UK Child Maintenance Calculator
Find out how much child maintenance you should pay or receive. Uses the official CMS formula, updated for 2026. Free, instant, and private.
No sign-up required. Takes under 2 minutes.
2026 Child Maintenance Rates
The CMS calculates maintenance as a percentage of the paying parent's gross weekly income:
- 1 child: 12% of gross income
- 2 children: 16% of gross income
- 3+ children: 19% of gross income
For example, on a £30,000 salary you'd pay around £300/month for one child. See all salary amounts
Why Use Our Calculator?
100% Accurate
Uses the exact same formula as the Child Maintenance Service. Updated for 2026 rates and thresholds.
Completely Free
Get instant results at no cost. Optional PDF reports available for those who need official documentation.
Private & Secure
Your data is never stored or shared. Calculations happen in your browser. No account required.
How It Works
Enter Income
Your gross annual income and pension contributions
Add Children
Number of children in this arrangement
Shared Care
How many nights the child stays with you
Get Results
Instant calculation with detailed breakdown
Frequently Asked Questions
How much child maintenance will I pay?
It depends on your gross income and number of children. The standard rates are 12% for 1 child, 16% for 2, and 19% for 3+. Shared care and pension contributions can reduce this. See amounts for every salary level
How accurate is this calculator?
Our calculator uses the exact same formula as the Child Maintenance Service. It accounts for income bands, shared care arrangements, and other children in the household.
How is child maintenance calculated in the UK?
The CMS takes your gross income, deducts pensions, divides by 52 for weekly income, then applies the percentage rate for your number of children. See the full calculation guide
Is my data safe?
Yes, all calculations happen locally in your browser. We don't store your personal or financial information.