Does shared care reduce child maintenance?

Yes. The CMS reduces maintenance based on overnight stays: 1 night/week = 1/7 reduction; 2 nights = 2/7; 3 nights = 3/7; 4+ nights = 50% reduction.

What happens if the paying parent doesn't pay?

If payments are missed under a CMS-managed arrangement, the CMS can take enforcement action including deducting directly from wages, taking money from a bank account, charging bailiffs, suspending a driving licence, or pursuing court action.

UK Child Maintenance Calculator

Q: How does the CMS calculate child maintenance?

The Child Maintenance Service uses the paying parent's gross weekly income as the starting point and assigns one of four rate bands: nil rate (under £100/wk), flat rate (£7/wk for £100–£199/wk), reduced rate (£200–£799/wk), or basic rate (£800–£3,000/wk). For income over £3,000/week, a lower basic plus rate applies to the excess.

Q: What income does the CMS use?

The CMS uses the paying parent's gross weekly income from all sources, verified via HMRC records. This includes employed earnings, self-employment income, pension income, and investment income.

Q: Can I arrange child maintenance privately without using the CMS?

Yes. A family-based arrangement (private agreement) is perfectly legal and free. You and the other parent can agree any amount you both feel is fair. If either parent wants to change to CMS-managed payments later, they can apply.

Estimate child maintenance using the official Child Maintenance Service (CMS) formula — covers all rate bands, shared care reductions, and household adjustments.

All calculations are private — nothing leaves your browser

Paying Parent Gross Income(annual gross)

Number of Children

Estimated Child Maintenance

£104/week

CMS Rate BandReduced rate

Monthly Payment£450/mo

Annual Total£5,396/yr

Gross Weekly Income£769/wk

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Advanced Calculator

Income band chart across all rate bands, shared care reduction visualisation, and multiple children impact table.

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Paying Parent Gross Income

Number of Children

Monthly Maintenance by Income Level

Monthly child maintenance by gross incomeYour income (£45,000/yr)

Your estimated monthly: £600/mo

The CMS uses gross weekly income. Income over £3,000/week triggers the Basic Plus rate. Income under £100/week results in a nil or flat rate.

Professional Simulator

Full CMS calculation with income from all sources, voluntary vs court-managed comparison, special expenses, and enforcement options detail.

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Income from All Sources (Paying Parent)

Employed / PAYE Earnings

Self-Employment Income

Pension Income

Investment / Dividend Income

Rental Income

Other Income

Household & Care Adjustments

Qualifying Children

Shared Overnight Stays

Other Children in Household

Full CMS Assessment

£600/month

Total Gross Income£45,000/yr

Gross Weekly Income£865/wk

Rate BandBasic rate

Base Weekly Amount£138/wk

Weekly After Reductions£138/wk

Annual Total£7,200/yr

How the UK Child Maintenance Calculator Works

This calculator applies the Child Maintenance Service (CMS) formula used by the UK government. It converts the paying parent's gross annual income into a weekly figure, assigns a rate band, and calculates the weekly, monthly and annual maintenance obligation.

The CMS uses four rate bands: nil rate (income under £100/week), flat rate (£100–£199/week), reduced rate (£200–£799/week), and basic rate (£800–£3,000/week). Above £3,000/week, additional income is assessed at a lower "basic plus" rate.

CMS Rate Bands

Nil rate: Gross weekly income < £100 → £0/week Flat rate: Gross weekly income £100–£199 → £7/week Reduced rate: Gross weekly income £200–£799 1 child = £7 + 17% of income above £200 2 children = £7 + 25% of income above £200 3+ children = £7 + 31% of income above £200 Basic rate: Gross weekly income £800–£3,000 1 child = 12% | 2 children = 16% | 3+ = 19% Basic Plus: Income above £3,000/week Additional 9% / 12% / 15% on excess

Shared care nights reduce the amount: 1 night/week = 1/7 reduction; 2 nights = 2/7; 3 nights = 3/7; 4+ nights = 50% reduction. If there are other children living with the paying parent, their gross income is reduced before applying the formula.

Example Calculation

Example: £40,000 income, 2 children

Gross annual income£40,000

Gross weekly income£769.23

Rate bandBasic rate

Rate for 2 children16%

Weekly maintenance£123.08

Monthly maintenance£533.33

Annual maintenance£6,400

With 2 shared overnight stays per week, the 2/7 reduction would reduce weekly maintenance to approximately £87.91 (£381/month).

Frequently Asked Questions

The Child Maintenance Service uses the paying parent's gross weekly income as the starting point. It assigns one of four rate bands: nil rate (under £100/wk), flat rate (£7/wk for £100–£199/wk), reduced rate (£200–£799/wk), or basic rate (£800–£3,000/wk). For income over £3,000/week, a lower "basic plus" rate applies to the excess. The result is then adjusted for shared care arrangements and other children in the paying parent's household.

Yes. The CMS reduces maintenance based on the number of overnight stays the child has with the paying parent each week on average. One night per week reduces maintenance by 1/7 (about 14.3%). Two nights reduces it by 2/7 (about 28.6%). Three nights reduces it by 3/7 (about 42.9%). Four or more nights per week halves the maintenance amount. These reductions only apply to basic, reduced or flat rate cases — not nil rate.

The CMS uses the paying parent's gross weekly income from all sources, verified via HMRC records. This includes employed earnings, self-employment income, pension income, and investment income. Certain benefits and Universal Credit payments are excluded. If the paying parent's income has changed by more than 25% since the last CMS calculation, a variation can be requested. The CMS updates calculations annually using HMRC data.

Yes. A family-based arrangement (private agreement) is perfectly legal and free. You and the other parent can agree any amount you both feel is fair. Many families use the CMS calculator figures as a reference point. If either parent wants to change to CMS-managed payments later, they can apply. A private agreement can also be formalised through a solicitor into a consent order, which makes it legally enforceable.

If payments are missed under a CMS-managed arrangement, the CMS can take enforcement action including: deducting directly from wages (deduction from earnings order), taking money from a bank account, charging bailiffs, suspending a driving licence, or pursuing court action that could result in a custodial sentence. The CMS charges a collection fee (2% added to the paying parent's payment, 4% deducted from the receiving parent's payment) for its collect and pay service.