Mileage Deduction Calculator

How it is calculated

The deduction is simple multiplication, and the tax saving applies your rate to it: deduction = business_miles × rate_per_mile, tax_savings = deduction × marginal_tax_rate ÷ 100 and per_month = deduction ÷ 12. Miles are the business miles for the whole year. The rate is the money value per mile in dollars (0.67, not 67 cents) and you must type it, because the tool has no rate table and the official mileage rate changes by year and country. The tax rate is a percentage (24 means 24%) and cannot exceed 100. A deduction lowers taxable income, so the real saving is the deduction times your marginal rate, not the deduction itself. Zero is accepted for any field; negative values and a tax rate above 100 return no result.

Common mistakes

• Typing the rate in cents (67) instead of dollars (0.67). The tool accepts it and shows a deduction of $804,000.00, a hundred times too large.
• Counting commuting miles between home and a regular workplace. Only qualifying business trips belong in the miles field, and the tool cannot tell the difference.
• Treating the deduction as money back. The tax saving is the deduction multiplied by your marginal rate, so $8,040 of deduction saves far less than $8,040.
• Typing the tax rate as a decimal (0.24) instead of 24. The tool accepts it, but the saving drops to $19.30.
• Entering your effective rate instead of your marginal rate. An extra deduction removes income from your top bracket, so the marginal rate gives the saving; the effective rate understates it.