Statutory Child Maintenance Calculation Rules (2026): Gross Income, Rates & Reductions
Who this is for. If you are a paying parent or receiving parent in England, Wales, or Scotland seeking to understand exactly how the Child Maintenance Service (CMS) calculates weekly liabilities, this guide breaks down the statutory mechanics in plain English.
1. The Five Statutory Rate Tiers (2026)
The Child Maintenance Service bases assessments on the paying parent's gross weekly income (before Income Tax and National Insurance, but after relievable pension contributions) as verified by HMRC PAYE/Self-Assessment records.
- Nil Rate (Under £7/wk): £0.00 liability (students, prisoners, children under 16).
- Flat Rate (£7 to £100/wk): £7.00 flat fee per week (means-tested benefits).
- Reduced Rate (£100 to £200/wk): £7.00 plus a graduated percentage on income over £100.
- Basic Rate (£200 to £800/wk): 12% (1 Child), 16% (2 Children), 19% (3+ Children).
- Basic Plus (£800 to £3,000/wk): Basic rate on first £800, plus 9% (1 Child), 12% (2 Children), 15% (3+ Children) on the excess up to £3,000.
2. Deductible Reductions Before Applying Percentages
Before percentages are applied, two key statutory deductions must be made:
- Relievable Pension Contributions: Both workplace and private pension payments reduce gross assessable income pound-for-pound.
- Other Children in the Household: 11% reduction for 1 other child, 14% for 2 other children, and 16% for 3+ other children living with the paying parent.
3. Shared Care Overnight Stay Reductions
Where a paying parent cares for the qualifying child overnight for 52 or more nights per year, statutory deductions apply:
- 52 to 103 nights (approx. 1 night/week): 1/7th deduction (14.29% off)
- 104 to 155 nights (approx. 2 nights/week): 2/7th deduction (28.57% off)
- 156 to 174 nights (approx. 3 nights/week): 3/7th deduction (42.86% off)
- 175+ nights (Equal shared care): 50% deduction PLUS additional £7/week relief per child
You can model your exact figures using our free Interactive 2026 CMS Calculator.
Is your child maintenance question part of a family court case? EvidenceCanvas is an online tool for people who represent themselves in the family court. It can help you put dates, messages and documents into a chronology and a draft statement for the family court. It does not deal with Child Maintenance Service assessments, mandatory reconsiderations or tribunal appeals.
It is a paid tool with monthly plans and one-off options, and a limited free plan to try it. Check the current prices on its website before you choose a plan. It is not a law firm, it does not give legal advice and it cannot tell you how your case will turn out. If you can get legal advice or legal aid, consider that first.
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