How to work out fuel cost for a journey without guesswork

Knowing how to work out fuel cost for a journey is the difference between quoting with your eyes open and finding out later that the diesel has eaten the margin. Drop your distance and MPG into the CTS fuel cost calculator and it returns litres used, total cost and pence per mile, with no registration. It is built for British road transport, uses imperial MPG, and keeps the arithmetic visible rather than hiding the answer behind a black box.

What the CTS calculator gives transport buyers

A quick estimate is useful to an owner driver checking a job, a traffic planner comparing vehicle sizes, or a buyer testing whether a rate makes commercial sense. The calculator accepts a vehicle preset or your own MPG, along with journey distance, a return journey choice and an editable diesel price. AdBlue can be included where relevant.

The output covers litres used, total fuel cost and pence per mile. It also prices the same mileage across every vehicle class, handy when the load could move on more than one type of truck. A PDF download makes the result easier to file or share. For businesses buying contract haulage, that comparison can expose an expensive vehicle choice before the work is placed.

It is still a fuel model, not a full operating cost. Tolls, driver time, maintenance, tyres and standing costs sit outside the calculation.

The numbers behind a credible fuel estimate

Fuel arithmetic is simple enough, but the inputs decide whether the answer belongs in a quote or in the bin. Litres are calculated by dividing miles by MPG, then multiplying by 4.54609, the number of litres in a UK imperial gallon. Fuel cost is litres multiplied by the price per litre. Pence per mile comes from dividing that fuel cost by the journey distance.

The preset economy figures are typical laden road averages: 28 MPG for a 3.5 tonne van, 17 MPG for a 7.5 tonne rigid, 12 MPG for an 18 tonne rigid, 10.5 MPG for a 26 tonne rigid and 9.5 MPG for a 44 tonne artic. They are sensible starting points, not promises. Load, gradients, speed, traffic and the person behind the wheel can all move the result. A known fleet MPG is the better figure for a firm quotation.

With AdBlue switched on, the estimate uses 5 percent of diesel volume. That is a practical rule of thumb for modern SCR engines, with 3 to 6 percent being a typical range, and the AdBlue price can be edited.

The diesel field defaults to the latest official UK average pump price from the DESNZ weekly road fuel prices statistics, refreshed each week. At 13 July 2026 it was 164.5p per litre. Treat that as a reference point. Your own pump, fuel card or bunker rate is the number that belongs in your costing.

Putting the journey into the calculator

Start with the job as it will actually run, rather than the tidy version written on the rate sheet.

1. Pick the closest vehicle preset, or enter your own MPG figure.
2. Enter the journey distance and select the return trip option where the vehicle is coming back over the same mileage.
3. Check the diesel price and replace the default with your own pump or bunker rate.
4. Switch on AdBlue if it applies, then amend its price if your actual rate is different.
5. Click Calculate fuel cost, then review the journey figure and the comparison across vehicle classes.

The preset economies are sensible laden starting points: 28 mpg for a 3.5 tonne van, 17 mpg for a 7.5 tonne rigid, 12 mpg for an 18 tonne rigid, 10.5 mpg for a 26 tonne rigid and 9.5 mpg for a 44 tonne artic. Use them for an early check, but not for a final buying decision if you have reliable fleet data. Load, terrain, driver, speed and traffic all move consumption. The default diesel price is the latest official UK average, 164.5p per litre at 13 July 2026, but your bunker rate may be the figure that matters.

Reading the result like a transport buyer

The litres figure tells you the expected volume burned. Total fuel cost gives the cash for that mileage, while pence per mile makes runs easy to compare. The vehicle class comparison helps you see whether a smaller unit really saves money, or whether its lower payload could create another trip. Download the PDF when you need a clean record for a file or rate review.

Keep the result in its proper place. It is a fuel estimate, not a haulage rate. Tolls, driver time, maintenance, tyres and standing costs sit outside the calculation, so do not compare the output directly with an operator quote. For a full cost per mile, use the separate CTS haulage cost calculator.

AdBlue is estimated at 5 percent of diesel volume when selected, within a typical range of 3 to 6 percent, and the price is editable. For repeat work, use your own MPG and fluid rates, save the PDF, then check actual consumption against the estimate. That is how to work out fuel cost for a journey without kidding yourself.

Use the CTS fuel cost calculator to price the fuel element of your next movement. For firm prices from vetted operators, request transport quotes from CTS.

Frequently asked questions

How do I calculate fuel cost for a journey in the UK?

Enter distance, MPG and fuel price, then the calculator works out litres, total fuel cost and pence per mile using UK imperial gallons. It applies litres equals miles divided by mpg multiplied by 4.54609, then multiplies by price per litre.

Should I use the default MPG figures in a fuel cost calculator?

The presets are typical laden averages by vehicle class, so they are a sound starting point. Real MPG varies with load, terrain, driver, speed and traffic, so a custom figure gives a firmer number.

Does a fuel cost calculator include all haulage costs?

The CTS tool models fuel only, so it excludes tolls, driver time, maintenance, tyres and standing costs. For a full cost per mile, a separate haulage cost calculator is required.