How e-bike range is calculated
Range is the distance an e-bike can travel on one full battery charge. The core relationship is simple energy accounting: the battery holds a fixed amount of energy, and the motor draws a certain amount of energy for every mile you ride.
Range (miles) = Battery capacity (Wh) ÷ Energy consumption (Wh per mile)
Battery capacity is rarely printed directly in watt-hours, so you compute it from the two numbers on the battery label:
Battery capacity (Wh) = Voltage (V) × Capacity (Ah)
For example, a 48 V battery rated at 14 Ah stores 48 × 14 = 672 Wh. If the bike averages 20 Wh per mile, its range is 672 ÷ 20 = 33.6 miles (about 54 km). This calculator lets you set a usable-capacity percentage as well, because it is common to reserve some charge and because batteries rarely deliver 100% of their rated energy in the real world.
Why energy use per mile is the number that matters
Battery size sets a hard ceiling, but Wh per mile is what actually varies from ride to ride. A typical commuter e-bike uses roughly 15–30 Wh per mile (about 10–19 Wh/km). Riders who pedal hard on flat pavement in a low assist level can drop to 10–15 Wh/mi; throttle-only riding, steep hills, headwinds, heavy cargo, low tire pressure, or fat knobby tires can push consumption past 30–35 Wh/mi. Because range scales inversely with this number, halving your energy use doubles your range.
Common reference points
- A 36 V, 10 Ah battery holds 360 Wh — enough for roughly 18–24 miles at 15–20 Wh/mi.
- A 48 V, 14 Ah battery holds 672 Wh — roughly 22–45 miles depending on assist level and terrain.
- A 52 V, 20 Ah battery holds 1,040 Wh — roughly 35–70 miles, typical of long-range commuters.
- 1 mile = 1.60934 km, so multiply a mileage figure by 1.609 to get kilometers, or divide by 1.609 to convert km back to miles.