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Fuel Cost Calculator – trip, L/100 km and MPG

Estimate trip fuel cost and convert consumption between L/100 km, km/L, mpg, and Swedish litres per mil.

Fuel economy and trip

Enter the vehicle's consumption, trip distance, and current fuel price.

Distance you want to estimate the cost for.

Enter the current petrol or diesel price at the pump.

Result

Converted consumption and estimated trip cost

Converted fuel economy
31.361944 mpg (US)

Details

Litres per Swedish mil
0.75 liter/mil
Litres per 100 km
7.5 L/100 km
Kilometres per litre
13.333333 km/L
Miles per gallon, US
31.361944 mpg (US)
Miles per gallon, UK
37.664125 mpg (UK)
Fuel required
22.5 L
Estimated trip cost
SEK 405
Fuel cost per 100 km
SEK 135

Analysis & guidance

  • Know which way is better

    Lower consumption units and higher distance-per-fuel units both indicate better efficiency.

  • Check the gallon

    Never compare US mpg directly with UK mpg without converting.

  • Real driving varies

    Weather, speed, tyres, load, and driving style all affect actual fuel use.

Common questions

How do I convert L/100 km to km/L?

Divide 100 by the L/100 km value. For example, 5 L/100 km equals 20 km/L.

How do I convert L/100 km to mpg?

Divide 235.214583 by L/100 km for US mpg, or 282.480936 for UK mpg.

Why are US and UK mpg different?

A UK imperial gallon is about 4.546 litres, while a US gallon is about 3.785 litres.

How is the trip fuel cost calculated?

Consumption is converted to L/100 km, multiplied by distance divided by 100, and then by the price per litre.

Consumption or distance

L/100 km measures fuel used over a fixed distance, while km/L and mpg measure distance travelled per unit of fuel.

Read the direction correctly

Lower is better for L/100 km and litres per mil. Higher is better for km/L and mpg.

US and UK gallons differ

The imperial gallon is larger than the US gallon, so UK mpg is higher for the same real-world consumption.

Convert fuel economy between L/100 km, km/L and mpg

Estimate fuel cost for a trip

Enter the distance and price per litre to see how much fuel the trip requires and what it costs. The tool converts consumption to L/100 km and uses litres = L/100 km × kilometres / 100, then multiplies litres by the pump price. This covers fuel only, not parking, tolls, wear, or depreciation.

Fuel economy figures can look completely different even when they describe the same car. Europe commonly uses litres per 100 kilometres, some countries use kilometres per litre, and the US and UK often use miles per gallon.

Consumption versus distance per unit

L/100 km measures fuel consumed over a fixed distance, so lower is better. Km/L and mpg measure distance travelled with a fixed amount of fuel, so higher is better. Because the direction changes, you cannot compare the raw numbers.

For example, 5 L/100 km equals 20 km/L. Halving consumption doubles the distance travelled per litre.

US mpg and UK mpg

The US gallon and imperial gallon are different sizes. An imperial gallon is larger, so the same vehicle receives a higher mpg UK figure than mpg US. Always identify which gallon a review or dashboard is using.

Estimating trip fuel

At 6.5 L/100 km, a 300 km journey uses about 19.5 litres. Multiply that amount by the local fuel price to estimate cost. Real use varies with speed, weather, traffic, load, tyres, terrain, and driving style.

Test figures versus real life

Official laboratory figures are useful for comparing vehicles under common conditions, but they do not predict every journey. For your own average, record several fill-ups and divide fuel added by distance travelled. Using multiple tanks reduces the effect of uneven fill levels.

Use the right source unit

Enter the number exactly as shown and select its unit before converting. If the answer looks surprising, check whether the original was consumption or distance-per-fuel, and whether mpg meant US or imperial. Those two checks explain most large discrepancies.

How to read this calculator

These results are meant as guidance. They are based on rules, assumptions, and simplified models that can differ from your exact real-world situation.

Estimate, not a legal decision

Use the result as decision support and planning help. For high-stakes choices, confirm the details with the relevant authority, lender, employer, or adviser.

Methodology

Each calculator uses defined inputs, assumptions, and logic. We explain the broader approach on the methodology page.

Read methodology

Sources and updates

Important calculators should be traceable back to official rules, public guidance, or other clearly stated references.

Read about sources

Common questions

Speed and Pace Converter – min/km, min/mile and km/h

Lower consumption units and higher distance-per-fuel units both indicate better efficiency.

Enter pace naturally as 5:30

Convert speed or pace

Swedish mileage allowance calculator 2026

Weather, speed, tyres, load, and driving style all affect actual fuel use.

SEK 25, 12, or 9.50 per Swedish mil

Calculate allowance

Swedish car commuting deduction calculator 2026

The imperial gallon is larger than the US gallon, so UK mpg is higher for the same real-world consumption.

SEK 15,000 threshold for income year 2026

Calculate commuting deduction