CMS Child Maintenance
Estimate weekly Child Maintenance Service liability using gross income, number of qualifying children, shared-care nights, and other-children reductions.
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How this is calculated
The Child Maintenance Service uses a gross-income-based formula since 2012 (Child Support (Maintenance Calculations) Regulations 2012). Five rate bands apply:
- Nil rate: gross weekly income under £7.
- Flat rate £7/week: £7 — £100/week.
- Reduced rate: £100.01 — £200/week (£7 + tapered % of income above £100).
- Basic rate: £200.01 — £800/week — 12% (1 child), 16% (2), 19% (3+).
- Basic-plus: £800.01 — £3,000/week — additional slice at 9% / 12% / 15%.
- Above £3,000/week: CMS calculates on £3,000; receiving parent can apply to court for a "top-up" order.
Other relevant children of the paying parent reduce gross income first: −11% / −14% / −16% for 1 / 2 / 3+. Shared care reduces the liability by 1/7 per overnight up to 6/7; from 175 nights/year (averaging ≥50%) the parents are treated as making equal contributions and no formula liability arises.