Child Maintenance Calculator
This calculator provides an estimate of child maintenance payments based on the Child Maintenance Service (CMS) formula. The actual amount may vary depending on individual circumstances.
How Child Maintenance Rates Work
The Child Maintenance Service uses five different rates to calculate payments. The rate applied depends on the paying parent’s gross weekly income and circumstances.
| Rate Type | Weekly Income | Amount |
|---|---|---|
| Nil Rate | Below £7 | £0 |
| Flat Rate | £7-£100 or on benefits | £7 per week |
| Reduced Rate | £100.01-£199.99 | £7 + percentage of income above £100 |
| Basic Rate | £200-£800 | Percentage of gross income |
| Basic Plus Rate | £800.01-£3,000 | Basic rate on first £800 + reduced percentage on remainder |
Percentage Rates by Number of Children
| Number of Children | Reduced Rate (£100-£200) | Basic Rate (£200-£800) | Basic Plus (£800+) |
|---|---|---|---|
| 1 child | 17% | 12% | 9% |
| 2 children | 25% | 16% | 12% |
| 3+ children | 31% | 19% | 15% |
Shared Care Reductions
When a child stays overnight with the paying parent, maintenance payments may be reduced. The reduction depends on the number of nights per year.
| Nights per Year | Reduction per Child | Percentage |
|---|---|---|
| 0-51 nights | No reduction | 0% |
| 52-103 nights | 1/7th reduction | 14.29% |
| 104-155 nights | 2/7ths reduction | 28.57% |
| 156-174 nights | 3/7ths reduction | 42.86% |
| 175+ nights | Half + £7 extra | 50% + £7 |
Payments at the basic, basic plus, or reduced rate cannot fall below £7 per week after shared care reductions are applied. If care is shared equally (around 182-183 nights each), no maintenance is payable through CMS.
Step-by-Step Calculation Process
- Determine gross weekly income: This includes salary, pension, and other taxable income before deductions.
- Identify the rate category: Match the income to the appropriate rate (nil, flat, reduced, basic, or basic plus).
- Apply the percentage: Calculate the base amount using the relevant percentage for the number of children.
- Adjust for other children: If the paying parent supports other children in their household, reduced percentages apply.
- Calculate shared care reduction: Subtract the appropriate fraction based on overnight stays.
- Apply minimum payment: Payments cannot fall below £7 per week (except for nil rate).
Adjustment for Other Children
When the paying parent has other children living with them or pays maintenance for other children, the percentage rates are reduced.
| Children Receiving | Other Children | Reduced Rate % | Basic Rate % |
|---|---|---|---|
| 1 | 1 | 14.1% | 9.5% |
| 1 | 2 | 13.2% | 8.9% |
| 1 | 3+ | 12.4% | 8.4% |
| 2 | 1 | 21.2% | 12.7% |
| 2 | 2 | 19.9% | 11.9% |
| 2 | 3+ | 18.9% | 11.3% |
| 3+ | 1 | 26.4% | 15.2% |
| 3+ | 2 | 24.9% | 14.3% |
| 3+ | 3+ | 23.8% | 13.7% |
Special Circumstances
Income Above £3,000 per Week
The CMS can only calculate maintenance on income up to £3,000 per week (£156,000 per year). If the paying parent earns more, the receiving parent can apply to the courts for additional maintenance on the excess income.
No Payment Scenarios
Maintenance is not payable when:
- Care is shared equally between parents
- The paying parent is a full-time student with no income
- The paying parent is in prison
- Income is below £7 per week (nil rate applies)
Default Rate
If income cannot be determined or verified, a default rate applies:
- £38 per week for 1 child
- £51 per week for 2 children
- £64 per week for 3 or more children
Worked Examples
Example 1: Basic Rate with No Shared Care
Scenario: Paying parent earns £500 per week, paying for 2 children, no other children, no shared care.
Calculation: £500 × 16% = £80.00 per week
Result: £80.00 per week total
Calculation: £500 × 16% = £80.00 per week
Result: £80.00 per week total
Example 2: Basic Plus Rate with Shared Care
Scenario: Paying parent earns £1,200 per week, paying for 1 child, no other children, 60 nights per year shared care.
Calculation:
– First £800: £800 × 12% = £96.00
– Remaining £400: £400 × 9% = £36.00
– Subtotal: £132.00
– Shared care reduction (52-103 nights): £132.00 × 1/7 = £18.86
Result: £113.14 per week
Calculation:
– First £800: £800 × 12% = £96.00
– Remaining £400: £400 × 9% = £36.00
– Subtotal: £132.00
– Shared care reduction (52-103 nights): £132.00 × 1/7 = £18.86
Result: £113.14 per week
Example 3: Reduced Rate with Other Children
Scenario: Paying parent earns £180 per week, paying for 1 child, 1 other child in household, no shared care.
Calculation:
– First £100: £7.00
– Remaining £80: £80 × 14.1% = £11.28
Result: £18.28 per week
Calculation:
– First £100: £7.00
– Remaining £80: £80 × 14.1% = £11.28
Result: £18.28 per week
Frequently Asked Questions
What income counts towards child maintenance calculations?
Gross weekly income includes salary, wages, bonuses, pension income, and other taxable earnings before tax and National Insurance deductions. It does not include benefits like Child Benefit or Universal Credit.
Can I pay less than the calculated amount?
If you arrange maintenance privately with the other parent, you can agree on any amount. However, if using the Child Maintenance Service, you must pay the calculated amount. The minimum payment through CMS is £7 per week (except for nil rate).
What happens if my income changes?
The CMS reviews income annually. If your circumstances change significantly (such as job loss or pay rise), you should notify CMS, who may recalculate the payment amount. Some changes take effect immediately, whilst others wait for the annual review.
Do school fees or childcare costs reduce maintenance?
No, the CMS calculation does not account for expenses like school fees or childcare costs. These are considered separate from statutory maintenance. Parents can make private arrangements that include such costs outside of CMS.
How is shared care verified?
Shared care is based on agreement between parents or a court order specifying overnight stays. If parents disagree and no court order exists, CMS assumes one night per week (52 nights annually), resulting in a one-seventh reduction.
Can maintenance be paid for children over 16?
Yes, maintenance can continue until age 20 if the child remains in approved full-time non-advanced education (such as A-levels or Scottish Highers). It stops when they leave education, start an apprenticeship, or turn 20.
What if the paying parent is self-employed?
Self-employed parents provide income information from their latest tax return. CMS uses the previous tax year’s figures. If accounts show very low income or losses, CMS may investigate further or use default rates.
Does remarrying affect child maintenance?
The receiving parent’s new relationship does not affect maintenance. However, if the paying parent has children with a new partner living in their household, this reduces the percentage rates applied to their income.
Private Arrangements vs CMS
Parents can choose between making a private family-based arrangement or using the Child Maintenance Service. Each option has different characteristics.
| Aspect | Private Arrangement | Child Maintenance Service |
|---|---|---|
| Flexibility | Full flexibility on amount and terms | Amount calculated by CMS formula |
| Cost | Free | Collection fees may apply |
| Enforcement | No automatic enforcement | Legal enforcement available |
| Changes | By mutual agreement | Annual reviews or change of circumstances |
| Additional Support | Can include extras (school fees, activities) | Fixed statutory calculation only |
If a private arrangement breaks down and payments stop, either parent can apply to the Child Maintenance Service. Previous private agreement amounts are not binding on CMS calculations.
Payment Collection Methods
When using the Child Maintenance Service, there are two collection options:
Direct Pay
- Parents arrange payment between themselves
- CMS provides the calculation but does not collect
- No collection charges
- Requires cooperation between parents
Collect and Pay
- CMS collects from paying parent and transfers to receiving parent
- Paying parent charged 20% collection fee on top of maintenance
- Receiving parent receives 4% less than calculated amount
- Used when Direct Pay is not working
- CMS can enforce payment through legal means
Common Mistakes to Avoid
Using Net Instead of Gross Income
Calculations must use gross income (before tax), not take-home pay. Using net income results in significantly lower maintenance amounts than legally required.
Miscounting Shared Care Nights
Only overnight stays count towards shared care. Day visits, even if lasting 12+ hours, do not qualify. The child must stay overnight for it to reduce maintenance.
Forgetting Annual Income Changes
Income used for calculations may be based on previous tax year data. Current earnings might differ from the figure used by CMS, especially for self-employed individuals.
Assuming Equal Split Means Half Payment
Equal care (182-183 nights each) means no payment through CMS. Slightly unequal care still triggers payments with shared care reductions applied.
Not Reporting Other Children
Failing to declare other children in the household or other maintenance obligations means paying higher rates than necessary.
When to Apply to CMS
Consider applying to the Child Maintenance Service when:
- Unable to reach a private agreement with the other parent
- The other parent refuses to pay or consistently misses payments
- You need help calculating a fair amount
- Previous private arrangement has broken down
- You need legal enforcement powers
- The other parent’s income is difficult to verify
Before applying to CMS, both parents must usually attend a free information session about family-based arrangements, unless exemptions apply (such as domestic abuse or child protection concerns).
Variations and Adjustments
In specific circumstances, either parent can apply for a variation to adjust the calculated amount:
Reasons for Variation Applications
- Additional income not included in the assessment (such as income from assets)
- Paying parent has high costs for contact (travel to see children)
- Paying parent pays for boarding school fees
- Paying parent has substantial property or lifestyle inconsistent with declared income
- Paying parent diverted income to avoid maintenance
Variations are not automatic and must be applied for with supporting evidence. CMS reviews each application individually.
References
1. Department for Work and Pensions (2025). “How child maintenance is worked out.” GOV.UK. Available at: https://www.gov.uk/how-child-maintenance-is-worked-out
2. Department for Work and Pensions (2025). “Calculate your child maintenance.” GOV.UK. Available at: https://www.gov.uk/calculate-child-maintenance
3. nidirect (2025). “Child maintenance rates explained.” Northern Ireland Direct Government Services. Available at: https://www.nidirect.gov.uk/articles/child-maintenance-rates-explained
4. nidirect (2025). “Shared care in child maintenance cases.” Northern Ireland Direct Government Services. Available at: https://www.nidirect.gov.uk/articles/shared-care-child-maintenance-cases
5. Child Maintenance Service (2025). Department for Work and Pensions. Available at: https://www.gov.uk/child-maintenance