EV vs Gas Fuel Cost Comparator

Compare the monthly energy cost of driving an electric car versus a gasoline vehicle.

What this calculator does

Compare monthly EV charging cost with monthly gasoline cost for the same driving distance. It converts EV efficiency and gasoline fuel economy into comparable energy or fuel usage, then estimates monthly and yearly savings.

Inputs explained

Monthly distance: Miles or kilometers driven each month.
EV efficiency: mi/kWh, kWh/100mi, or kWh/100km.
Electricity rate: Price per kWh for EV charging.
ICE fuel economy: MPG, km/L, or L/100km.
Gas price: Price per gallon or per liter, based on the fuel economy unit.

How it works / Method

Convert EV efficiency to kWh per mile or kilometer.
Multiply by monthly distance to get EV energy use and cost.
Convert fuel economy to gallons or liters per distance for the ICE vehicle.
Multiply by monthly distance to get gasoline use and cost.
Subtract EV cost from ICE cost to estimate savings.

Formula(s) used

EV_kWh = distance * kWh_per_unit

EV_cost = EV_kWh * electricity_rate

Gas_used = distance / MPG or distance * (L/100km) / 100

Gas_cost = Gas_used * fuel_price

Monthly_savings = Gas_cost - EV_cost

Units: distance in mi or km, electricity rate in currency per kWh, gas price per gallon or liter.

Inputs

Currency

Monthly Distance

Electric Vehicle

Efficiency

Electricity Rate

$ /kWh

Gas Car (ICE)

Fuel Economy

Gas Price

$ /gal

Comparison

EV Monthly Cost -

Gas Monthly Cost -

Monthly Savings -

Yearly Savings -

Step-by-step example

Example inputs: 1,000 miles per month, EV efficiency 3.3 mi/kWh, electricity rate $0.16/kWh, gasoline vehicle 28 MPG, gas price $3.75/gal.

EV energy: 1,000 * (1 / 3.3) = 303 kWh.
EV cost: 303 * $0.16 = $48.48 per month.
Gas used: 1,000 / 28 = 35.7 gallons.
Gas cost: 35.7 * $3.75 = $133.93 per month.
Monthly savings: $133.93 - $48.48 = $85.45.
Yearly savings: $85.45 * 12 = $1,025.40.

Use cases

Compare monthly fuel costs between an EV and a gasoline car.
Estimate savings after switching to an EV.
Test how fuel prices affect the savings gap.
Compare different EV efficiencies or gas vehicle MPG.
Plan a household budget based on monthly driving distance.
Validate savings before investing in home charging.

Assumptions & limitations

Charging losses are not included in EV energy use.
Public charging fees or session costs are not modeled.
Fuel prices are treated as constant for the month.
Maintenance, depreciation, and insurance are not included.
Fuel economy can vary with speed, terrain, and weather.
Results are estimates for planning, not a guarantee.

Disclaimer: Results are estimates for planning only. Real world costs vary by driving behavior and energy prices.

Frequently Asked Questions

Does this include charging losses or maintenance?

No. This calculator compares only energy costs. Charging losses, tire wear, maintenance, and other ownership costs are outside the scope. If you want to include charging losses, increase the electricity rate slightly or use the EV charging cost calculator to estimate grid energy use. For full ownership costs, combine energy with maintenance and depreciation estimates.

Should I enter monthly or annual distance?

The input is monthly distance. If you only know your annual mileage, divide by 12 to get a monthly average. You can also enter a seasonal average to reflect months when you drive more or less. Keeping the distance monthly makes the savings and cost numbers easier to compare with monthly utility or fuel bills.

Why does the gas price unit change with MPG or km/L?

MPG is measured in miles per gallon, so the fuel price is per gallon. Metric units like km/L or L/100km use liters, so the calculator switches to price per liter. This keeps the math correct without requiring manual conversion. If you only know fuel price in one unit, convert it to the matching unit before entering it.

How do I choose EV efficiency and gas fuel economy?

Use real world averages from your dashboard or fuel economy logs when possible. Rated values can be optimistic, especially at highway speeds or in cold weather. If you only have EPA or manufacturer ratings, start there and adjust based on your driving style. The calculator will convert between units as needed.

What if I charge mostly at public stations?

Public charging often costs more than residential electricity. You can reflect that by entering a higher electricity rate or by using a blended rate that matches your mix of home and public charging. If your public station bills per minute or session fee, the charging session pricing calculator can help estimate an effective rate per kWh.

Why are my savings negative?

Negative savings mean the EV energy cost is higher than the gasoline cost for the inputs you chose. This can happen if electricity prices are high, gasoline prices are low, or the EV efficiency is poor. It can also occur if you use a conservative EV efficiency. Adjust the inputs with your actual rates to see realistic savings for your situation.

Sources & references

U.S. Energy Information Administration: Measuring electricity - Defines kW and kWh used in cost math.
U.S. DOE Energy Saver: Fuel economy in cold weather - Notes real world efficiency impacts.
U.S. EPA: Fuel economy and EV range testing - Explains fuel economy metrics used for comparisons.
Schema.org: FAQPage, WebPage, and BreadcrumbList - Structured data definitions used on this page.