UK Child Maintenance Calculator (2026)
Enter gross weekly income, the number of qualifying children, any other children in the paying parent's household, and shared-care overnights to see an estimated weekly and monthly child maintenance figure, with the full step-by-step working shown. Free, instant, and calculated entirely in your browser; no email or phone number required.
Estimated Child Maintenance
£96.00 /week
Basic rate · estimate only, not a CMS decision
Per week
£96.00
Per month
£416.00
This tool estimates the CMS 2012 scheme gross-income formula only: nil rate below £7/week, a flat £7/week from £7 to £100, a reduced rate from £100.01 to £199.99, a basic rate from £200 to £800, and a basic plus rate above £800 (after any reduction for other children) up to the £3,000 income ceiling. It does not check eligibility, verify income, model the benefit-based flat rate, handle children with different shared-care nights, or apply variations. The Child Maintenance Service makes the binding calculation from verified income and full case details.
How Child Maintenance Is Calculated
Child maintenance under the Child Maintenance Service's (CMS) 2012 scheme is worked out from the paying parent's gross weekly income, using a set of published income bands and percentage rates:
- Nil rate: gross weekly income below £7.00
- Flat rate: £7.00 to £100.00 a week, a fixed £7.00 regardless of income within the band
- Reduced rate: £100.01 to £199.99 a week
- Basic rate: £200.00 to £800.00 a week
- Basic plus rate: £800.01 up to the £3,000.00 income ceiling (tested after any reduction for other children)
The percentage used within the reduced, basic, and basic plus bands depends on how many qualifying children the maintenance is for (one, two, or three or more). If the paying parent has other children living in their own household, gross income is reduced by 11%, 14%, or 16% (for one, two, or three or more other children) before the basic or basic plus rate is applied. In the reduced rate band the other children are allowed for differently: the percentage itself is lower (for example 21.2% instead of 25% for two qualifying children and one other child), using the table in regulation 43 of the 2012 regulations.
Finally, if the children stay overnight with the paying parent, the basic or reduced rate amount is reduced for shared care: by one-seventh for 52 to 103 nights a year, two-sevenths for 104 to 155 nights, three-sevenths for 156 to 174 nights, and by half for 175 nights or more, with a further £7.00 a week taken off for each child who stays 175 nights or more. Shared care cannot bring the amount below £7.00 a week. It does not reduce the flat rate when that applies because of low income; if the flat rate applies because the paying parent gets certain benefits, 52 or more nights reduces it to nil. Income above £3,000.00 a week is not used in the formula, though a court can sometimes order an additional "top-up" amount above that ceiling.
Worked examples
| Gross weekly income | Children | Other children / shared care | Working | Weekly |
|---|---|---|---|---|
| £600 | 2 | None | 16% × £600 | £96.00 |
| £600 | 1 | 52 to 103 nights | 12% × £600 = £72, less 1/7 | £61.71 |
| £500 | 1 | 2 other children | 12% × (£500 less 14%) | £51.60 |
| £1,000 | 2 | None | 16% × £800 + 12% × £200 | £152.00 |
| £180 | 2 | 1 other child | £7 + 21.2% × £80 | £23.96 |
| £400 | 2 | 175+ nights | 16% × £400 = £64, halved, less £7 × 2 | £18.00 |
| £250 | 3 | 175+ nights | £47.50 halved, less £7 × 3 = £2.75, raised to the minimum | £7.00 |
| Not known | 1 | n/a | CMS default rate | £39.00 |
Where this applies, and what it does not cover
The same formula and rates are used across the UK: by the Child Maintenance Service for England, Wales and Scotland, and by the separate Child Maintenance Service in Northern Ireland under matching Northern Ireland regulations. The calculator does not model the benefit-based flat rate, children who stay different numbers of nights, more than one receiving parent, variations for extra income or special expenses, or maintenance agreed privately or ordered by a court.
The official explanation of this formula is published at gov.uk: How child maintenance is worked out, and the rates are set in Schedule 1 to the Child Support Act 1991 and the Child Support Maintenance Calculation Regulations 2012 (checked against legislation.gov.uk on 26 September 2026). See the full child maintenance guide for how to apply, how payments are collected, what the CMS charges, and worked examples at different income levels.
Who Has To Pay
Child maintenance is normally payable by the parent who does not have day-to-day (main) care of a child, to the parent or person who does, until the child turns 16 (or 20 if still in full-time non-advanced education). Either parent can apply to the Child Maintenance Service, or parents can arrange payments privately between themselves without involving the CMS. This tool does not check who is eligible to apply or receive maintenance; it only calculates the amount the statutory formula would produce from the figures you enter.
Frequently Asked Questions
How accurate is this child maintenance calculator?
It applies the CMS 2012 scheme gross-income formula to the figures you enter. It is still an estimate: the Child Maintenance Service verifies income (usually with HMRC data), checks for other children and shared care in detail, and can apply variations for things like additional income or expenses that this calculator does not model.
What counts as gross weekly income for child maintenance?
Broadly, it is income before tax and National Insurance, but after deducting pension contributions, from employment, self-employment, and some other regular income sources. The CMS normally gets this figure from HMRC records for the most recent tax year.
Does shared custody reduce child maintenance?
Yes, at the basic and reduced rates. Overnight stays with the paying parent reduce the weekly amount: by one-seventh for 52 to 103 nights a year, rising to a half for 175 nights or more, with a further £7 off for each child who stays that often. Shared care cannot take the amount below £7 a week. If care is genuinely equal, no maintenance is normally payable at all, though this is decided case by case, and the parent who gets Child Benefit is usually treated as providing more care.
Do other children in the paying parent’s household reduce the amount?
Yes, at the basic, basic plus and reduced rates. From £200 a week, gross income is reduced by 11% for one other child, 14% for two, or 16% for three or more, before the rate is applied. Between £100 and £200 a week, a lower reduced-rate percentage is used instead (set out in regulation 43). The flat rate is not affected.
What if I do not know the other parent’s income?
You do not need to know it to apply: the Child Maintenance Service normally gets income figures from HMRC. If the CMS cannot get enough information, it can make a default decision at a fixed £39 a week for one child, £51 for two, or £64 for three or more, and can replace it with a full calculation once it gets the information. Choose "No, I do not know it" in the calculator to see the default rate.
Are there fees for using the Child Maintenance Service?
Applying is free (in England, Scotland and Wales the £20 application fee was removed on 26 February 2024; Northern Ireland never charged one). If parents use Direct Pay and arrange payments between themselves, there are no collection fees. If the CMS collects and passes on the money (Collect and Pay), the paying parent pays a 20% fee on top of the maintenance and the receiving parent has 4% deducted.
What is the maximum child maintenance someone can be asked to pay?
The statutory formula only uses gross weekly income up to £3,000; income above that is ignored by the CMS calculation. A parent receiving maintenance can sometimes apply to a court for an additional "top-up" order if the paying parent earns more than that.
Does this tool store or send my information anywhere?
No. All of the math runs in your browser. Nothing you type into this calculator is saved, transmitted, or used to contact you.
This calculator estimates the CMS 2012 scheme gross-income formula published at gov.uk. It is general information, not legal or financial advice, and RecordingLaw.com is not affiliated with the Child Maintenance Service or the UK government. The figure shown is an estimate only; the Child Maintenance Service makes the binding calculation for any actual case, based on verified income and full case details.
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