If you are separated from your child’s other parent you are required to have child maintenance which is calculated, in most cases, through the Child Maintenance Service (CMS) which can seek information from the Inland Revenue. If you earn more than the maximum CMS threshold, the court can award top-up maintenance to the other parent. Calculating payments is not always straightforward, but you can use this calculator: https://www.cmoptions.org/en/calculator/
If you do not agree to the amount of maintenance, you can ask the CMS to re-consider and ultimately appeal the decision to an independent tribunal. Contact our family solicitors for more information.