What This Calculator Does
The Gallons of Gas for Trip Calculator tells you how much fuel a journey will consume based on the distance you plan to drive and your vehicle's fuel economy in miles per gallon (MPG). Enter an optional gas price and it also estimates the total cost of the trip — perfect for budgeting a road trip or commute.
How to Use It
Enter three values: the trip distance in miles, your vehicle's average fuel economy (MPG), and optionally the local gas price per gallon. The calculator divides distance by MPG to find the gallons required, then multiplies by the price for an estimated fuel cost.
The Formula Explained
The core equation is simple: \(\text{Gallons} = \text{Trip Miles} \div \text{MPG}\). If your car gets 25 MPG and you drive 300 miles, you need \(300 \div 25 = 12\) gallons. Cost is then \(\text{Gallons} \times \text{Price per Gallon}\). Use your real-world average MPG (often a bit lower than the EPA sticker number) for the most accurate estimate, and add a small buffer for traffic, hills, or air conditioning.
Worked Example
Suppose you plan a 420-mile drive in a vehicle that averages 30 MPG, with gas at $3.75/gallon. $$\text{Gallons} = 420 \div 30 = 14 \text{ gallons}$$ $$\text{Estimated cost} = 14 \times \$3.75 = \$52.50$$
FAQ
What MPG should I enter? Use your vehicle's average real-world MPG. Highway trips usually beat city driving, so pick a figure that matches your route.
Does this account for stops or idling? No — it's a straight distance-based estimate. Add 5–10% to be safe for stop-and-go conditions.
Can I use it for kilometers or L/100km? This version uses miles and MPG. Convert your distance to miles first if needed.
