User Rating 0.0
Total Usage 1 times
Fuel & Distance Data
miles
Miles driven since last fill-up
gal
Amount required to fill tank
$
Efficiency
0.0
MPG (US)
Metric 0.0 L/100km
Cost / Mile $0.00
Total Cost $0.00
Trip Budget Visualizer
Est. Cost: $0.00
Fuel Needed: 0 gal
"What If" Savings Projector

Annual savings (12k miles/yr): $0.00

Fill-Up Logbook Running Average: 0.0 MPG
Date Dist Vol MPG Cost
Is this tool helpful?

Your feedback helps us improve.

About

Tracking fuel efficiency offers immediate insight into engine health and driving habits. While modern dashboard displays provide estimates, they often rely on short-term sensor data that fluctuates with idling or sensor drift. Calculating Miles Per Gallon (MPG) manually using odometer readings and pump receipts remains the gold standard for accuracy.

This tool addresses the discrepancy between manufacturer ratings (EPA/WLTP) and real-world performance. Variations in tire pressure, aerodynamics, and cargo load significantly alter consumption. For fleet managers and commuters, a deviation of 2 to 3 MPG represents a substantial annual financial variance.

We include specific modules for Electric Vehicle (EV) equivalents using the MPGe standard, allowing hybrid owners to compare efficiency directly against internal combustion engines. The integrated logbook persists data locally, enabling the calculation of a running average that smooths out anomalies from single tank fills.

fuel economy gas mileage trip cost vehicle efficiency mpge

Formulas

The core calculation relies on the differential in odometer readings divided by the fuel volume required to refill the tank. Accuracy depends on filling the tank to the same level (usually the automatic click-off) each time.

{
MPG = dVgalL/100km = 235.21MPGUS

For Electric Vehicles, the MPGe (Miles Per Gallon equivalent) is derived using the EPA standard where 33.7 kWh of electricity contains the energy equivalent of one gallon of gasoline.

MPGe = Distance × 33.7EnergykWh

Reference Data

Efficiency ClassMPG (US)MPG (UK)L/100kmCost/100mi ($3.50/gal)
Heavy Duty / Towing89.629.4$43.75
Full-Size SUV1518.015.7$23.33
Average Sedan (2010s)2530.09.4$14.00
Modern Crossover3036.07.8$11.67
Compact / Economy3542.06.7$10.00
Hybrid (City/Hwy Mix)5060.04.7$7.00
PHEV (Gas Mode)5566.14.3$6.36
Electric (MPGe Low)90108.12.6 (eq)$3.89 (eq)
Electric (MPGe Avg)110132.12.1 (eq)$3.18 (eq)
Electric (MPGe High)140168.11.7 (eq)$2.50 (eq)

Frequently Asked Questions

Dashboard computers measure fuel flow rate through the injectors and approximate consumption. They often accumulate error over time due to calibration drift or tire size changes. Manual calculation (Miles divided by Gallons at the pump) is an empirical measurement of what actually left the tank, making it the definitive metric for efficiency.
You should strictly avoid topping off. To get an accurate calculation, the tank must be filled to the exact same "full" state every time. The automatic shut-off valve on pumps is the most consistent reference point. Forcing more fuel in after the click distorts the fuel volume data (V), resulting in artificially low MPG calculations for that specific leg.
Yes. The air conditioning compressor places a mechanical load on the engine (or electrical load in EVs/Hybrids). At low speeds or idling, this can reduce efficiency by 15% to 20%. At highway speeds, however, the drag penalty from opening windows often exceeds the fuel penalty of running the AC.
This is a common source of error in international discussions. One US Gallon is approximately 3.785 Liters, while one Imperial (UK) Gallon is 4.546 Liters. A car achieving 30 MPG in the US would be rated at roughly 36 MPG in the UK for the exact same efficiency. Always verify which gallon unit your vehicle or manual references.
MPGe bridges the gap between electrons and hydrocarbons. The EPA determined that 33.7 kilowatt-hours (kWh) of electricity holds the same potential energy as one gallon of gasoline. If your EV travels 100 miles on 33.7 kWh, it has an MPGe of 100. This allows you to directly compare the energy efficiency of an electric motor against a combustion engine.