Why Cost Per Mile Matters
Understanding your cost per mile lets you:
- Compare EV costs to gas vehicles accurately
- Choose the cheapest charging options
- Budget for road trips
- Maximize your savings
This guide gives you the formulas and tools to calculate your exact costs.
The Basic Formula
Cost Per Mile = (Electricity Price per kWh) ÷ (Vehicle Efficiency in miles/kWh)
Or alternatively:
Cost Per Mile = (Electricity Price per kWh) × (Vehicle Consumption in kWh/mile)
Understanding Your Vehicle's Efficiency
Finding Your Efficiency Rating
Your EV's efficiency is measured in miles per kWh (mi/kWh) or kWh per 100 miles.
Common EV Efficiencies:
| Vehicle | mi/kWh | kWh/100mi |
|---|---|---|
| Tesla Model 3 RWD | 4.2 | 24 |
| Tesla Model Y LR | 3.5 | 29 |
| Hyundai Ioniq 6 | 4.0 | 25 |
| Ford Mustang Mach-E | 3.2 | 31 |
| Rivian R1T | 2.4 | 42 |
| Chevy Bolt EUV | 3.8 | 26 |
| BMW iX xDrive50 | 2.8 | 36 |
Real-World vs EPA
EPA ratings are tested under ideal conditions. Real-world efficiency is typically:
- City driving: Similar to EPA or better
- Highway driving: 10-20% worse than EPA
- Cold weather: 20-40% worse than EPA
- Hot weather: 5-15% worse than EPA
Rule of Thumb: Use 80-90% of EPA efficiency for real-world calculations.
Home Charging Cost Calculations
Step 1: Find Your Electricity Rate
Check your utility bill for:
- Standard rate: Your default per-kWh charge
- Time-of-use (TOU) rate: If you have different rates by time
- EV rate: Special EV charging rate (if available)
Example Rates:
- Standard: $0.14/kWh
- Off-peak (TOU): $0.09/kWh
- Peak (TOU): $0.25/kWh
Step 2: Calculate Cost Per Mile
Formula: Cost per mile = Electricity rate ÷ Efficiency
Example: Tesla Model 3 at home
- Efficiency: 3.5 mi/kWh (real-world)
- Off-peak rate: $0.09/kWh
- Cost per mile: $0.09 ÷ 3.5 = $0.026/mile
Example: Rivian R1T at home
- Efficiency: 2.2 mi/kWh (real-world)
- Standard rate: $0.14/kWh
- Cost per mile: $0.14 ÷ 2.2 = $0.064/mile
Step 3: Calculate Monthly Cost
Formula: Monthly cost = (Miles driven ÷ Efficiency) × Electricity rate
Example: 1,000 miles/month, Model 3
- kWh needed: 1,000 ÷ 3.5 = 286 kWh
- Cost: 286 × $0.09 = $25.74/month
Public Charging Cost Calculations
Level 2 Public Charging
Pricing varies widely:
- Free: Many retail, workplace locations
- Per kWh: $0.15-0.35/kWh
- Per hour: $1-3/hour
- Per session: Flat fee (rare)
Example: Level 2 at $0.25/kWh
- Efficiency: 3.5 mi/kWh
- Cost per mile: $0.25 ÷ 3.5 = $0.071/mile
DC Fast Charging
More expensive but much faster:
- Tesla Supercharger: $0.25-0.50/kWh
- Electrify America: $0.43-0.53/kWh (guest), $0.36-0.40/kWh (Pass+)
- EVgo: $0.31-0.46/kWh (varies)
- ChargePoint DC: $0.30-0.55/kWh
Example: Electrify America at $0.48/kWh
- Efficiency: 3.0 mi/kWh (highway driving)
- Cost per mile: $0.48 ÷ 3.0 = $0.16/mile
Cost Per Mile Comparison Table
| Charging Method | $/kWh | Efficiency | $/Mile |
|---|---|---|---|
| Home off-peak | $0.09 | 3.5 mi/kWh | $0.026 |
| Home standard | $0.14 | 3.5 mi/kWh | $0.040 |
| Free public L2 | $0.00 | 3.5 mi/kWh | $0.000 |
| Paid public L2 | $0.25 | 3.5 mi/kWh | $0.071 |
| Tesla Supercharger | $0.35 | 3.0 mi/kWh | $0.117 |
| Electrify America | $0.48 | 3.0 mi/kWh | $0.160 |
| Gasoline ($3.50, 30MPG) | - | - | $0.117 |
Blended Cost Calculation
Most EV owners charge from multiple sources. Calculate your blended rate:
Formula: Blended cost = Σ(% from source × cost per mile for source)
Example:
- 70% home off-peak: 0.70 × $0.026 = $0.0182
- 15% free public: 0.15 × $0.00 = $0.000
- 10% paid public L2: 0.10 × $0.071 = $0.0071
- 5% DC fast: 0.05 × $0.14 = $0.0070
Blended Cost: $0.0182 + $0.000 + $0.0071 + $0.0070 = $0.032/mile
Road Trip Cost Calculations
Road trips typically use more DC fast charging.
Example: 500-Mile Road Trip
Assumptions:
- Start with full charge from home
- Vehicle: 300-mile range, 3.0 mi/kWh highway
- Two DC fast charging stops
Calculation:
- Home charge: 100 kWh × $0.14 = $14.00
- DC stop 1: 60 kWh × $0.45 = $27.00
- DC stop 2: 50 kWh × $0.45 = $22.50
- Total: $63.50 for 500 miles = $0.127/mile
Compared to Gas:
- 500 miles ÷ 30 MPG = 16.7 gallons
- 16.7 × $3.50 = $58.45
Road trips are where EVs and gas cars are closest in cost. Daily driving is where EVs save the most.
Annual Cost Projections
Example: 12,000 Miles/Year
Scenario A: Heavy Home Charging
- 80% home ($0.03/mi): $288
- 15% free public: $0
- 5% DC fast ($0.14/mi): $84
- Annual Total: $372
Scenario B: Apartment Dweller
- 40% workplace (free): $0
- 30% public L2 ($0.05/mi): $180
- 30% DC fast ($0.14/mi): $504
- Annual Total: $684
Scenario C: Gas Car (30 MPG, $3.50/gal)
- 12,000 ÷ 30 = 400 gallons
- 400 × $3.50 = $1,400
Savings: $728-$1,028/year compared to gas
Tracking Your Actual Costs
Method 1: Manual Tracking
Keep a simple log:
| Date | kWh Added | Cost | Miles Since Last |
|---|
Method 2: EV App Data
Most EVs track charging automatically:
- Tesla app shows energy added and locations
- Manufacturer apps often show charging history
- Third-party apps like TezLab provide detailed analytics
Method 3: Home Energy Monitor
Devices like Emporia Vue or Sense can track your charger's exact usage separately from household electricity.
Cost Optimization Tips
1. Maximize Home Charging
Every kWh charged at home instead of DC fast saves $0.20-0.35
2. Use Time-of-Use Rates
Off-peak charging can cut costs by 30-50%
3. Find Free Charging
Many retail locations offer free L2—costs you nothing but time you'd spend anyway
4. Get Network Memberships
EA Pass+ ($4/month) saves ~$0.10/kWh if you fast charge regularly
5. Drive Efficiently
10% efficiency improvement = 10% cost reduction
Quick Reference Formulas
Cost Per Mile:
`
$/mile = $/kWh ÷ mi/kWh
`
Monthly Cost:
`
$/month = (miles ÷ mi/kWh) × $/kWh
`
Blended Rate:
`
$/mile = Σ(% × $/mile for each source)
`
EV vs Gas Savings:
`
Annual savings = (Gas $/mile - EV $/mile) × Annual miles
`
Conclusion
Calculating your cost per mile helps you:
- Understand your true EV running costs
- Make smarter charging decisions
- Compare accurately against gas alternatives
- Plan and budget for trips
For most drivers with home charging, EV costs are $0.03-0.05/mile—roughly 1/3 the cost of a typical gas car. Even apartment dwellers with mixed charging sources typically pay less than gasoline.
Use ChargeFind to find the most affordable charging options near you and minimize your cost per mile.