Allowance and mileage projection
Multiply annual allowance by the term in years. Divide miles driven by elapsed months, then extend that pace across the full term. This is a constant-pace projection, not a prediction of actual future driving. Exclude the vehicle starting odometer reading: use miles driven during your lease.
excess charge = max(0, projected miles − annual allowance × term months ÷ 12) × contract rate
Example: a 36-month lease
A 36-month lease at 12,000 miles per year permits 36,000 miles. Driving 24,000 miles in 18 months projects 48,000 miles at the end, or 12,000 excess miles. At $0.25 per mile, the projected charge is $3,000.
What to check in the agreement
Check total allowance, per-mile rate, early-return terms and how charges are assessed. Buying extra miles, purchasing the vehicle or changing the agreement can have separate conditions. Wear, damage and disposition charges are not included in this mileage calculation.