Which gallon is used?

US gallon (3.785 liters). For imperial gallon, multiply US MPG by ~1.201 to convert.

Why does L/100km drop when MPG rises?

L/100km measures fuel consumed per distance, so lower is better; MPG measures distance per fuel, so higher is better—they move in opposite directions.

Can I use this for any vehicle type?

Yes. It’s a pure unit conversion for cars, trucks, motorcycles, or fleets. Just enter the MPG you have.

Can I compare WLTP vs EPA with this?

You can convert units, but test cycles differ. Use real-world MPG where possible, then convert for a fair comparison.

Does this apply to flex-fuel (E85) or diesel?

Yes for unit conversion, but be aware MPG can vary by fuel type. Enter the actual MPG for the fuel you’re using.

Can I estimate CO2 or cost from this?

Not directly. Pair the output with fuel carbon intensity or price to estimate emissions or trip cost.

What about plug-in hybrids with mixed electric/gas miles?

This tool converts a single MPG figure. For PHEVs, compute your blended MPG (gas miles ÷ gallons used) for the trip, then convert that value.

Do I need to adjust for altitude or cold weather?

Those factors change real MPG but not the conversion. Use the MPG actually observed in your conditions for best results.

Can I input Km/L directly?

Convert Km/L to MPG first: MPG = Km/L ÷ 0.425144. Then enter that MPG here to see L/100km and Km/L echoed back for validation.

Why is the conversion constant 235.215?

It comes from unit relationships: 100 km = 62.137 miles and 1 US gallon = 3.78541 liters. Combining those gives 235.215 as the conversion factor between MPG and L/100km.

Does this work for fleet reporting?

Yes, as long as you use a consistent MPG value for each vehicle. For fleet summaries, convert each vehicle’s MPG to the same unit before averaging so you don’t mix inverse scales.

everyday calculator

Fuel Economy Converter

Convert MPG to L/100km and km/L for quick car comparisons.

Results

L/100km: 7.84
MPG: 30.00
Km/L: 12.75

Overview

Swap between US MPG and metric fuel economy for vehicle shopping, trip planning, or comparing reviews across regions.

Fuel economy numbers can be confusing because they point in opposite directions depending on the unit system: higher MPG is better, but lower L/100km is better. This converter makes that relationship explicit and lets you move between US MPG, liters per 100 km, and kilometers per liter with one input.

It’s especially useful when you’re reading overseas reviews, comparing an import to a US‑spec model, or planning a trip where fuel economy labels are shown in L/100km. Instead of doing mental math or hunting for conversion charts, you get a clean, consistent translation you can trust.

For comparisons, convert city and highway MPG separately so you can see how driving mix changes the metric numbers. This also helps when you want to compare two vehicles that look close in MPG—L/100km can reveal clearer differences in actual fuel burned.

Use real‑world MPG whenever possible (trip computer averages or fill‑up math) to make the metric numbers more accurate for your driving conditions.

How to use this calculator

Enter your vehicle’s MPG (real-world or sticker).
See the equivalent L/100km and Km/L instantly.
Try city vs highway MPG to see the range of metric values.
Reverse a metric rating by converting it to MPG (235.215 ÷ L/100km) if needed.
If you’re comparing imperial gallon figures, convert MPG (imp) to MPG (US) by dividing by ~1.201, then run the tool.

Inputs explained

MPG: Miles per gallon figure to convert using US gallons. Use observed MPG for the most accurate real‑world conversion, or label MPG for quick comparisons across models.

Outputs explained

L/100km: Liters consumed per 100 kilometers. Lower is better because it represents less fuel used to travel the same distance.
MPG: Miles per US gallon. Higher is better because it represents more distance traveled on each gallon of fuel.
Km/L: Kilometers traveled per liter of fuel. Higher is better and is often used in some international markets and vehicle dashboards.

How it works

The converter is based on standard unit relationships between miles, kilometers, gallons, and liters.

For US MPG to L/100km, we use the constant 235.215, derived from 100 km per 62.137 miles and 1 US gallon = 3.78541 liters. The formula is L/100km = 235.215 ÷ MPG.

For US MPG to Km/L, we multiply by 0.425144, which is the ratio of kilometers per mile divided by liters per US gallon.

The conversion is reversible: if you have L/100km, you can compute MPG as 235.215 ÷ L/100km.

Because MPG and L/100km are inversely related, small changes at high MPG values can create noticeable shifts in L/100km—this is normal and expected.

All calculations use US gallons (not imperial gallons). If you have imperial MPG, convert to US MPG first before using the tool.

Formula

L/100km = 235.215 ÷ MPG (US). Km/L = MPG × 0.425144. MPG (US) = 235.215 ÷ L/100km.

When to use it

Comparing US MPG to metric ratings when shopping international models or reading European/Canadian reviews.
Planning road trips abroad and translating your car’s MPG into local L/100km signage.
Checking consumption targets for fleets that report in different units.
Benchmarking hybrids, trucks, or motorcycles across MPG, L/100km, and Km/L.
Translating a friend’s Km/L brag into MPG to see how it stacks up.
Normalizing fuel economy when evaluating used imports that list imperial MPG on the window sticker.
Explaining efficiency differences to customers when selling vehicles across markets.
Aligning corporate sustainability reports that quote fuel use in mixed units.
Converting test drive results (e.g., km traveled per liter refilled) into MPG for US-based teammates.
Training sales or support teams that need quick, accurate US-to-metric fuel economy conversions.

Tips & cautions

Real-world MPG often differs from EPA/label values—use your own trip computer or tank averages for precision.
Higher MPG means lower L/100km; they move inversely.
If you only know L/100km, divide 235.215 by that number to get MPG; then re-enter MPG to double-check.
Diesel and hybrid ratings can be high; ensure you’re comparing same fuel type and driving mix.
City vs highway MPG differ—convert both to understand your realistic range.
If you have imperial MPG, convert to US MPG by dividing by ~1.201 before using this calculator.
For EVs using MPGe, convert MPGe as if it were MPG to get rough L/100km-equivalent energy usage, but note it’s not liquid fuel.
When comparing WLTP vs EPA ratings, expect WLTP to read optimistically; use real-world MPG where possible.
If you track fuel with receipts, divide miles driven by gallons pumped to get actual MPG before converting—this removes trip computer bias.
Use decimal precision on MPG input (e.g., 27.5) to get tighter L/100km outputs when benchmarking close competitors.
If your car displays Km/L, convert it to MPG before sharing with US audiences to avoid confusion.
Keep rounding in mind: small MPG differences can materially shift L/100km at higher efficiency levels (e.g., 60 vs 58 MPG).
For fleet reports, convert every vehicle to the same unit before averaging so you don’t mix inverse scales.
If you’re comparing two cars with close MPG values, use L/100km to see the difference in fuel burned more clearly.
Round inputs consistently when comparing multiple vehicles.
Pure unit conversion—does not account for load, driving style, terrain, weather, or fuel type.
Uses US gallon (3.785 L). Imperial gallon conversions differ (~1.201×).
Does not estimate fuel cost or range; pair with a trip cost/fuel price calculator for budgeting.
Does not handle CO2 grams/km or kWh/100km; this is liquid-fuel focused.
WLTP/JC08/CLTC test cycles vary; this tool only reconciles units, not test methodology differences.

Worked examples

30 MPG compact

L/100km ≈ 7.84
Km/L ≈ 12.75
Typical for many small gas sedans.

Efficient hybrid at 52 MPG

L/100km ≈ 4.52
Km/L ≈ 22.1
Shows strong efficiency on metric scales.

Truck at 20 MPG

L/100km ≈ 11.76
Km/L ≈ 8.5
Useful for planning fuel stops on long hauls.

Reverse from L/100km

6.5 L/100km → MPG ≈ 36.2
Enter 36.2 MPG to see Km/L ≈ 15.3 for double-checking.

Imperial to US MPG comparison

Window sticker shows 50 MPG (imperial). Convert to US MPG: 50 ÷ 1.201 ≈ 41.6.
Enter 41.6 MPG here to see L/100km ≈ 5.65 and Km/L ≈ 17.7.
Lets you compare UK/Canadian figures to US labels apples-to-apples.

City vs highway range

City MPG 24, Highway MPG 33.
City: L/100km ≈ 9.80, Km/L ≈ 10.2. Highway: L/100km ≈ 7.13, Km/L ≈ 14.0.
Shows how driving mix changes metric efficiency; plan trips with the right number.

EV MPGe rough comparison

EPA MPGe 120 (combined). Treat as MPG for unit conversion: L/100km ≈ 1.96, Km/L ≈ 51.0.
Highlights efficiency but remember MPGe is energy-equivalent, not actual fuel.

Motorcycle scenario

MPG = 55 on a touring bike.
L/100km ≈ 4.28, Km/L ≈ 23.4.
Shows how bikes compare to compact cars on a metric basis.

Low-MPG towing case

MPG = 12 while towing.
L/100km ≈ 19.6, Km/L ≈ 5.1.
Good for budgeting fuel on heavy haul trips in metric countries.

Deep dive

Use this fuel economy converter to flip MPG into L/100km and Km/L for easy comparisons across US and metric systems.

Enter MPG to see metric equivalents—great for shopping cars abroad, reading reviews, or planning trips with L/100km signage.

Translate hybrids, trucks, or motorcycles across MPG, L/100km, and Km/L with one quick input.

Reverse a metric rating back to MPG using 235.215 ÷ L/100km to sanity-check efficiency claims.

Convert imperial MPG to US MPG first, then to L/100km to align UK/Canada figures with US labels.

Compare city vs highway MPG in metric terms to plan realistic fuel use on your next trip.

Normalize fleet reports by converting mixed-unit fuel economy into one standard before analyzing trends.

Help customers understand overseas reviews by translating L/100km and Km/L into familiar US MPG.

Budget towing or motorcycle fuel use abroad by converting your MPG into L/100km for local signage and pumps.

Use a single MPG input to get L/100km, Km/L, and a reversible formula for quick back-of-the-envelope comparisons.

Train teams on US vs metric fuel units with one converter that highlights the inverse MPG/L/100km relationship.

Share quick conversions with friends shopping imports so everyone talks the same numbers.

Because MPG and L/100km move in opposite directions, this tool helps you interpret efficiency correctly no matter which format a review uses.

Pair the conversion with your real‑world fuel logs to compare trip efficiency across different vehicles or driving conditions.

If you track fuel in liters on trips abroad, convert your car’s MPG to L/100km before you go so you can budget at the pump.

Use the Km/L output when you’re comparing motorcycles or small cars in markets where Km/L is the most common spec.

Methodology & assumptions

Uses US gallon definitions: 1 US gallon = 3.785411784 liters.
Uses exact distance conversion: 1 mile = 1.609344 kilometers.
Computes L/100km from MPG using L/100km = 235.215 ÷ MPG.
Computes Km/L from MPG using Km/L = MPG × 0.425144.
Computes MPG from L/100km using MPG = 235.215 ÷ L/100km.
Assumes a single MPG input; does not model driving conditions or test cycles.
Treats the conversion as a pure unit translation (no efficiency adjustments).
Outputs are rounded by the UI formatter for readability.

Sources

NIST — Guide to the SI (Appendix B: Conversion Factors)Reference for mile‑kilometer and gallon‑liter conversion constants.
U.S. EPA — Fuel Economy BasicsContext on MPG usage and real‑world factors affecting fuel economy.

FAQs

Which gallon is used?: US gallon (3.785 liters). For imperial gallon, multiply US MPG by ~1.201 to convert.
Why does L/100km drop when MPG rises?: L/100km measures fuel consumed per distance, so lower is better; MPG measures distance per fuel, so higher is better—they move in opposite directions.
Can I use this for any vehicle type?: Yes. It’s a pure unit conversion for cars, trucks, motorcycles, or fleets. Just enter the MPG you have.
Can I compare WLTP vs EPA with this?: You can convert units, but test cycles differ. Use real-world MPG where possible, then convert for a fair comparison.
Does this apply to flex-fuel (E85) or diesel?: Yes for unit conversion, but be aware MPG can vary by fuel type. Enter the actual MPG for the fuel you’re using.
Can I estimate CO2 or cost from this?: Not directly. Pair the output with fuel carbon intensity or price to estimate emissions or trip cost.
What about plug-in hybrids with mixed electric/gas miles?: This tool converts a single MPG figure. For PHEVs, compute your blended MPG (gas miles ÷ gallons used) for the trip, then convert that value.
Do I need to adjust for altitude or cold weather?: Those factors change real MPG but not the conversion. Use the MPG actually observed in your conditions for best results.
Can I input Km/L directly?: Convert Km/L to MPG first: MPG = Km/L ÷ 0.425144. Then enter that MPG here to see L/100km and Km/L echoed back for validation.
Why is the conversion constant 235.215?: It comes from unit relationships: 100 km = 62.137 miles and 1 US gallon = 3.78541 liters. Combining those gives 235.215 as the conversion factor between MPG and L/100km.
Does this work for fleet reporting?: Yes, as long as you use a consistent MPG value for each vehicle. For fleet summaries, convert each vehicle’s MPG to the same unit before averaging so you don’t mix inverse scales.

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