Plug-in Hybrid Economy Calculator

To determine your overall fuel economy (expressed as an equivalent MPG) and your monthly fuel expenses, the calculator separates your monthly mileage into short trips (which typically run entirely on battery power) and long trips (where gasoline engines supplement battery range). The core formula for your hybrid fuel economy takes your total monthly mileage and divides it by the sum of your gasoline consumption and electric energy conversion (using an energy equivalence of 33.7 kWh per gallon of gasoline). Monthly financial savings are computed by taking the estimated cost of operating a traditional gasoline-only vehicle and subtracting the combined costs of gasoline and electricity used by the PHEV.

Imagine you drive a total of 1,000 miles per month, split between short daily commutes and occasional long trips. Your regular car gets 25 MPG, while your PHEV operates at 40 MPG on gas and consumes 30 kWh per 100 miles on electric power. If gas costs $3.50 per gallon and electricity costs $0.15 per kWh, your electric range covers 400 miles while your gas engine covers 600 miles. Your partial gas cost amounts to $52.50, and your electricity cost totals $18.00, resulting in a total monthly PHEV cost of $70.50. Compared to spending $140.00 on a traditional gas-only vehicle, you save $69.50 every month.

Maximize your financial return by plugging in your vehicle as frequently as possible, especially during off-peak electricity hours when utility rates are lowest. Match your daily commute distance closely to the vehicle's pure electric range to avoid burning gasoline on routine errands. Additionally, account for any local government rebates and home charger installation costs to get a precise estimate of your long-term payback period.