Answers · UK 2025/26
How is child maintenance calculated when the paying parent is self-employed?
The Child Maintenance Service (CMS) generally uses the self-employed parent's gross taxable income as reported to HMRC for the most recent tax year, applying the same percentage rates as for employed parents (12% for one child, 16% for two, 19% for three or more, on income between £7-£3,000 a week). Because self-employed income can be manipulated more easily than PAYE income, the CMS has specific powers to investigate suspected under-reporting.
Full answer
The Child Maintenance Service calculates maintenance for a self-employed paying parent using broadly the same framework as for employed parents, but the starting income figure is sourced differently: rather than pulling PAYE data automatically from HMRC in near real-time (as happens for most employed paying parents), the CMS typically uses the gross taxable profit figure declared on the paying parent's most recent Self Assessment tax return, which can mean the calculation is based on income from up to 18-20 months earlier than the current date, and does not automatically reflect a self-employed parent's income having risen or fallen more recently. Once the relevant gross weekly income figure is established, the same standard percentage rates apply as for any paying parent: 12% of gross weekly income between £7 and £199.99 for one qualifying child, rising to 16% for two children and 19% for three or more children within that lower band, then a further slice at 9%/12%/15% respectively for income between £200 and £800 a week, and 6%/8%/10% respectively for income between £800.01 and £3,000 a week (the CMS calculation is capped at £3,000 gross weekly income, with anything above requiring a court application for additional maintenance called a top-up order). Because self-employed profit figures are more easily influenced by legitimate but income-reducing decisions (reinvesting profit in the business, paying a spouse a salary through the business, taking dividends rather than salary, or simply under-declaring income) than PAYE employment income, the receiving parent can apply for a variation if they believe the self-employed parent's declared income does not reflect their true lifestyle or earning capacity — the CMS has powers to investigate lifestyle inconsistency (for example, considering assets, spending or lifestyle that appears inconsistent with the declared income) and can adjust the calculation accordingly, including treating certain dividend income, rental income, or additional unearned income as part of gross income for the calculation even where it would not appear on a standard employed parent's payslip. Use the Child Maintenance and Benefit Entitlement calculators alongside official CMS guidance to estimate a likely calculation.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.