Useful next calculations
Rates and sources
DVLA, HMRC fuel advisory rates and manufacturer-published figures. Real-world results vary by driving style.
Source: DVLA / HMRC fuel advisory rates. Check the linked guidance and any live quote before acting.
When to use this calculator
- When you need a fast estimate before making a bigger decision.
- When you want to compare a few scenarios using the same assumptions.
- When you need a clearer starting point before using a detailed quote or formal document.
- When you want to sanity-check a figure you have seen elsewhere.
A worked example
These are the example figures the calculator opens with.
| Input | Value |
|---|---|
| Miles Per Year | 10,000 |
| MPG (Miles Per Gallon) | 40 |
| Fuel Price Per Litre (£) | £1.5 |
For those figures the calculator returns:
- Annual fuel cost: £1,704.78
- Monthly: £142.07
- Cost per mile: 17.05p
Method & assumptions
This calculator estimates fuel costs for a journey or over a given period based on the distance travelled, your car's fuel economy (in MPG or L/100km), and the current fuel price per litre. It applies a straightforward formula: distance divided by fuel economy gives litres consumed, which is then multiplied by the price per litre. The result does not include oil top-ups, AdBlue costs for diesel cars, or the efficiency impact of carrying heavy loads and using roof boxes. Fuel economy varies with driving conditions, so for planning purposes consider entering a figure 10–15% worse than your car's official rating to get a more realistic estimate of real-world costs.
Common mistakes
- Using optimistic assumptions without testing a more cautious scenario.
- Comparing outputs from different tools without checking that the inputs match.
- Treating the result as a final quote instead of a planning estimate.
- Rounding inputs too aggressively.
What to do next
- Try at least one more scenario so you can compare a realistic range.
- Use the related calculators below to cross-check the decision from another angle.
- Write down the key outputs from your best scenarios before you decide.
- If the result surprises you, change one input at a time to isolate the driver.