Child Maintenance Calculator for Divorce

Child maintenance is one of the most significant financial aspects of divorce where children are involved. In England and Wales, child maintenance is calculated using the Child Maintenance Service (CMS) formula — a government-set calculation based on income and the number of children. Understanding what you are likely to pay or receive is essential to planning your financial position after divorce.

How the CMS Formula Works

The CMS calculates child maintenance based on the gross weekly income of the paying parent (the parent with whom the child does not primarily live). The gross income figure used is taken from HMRC records — typically the most recent tax year — and includes employment income, self-employment profits, pension income, and rental income above certain thresholds.

The basic rate applies to most paying parents. The percentage applied to gross income depends on the number of qualifying children: 12% for one child, 16% for two children, 19% for three or more children. These percentages are applied to gross income between approximately £100.01 and £800 per week; a reduced rate applies to the first £100 per week, and an additional rate applies to income above £800 per week.

Basic, Reduced and Nil Rates

• Nil rate: Applies where the paying parent earns below approximately £100 per week gross, or falls into specific exempt categories
• Flat rate: A fixed amount (currently £7 per week) where gross weekly income is between £100 and £100.99
• Reduced rate: A tapering calculation for gross weekly income between £101 and £199.99
• Basic rate: The standard percentage-based calculation for income above £200 per week
• Basic plus rate: Additional percentage applied to income above £800 per week gross

Overnight Stays and Shared Care

The CMS calculation is reduced where the paying parent has overnight stays with the child. The reductions are applied in bands: 1/7 reduction for 52 to 103 nights per year, 2/7 reduction for 104 to 155 nights, 3/7 reduction for 156 to 174 nights, and a 50% reduction plus a further flat-rate deduction where shared care is above 175 nights per year.

Special Expenses

The CMS can make deductions for certain special expenses, including travel costs for maintaining contact with the child, costs for caring for a child who has a disability or long-term illness, and boarding school fees. These deductions reduce the gross income figure used in the calculation.

How Child Maintenance Affects Divorce Settlement

Child maintenance and the financial settlement in divorce are legally separate. The Family Court cannot include child maintenance in a consent order (except in limited circumstances). Child maintenance is dealt with through the CMS. However, the amount of child maintenance affects the financial planning of both parties — the receiving parent's income needs in the settlement, and the paying parent's disposable income for housing and other costs.

DivorceIQ calculates your expected CMS child maintenance figure as part of the full assessment and integrates it into the 10-year cashflow model, so you can see the full financial picture in one place.

Legal disclaimer: DivorceIQ provides financial information and modelling only. It is not legal advice and does not replace advice from a qualified solicitor. Divorce law outcomes depend on individual circumstances. DivorceIQ is designed for England and Wales only.