Car, Fuel & Commuting

Commute petrol expenses, road trip fuel cost sharing, and UK/US MPG unit economy converters.

Car and travel calculators work out what a car costs to run, tax and finance in the UK, the US and Canada. They cover fuel for a single trip or a year of commuting, UK vehicle tax, company car tax and monthly finance payments, and show the formula behind each figure.

The Fuel Cost Calculator prices a trip or a commute in miles or kilometres, splits a trip between passengers and compares a petrol or diesel car with an electric car charged at home or at a public charger. For commuting it assumes 46 working weeks a year, which is 52 weeks less the 5.6 weeks of UK statutory holiday, and you can change it. The MPG Converter switches between UK MPG, US MPG, litres per 100km and km per litre. A UK gallon is 4.546 litres and a US gallon 3.785, so 40 UK mpg is only 33.3 US mpg, and mixing them up throws a fuel estimate out by about a sixth.

The Car Tax Calculator gives UK vehicle excise duty for 2026/27 from the registration date, CO2 and list price. Most cars registered since April 2017 pay the £200 standard rate, cars with a list price over £40,000 add a £440 supplement in years 2 to 6, and electric cars have paid vehicle tax since 1 April 2025. The Company Car Tax Calculator works out benefit-in-kind tax for 2026/27 and 2027/28: electric cars are at 4% in 2026/27, so a £40,000 car costs a basic rate taxpayer £320 a year.

The Car Finance Calculator compares PCP, hire purchase and a car loan. On a £25,000 car with £2,500 down at 9.9% APR over 48 months, PCP costs £392.88 a month and HP £565.03, but HP charges less interest overall. It follows the UK rule that APR is an effective annual rate and the US rule that it is a nominal one, so the same quote gives slightly different payments in each country.

Fuel figures cover fuel or charging only, not insurance, servicing, parking or wear.

  • MPG Converter

    Convert fuel economy between UK MPG, US MPG, litres per 100km and kilometres per litre. Type one figure and see all four.

  • Car Tax Calculator

    Check UK car tax (VED) for 2026/27 by registration date, CO2 and list price, including the first-year rate, the £440 supplement and Direct Debit costs.

  • Company Car Tax Calculator

    Work out UK company car tax for 2026/27 and 2027/28 from the list price, CO2, electric range and your tax band, plus employer Class 1A NIC.

  • Car Finance Calculator

    Work out monthly payments on PCP, hire purchase or a car loan from the price, deposit, APR and term, with total interest and a yearly balance table.

  • Fuel Cost Calculator

    Work out the fuel cost of a trip or your commute in miles or km, and compare a petrol or diesel car with an electric car per trip, month and year.

Common questions about car, fuel & commuting

What is the difference between UK and US MPG?

A UK gallon is 4.546 litres and a US gallon is 3.785 litres, so the same car shows a higher MPG in UK figures. 40 UK mpg is 33.3 US mpg, even though the car uses exactly the same fuel. The MPG Converter handles both gallons, plus litres per 100km and km per litre.

How much is car tax for 2026/27?

Most cars registered since 1 April 2017 pay the standard rate of £200 a year from 1 April 2026. Cars with a list price over £40,000 pay £640 in years 2 to 6. Older cars pay by CO2 band, from £20 in band A to £790 in band M. The Car Tax Calculator finds your rate.

Is PCP or hire purchase cheaper?

Hire purchase usually costs less interest, while PCP has lower monthly payments. On a £25,000 car with £2,500 down at 9.9% APR over 48 months, HP is £565.03 a month with £4,621.28 of interest. PCP is £392.88 a month, but £6,358.30 of interest if you pay the final amount to keep the car.

How much tax will I pay on an electric company car?

Electric company cars have a 4% benefit-in-kind rate in 2026/27 and 5% in 2027/28. On a £40,000 car the taxable benefit is £1,600 in 2026/27, so you pay £320 a year at 20% or £640 at 40%. The Company Car Tax Calculator also covers hybrids and petrol cars.

How do I split fuel costs on a road trip?

Work out the total fuel cost and divide it by the number of people sharing. At 30 US mpg a 300-mile trip uses 10 US gallons, which costs $44.78 at $4.478 a gallon, or $14.93 each for three people. The Fuel Cost Calculator does this in miles or kilometres, one way or return.