Fuel and Emissions
Fuel Tank Range Calculator
Estimate usable driving range while retaining a chosen fuel reserve. Gauge behavior and usable capacity vary by vehicle.
Replace the example values
Use a separate saved result when one uncertain measurement needs a cautious alternative.
Start with the operating case
Estimate usable driving range while retaining a chosen fuel reserve — this page measures one relationship rather than diagnosing the entire vehicle.
Gauge behavior and usable capacity vary by vehicle — that condition defines when planned driving range is comparable with another result.
When you need to compare fuel use over the same distance at two measured or modeled cruising economies, avoid adding an improvised field here and open the Driving Speed Fuel Economy Comparison.
Building one consistent data set
Usable fuel capacity. Fuel volume available before the intended refill point — for this measurement, match the fuel quantity to the same distance, fill method, and operating period.
Document Expected fuel economy as economy expected for the planned driving conditions — this means you should match the fuel quantity to the same distance, fill method, and operating period.
For Reserved fuel, use the quantity described as fuel intentionally left unused as a planning buffer — in the vehicle record, match the fuel quantity to the same distance, fill method, and operating period.
The mathematical relationship
In “planned range = (tank capacity − reserve) × MPG,” the printed units define how each term is interpreted.
No term beyond usable fuel capacity, expected fuel economy, and reserved fuel is introduced in “planned range = (tank capacity − reserve) × MPG.”
Planned driving range answers “Estimate usable driving range while retaining a chosen fuel reserve.” The additional displays, Full-tank theoretical range and Reserve range, are a different view of the same entered measurements.
Do not treat the theoretical range as permission to run the tank dry — when that condition changes, compare separate calculator runs instead of blending the inputs.
Because gauge behavior and usable capacity vary by vehicle, a disagreement between planned driving range and an outside reference should trigger a review of usable fuel capacity and reserved fuel.
What remains a separate check
The equation cannot determine whether usable fuel capacity was recorded with a calibrated instrument or under a repeatable operating condition — for usable fuel capacity, the page specifically expects fuel volume available before the intended refill point.
Keep this result separate from the task to estimate the economy and fuel-use change associated with a roof rack or rooftop cargo, which is available in the Roof Rack Fuel Economy Penalty.
Interpreting this calculator
What measurement source fits Usable fuel capacity when it represents fuel volume available before the intended refill point?
Because usable fuel capacity represents fuel volume available before the intended refill point, use a source tied to the exact vehicle, component, and operating period described by the other fields.
How does the warning “Gauge behavior and usable capacity vary by vehicle” affect Planned driving range?
The condition “Gauge behavior and usable capacity vary by vehicle” is not corrected automatically by the numeric inputs, so create a separate fuel tank range case when it changes.
What assumption is expressed by “planned range = (tank capacity − reserve) × MPG”?
In “planned range = (tank capacity − reserve) × MPG,” usable fuel capacity and expected fuel economy are treated as parts of one vehicle case.
How narrowly is Expected fuel economy defined by “Economy expected for the planned driving conditions”?
The definition “Economy expected for the planned driving conditions” excludes a similarly named rating or a measurement taken at another reference point.