MapQuest Gas Calculator
To estimate the gas cost of a trip, you need three inputs: the distance you will drive, your vehicle’s expected fuel economy and the price of the fuel it uses. A route supplies only the first of those inputs.
For miles and US gallons, divide trip miles by miles per gallon, then multiply by the price per gallon. This is a calculation guide using route mileage, not an interactive MapQuest calculator or a feed of current fuel prices. Every price shown below is an illustrative assumption.
An independent guide from maps-directions.com. We are not affiliated with MapQuest.
Gather the right three inputs
Start with the road distance for the journey you intend to take. Include the return trip, local driving and detours to planned stops. The straight-line distance between two cities will understate fuel needs when the road route is longer.
Next, choose a realistic fuel-economy assumption. Your recent experience in the same vehicle may be more useful for budgeting than its best recorded journey. A loaded vehicle, a roof carrier, congestion or a different balance of city and highway driving can change consumption.
Finally, choose a price for the appropriate fuel grade and unit. A price per liter cannot be used as if it were a price per gallon. A lower advertised price is not necessarily the price available for your fuel, payment method or arrival time.
Calculate fuel cost in miles and gallons
Suppose an illustrative trip covers 360 miles, your assumed fuel economy is 30 miles per US gallon, and your budget uses a price of $3.60 per US gallon. The trip needs an estimated 12 gallons: 360 divided by 30. Multiplying 12 by $3.60 gives a fuel estimate of $43.20.
| Assumed fuel economy | Estimated fuel | Estimated cost |
|---|---|---|
| 24 mpg | 15 US gallons | $54.00 |
| 30 mpg | 12 US gallons | $43.20 |
| 36 mpg | 10 US gallons | $36.00 |
The table changes one assumption at a time. That makes the sensitivity visible: a vehicle returning 24 mpg uses more fuel than one returning 30 mpg over the same route. Do not treat the middle row as a forecast for your vehicle simply because it looks convenient.
These examples use US gallons. Imperial gallons are a different volume, so an MPG figure based on imperial gallons cannot be substituted into a US-gallon calculation without conversion.
Use a different formula for liters per 100 kilometers
Fuel economy expressed as liters per 100 kilometers describes consumption over a set distance. Multiply distance by that consumption figure and divide by 100 to estimate liters. Then multiply the result by the price per liter.
For an illustrative 600-kilometer journey at 7.2 liters per 100 kilometers, estimated fuel use is 43.2 liters. At an assumed 1.70 currency units per liter, the cost is 73.44 currency units. Use the same currency throughout the calculation.
Keep the original unit labels alongside each number when writing the estimate down. This is especially useful when comparing vehicles or planning travel in a country that displays fuel economy differently.
Budget for the whole trip, not only the main drive
A return journey may be longer than the outbound journey, and a weekend usually includes more movement than the drive to the hotel. Add realistic local mileage before applying the formula. That produces a clearer estimate than quietly padding the final price without recording why.
For example, 180 outbound miles, 195 return miles and 25 local miles total 400 miles. At an assumed 32 mpg and $3.60 per US gallon, the fuel estimate is $45.00. Parking, tolls, food and accommodation are separate costs and are not included in that result.
If you want a cautious budget, calculate a second scenario with less favorable fuel economy or a higher fuel price. Keep both scenarios labeled. A range with transparent assumptions is more useful than a single number presented with unwarranted certainty.
Understand what a MapQuest fuel estimate represents
MapQuest’s developer documentation includes fuel-use output and a vehicle highway-efficiency input. Those are documented API capabilities; they do not establish that every consumer website or app screen includes an identical gas-calculator interface.
If the version you are using displays a fuel estimate, inspect its assumptions before relying on it. Otherwise, use the route distance with the arithmetic above. Neither method predicts the exact amount you will pay at a particular pump, and neither makes the journey’s other expenses disappear.
Source: MapQuest documentation: route types, distance and fuel estimates
Check whether a cheaper station saves enough
Consider the total detour rather than the pump-price difference alone. An illustrative discount of $0.10 per gallon saves $1.20 on a 12-gallon purchase. An eight-mile detour at 25 mpg uses 0.32 gallons; at $3.60 per gallon, that adds about $1.15 in fuel cost.
In that example, almost all the advertised saving disappears before you count the extra time. A station already on your route may be more convenient. Use actual detour distance, the quantity you intend to buy and a relevant fuel-price assumption when making your own comparison.
Common questions
Are the gas prices in this guide current?
No. All prices are illustrative inputs chosen to explain the arithmetic. Use a current price for the correct grade, unit and location when preparing your own budget.
Should I simply double a one-way fuel estimate?
Only if the return distance and assumptions are equivalent. For a more useful budget, add outbound, return and local distances first, then calculate the fuel needed for the complete trip.
Does a gas estimate include tolls and parking?
The formulas here estimate fuel only. Keep tolls, parking and other travel expenses as separate items so you can see exactly what the total budget includes.
Written for this website using the official references linked above. Worked examples are illustrative. Product screens and availability can change; use MapQuest’s help for its current controls.