Road Trip Fuel Planner
Plan fuel stops and the total fuel cost for a long drive.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
About this calculator
Estimate fuel from total distance, fuel economy, tank capacity, fuel price and a reserve percentage. All monetary values are USD; the model assumes you start with a full tank and refill to full at each stop. Stops use the usable range after your chosen reserve and are a planning estimate, not a guaranteed route plan.
Worked example
calculated with the default values below
Total trip distance 1,200 mi · Fuel economy 28 mi/gal · Tank size 15 gal · Reserve kept in tank 15 % · Fuel price 3.5 USD/gal Total fuel needed 42.86 gal · Total fuel cost 150.00 USD · Usable range per tank 357 mi · Fuel stops needed 3 · Cost per mile 0.125 USD/mi
Method and assumptions
G = D ÷ M; R = K × M × (1 - r ÷ 100); s = max(0, ceil(D ÷ R) - 1) Usable range = tank gallons × mpg × (1 − reserve%). Stops assume a full tank at departure and refilling to full; the initial fill is not counted. Estimate fuel from total distance, fuel economy, tank capacity, fuel price and a reserve percentage. All monetary values are USD; the model assumes you start with a full tank and refill to full at each stop. Stops use the usable range after your chosen reserve and are a planning estimate, not a guaranteed route plan. Use the cited guidance and your own measurements, bills or product specifications to choose inputs. Sample defaults are not current local data.
Data sources
Use the cited guidance and your own measurements, bills or product specifications to choose inputs. Sample defaults are not current local data.
Disclaimer
These calculators give estimates for general information only. Real fuel consumption, performance and range vary with driving style, load, terrain, temperature and vehicle condition. Do not rely on these results for towing limits, payload or braking decisions — use the rating plate of your vehicle.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
G = D ÷ M; R = K × M × (1 - r ÷ 100); s = max(0, ceil(D ÷ R) - 1)
- D
- Distance (mi)
- M
- Fuel economy (mpg)
- K
- Tank capacity (gal)
- r
- Reserve kept in tank (%)
- s
- Refuelling stops
Usable range = tank gallons × mpg × (1 − reserve%). Stops assume a full tank at departure and refilling to full; the initial fill is not counted.
Frequently asked questions
How does the planner estimate fuel stops?
It assumes the trip starts with a full tank and each stop refills the usable range. At 15 gallons, 28 mpg, and a 15% reserve, usable range is 357 miles; a 1,200-mile trip gives three refill stops. The initial tank is not counted as a stop. This is a planning estimate, not a route or station guarantee.
Which inputs and limits apply to Road Trip Fuel Planner?
Use the units shown beside each field. These are form limits, not recommended settings. Total trip distance: 1–50,000 mi; Fuel economy: 1–200 mi/gal; Tank size: 1–200 gal; Reserve kept in tank: 0–50 %; Fuel price: 0–30 USD/gal G = D ÷ M; R = K × M × (1 - r ÷ 100); s = max(0, ceil(D ÷ R) - 1) Usable range = tank gallons × mpg × (1 − reserve%). Stops assume a full tank at departure and refilling to full; the initial fill is not counted. Estimate fuel from total distance, fuel economy, tank capacity, fuel price and a reserve percentage. All monetary values are USD; the model assumes you start with a full tank and refill to full at each stop. Stops use the usable range after your chosen reserve and are a planning estimate, not a guaranteed route plan. Use the cited guidance and your own measurements, bills or product specifications to choose inputs. Sample defaults are not current local data.
What is a complete worked example for Total trip distance = 1,200 mi; Fuel economy = 28 mi/gal?
Inputs: Total trip distance = 1,200 mi; Fuel economy = 28 mi/gal; Tank size = 15 gal; Reserve kept in tank = 15 %; Fuel price = 3.5 USD/gal. Calculation: G = D ÷ M; R = K × M × (1 - r ÷ 100); s = max(0, ceil(D ÷ R) - 1). Results: Total fuel needed = 42.86 gal; Total fuel cost = 150.00 USD; Usable range per tank = 357 mi; Fuel stops needed = 3; Cost per mile = 0.125 USD/mi.