; check current fees before applying. Additional Applications: Financial orders or child arrangements.
Legal representation	Solicitors may charge fixed fees or hourly rates. Obtain a written quote showing VAT, included work and additional charges; costs depend on the case and provider.
Barrister Fees	For cases that go to court or require specialised legal advice. The cost of this will be completely dependent on your case and preferences.
Financial Advisor or Accountant Fees	For cases involving complex financial matters. The cost of this will be completely dependent on your case and preferences.
Valuation Fees	You may need to pay for property, business, or pension valuations as part of the financial settlement. The cost of this will be completely dependent on your case and preferences.
Out-of-Court Options	Mediation, collaborative law and arbitration have different charging structures. Ask for a written estimate and check eligibility for legal aid or any current mediation support scheme.
Indirect Costs	Time off work to attend court hearings or meetings with solicitors. Child maintenance costs.

Who pays in 50-50 custody (UK)?

CMS assesses who provides day-to-day care. Child Benefit can be relevant evidence but is not a universal rule making the other parent liable whenever nights are equal.

Source: https://forums.moneysavingexpert.com/discussion/697829/child-support 

Where day-to-day care is unequal but overnight care is shared, the relevant shared-care reduction may apply.

It’s important to remember that child support payments are for the benefit of the children and help to contribute to their education, health, and overall happiness and well-being.

How is it enforced?

As part of your divorce or separation, you can negotiate and arrange the payment of child support independently.

However, if there is animosity or mistrust, you might want to ensure payments will be made by the paying parent. There are different ways to do this. 

In England and Wales, as part of a divorce, you may choose to get a Consent Order.

A consent order can include child maintenance. It does not automatically expire after one year: once the relevant 12-month restriction has passed, a qualifying CMS application can replace its ordinary child-maintenance provisions, subject to exceptions. See related guidance.

There are legal and court costs to get a Consent Order, but you might qualify for financial assistance.

Another option is to get the CMS to enforce child support directly through a service called Collect and Pay.

Note this is different to the Direct Pay service they also offer. 

Under Collect and Pay, the paying parent normally pays 20% on top of the maintenance, while 4% is deducted from the receiving parent’s payment. Direct Pay has no collection fee.

You could also consider mediation to help you resolve child maintenance disputes amicably without going to court, potentially saving you money and time.

What if my ex doesn’t pay what they owe?

For unpaid CMS maintenance, deductions can be made from earnings or bank accounts where the legal conditions are met. These are not confined to mutually exclusive employed and unemployed categories.

Further enforcement can involve a liability order and the applicable legal process, including enforcement against goods or property. Such steps are not automatic.

Courts have additional powers in serious cases, including disqualification or imprisonment where the statutory tests are met. CMS cannot simply impose these penalties itself.

References

1. Money Helper – Divorce Costs