Start here: Financial Checklists Hub.
When parents separate, the parent without main day-to-day care typically pays child maintenance to help cover the child’s costs. In the UK, the Child Maintenance Service (CMS) calculates amounts using a standard formula based on income.
This guide explains how the calculation works, what you might pay or receive, and how to arrange maintenance.
Quick Calculator
Use this table to estimate child maintenance based on gross weekly income:
| Gross Weekly Income | 1 Child (12%) | 2 Children (16%) | 3+ Children (19%) |
|---|---|---|---|
| £200 | £24 | £32 | £38 |
| £300 | £36 | £48 | £57 |
| £400 | £48 | £64 | £76 |
| £500 | £60 | £80 | £95 |
| £600 | £72 | £96 | £114 |
| £700 | £84 | £112 | £133 |
| £800 | £96 | £128 | £152 |
| £1,000 | £120 | £160 | £190 |
| £1,500 | £180 | £240 | £285 |
Note: These are base rates before any reductions for shared care or other children.
How Child Maintenance Is Calculated
The Child Maintenance Service uses this formula:
Step 1: Establish Gross Weekly Income
The CMS gets your gross income directly from HMRC. This includes:
- Employment income (wages, salary)
- Self-employment profits
- Benefits that count (e.g., State Pension, Carer’s Allowance, bereavement benefits)
- Occupational and private pensions
- Tax credits and Universal Credit do not count
Step 2: Deduct for Other Children
If the paying parent has other children living with them or pays maintenance for other children, their income is reduced first:
| Other Qualifying Children | Income Reduction |
|---|---|
| 1 child | 11% |
| 2 children | 14% |
| 3+ children | 16% |
Step 3: Apply the Rate
| Number of Children Maintenance Is For | Rate |
|---|---|
| 1 child | 12% |
| 2 children | 16% |
| 3 or more children | 19% |
Worked Example
Scenario: James earns £40,000/year gross (£769/week). He has 1 child with his ex-partner. He also has 1 new child living with him.
| Step | Calculation |
|---|---|
| Gross weekly income | £769 |
| Deduction for 1 other child (11%) | −£84.59 |
| Income after deduction | £684.41 |
| Maintenance for 1 child (12%) | £82.13/week |
| Monthly equivalent | £356/month |
Shared Care Reductions
If the child stays overnight with the paying parent, maintenance is reduced:
| Nights Per Week (Average) | Reduction |
|---|---|
| Less than 1 night | No reduction |
| 1 night | 14% |
| 2 nights | 28% |
| 3 nights | 42% |
| 4+ nights (shared care) | 50%+ depending on exact split |
Example: If James has his child 2 nights per week on average:
- Base maintenance: £82.13
- Reduction of 28%: −£23.00
- Revised maintenance: £59.13/week
The reduction is calculated over a year — so 1 night per week is approximately 52 nights per year.
Income Brackets and Rates
Nil Rate (No Maintenance Due)
You pay nothing if:
- Your gross weekly income is under £7, AND
- You receive certain benefits (Universal Credit, Income Support, income-based JSA/ESA, Pension Credit)
Flat Rate: £7/Week
You pay a flat £7/week regardless of how many children if:
- Your gross weekly income is between £7 and £100, OR
- You receive certain benefits (see above)
Reduced Rate
If your gross weekly income is between £100 and £199/week, a reduced rate applies using a sliding scale.
Basic Rate
For income between £200 and £800/week:
- 12% for 1 child
- 16% for 2 children
- 19% for 3+ children
Basic Plus Rate
For income between £800 and £3,000/week:
- Income up to £800 uses basic rates
- Income above £800 uses lower rates:
- 9% for 1 child
- 12% for 2 children
- 15% for 3+ children
Maximum Maintenance
The CMS only considers income up to £3,000/week gross. If the paying parent earns more, you can apply to court for a “top-up” order for additional maintenance.
Three Ways to Arrange Child Maintenance
Option 1: Family-Based Arrangement (Free)
You agree the amount directly with the other parent without involving the CMS.
| Pros | Cons |
|---|---|
| Completely free | No enforcement if payments stop |
| Flexible — can adjust easily | May favour the more persuasive parent |
| Maintains parental relationship | No official record |
This works best when:
- You’re on good terms with your ex
- You both agree on a fair amount
- Payments are likely to continue reliably
Option 2: CMS Direct Pay
The CMS calculates the amount, but payments are made directly between parents.
| Fees | |
|---|---|
| Application fee | £20 (waived if domestic abuse evidence) |
| Ongoing fees | None |
The CMS tells you both how much should be paid and when. You arrange the actual payments yourselves.
Option 3: CMS Collect & Pay
The CMS calculates the amount AND collects/pays the money.
| Fees | |
|---|---|
| Application fee | £20 (waived if domestic abuse evidence) |
| Paying parent surcharge | 20% added to amount owed |
| Receiving parent deduction | 4% deducted from payments received |
Example: If maintenance is £200/month:
- Paying parent pays: £240/month (£200 + 20%)
- Receiving parent gets: £192/month (£200 − 4%)
This option is best when:
- Direct payments aren’t reliable
- There’s a history of missed payments
- Communication between parents is difficult
How to Apply to the CMS
- Call Child Maintenance Options on 0800 171 2345 (free) — they’ll explain your options
- If you choose CMS, they’ll transfer you or give you the number
- Provide your details, the other parent’s details, and information about the children
- The CMS contacts HMRC for income information
- They calculate the amount and notify both parents
- Payments start (either Direct Pay or Collect & Pay)
What If Maintenance Isn’t Paid?
Family-Based Arrangement
If your ex stops paying a family-based arrangement, you have limited options:
- Try to renegotiate
- Apply to the CMS to take over
CMS Direct Pay
If payments stop:
- Report it to the CMS
- They may move you to Collect & Pay
- Enforcement action can begin
CMS Collect & Pay
The CMS has strong enforcement powers:
| Enforcement Action | What It Means |
|---|---|
| Deduction from Earnings Order | Money taken directly from wages |
| Deduction Order | Money taken from bank accounts |
| Regular Deduction Order | Ongoing deductions from bank |
| Liability Order | Court order enabling further action |
| Bailiff action | Seizing property/assets |
| Driving licence removal | Disqualification from driving |
| Imprisonment | Up to 6 weeks (rare, last resort) |
Changing Circumstances
You can request a review if:
- The paying parent’s income changes by 25% or more
- Shared care arrangements change
- A new child is born to either parent
- The child reaches 16/18/20 (education dependent)
Either parent can request a review — the CMS will recalculate based on current circumstances.
When Does Child Maintenance Stop?
Child maintenance normally stops when:
| Circumstance | When It Ends |
|---|---|
| Child turns 16 | If not in full-time education |
| Child turns 18 | If in full-time education (A-levels or equivalent) |
| Child turns 20 | Maximum age even if still in education |
| Child leaves full-time education | Before age 20 |
| Child starts living with the paying parent | Arrangements would need to change |
FAQs
Can my ex hide income to pay less?
The CMS uses HMRC records, so it’s hard to hide employment income. However, self-employed income is based on the previous tax return. If you believe income is understated, you can request an investigation.
Do I pay maintenance if I have 50/50 shared care?
If both parents have exactly equal care, maintenance may be nil or very low. The CMS calculates based on overnight stays over a year.
What about university costs?
Child maintenance through the CMS ends by age 20, and doesn’t cover university. Any financial support for university-age children is a private matter between parents.
Can I claim arrears?
CMS can collect arrears going back to when the case opened. Family-based arrangements have no legal route for arrears — you’d need to apply to the CMS going forward.
Related Guides
- Marriage and Finances UK — Money Guide for Getting Married and Divorcing 2026
- Divorce Financial Checklist
- Benefits for Single Parents
- Child Benefit Guide
- Tax-Free Childcare Guide
Summary
| Basic rates | 12% (1 child), 16% (2 children), 19% (3+) |
| Gross income used | From HMRC records |
| Shared care | Reduces amount: 1 night/week = 14% off |
| Other children | Reduce income first: 11-16% |
| Family arrangement | Free, no enforcement |
| CMS Direct Pay | £20 fee, you make payments directly |
| CMS Collect & Pay | £20 fee + 20% surcharge (paying parent) / 4% deduction (receiving parent) |
For a personalised calculation, use the official GOV.UK child maintenance calculator.