🛣️ Gas Mileage & Range Calculator
Enter your MPG and tank size to see how far you can drive, keep a reserve in the tank, and check whether a trip fits in one fill-up.
⛽ Plan Your Range
🛣️ Range on 12.0 gal at 30.0 MPG
What is a Gas Mileage & Range Calculator?
It answers the two questions every road trip raises: how far can I go on this tank, and will I make it to the next stop? Feed it your fuel economy and tank capacity and it returns your full-tank range and, once you set a reserve, the usable range you can safely rely on.
Add a trip distance and it also tells you the gallons that leg will burn and whether your usable range covers it — so you know before you set off whether to top up or plan a fuel stop.
❓ Frequently Asked Questions
How is driving range calculated?
Range is simply your fuel economy multiplied by the fuel available: MPG × gallons. For a full tank that is MPG × tank capacity; with a reserve, the calculator first removes the reserve gallons and multiplies by what is left, giving a range you can actually count on.
What reserve percentage should I use?
Many drivers plan to refuel with 10–15% of the tank still in reserve, which on most cars is roughly the point the low-fuel light comes on. Keeping a buffer avoids running the fuel pump dry and gives you margin if the next station is farther than expected.
How many gallons will my trip need?
Divide the trip distance by your MPG. The calculator does this and compares the result against your usable range, flagging whether the trip fits in one tank or whether you should plan a fuel stop along the way.
Why is my range shorter on the highway sometimes and longer other times?
Range follows real MPG, which shifts with speed, terrain, wind, load, and climate control. Steady speeds around 55–60 mph on flat ground stretch a tank furthest; high speeds, hills, headwinds, and heavy cargo all shorten it.