Nick Gassmann

Senior UX designer, The Harker School

Is an EV Cheaper for Me?

I kept asking whether an EV would be cheaper for me, so I built the calculator.

My role
UX and UI, with AI agents as developer
Three phone screens from Is an EV Cheaper for Me?: the result, the gas and EV math, and the cost breakdown(full size)

Why I Built It

Most EV calculators compare a gallon of gas with a kilowatt-hour and stop there, and that never really answered my question. It was important to me that this one count the whole cost of owning each car.

What It Counts

  • It counts energy, buying or leasing, tax and fees, insurance, registration, maintenance and tires.
  • Fuel economy comes from the EPA’s fueleconomy.gov lookup by year, make and model.
  • It handles the cases fuel-only calculators skip: an EV lease, a gas car that still has payments, free charging at work and selling the old car.
  • The result shows per year, per month and per mile, with the gas price where the EV starts saving money.

It’s live at ev.colossalhippo.com.

Data

Fuel economy comes from the EPA lookup, and the maintenance estimate starts from a Consumer Reports owner survey, which you can replace with your own number.

Design

I handled the UX and UI myself. The UX is one long form with the result live under it, so you see the answer change as you fill it in. In the UI, the form splits into five tabs on a phone, and the result shows each cost’s share of the difference.

The calculator form on a desktop: basics, the EV and the gas car(full size)
The Form Basics, the EV and the gas car, on a desktop.
The result on a desktop: the EV costs $28,790 more over five years in this example, with the energy math and total cost bars(full size)
The Result The total difference, the yearly energy math and the total cost over the years you own it.

Build

AI agents were my developers on this one. I gave them a written product brief and a design spec, and they built it a piece at a time in plain HTML, CSS and JavaScript, with no framework and no server of its own. Once it was built, I ran a design review on the result, and 73 tests cover the math.