How it's calculated
Deduction = business miles × the IRS standard mileage rate for the year ($0.70 per mile for 2025; for 2026, $0.725 to June 30 and $0.76 from July 1, which averages about $0.743 over a full year). The tax saving estimate adds self-employment tax (15.3% on 92.35% of earnings) to the income tax bracket you pick. It's a rough guide, not tax advice. Your actual saving depends on your total income, other deductions and your state.