What this calculator does
This tool compares the cost to drive one mile in a VinFast electric vehicle against the cost of driving the same mile in a gasoline car. It is currency-neutral but uses US-style units (dollars, gallons, MPG, miles); enter values in your own currency if you prefer. The result shows cost per mile for each option, the per-mile savings of going electric, and the projected annual fuel cost difference.
How to use it
Enter your VinFast's energy use in kWh per mile (the VF 8, for example, typically uses about 0.26–0.32 kWh/mi in mixed driving), your home or charging electricity rate in dollars per kWh, the local gas price per gallon, and the MPG of the gas car you are comparing against. Add your annual mileage to see yearly totals.
The formula explained
Electric cost per mile is simply efficiency multiplied by rate: a car using 0.28 kWh/mi at $0.16/kWh costs \(0.28 \times 0.16 = \$0.0448\) per mile. Gas cost per mile is price divided by economy: $3.50/gal at 28 MPG is \(3.50 \div 28 = \$0.125\) per mile. The difference, multiplied by miles driven, is your savings.
$$\text{Annual Savings} = \left( \frac{\text{Gas Price}}{\text{MPG}} - \text{kWh/mi} \times \text{Rate} \right) \times \text{Annual Miles}$$
Worked example
With 0.28 kWh/mi, $0.16/kWh, $3.50/gal gas, 28 MPG and 12,000 miles: EV costs $0.0448/mi ($537.60/yr), gas costs $0.125/mi ($1,500/yr), saving about $0.08/mi or $962.40 per year.
$$\text{Annual Savings} = \left( \frac{3.50}{28} - 0.28 \times 0.16 \right) \times 12{,}000 = \$962.40$$
FAQ
Where do I find my kWh per mile? Your VinFast trip computer reports efficiency; divide kWh used by miles driven, or invert a Wh/mi reading (280 Wh/mi = 0.28 kWh/mi).
Should I use peak or off-peak electricity rates? Use the rate you actually charge at. Off-peak home charging is usually cheapest; public DC fast charging can cost several times more.
Does this include maintenance? No — it compares fuel/energy cost only. EVs often have lower maintenance, which would add to the savings shown.
