The Hidden Ledger: Fuel Cards, Receipts and Reimbursement Costed for 2026
Photo: Scriblerius, tertius, Public domain, via Wikimedia Commons
Fuel cards, receipted expenses and mileage reimbursement are often compared on the wrong line of the spreadsheet. A card fee of £1.50 per vehicle per month looks expensive beside a free receipt app. A 45p mileage rate looks generous beside a pump price. The all-in cost per mile tells a different story once VAT recovery, admin labour, leakage and cashflow are included. This is a road test of the numbers a UK fleet manager should actually use in 2026.
Define the cost lines first
The useful metric is all-in pence per business mile: fuel or reimbursement gross, less recoverable VAT where valid, plus card or processing fees, admin hours at a loaded rate, leakage and lost claims, and the cashflow cost of funding the method. For company-owned vehicles, the fuel card and receipted expense models are comparable. Mileage reimbursement under HMRC approved mileage rates is a different product: it is designed for employees using their own vehicles and covers wear, insurance and depreciation, not just diesel.
VAT is the first quiet swing. A VAT-registered business can usually recover VAT on business fuel bought with a fuel card or a valid receipt. The pump price includes 20% VAT, so the recoverable amount is one sixth of the gross fuel spend, subject to the usual evidence rules. Receipt-based schemes lose recovery where drivers miss receipts or submit card slips rather than VAT invoices. Mileage reimbursement does not carry a VAT recovery on the 45p or 25p rate.
A worked comparison for 25 diesel vans
Assume 25 diesel LCVs, 14,000 business miles each a year, 32 mpg, diesel at £1.52 per litre including VAT, and 350,000 total miles. Loaded admin time is £28 an hour. These are illustrative figures for the model, not a market quote.
| Cost line | Fuel card | Receipted expenses | Mileage reimbursement, own car |
|---|---|---|---|
| Gross fuel or reimbursement | £75,591 | £75,591 | £137,500 |
| Recoverable VAT | £12,599 | £11,843 | £0 |
| Net fuel or reimbursement | £62,993 | £63,748 | £137,500 |
| Card, transaction or processing fees | £947 | £0 | £0 |
| Admin labour | £4,200 | £21,000 | £6,300 |
| Leakage, lost VAT and duplicate claims | £630 | £1,912 | £1,375 |
| Cashflow and funding cost | £1,000 | £2,500 | £0 |
| All-in annual cost | £69,770 | £89,160 | £145,175 |
| Cost per business mile | 19.9p | 25.5p | 41.5p |
The receipted expense column has no card fee, yet it is roughly £19,400 a year more expensive than the fuel card model in this example. Most of that is admin time and lost VAT recovery, with leakage on top. The mileage reimbursement column is not a like-for-like fuel comparison; it is the true cost of using a private car. At 41.5p per mile it is more than double the fuel-card cost per mile, but it transfers wear, insurance and residual-value risk to the driver. For a company-owned van, that line should not be used as a fuel strategy.
Where the cheap option loses money
Receipted expenses look lean because the visible fee is zero. The cost moves into the back office: chasing receipts, checking mileage, matching fuel purchases to journeys and correcting duplicates. A 2.5-hour monthly admin load per vehicle is plausible for a paper or photo-receipt process; at 25 vans that is 750 hours a year. Add the VAT that never gets reclaimed and the fuel that cannot be matched to a vehicle, and the cheap option becomes the expensive one.
Fuel cards are not automatically clean. Cards without vehicle, site, time or volume restrictions can still leak. The advantage is that the data arrives in a usable format and exceptions can be tested. A card that is restricted to UK fuel sites, driver PINs and realistic tank capacities is easier to audit than a shoebox of receipts.
Mileage reimbursement is often the right answer for genuinely private vehicles, low-mileage drivers and grey-fleet arrangements. It is a poor fit for a company-owned van fleet because the rate is not a fuel price; it is a full running-cost allowance.
Decision checklist for 2026
- Confirm vehicle ownership: company-owned, contract hire, private or grey fleet.
- Calculate annual business miles per vehicle, not just fleet average.
- Test VAT recovery: can every fuel purchase be supported by a valid VAT invoice?
- Put a loaded hourly rate on admin time, including driver time.
- Estimate leakage: duplicate claims, missing receipts, out-of-hours fills and ghost fills.
- Check cashflow: who funds fuel, for how long, and at what cost?
- Review card controls: site restrictions, time windows, tank capacity, odometer prompts.
- Check telematics integration: can fuel litres be matched to idle hours, routes and fill events?
The spreadsheet verdict
For a company-owned UK fleet above a modest size, the fuel card usually wins on all-in cost per mile because VAT recovery is cleaner, admin is lower and exception reporting is stronger. Receipted expenses can work for very small fleets or low-volume pools where the card fee and controls are disproportionate. Mileage reimbursement should be judged as a private-vehicle running cost, not as a cheap fuel system. The cheapest headline is rarely the cheapest mile.
