UK Child Maintenance Guide 2026: CMS Formula, Direct Pay vs Collect & Pay

The CMS Formula

The current CMS calculation is based on the non-resident parent's (NRP's) gross weekly income. Gross income is the pre-tax, pre-NI figure — the CMS does not deduct income tax, NI or pension contributions before applying the percentage. This makes the CMS calculation more straightforward than the pre-2012 net income system but results in higher nominal amounts for higher earners.

Where the NRP has children living with them in their own household (including stepchildren they are financially responsible for), the applicable percentage is reduced:

For income above £3,000 per week, the receiving parent can apply to the family court under Schedule 1 of the Children Act 1989 for a top-up order. Courts consider the standard of living the child would have had if the parents had remained together, as well as the NRP's assets and overall financial circumstances.

What Income CMS Uses

CMS receives income data directly from HMRC via its Real Time Information system. For employed NRPs, the income used is the most recent P60 gross figure. For self-employed NRPs, it is the gross profit figure from the most recent Self Assessment return. CMS includes the following in its income assessment:

• Employment income (pre-tax, pre-NI gross)
• Self-employment profit (net of allowable business expenses, but before tax)
• Pension income (occupational and private — not State Pension)
• Rental income (net of allowable property expenses)
• Most investment income above the savings rate (variation needed to include this)

Not included by default: most state benefits (Universal Credit, Housing Benefit, Child Benefit, DLA/PIP), the State Pension, Working Tax Credit. Receiving large benefits does not reduce a CMS assessment — only earned income matters for the basic calculation.

CMS uses the income figure available at the time of assessment. Because HMRC data has a lag (especially for self-employed people whose SA return may be for the prior tax year), the income used may be 12–18 months out of date. Either parent can request an in-year review if income has changed significantly.

Low Income and Flat Rates

Special rules apply when the NRP's gross income is low:

The flat rate of £7 per week applies regardless of the number of children — it is a total figure, not per child. It applies when the NRP is receiving certain means-tested benefits. If the NRP is a student or a child themselves (under 16), a nil rate may apply.

Shared Care Overnight Reductions

When children spend overnight time with the non-resident parent, CMS reduces the weekly maintenance amount to reflect the direct costs the NRP bears during that time. Overnight stays are counted per year (per child):

If the child has multiple siblings covered by the same CMS case but spends different amounts of time with the NRP, each child's overnight nights are counted separately.

Where the 50% reduction applies and both parents have similar incomes, the net maintenance may be very small or even nil. Some parents in equal shared care arrangements choose to have no formal maintenance order and instead split child costs directly (school trips, activities, clothing) — a Family-Based Arrangement may be the simplest route in this situation.

Three Routes: FBA, Direct Pay and Collect & Pay

Parents have three options for how child maintenance is arranged and paid:

There is a one-off application fee of £20 to use CMS (waived for under-19s, victims of domestic abuse, and those on certain benefits). There is no fee for Family-Based Arrangements.

Consent Orders: Making It Legally Binding

A private child maintenance agreement (FBA) is not automatically enforceable in court. To make it legally binding, parents can apply to the family court for a Consent Order — a court order that records and approves the agreed terms. Key points:

• A Consent Order is legally binding and can be enforced via court proceedings if breached.
• The court must be satisfied the arrangement is fair and in the child's best interests — it will not simply rubber-stamp any agreement.
• Consent Orders for child maintenance are limited to 12 months where a CMS assessment is or has recently been in force — after 12 months, either parent can apply to CMS to override the Consent Order.
• Consent Orders can be varied by the court if circumstances change significantly (e.g. significant income change, change in living arrangements).

Self-Employed Non-Resident Parents

Self-employed NRPs are assessed using their gross profit figure from the most recent Self Assessment return filed with HMRC. This creates particular challenges:

• Time lag: The most recent SA return may be for the tax year ending 18 months before the current assessment — particularly if the NRP filed late. A successful business may have grown considerably since then.
• Current year assessment:If income has fallen by more than 25% from the previous year, the NRP can request a current-year assessment using actual, up-to-date accounts. CMS requires verifiable documentation — management accounts, bank statements or a formal accountant's report.
• Lifestyle inconsistency variation:If there is evidence that the self-employed NRP's actual lifestyle is inconsistent with their declared income — for example, driving an expensive car, taking luxury holidays, or owning investment properties — the receiving parent can apply for a variation on the grounds of lifestyle inconsistency. CMS will consider bank statements, asset ownership and other evidence.
• Assets used to generate income: If the NRP has significant assets (savings, investments, pension drawdowns) that generate income not captured in their SA return, a variation may include this income.

Variation Applications

Either parent can apply to CMS for a variation to adjust the standard calculation amount. Grounds include:

Variation applications must be made in writing. Both parents can submit evidence and representations. CMS will make a decision and issue a revised calculation if the variation is granted. Either party can appeal to the First-tier Tribunal (Social Entitlement Chamber) if they disagree with CMS's decision.

Annual Reviews

CMS automatically reviews every case each year using updated HMRC income data. The review compares the NRP's current income with the figure used for the current assessment. If income has changed by more than 25% in either direction, CMS will revise the maintenance amount.

Changes to other relevant circumstances — such as the number of qualifying children, the shared care arrangements, or household children — can be reported to CMS at any time and will trigger an unscheduled review. CMS sends both parents a letter confirming any change in the maintenance amount and the date from which it applies.

Annual reviews do not require any action from either parent — they happen automatically based on HMRC data. However, it is worth checking whether the income CMS is using is correct, particularly for self-employed NRPs whose figures may be out of date.

Enforcement: What Happens If They Don't Pay

Under Collect & Pay, CMS has significant enforcement powers for non-payment. The escalation process typically follows this order:

1. Deduction from Earnings Order (DEO):CMS instructs the NRP's employer to deduct maintenance directly from wages and pay it to CMS. This is highly effective for employed NRPs.
2. Regular deduction order:Deductions taken directly from the NRP's bank account on a regular basis.
3. Lump-sum deduction order: A one-off deduction from a bank or building society account to clear arrears.
4. Charging order:A charge secured against the NRP's property, recoverable when the property is sold.
5. Enforcement agents (bailiffs):CMS can instruct bailiffs to seize and sell the NRP's goods.
6. Driving disqualification: The NRP can be disqualified from driving for up to 2 years for serious non-compliance.
7. Passport disqualification: The NRP can be prevented from holding a UK passport.
8. Committal: In extreme cases of deliberate evasion, the court can sentence the NRP to up to 2 years in prison.

Arrears under CMS can accumulate and are collectable regardless of how old they are — there is no limitation period for CMS arrears. Outstanding arrears are reported to credit reference agencies in some circumstances.

Overseas Non-Resident Parents

CMS can only act where the NRP is habitually resident in the UK. If the NRP lives abroad:

• Reciprocal agreements: The UK has maintenance enforcement agreements with a number of countries (including most EU members, Australia, New Zealand and others). Under these agreements, a UK maintenance order can be registered and enforced in the overseas country — and vice versa.
• EU post-Brexit:Since 1 January 2021, the EU Maintenance Regulation no longer applies in the UK. UK orders must be enforced in EU countries under each country's domestic rules, which varies. This has made cross-border enforcement more complex and expensive.
• Court route: Where no reciprocal agreement exists, the receiving parent must apply to the family court for an order and seek enforcement in the overseas country under local law — an expensive and uncertain process.
• Less than 100 countries have maintenance reciprocal agreements with the UK. For all others, enforcement is extremely difficult in practice.

Tax Treatment of Child Maintenance

Child maintenance has a straightforward tax treatment:

• Not taxable income for the recipient: Child maintenance received is not subject to income tax. You do not declare it on your Self Assessment return, and it does not affect your income for tax credit or Universal Credit purposes.
• Not deductible for the payer: Paying child maintenance does not reduce your income tax. The payments are made from post-tax income and receive no relief.
• No effect on Child Benefit / HICBC:Receiving child maintenance does not affect the recipient's eligibility for Child Benefit or trigger the High Income Child Benefit Charge. Child maintenance is completely separate from Child Benefit.
• No effect on benefit calculations: Child maintenance does not count as income for Universal Credit, Housing Benefit, Council Tax Reduction or other means-tested benefits.

Worked Example