Checker

Income Change Checker

The CMS will only reassess maintenance if the paying parent's income has changed by 25% or more. Check whether the threshold has been met and see your estimated new maintenance amount.

Check the 25% income change threshold

The CMS will only reassess maintenance if the paying parent's income has changed by 25% or more since the last assessment. Enter both figures to check.

Current CMS-assessed gross income (annual)

The income figure the CMS currently uses

New gross income (annual)

The paying parent's current actual income

Qualifying children (children in the case)

Relevant other children (paying parent's household)

Children the paying parent supports in their home

About the 25% threshold

The CMS uses income data from HMRC, usually from the most recent tax year. Once an assessment is made, it will only be changed (known as a supersession) if:

–The paying parent's income has increased by 25% or more
–The paying parent's income has decreased by 25% or more
–A relevant change in circumstances has occurred
–An annual review is triggered (typically every 12 months)

What income does the CMS use?

The CMS uses gross annual income from HMRC — usually employment income, self-employment income, and some other sources. It divides by 52 to get a weekly figure.

Salary sacrifice pensions reduce the gross income the CMS sees. Personal pension contributions do not affect the CMS gross income figure.

Annual review

Even if the 25% threshold is not met, the CMS conducts an annual review using the latest HMRC income data. You do not need to request this — it happens automatically.