How to calculate your vehicle's fuel consumption
Use the calculator on this page or let Drivvo do the maths at every fill-up: the average, the cost per mile and when your next fill-up is due.
- Average from full tank to full tank, including partial fill-ups in between
- The fuel cost per mile at every fill-up
- For cars, motorbikes, lorries, natural gas and electric vehicles
Rated 4.8 on Google Play, with more than 5 million downloads
Fuel consumption calculator
Fill the tank, note the odometer reading and drive as usual. The next time you fill up, enter the figures below.
Result
- Fuel efficiency
- 28 Mile/Gallon Imperial
- The same fuel consumption in the other format
- 3.57 Gallon Imperial/100Mi
- Distance travelled
- 280 mi
This is an estimate based on the figures you entered. In Drivvo, the average is calculated automatically at every fill-up using your history.
How to calculate fuel consumption
The most reliable way is the full-tank method. It measures how much fuel the vehicle actually used over a distance.
- Fill the tank and note the odometer reading.
- Drive as usual, for as long as you like.
- Fill the tank again and note the odometer reading and the amount added.
- Divide the distance driven by the amount added the second time.
Example: the odometer went up by 280 mi and you added 10 Gal to fill the tank. The average is 28 Mile/Gallon Imperial.
Partial fill-ups and full tanks
If you don't fill the tank, you can't know how much fuel was left in it. That's why the average can only be calculated between two full tanks. Any partial fill-ups in between count towards the next full tank.
- In the app, tick Are you filling the tank? only when you fill the tank.
- Forgot to log a fill-up? Tick Missed previous refuelling? on the next one, and the calculation starts again without errors.
- If you usually add only a little at a time, fill the tank every three to five fill-ups. That's enough for the average to appear.
How Drivvo calculates fuel consumption
Log the fill-up and the app does the rest, on Android, iPhone and the Web.
Log the fill-up
Enter the odometer reading and two of these three values: the price, the total cost or the amount. The app works out the third. Tick Are you filling the tank? when you fill the tank.
See the average for the distance driven
The fill-up shows the average, the distance driven and the cost per mile. Once you save it, the app compares this average with your last five.
Track it month by month
In History, each month's summary shows spending, distance and average. This makes it easy to spot changes in fuel consumption.
Reports
Fuel report
In Reports, on the Refuelling tab, you can see fuel consumption for your chosen period.
- Overall average, with the lowest and highest in the period
- Total cost, per day and per mile
- Average price paid, with the lowest and highest
- Distance between fill-ups and how often you fill up
- How much you paid at each petrol station and how much you could have saved
- Charts of spending by month, fuel and petrol station
Fuel cost per mile
The cost per mile shows how much you spend on fuel for each mile driven. The simple maths is the price divided by fuel efficiency.
In Drivvo, the cost of each stretch uses the price you paid for that fuel, with the discount already applied. It is not the total paid divided by the distance, because some of the fuel you added is still in the tank.
Next fill-up forecast
Using your latest fill-ups, the app works out how far you drive each day and estimates the date and odometer reading of your next fill-up. The Next refuelling card appears at the top of History.
On Android and iPhone, a notification reminds you on that date and shows your latest average. It is an estimate: the more regularly you drive, the more accurate it gets.
A separate average for each fuel
The app keeps a separate average for each type of fuel and handles cases that usually skew the figures.
More than one fuel
Up to three fuels in the same fill-up, under More options. Petrol and ethanol in the same tank count together in the average.
Two tanks
A vehicle with natural gas and petrol? In the vehicle settings, choose Two tanks and enter the fuel and capacity of each tank.
Electric
When charging, enter the kWh and the Battery level at the start and end. The average is calculated for each stretch, with no need to charge to 100%.
Diesel and AdBlue
AdBlue has its own average and cost, separate from diesel.
Machines with an hour meter
For machines and vehicles with an hour meter, consumption is shown per hour of use.
Why fuel consumption changes
A worse average than usual often has a simple cause. The most common are:
- Low tyre pressure
- Extra weight in the vehicle or on the roof rack
- Air conditioning on all the time
- Stop-start traffic and short journeys
- Overdue maintenance, such as a dirty air filter
- A change in fuel type
In the app, the average for each stretch appears alongside the lowest and highest, and the report has a chart of the averages. If it gets worse, you'll notice at the next fill-up.
See how to keep track of maintenanceFleet fuel tracking
In a fleet, drivers log each fill-up on their phone, even offline, with the petrol station and payment method. Managers see every vehicle on the Web, with its average, highest, lowest and cost per mile, and can filter by driver.
See Drivvo fleet managementPay less at every fill-up
The app's Where to refuel shows fuel prices at petrol stations near you on a map.
See how Where to refuel worksFrequently asked questions
How do I calculate my car's fuel efficiency?
Fill the tank, note the odometer reading and drive. When you fill up again, divide the distance driven by the amount of fuel added. The calculator on this page does the maths, and Drivvo does it automatically at every fill-up.
What does fuel efficiency mean?
It is how far the vehicle goes on each unit of fuel, or how much fuel it uses per 100 units of distance. Comparing one month's average with another's shows whether the vehicle has started using more fuel.
How do I calculate fuel consumption per 100 mile?
Divide 100 by the fuel efficiency. A vehicle that travels 12.5 per unit of fuel uses 8 per 100.
What is good fuel efficiency?
It depends on the vehicle, engine, fuel and how you drive. The best reference is your own vehicle's average: the app shows the lowest and highest figures and compares each stretch with the previous five.
How do I calculate the fuel cost per mile?
Divide the fuel price by the fuel efficiency. In the app, each fill-up shows the cost per mile for that stretch, with any discount already applied.
How much fuel can I buy for a given amount?
Divide the amount by the price per unit. In the app, just enter the price and total cost: the quantity is filled in automatically.
Can I calculate fuel efficiency without filling the tank?
Not accurately, because you cannot know how much fuel is left in the tank. Partial fill-ups count towards the next full tank. For electric cars, the battery level solves this: you do not need to charge to 100%.
Why isn't the average shown on my last fill-up?
Because that fuel has not been used yet. The average appears when you fill the tank again. In Where to show fuel economy, you can choose whether it appears on the fill-up that starts the stretch or the one that ends it.
Which app calculates fuel consumption and fuel costs?
Drivvo calculates average fuel consumption, the cost per mile and the forecast for the next fill-up. It's free, works on Android, iPhone and the Web, and logs entries even offline.
How do I track fuel for a fleet?
Drivers log each fill-up in the app, and the manager tracks every vehicle on the Web, with its average fuel consumption and costs. The Fleet plan has a 15-day free trial.
Does Drivvo calculate consumption for electric and natural gas vehicles?
Yes. For charging, it calculates the average from the kWh and battery level. For natural gas, the vehicle settings have a Two tanks option for each tank's fuel and capacity.
Does the app tell me when I'll need to fill up?
Yes. The app estimates the date and odometer reading for your next fill-up and shows them in History. You'll also get a notification on Android and iPhone.
Find out your vehicle's real fuel consumption
Download Drivvo, log your next fill-ups and see your average fuel consumption and the cost of each journey.
Want to see all your spending, not just fuel? Discover the car expense tracker