How do I accurately calculate my car's gas mileage manually?

Fill your fuel tank completely and record your odometer reading. Drive normally until the tank is partially or mostly empty. Fill the tank completely again, note the exact gallons pumped, and subtract your previous odometer reading from your current reading. Divide the miles driven by the gallons pumped.

What is considered good gas mileage for a car today?

For conventional gasoline cars, a combined rating above 30 MPG is considered good, while 35+ MPG is very good. Hybrids routinely achieve 45–55+ MPG. Trucks and full-size SUVs typically average 18–24 MPG.

How can I improve my car's gas mileage?

Ensure proper tire inflation (adds up to 3% MPG), avoid aggressive rapid acceleration and hard braking (improves highway MPG by up to 15%), observe highway speed limits, remove unnecessary trunk weight, and change air filters regularly.

What is the difference between MPG and L/100km?

MPG measures how far you can travel on a single unit of fuel (higher is better). Liters per 100 km (L/100km) measures how much fuel is needed to cover a fixed 100 km distance (lower is better).

Does driving at higher speeds consume significantly more gas?

Yes. Due to aerodynamic drag, fuel economy drops rapidly above 50 mph (80 km/h). Driving at 75 mph consumes approximately 20% more fuel than driving at 60 mph.

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Gas Mileage Calculator — Calculate MPG, Fuel Economy & Trip Cost

Free online Gas Mileage Calculator. Calculate exact miles per gallon (MPG), fuel cost per mile, distance achievable per tank, and total road trip gas cost in metric (L/100km, km/L) or US imperial units.

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How to use this calculator

👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉

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In plain English — what does this do?

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📌 Direct Answer & Summary

A Gas Mileage Calculator determines your vehicle's real-world fuel economy by calculating Miles Per Gallon (MPG) or Liters per 100 Kilometers (L/100km). It helps drivers track vehicle efficiency, detect engine performance issues, and calculate exact fuel costs for upcoming road trips or daily commutes.

🚗 Distance Traveled (miles)

⛽ Fuel Used (gallons)

💵 Gas Price per Gallon ($)

🛢️ Fuel Tank Capacity (optional, gallons)

Vehicle Fuel Economy

28.00 MPG

Equivalent to 8.40 L/100 km (11.90 km/L)

Cost Per Distance

$0.125 / mi

Total Trip Fuel Cost

$43.75

Full Tank Range

392 miles

Fuel to Drive 100 mi

3.57 gal

What is Gas Mileage Calculator — Calculate MPG, Fuel Economy & Trip Cost?

How to use it

1️⃣ Select your calculation mode: Trip Gas Mileage (MPG) or Trip Fuel Cost.
2️⃣ Enter your starting and ending odometer readings, or total distance traveled.
3️⃣ Input the total amount of fuel added to fill up the tank (in gallons or liters).
4️⃣ Enter the current price per gallon or liter of fuel.
5️⃣ View your exact MPG, fuel cost per mile/km, and total fuel expenditure.

Formula & Variables

Miles Per Gallon: MPG = Distance (miles) ÷ Fuel Used (gallons) Metric Fuel Economy: L/100km = (Fuel Used in Liters × 100) ÷ Distance (km) Cost Per Mile: Cost/Mile = Fuel Price per Gallon ÷ MPG

Variable Definitions:

MPG Miles Per Gallon (vehicle fuel efficiency rating)

Distance Total miles or kilometers driven between fuel fill-ups

Fuel Used Volume of fuel consumed (gallons or liters)

Cost/Mile Monetary cost incurred per mile of driving

💡 See it in action — a real example

If you drive 350 miles and pump 12.5 gallons of gasoline costing $3.60 per gallon: MPG = 350 ÷ 12.5 = 28.0 MPG. Cost per mile = $3.60 ÷ 28 = $0.129 (12.9¢ per mile). Total trip cost = 12.5 × $3.60 = $45.00.

📊 Typical Vehicle Gas Mileage Benchmarks (MPG & L/100km)

Average real-world fuel economy across vehicle classifications according to EPA data.

Vehicle Category	City MPG	Highway MPG	Metric (L/100km)	Efficiency Rating
Hybrid / Plug-in (PHEV)	45 – 55 MPG	48 – 58 MPG	4.1 – 5.2 L/100km	Exceptional
Compact / Sedan (4-cyl)	28 – 34 MPG	36 – 42 MPG	6.2 – 7.8 L/100km	Good
Compact SUV / Crossover	24 – 28 MPG	30 – 35 MPG	7.5 – 9.0 L/100km	Moderate
Full-size SUV / Minivan	16 – 20 MPG	22 – 26 MPG	10.5 – 13.0 L/100km	Low
V8 Truck / Performance Car	12 – 16 MPG	17 – 21 MPG	13.5 – 18.0 L/100km	Very Low

* Based on US EPA combined laboratory and real-world consumer testing averages.

❓ Common questions

How do I accurately calculate my car's gas mileage manually?: Fill your fuel tank completely and record your odometer reading. Drive normally until the tank is partially or mostly empty. Fill the tank completely again, note the exact gallons pumped, and subtract your previous odometer reading from your current reading. Divide the miles driven by the gallons pumped.
What is considered good gas mileage for a car today?: For conventional gasoline cars, a combined rating above 30 MPG is considered good, while 35+ MPG is very good. Hybrids routinely achieve 45–55+ MPG. Trucks and full-size SUVs typically average 18–24 MPG.
How can I improve my car's gas mileage?: Ensure proper tire inflation (adds up to 3% MPG), avoid aggressive rapid acceleration and hard braking (improves highway MPG by up to 15%), observe highway speed limits, remove unnecessary trunk weight, and change air filters regularly.
What is the difference between MPG and L/100km?: MPG measures how far you can travel on a single unit of fuel (higher is better). Liters per 100 km (L/100km) measures how much fuel is needed to cover a fixed 100 km distance (lower is better).
Does driving at higher speeds consume significantly more gas?: Yes. Due to aerodynamic drag, fuel economy drops rapidly above 50 mph (80 km/h). Driving at 75 mph consumes approximately 20% more fuel than driving at 60 mph.