How Child Maintenance Is Calculated (UK CMS Estimate)

This calculator gives an estimate based on official CMS-style rules including income, number of children, shared care, and other dependents.

Many parents use this tool to check if their current payments are accurate or if something may be missing from the calculation.

After you get your result, the next page explains what actions you can take if it does not match your situation.

Child Maintenance Calculator (Estimate)

Disclaimer: This is an estimate based on general CMS guidelines and is not an official calculation.

Additional Financial Contributions (Do NOT reduce CMS automatically)

What This Result Means

This is an estimated CMS-style calculation based on the information entered.

If your real-life situation includes additional payments, shared care variations, or informal arrangements, your actual position may be different.

Some extra payments may appear as overpayments in this calculation. However, under strict CMS rules, not all additional payments are automatically recognised.

  • CMS typically only considers official liability
  • Voluntary contributions may not be recognised
  • Informal support arrangements may not be included
  • Separate or additional payments may not be credited or offset
  • Payments not formally agreed or recorded may be ignored

To understand whether your result is accurate — and what you can do next — continue below.

How CMS Payment Bands Work

Nil Rate: £0 if income is very low or certain benefits apply.

Flat Rate: Around £7 per week if on benefits.

Reduced Rate: Lower payments for income roughly £100–£200/week.

Basic Rate: Standard calculation used for most working parents.

What Can Be Considered in Your Calculation?

Most everyday costs do not automatically reduce CMS payments. Examples include:

  • School fees
  • Travel for regular contact
  • Clothing, essentials, holidays, or activities
  • Voluntary additional payments

In exceptional circumstances, some contributions may be considered:

  • Childcare costs above the standard expected contribution
  • School fees in specific cases
  • Travel costs for maintaining contact where not covered elsewhere

Each case depends on the evidence provided and circumstances.

What To Do After You Get Your Result

Once you calculate your estimated child maintenance, you have 3 possible situations:

  • Your result looks correct → you can use it as a guide for budgeting or CMS comparison
  • Your result seems too high or too low → this may mean shared care, income, or other children are not fully reflected
  • You are already paying more than expected → this may indicate overpayments or a need for reassessment

To understand whether your result is accurate — and what you can do next — continue below.

If your payments don’t match your real situation, this is where most parents start.

Want More Insight?

Get a clear breakdown of your result, understand whether it is accurate, and learn what steps to take next if it does not match your real situation.

Learn More About Your Calculation