Your own rate
Rates per distance, in the settings: a rate per mile or per kilometre for each purpose, in your currency. The rate changed during the year? Add a rate change with its start date: each trip is valued at the rate of its own day.
Your country's tax rules
Tax rules offers dated presets for the United States (IRS), the United Kingdom (HMRC), Canada (CRA), Australia (ATO), France, Germany, the Netherlands and Sweden. They handle tiered rates, like the UK 10,000-mile threshold or Canada's 5,000 km, the Australian cap of 5,000 km per car, a tax year starting in April or July, and the French scale by fiscal horsepower. Tax year picks the year.
A starting point, not advice
The year of each figure is shown, and every figure can be changed. Your employer or your tax authority has the final word. See Mileage rates by country.