Formulas
Office days/year = office days/week × working weeks/year. Annual miles = one-way distance × 2 × office days/year.
Fuel = annual miles ÷ MPG × gas price. Parking and tolls = daily amount × office days/year. Wear allowance = annual miles × cost/mile.
Direct annual cost = fuel + parking + tolls + wear − employer reimbursement, with reimbursement capped at modeled expenses.
Annual commute hours = one-way minutes × 2 × office days/year ÷ 60. Time value = annual hours × assigned hourly value.
Scope, assumptions, and limitations
Working weeks, gas price, and default usage values are examples. Replace them with your own data. The default $0.10/mile wear amount is illustrative; AAA’s optional 2025 reference is $0.1104/mile for new vehicles.
The model excludes fixed insurance, financing, depreciation, lunch, childcare, and tax consequences. Wear is an allowance, not an immediate out-of-pocket bill.
Employer benefit is an annual reimbursement, held constant across office-day scenarios and capped at modeled cost. Unused benefit is reported; no cash surplus is assumed.
Transit comparison uses 12 monthly fares and the same annual office days for travel time. No employer reimbursement is assumed for transit. Job-offer income is an after-tax estimate.
Confidence and precision
Calculations retain precision until display formatting. The input-quality indicator is based on your classification of the source groups, not whether a field happens to contain a value. It does not measure the probability that a future outcome will match the estimate.
Example inputs are for learning the tool. Replace them with your own values, and compare a less favorable scenario to understand sensitivity.
Primary sources
AAA: Your Driving Costs 2025 fact sheet ↗
September 16, 2025 · Checked September 5, 2026
Internal Revenue Service: Standard mileage rates ↗
Live reference table · Checked September 5, 2026
Methodology version 1.0 · Reviewed September 5, 2026.