CMS Help Fair CMS. Clear Numbers. Real Support.
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For parents who pay child maintenance

CMS Help

Fair CMS. Clear Numbers. Real Support.

If a Child Maintenance Service figure looks wrong, this site helps you check the numbers, keep your evidence, and write the next letter — one clear step at a time.

Start here Check my figures

Free to use. No account needed for the calculator, letters, or arrears check. Not a law firm — information support only.

Start here — pick what matches you

You do not need to read the whole site. Choose one line and follow it.

What this site helps with

Information support for paying parents — not a law firm and not legal advice.

CMS Help is for parents who pay child maintenance and need to challenge a wrong calculation, unexplained arrears, or enforcement that does not match a correct figure. Children are entitled to support; the amount should be accurate and explained in writing.

We help you

  • Check whether a CMS figure looks plausible
  • Keep a dated list of payments and letters
  • Draft formal letters for the next step
  • Store evidence privately (My Case)
  • Understand deadlines for reconsideration, tribunal, and complaints

This site is not

  • Legal advice or representation
  • A campaign about unpaid maintenance
  • A replacement for your official CMS letters

Always check tool results against your CMS decision letters before you escalate. Older Child Support Agency (CSA) debt is separate from current CMS calculations.

Common problems we cover

If you disagree with CMS — the usual steps

Based on GOV.UK and Citizens Advice. Check your letters for the exact deadline on your case.

If the amount or decision looks wrong

  1. Ask for a written calculation and arrears breakdown.
  2. Request mandatory reconsideration — usually within 30 days of the decision letter.
  3. Keep the mandatory reconsideration notice.
  4. If still unhappy, appeal to the tribunal (form SSCS2) — usually within one month of that notice.

Full dispute guide

If the service handling is poor

  1. Raise a CMS/DWP service complaint (delays, missing explanations, poor handling).
  2. Ask for a complaint review if the first reply is not enough.
  3. After a final reply that points you to the Independent Case Examiner (ICE), escalate there — usually within 6 months.

Complaint guide

You can do both

Challenging a figure is not the same as complaining about how you were treated. Where both apply, you can run both at the same time.

Late applications can sometimes be accepted — explain the delay in writing and keep proof of posting or online submission.

Tools — free on this page

No account needed below. My Case is optional if you want to save files online.

1. Estimate calculator

Rough weekly and yearly amount from income, children, and shared care.

2. Arrears check

Compare what you think you should have owed with what CMS claims.

3. Letter builder

Word and PDF drafts for the next formal step.

4. Case timeline

Dated log of payments and letters — stored in your browser only.

5. My Case

Optional account to upload evidence and download your documents.

6. Guides

Short how-to for figure jumps, arrears, deadlines, and enforcement.

Also useful: Dispute route Enforcement Variations Evidence tips Findings FOI Register

Not legal advice. For tribunal or court action, seek regulated advice (for example Citizens Advice or a solicitor).

Estimate calculator

Rough estimate only. Check against your CMS decision letter.

Enter figures and press Calculate.

Shows which CMS rate applies (nil, flat, reduced, basic, or basic-plus — the official rate names). See Methodology for assumptions and sources.

Case timeline

Stored only in your browser. Download before clearing. Want to upload files and save online? Open My Case.

Date Type Amount Notes Evidence

Letter Builder

Follows the usual CMS steps: written explanation → mandatory reconsideration → tribunal → service complaint → complaint review → Independent Case Examiner. Export as Word or PDF. Signed-in users can save drafts straight into My Case.

1. Breakdown 2. Reconsideration 3. Tribunal 4. Complaint 5. Review 6. Independent Case Examiner
Additional grounds (optional — tick all that apply)

Select a letter type, complete the form, then generate a professional draft.

Arrears check

Compare what you think you should have owed with payments and CMS claims. Download Excel.

Optional payment list — add line items; they can fill Total paid.

Date Amount (£) Reference

Run an audit to see results and enable Excel export.

Resources

Official steps, key deadlines, and references — based on GOV.UK and Citizens Advice. Official links last verified August 2026.

Two routes. Disagree with a decision (amount, shared care, arrears figure)? Use explanation → mandatory reconsideration → tribunal. Unhappy with service (delays, missing explanations, poor handling)? Use complaint → complaint review → Independent Case Examiner. You can run both routes at the same time where both apply.

Decision challenge route

  1. Request a written calculation and arrears breakdown.
  2. Ask for mandatory reconsideration within 30 days of the decision letter date.
  3. Keep the mandatory reconsideration notice.
  4. If still unhappy, appeal to the Social Security and Child Support Tribunal (form SSCS2), usually within one month of that notice.

Service complaint route

  1. Use the DWP/CMS complaints procedure for delays, missing explanations, or poor handling.
  2. Ask for a complaint review if the first reply is inadequate.
  3. After a final complaint response that refers you to the Independent Case Examiner (ICE), escalate there — usually within 6 months (check your letter).
  4. The Parliamentary and Health Service Ombudsman (PHSO) is via your MP if needed after ICE.

Key deadlines

  • Mandatory reconsideration: usually 30 days from the decision letter.
  • Tribunal: usually 1 month from the reconsideration notice.
  • Independent Case Examiner: usually 6 months from the final complaint response.
  • Late applications can sometimes be accepted — explain the delay in writing.