CMS Mileage Claims Explained (2026): Child Maintenance, Fuel Rates and Contact Costs

CMS Mileage Claims Explained (2026)

How contact costs, fuel rates and Child Maintenance Service rules affect paying parents in England, Wales and Scotland

If you are a paying parent and you regularly travel to see your child, the Child Maintenance Service (CMS) may be able to take some of those travel costs into account.

The key point is this: CMS does not pay you mileage back in cash, and it does not use the standard 45p per mile business mileage rate that many people know from work expenses. Instead, travel for contact can be treated as a special expense, which may reduce the income figure CMS uses when calculating child maintenance.

This guide explains how CMS mileage claims work, who can claim, the current advisory fuel rates, and what evidence can help if you apply.

Who can claim mileage through CMS?

Only the paying parent can claim mileage as a contact cost through CMS.

This is one of the most common points of confusion. The receiving parent cannot use this special-expenses route to claim mileage.

Older guidance and articles often refer to the “resident parent” and “non-resident parent”. More recent language usually uses receiving parent and paying parent, but the practical point stays the same: the mileage rule only applies to the paying parent who is incurring contact costs.

What counts as a contact cost?

Mileage is only one part of contact costs.

Where the facts support it, CMS may also look at things such as:

• public transport fares
• taxi fares in limited situations, for example where disability or long-term illness makes other travel impracticable
• car hire where it is cheaper overall
• overnight accommodation where a same-day return is impracticable or contact takes place over consecutive days
• some tolls, bridge charges and road charges
• in some cases, the cost of a necessary third party travelling with the paying parent or child

That said, not every motoring cost counts. The guidance is about fuel for contact journeys, not wider running costs such as insurance, servicing, tyres or depreciation.

CMS does not use 45p per mile

Many parents assume CMS uses the standard 45p per mile HMRC business mileage rate. It does not.

Instead, CMS uses HMRC advisory fuel rates when looking at fuel costs for contact journeys. These rates change during the year and vary depending on vehicle type, engine size, and in the case of electric vehicles, the charging method.

This means the amount allowed for mileage can be much lower than many people expect.

Current HMRC advisory fuel rates used in CMS mileage cases

Below are the current advisory fuel rates used for this article.

HMRC advisory fuel rates from 1 March 2026

Fuel type	Vehicle / charging category	Rate per mile	Miles needed to reach £10 a week
Petrol	1400cc or less	12p	About 84 miles
Petrol	1401cc to 2000cc	14p	About 72 miles
Petrol	Over 2000cc	22p	About 46 miles
Diesel	1600cc or less	12p	About 84 miles
Diesel	1601cc to 2000cc	13p	About 77 miles
Diesel	Over 2000cc	18p	About 56 miles
LPG	1400cc or less	10p	About 100 miles
LPG	1401cc to 2000cc	12p	About 84 miles
LPG	Over 2000cc	19p	About 53 miles
Electric	Home charging	7p	About 143 miles
Electric	Public charging	15p	About 67 miles

Hybrid vehicles are generally treated as either petrol or diesel for advisory fuel rate purposes.

Why the £10 weekly threshold matters

The £10 weekly threshold is important.

If your contact costs do not reach at least £10 a week, the variation is unlikely to help. This is why some parents technically qualify for mileage in principle, but still see no practical benefit.

For example:

• a home-charged electric car at 7p per mile would need around 143 miles a week to reach £10
• a petrol car over 2000cc at 22p per mile would need around 46 miles a week to reach £10

Before you apply, it is worth working out your usual weekly contact mileage so you can see whether you are realistically over the threshold.

How a mileage claim affects child maintenance

A successful mileage claim does not mean CMS sends you money for fuel.

Instead, if CMS accepts the contact cost as a special expense, the approved weekly amount is usually deducted from the paying parent’s gross weekly income before child maintenance is recalculated.

So if CMS allows £20 a week in contact costs, it does not refund £20. It reduces the income figure used in the formula, and the maintenance calculation is then worked out again.

In practice, the actual saving depends on things such as:

• the paying parent’s gross weekly income
• the number of qualifying children
• whether there are any relevant other children in the paying parent’s household
• shared care arrangements
• whether any other adjustments apply

This is why a mileage claim can sound significant on paper but still lead to only a modest reduction in the weekly maintenance amount.

What evidence helps with a CMS mileage claim?

Good evidence matters.

If you are applying for a contact costs variation, keep your records clear and consistent. Helpful evidence can include:

• a mileage log
• dates of contact
• start and end postcodes
• the vehicle’s fuel type and engine size
• receipts or other records supporting the journeys
• toll, parking or accommodation records where relevant

A simple weekly log is often much more effective than loose receipts with no explanation.

It is also sensible to make sure the journey being claimed is clearly linked to contact with your child. Keeping your records organised from the start can make the application easier to follow and strengthen your case.

Practical tips if you are planning to apply

If you are a paying parent thinking about a claim, these points can help:

1. Work out the numbers first

Before applying, calculate your average weekly contact mileage using the correct advisory fuel rate for your vehicle.

2. Keep a regular record

If your contact pattern is weekly, fortnightly or during school holidays, log it carefully so the pattern is easy to understand.

3. Record the right journey

The strongest claims clearly show that the travel is for contact with the child.

4. Keep supporting documents

Receipts, booking confirmations and toll records can all help where they support the journey pattern.

5. Be realistic about the result

Even if your claim is accepted, the reduction in maintenance may be smaller than expected.

How to apply for a CMS variation

You can ask CMS to consider a variation when you first apply for child maintenance or after a calculation is already in place.

If you are relying on contact costs, gather your evidence before or while making the request so you can explain:

• the contact pattern
• the journeys involved
• how often they happen
• the weekly cost
• why the costs are necessary

CMS can take time to review a variation, so it helps to keep ongoing records rather than trying to rebuild the history later.

What if CMS says no?

If CMS refuses the variation, or allows less than you think is correct, you can ask for a mandatory reconsideration.

This means CMS looks at the decision again.

If the outcome still seems wrong after mandatory reconsideration, you may be able to appeal to the tribunal. Deadlines usually apply, so it is important to act promptly and keep copies of your paperwork.

Frequently asked questions about CMS mileage claims

Can the receiving parent claim mileage from CMS?

No. Only the paying parent can claim mileage as a contact cost through this special-expenses route.

Does CMS use 45p per mile?

No. CMS uses HMRC advisory fuel rates, not the 45p per mile business mileage rate.

Can electric car drivers claim contact costs?

Yes. Electric vehicle drivers can still claim contact costs, but the advisory rate is much lower than many parents expect. The charging method can also affect the rate used.

Do I need regular contact to claim?

Regular contact makes this type of application much stronger. One-off or occasional trips are much less likely to fit the contact-cost rules in a useful way.

Can tolls or overnight stays count?

Sometimes, yes. Depending on the circumstances, certain tolls, road charges, bridge charges and overnight accommodation may be relevant.

Final word

For most parents, the two biggest misunderstandings are these:

• CMS does not use 45p per mile
• only the paying parent can claim mileage as a contact cost

That matters because many parents overestimate what they can claim, or assume both parents can use the same route.

In reality, CMS contact-cost claims are based on special expenses for the paying parent, and the fuel element is assessed using HMRC advisory fuel rates rather than the standard business mileage allowance.

If you are a paying parent with regular contact and meaningful weekly travel costs, a well-prepared variation request may help reduce your child maintenance calculation. The reduction may not be large, but where the figures genuinely stack up, it can still be worth pursuing.