Fuel costs rarely stay still for long. One month the numbers look manageable. The next, you’re trying to work out why similar vehicles are using different amounts of fuel on similar jobs. For many fleet operators, that’s where the real challenge starts. It’s not just about what fuel costs at the pump. It’s about understanding where fuel is being used, where it’s being wasted and what you can do about it.
RAC figures reported in March 2026 showed the average UK diesel price at 160.3 pence per litre, compared with 142.4 pence per litre on 28 February. That sharp rise underlines how quickly fuel spend can shift and why close monitoring remains important for fleets.
Fuel consumption calculator
Calculate your fuel consumption (petrol, diesel) with our online calculatorWhat formula can I use to work out my diesel or petrol consumption?
In case you’re curious about the methodology our fuel consumption calculator uses, we’ll give you the mathematical formula for it right now:
Expected mileage ÷ Average miles per gallon x 4.54609 x Fuel price per litre = Fuel cost
In the UK, we measure fuel efficiency in average miles per gallon but pay for fuel by the litre. It’s therefore necessary to do a miles-per-litre conversion, which is where the gallon x 4.54609 part of the formula comes in (an Imperial gallon is 4.54609).
What affects fuel consumption?
In real-world fleet operations, the biggest influences often include the type of route, driving behaviour, speed and tyre condition. Urban work with frequent stops will usually produce a different result from long motorway runs. A vehicle driven smoothly will typically perform differently from one exposed to harsh acceleration and braking. Tyres also play a part, especially if they’re not properly maintained.
This is why average consumption figures should be treated as a guide, not a verdict. If a van or truck looks less efficient than another, the reason may be mechanical, behavioural or operational. The value comes from using the data to understand what’s really happening.
Why spreadsheets only show part of the picture
Many fleets start by tracking fuel manually. That can work for a small number of vehicles, but it becomes harder to manage as operations grow.
Software-based fuel monitoring has changed that. Fleet systems have evolved from basic spreadsheet tracking to tools that continuously collect vehicle data, making it easier to analyse fuel patterns and identify inefficiencies over time, take Webfleet for example.
That extra visibility matters because fuel waste is rarely caused by one big issue. More often, it builds up through small, repeated losses across the week. A longer idle here, a less efficient route there, a vehicle that’s due maintenance but keeps working as normal. On their own, these things can be easy to miss. Across a fleet, they add up quickly.
A more practical way to monitor fuel use
When you track it consistently, it becomes easier to see where costs are rising, where vehicles may be underperforming and where small operational changes could have a meaningful impact. For UK fleets facing continued cost pressure, that kind of visibility can make day-to-day decisions more confident and more effective.
If you’re looking at ways to get a more accurate view of fuel use across your vehicles, a fuel monitoring system can help you move beyond estimates and start working with live operational insight. This is where Webfleet comes in. Discover how connected vehicle data can support your journey to reduced operational costs.
