Mileage Log Spreadsheet for 1099 Drivers and Real Estate Agents — IRS Schedule C Deduction Calculator

Every 1,000 business miles you cannot document is $700 of deduction gone at the IRS business standard mileage rate of $0.70 per mile (IRS Notice 2025-05), and a deduction disallowed for lack of written evidence can carry the 20% accuracy-related penalty under IRC §6662. Eight cells in, four sheets out: your Schedule C line 44a/44b/44c split, your business-use percentage, and the tax those miles actually save.

Your numbers

Odometer on January 1 (or the day the car went into service)Odometer todayBusiness miles logged so far — Schedule C line 44aHome-to-first-stop commuting miles — Schedule C line 44b, never deductible (Pub 463)IRS business standard mileage rate for YOUR tax year, dollars per mile (2025 = 0.70, IRS Notice 2025-05 — overwrite when the new notice is published)Your marginal income tax rate, federal plus state, as a decimal (0.24 = the 24% federal bracket)%Self-employment tax rate on net earnings — 15.3% by statute (12.4% Social Security + 2.9% Medicare)%Actual vehicle costs paid so far this year: gas, insurance, repairs, tires, registration, lease or depreciation

Your result

Total miles driven this year (odometer difference — the total in the Schedule C line 44 header)	-
Other and personal miles — Schedule C line 44c, filled in for you	-
Business-use percentage of the vehicle	-
Standard mileage deduction so far this year	-
Self-employment tax saved (SE tax applies to 92.35% of net earnings)	-
Income tax saved, net of the one-half SE tax deduction (IRC §164(f))	-
Total tax these logged miles save you this year	-

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