Child maintenance explained: How to use a child maintenance calculator

Working out child maintenance is often a source of worry and confusion. Whether you're going to be paying it or receiving it, you want to know the amount is fair.

In this blog, we'll explain how child maintenance calculators work, what information you need and what affects the amount you'll pay or receive.

"Many parents worry they're paying too much or not receiving enough. Using a calculator removes emotion from the equation and gives you both a fair starting point to work from." Katie Reid, amicable

Child maintenance calculators take the guesswork out of working out fair payments and give you a clear figure to work with. They use the paying parent's income, number of children and overnight stays to calculate a weekly amount.

The government's official calculator can give you a clear starting point, whether you arrange maintenance privately or through the Child Maintenance Service (CMS).

What is child maintenance?

Child maintenance is a regular payment from the parent who doesn't live with the children most of the time. It goes to the parent who does most of the day-to-day care.

It's important to understand that child maintenance is completely separate from any arrangements about spending time with the children. Paying maintenance doesn't affect when or how often you see your children, and spending time with them doesn't mean you don't have to pay.

You can arrange child maintenance privately between you, or you can go through the Child Maintenance Service, or CMS.

Learn more about child maintenance and how long it takes to process here.

How is child maintenance worked out?

Child maintenance is based on the paying parent's gross income: their income before tax is taken off.

The calculation takes into account the number of children you have together. It also considers how many nights the children stay with the paying parent. If the paying parent has other children from another relationship, that affects the amount too.

The basic principle is simple: the more you earn, the more you pay. But there are different bands that affect how much is calculated.

Child maintenance calculator table

Keep in mind these are the rules the CMS uses. If you're making a private arrangement between you, you can agree whatever amount works for both of you.

What information do you need to calculate child maintenance?

To use a child maintenance calculator, you need a few pieces of information.

Gross annual income

You need the paying parent's gross annual income, or their weekly income before tax. You also need to know the number of children you're arranging maintenance for, and how many other children the paying parent has, if any.

How many nights per year the child stays with the paying parent

You'll need to work out how many nights per year the children stay with the paying parent. And finally, you need to know whether the paying parent receives certain benefits.

Gross income is on payslips, your P60 or tax returns if you're self-employed. If you're employed, it's easiest to use last year's gross income. If you're self-employed, the calculation is based on your most recent tax return.

For benefits, check your most recent letters or your online account.

How to use a child maintenance calculator

You can find the government’s child maintenance calculator here, or by searching for ‘calculate child maintenance’.

Step one: start by entering the paying parent's gross weekly or annual income. The calculator will convert it to weekly for you if you enter the annual amount. Then enter how many children you're calculating maintenance for.

Step two: factor in how many other children the paying parent has to support. This includes children from other relationships who they're paying maintenance for, or children who live with them.

Then you need to enter how many nights per year the children stay with the paying parent. This is important because if children stay overnight regularly, the maintenance amount reduces.

Step three: include whether the paying parent receives certain benefits like Universal Credit or Income Support. This might mean they pay the flat rate instead of a percentage of their income.

Hit calculate, and you'll get the weekly amount.

Things that change the maintenance amount

Several factors can change how much child maintenance is paid.

Income

The biggest difference is a change in income. If the paying parent gets a pay rise, the maintenance amount increases. That's why it's worth reviewing the amount regularly, especially if circumstances shift.

Overnight stays

Overnight stays are a big factor. The more nights children stay with the paying parent, the less maintenance they need to pay.

Number of children

If the paying parent has another child, maintenance for the existing children reduces. This is because they now have more children to support overall.

Do you have to use the government’s calculated amount?

No. If you're making a private arrangement, you can agree whatever works for you.

Many couples agree an amount that's different to what the calculator suggests. You might agree more than the calculator amount if the paying parent earns a good income and wants to contribute more. Or you might include additional costs on top of the basic maintenance, like half of school trips or extracurricular activities.

You might also agree less than the calculator suggests if the paying parent covers specific expenses directly. For example, if they pay the school fees or nursery costs, you might agree a lower maintenance payment to reflect this.

Private arrangements give you flexibility to create something that genuinely works for your family. But both of you need to agree and trust that it's fair.

If you use the CMS, you have to follow their calculation.

The calculator is a helpful starting point even if you end up negotiating something different. It gives you both a sense of what's considered fair and reasonable, which makes discussions easier.

Whatever you agree, put it in writing. This protects both of you and means you're both clear about what's been agreed.

Need help agreeing on child maintenance?

Amicable’s Separating with Children Service can help you reach a fair agreement on child maintenance that works for both of you.

Our Divorce Specialists can walk you through the calculator and help you understand what the figure means for your situation. We can help you negotiate if the calculator amount doesn't quite fit your circumstances or if there are additional costs you need to factor in.

We can also help you work out how to handle things like extracurricular activities, school trips, uniforms and other expenses that aren't covered by basic maintenance.

Once you've agreed on an amount, we can help you put it in a legally binding consent order or separation agreement. This protects both of you and means the arrangement can't be changed without agreement or a significant change in circumstances.

Getting child maintenance sorted early means one less thing to worry about. And when both of you feel the arrangement is reasonable, it's easier to stick to and less likely to cause conflict further down the line.

You can book a free 15-minute advice consultation with one of our Divorce Specialists to discuss your child maintenance arrangements and get clear advice on your next steps.

FAQs about child maintenance

What does child maintenance cover?

Basic child maintenance covers day-to-day costs like food, clothes and housing. It doesn't automatically include extras like school trips, activities or uniforms. You can agree separately with your co-parent how to split these costs.

How quickly can child maintenance be set up?

A private arrangement can be set up in a single day if you’re able to agree on everything. If you use the CMS it can take several weeks.

What’s the biggest factor that impacts how much you pay for child maintenance?

Income is the primary factor that influences how much people pay for child maintenance. The more you earn, the more you pay. The other main factor is how many nights the child stays with their primary caregiver.

Can child maintenance be changed once it's agreed?

Yes. If either parent's circumstances change significantly (income, overnight stays or number of children), you can review and adjust the amount. If you have a private arrangement, you'll need to agree changes between you. If you use the CMS, they'll reassess based on updated information.