How Fuel Cost is Calculated

Litres used = miles ÷ MPG × 4.546 (litres per UK gallon). Cost = litres × pump price. A 100-mile journey at 45mpg uses about 10.1 litres — around £14.65 at 145p/litre.

HMRC Mileage Rates

If you use your own car for business, HMRC's approved mileage allowance is 45p per mile for the first 10,000 business miles per year and 25p thereafter. This covers fuel plus wear, insurance and depreciation — typically well above pure fuel cost.

Improving Your MPG

• Keep tyres at correct pressure (under-inflation can cost 3% in economy)
• Remove roof boxes and racks when not in use
• Smooth acceleration and anticipating traffic saves 10–20%
• Air con at low speeds costs more than open windows; the reverse on motorways