Cycling & E-bike
E-bike range.
Range is battery energy divided by how much energy each kilometre costs you. Enter the battery in Wh and your consumption, or your average watts and speed, and see the distance in km and miles. Runs in your browser.
Battery and consumption
Range
Fill the form and press Calculate.
Worked example
A 500 Wh battery with 90% usable gives 450 Wh. At 12 Wh/km that is 450 / 12 = 37.5 km (23.3 mi). At a thrifty 8 Wh/km the same pack goes 56.3 km, and at a hungry 20 Wh/km only 22.5 km. From power instead: drawing 150 W at 20 km/h costs 150 / 20 = 7.5 Wh/km, so the same battery goes 60.0 km. In reverse, an 80 km trip at 10 Wh/km uses 800 Wh, which needs a 889 Wh rated battery at 90% usable.
How it works
Range = battery Wh × usable share ÷ Wh per km. Energy is power multiplied by time, so a battery's watt-hours divided by the watt-hours each kilometre takes is the distance. If you know average battery draw in watts and your speed in km/h, Wh per km = watts ÷ km/h. For a trip: rated Wh = distance × Wh per km ÷ usable share.
Your Wh per km is the whole answer. This page does not guess it, because it changes with assist level, weight, hills, wind and tires. Measure it: note the battery percentage before and after a ride of known length, multiply the drop by the battery Wh, and divide by km. The page’s power model for hills and speed is on the bike power to speed calculator.
Sources and basis (opened 2026-10-08): Wikipedia, Kilowatt-hour (energy is power multiplied by time; one kWh is 3.6 MJ).
FAQ
How far will a 500 Wh e-bike battery go?
With 90% usable it is 450 Wh. At 12 Wh/km that is 37.5 km; at 8 Wh/km 56.3 km; at 20 Wh/km 22.5 km. The spread is why your own Wh per km matters more than the battery size alone.
How do I work out Wh per km?
Divide average battery draw in watts by speed in km/h: 150 W at 20 km/h is 7.5 Wh/km. Or divide the Wh used on a ride by the km ridden.
What size battery do I need for an 80 km ride?
At 10 Wh/km you use 800 Wh, so with 90% usable you want about 889 Wh rated. Higher assist or hills push the Wh per km up.
Why is there a usable share?
Entering a share below 100 lets you allow for an ageing battery, cold weather or a reserve you want to keep. The default 90 is a common rule of thumb, not a published standard.
Is Wh the same as Ah?
No. Watt-hours are volts times amp-hours, so a 36 V 14 Ah pack is 504 Wh. Compare packs in Wh; use the e-bike battery Wh calculator to convert.
Disclaimer
Planning estimate only. Real range depends on assist level, rider and cargo weight, hills, wind, temperature, tire pressure and battery age, so test your own bike before relying on a number for a trip.