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EV range calculator

Enter the battery's usable energy and how efficiently the car drives. See the range on a full battery, the range between two charge levels, and what happens if efficiency changes by a percentage you choose.

Battery and efficiency

Usable battery capacity

kWh

Enter a capacity from 1 to 500 kWh.

Efficiency

Enter a number above zero.

Unit

Use the efficiency your car's trip display shows over a long drive: it counts energy out of the battery, which is what range depends on. Window-sticker figures count energy from the wall, charging losses included, so they give a lower range.

Start charge

Enter a percentage from 1 to 100.

Arrive with

Enter a percentage below the start charge.

What if efficiency changes

Change in distance per kWh

Enter a percentage from −90 to 200.

Your own assumption, not a stated fact: enter −20 to see the range if the car goes 20% fewer miles per kWh, for example on a cold day you have measured.

kWh to miles

Energy

kWh

Enter a number above zero.

Uses the efficiency entered above.

What the inputs mean

Usable battery capacity: the energy the car can use, in kWh. Some makers quote a gross figure that includes a reserve the car never uses; the usable figure gives the right range.
Efficiency: energy per distance. Enter it in the unit you have: kWh per 100 miles, miles per kWh, watt-hours per mile, or the metric versions. The car's trip display over a long drive is the best source, because it counts energy out of the battery.
Start charge and arrive with: most drivers do not run from 100% to 0%. The range between two charge levels shows what a real trip leg gives you.
Change in distance per kWh: a what-if you set yourself, for example −20% for conditions where you have seen the car do worse.

The formulas

range (mi) = usable kWh ÷ kWh per 100 mi × 100range between charges = usable kWh × (start % − arrive %) ÷ 100 ÷ kWh per 100 mi × 100mi/kWh = 100 ÷ kWh per 100 mi Wh/mi = 10 × kWh per 100 mi

For the what-if, the range scales by (1 + change ÷ 100). A −20% change in miles per kWh is a 25% rise in energy per mile, because 1 ÷ 0.8 = 1.25.

Worked example

A 60 kWh usable battery and 30 kWh per 100 miles, which is 3.33 mi/kWh or 300 Wh/mi. Full range: 60 ÷ 30 × 100 = 200 miles. From 90% down to 10%, the car uses 48 kWh and covers 160 miles.

If the car goes 20% fewer miles per kWh, energy use becomes 30 ÷ 0.8 = 37.5 kWh per 100 miles. The full range drops to 160 miles and the 90% to 10% leg to 128 miles.

kWh to miles: 10 kWh at 30 kWh per 100 miles is 33.3 miles. In metric, 60 kWh at 18 kWh per 100 km is 333.3 km, and 10 kWh is 55.6 km.

What this leaves out

The result is maths from the numbers entered. Real range moves with speed, temperature, heating or air conditioning, hills, wind, tire pressure and load, and the car keeps a small buffer below 0% on its display. Run it with your best and worst measured efficiency to see the spread.

Questions

How do I calculate EV range?

Divide the usable battery kWh by the kWh per 100 miles and multiply by 100. A 60 kWh usable battery at 30 kWh/100 mi gives 200 miles.

How many miles is 1 kWh?

It is the car's miles per kWh. At 3.5 mi/kWh, 1 kWh is 3.5 miles; at 30 kWh per 100 miles, 1 kWh is 3.33 miles.

How do I convert kWh to miles?

Multiply the kWh by the miles per kWh, or divide by kWh per 100 miles and multiply by 100. 10 kWh at 30 kWh/100 mi is 33.3 miles; 50 kWh at 4 mi/kWh is 200 miles.

How do I convert Wh/mi to range?

Divide the battery's usable watt-hours by the Wh per mile. 75 kWh is 75,000 Wh; at 280 Wh/mi that is 267.9 miles.