Child Maintenance (CMS) Calculator UK (2026/27)

The Child Maintenance Service (CMS) calculates maintenance through 6 statutory steps: (1) determine the paying parent’s gross annual taxable income from HMRC; (2) deduct all private and workplace pension contributions to find net weekly gross income; (3) apply percentage reductions if other children live with the paying parent (11% for 1 child, 14% for 2, 16% for 3+); (4) apply the statutory rate band (nil, flat, reduced, basic, or basic plus); (5) apply overnight shared care reductions (from 1/7th up to 50%); and (6) produce the final weekly maintenance payment.

The paying parent’s gross weekly income is the single most decisive factor. CMS evaluates gross income before PAYE tax and National Insurance deductions, with gross earnings derived automatically from HMRC payroll returns. Pension contributions and the number of qualifying children are the next largest determinative factors.

The lowest nonzero statutory amount is the £7.00 per week flat rate, which applies to paying parents with gross weekly earnings between £7.01 and £100.00, or those receiving qualifying income-related benefits (like Universal Credit). Paying parents earning £7.00 or less per week, full-time students, or prisoners qualify for the nil rate (£0.00).

Under the basic rate tier (£200.01 to £800/wk gross), a paying parent pays 12% of gross weekly income for 1 child, 16% for 2 children, or 19% for 3 or more children. For instance, on a median weekly wage of £650.00 with 1 qualifying child and no shared care, the statutory liability is exactly £78.00 per week (£4,056.00 annually).

The non-resident parent (the paying parent) pays child maintenance to the parent who has day-to-day care of the child (the receiving parent). Child maintenance obligations apply equally regardless of gender, marital history, or whether the parents were ever in a formal relationship.

Yes. Both biological and adoptive parents have a strict statutory legal duty under the Child Support Act 1991 to financially support their children. If a paying parent refuses to agree to a voluntary family-based arrangement, the receiving parent can open an official CMS case, creating an enforceable statutory debt.

Child maintenance is legally payable until the child reaches age 16, or up to age 20 if they remain in approved full-time non-advanced education (such as A-levels, International Baccalaureate, T-levels, Scottish Highers, or NVQ Level 3). It ceases immediately if the child marries, registers a civil partnership, enters higher education (university), or starts claiming qualifying benefits.

Under CMS regulations, if overnight care is split exactly 50/50 (182 or 183 nights per year each) and both parents provide equal day-to-day care, neither parent is legally classed as the non-resident parent. In genuine equal shared care cases, the paying parent has no statutory child maintenance liability through CMS.

Overnight stays reduce maintenance in tiered fractions: 52 to 103 nights/year reduces weekly maintenance by 1/7th; 104 to 155 nights reduces by 2/7ths; 156 to 174 nights reduces by 3/7ths; and 175 or more nights reduces maintenance by 50% (plus a further £7 per child weekly deduction). On a £48/wk base liability, 120 nights of shared care reduces maintenance by £13.71 to £34.29 per week.

If your income drops due to job loss, illness, or pay cuts by 25% or more, you must contact CMS immediately to request a formal reassessment. Your weekly maintenance will be recalculated against your new earnings or moved to the £7.00/wk flat rate if on benefits. Never simply stop paying, as arrears accumulate as an enforceable legal debt.

CMS possesses draconian statutory enforcement powers without needing court orders: they can issue a Deduction from Earnings Order (DEO) directly to your employer, freeze and seize bank accounts (regular or lump-sum deduction orders), register county court judgments, seize passports or driving licences, and pursue committal to prison.

Statutory child maintenance covers everyday living expenses: food, clothing, housing, and routine utility costs. It does not legally cover private school tuition fees, university living expenses, orthodontic treatment, or overseas school trips. Receiving parents seeking contributions for school fees must apply to the Family Court for a specific court order.

No. Statutory CMS percentages on gross income are capped at 12%, 16%, or 19% under basic rate, and 9%, 12%, or 15% on income above £800/wk. When CMS enforces deductions from earnings orders (DEOs), legislation strictly mandates a Protected Earnings Proportion (PEP) ensuring the parent retains at least 60% of their net take-home pay.

You can legally reduce child maintenance through legitimate avenues: (1) Increasing overnight shared care past 52, 104, 156, or 175 night thresholds; (2) Contributing to a registered workplace or personal pension, which CMS deducts from your gross income prior to assessment; and (3) Agreeing a voluntary family-based arrangement directly with the other parent to avoid CMS collection fees.

Yes, if the young person remains in approved full-time non-advanced education (e.g., repeating A-levels or completing college vocational courses up to Level 3) and Child Benefit remains payable for them, up until their 20th birthday. If they attend university (advanced education) or enter full-time employment, CMS maintenance ends.

Child maintenance is financial support paid towards a child’s everyday living costs. It is paid either via Direct Pay (free; parents arrange payments directly between bank accounts using CMS calculations) or Collect and Pay (CMS collects and transfers funds, but charges a 20% surcharge to the paying parent and deducts a 4% fee from the receiving parent).

You can legally stop paying when: the child reaches 16 and is not in approved non-advanced education; the child reaches age 20; the child leaves full-time education to work or claim benefits; either parent or the child passes away; the child marries; or care arrangements change so the child lives with you full-time.

No. An ex-partner’s remarriage, cohabitation, or new partner’s income has zero impact on statutory CMS maintenance. Child maintenance is solely the biological or adoptive parents’ legal responsibility and is assessed strictly on the paying parent’s gross income.