Most online e-bike range calculators are fundamentally broken. They claim a large 48V 15Ah battery will only last 35 miles, or that a 1,040 Watt-hour pack dies after 52 miles. In the real world, UK riders regularly get double that distance.
Those flawed calculations rely on a single lazy assumption: that an electric bike burns a flat 20 Watt-hours per mile. That figure comes from electric mopeds running on full throttle with dead legs. UK electric bikes are pedal-assist machines. When you pedal, you supply 75 to 150 watts of your own mechanical power. That human effort cuts electrical consumption in half. Real-world riding consumes between 8 and 14 Watt-hours per mile. A 48V 15Ah pack reliably delivers 50 to 60 miles on rolling roads, while a 52V 20Ah pack will comfortably clear 80 to 120 miles.
Real-World E-Bike Range Calculator
Calculates realistic mileage based on human pedal input, tyre drag, load, and assist levels. Built for pedal-assist bicycles, not electric mopeds.
Real-World E-Bike Battery Range Table
The table below lists realistic mileage for standard 36V, 48V, and 52V lithium-ion batteries across the three primary pedal assist brackets:
| Battery Pack | Capacity | Eco Assist (7 to 10 Wh/mi) | Tour / Mixed (11 to 14 Wh/mi) | Turbo / Hills (20+ Wh/mi) | Application |
|---|---|---|---|---|---|
| 36V, 7.8Ah | 280.8 Wh | 28 to 35 mi | 20 to 25 mi | 12 to 15 mi | Ultra-light and folding urban |
| 36V, 10.4Ah | 374.4 Wh | 38 to 48 mi | 27 to 34 mi | 16 to 20 mi | Standard city commuter |
| 36V, 14Ah (500Wh class) | 504.0 Wh | 52 to 65 mi | 38 to 46 mi | 22 to 28 mi | Bosch and Shimano 500Wh hybrid |
| 36V, 17.5Ah (625Wh class) | 630.0 Wh | 65 to 80 mi | 48 to 58 mi | 28 to 35 mi | Long-range touring and trekking |
| 48V, 10.4Ah | 499.2 Wh | 50 to 62 mi | 36 to 45 mi | 22 to 28 mi | Standard 48V hardtail |
| 48V, 13Ah (624Wh) | 624.0 Wh | 65 to 78 mi | 46 to 55 mi | 28 to 34 mi | Popular UK trail e-MTB |
|
48V, 15Ah (720Wh) REAL-WORLD BENCHMARK: 50 TO 60 MILES | 720.0 Wh | 75 to 88 mi | 52 to 62 mi | 32 to 38 mi | Fat tyre bikes and heavy cruisers |
| 48V, 17.5Ah (840Wh) | 840.0 Wh | 85 to 102 mi | 62 to 74 mi | 38 to 45 mi | Heavy duty cargo and touring |
| 48V, 20Ah (960Wh) | 960.0 Wh | 100 to 118 mi | 72 to 85 mi | 44 to 52 mi | Dual-battery and endurance |
| 52V, 14Ah (728Wh) | 728.0 Wh | 75 to 90 mi | 54 to 64 mi | 34 to 40 mi | High-voltage performance |
| 52V, 17.5Ah (910Wh) | 910.0 Wh | 95 to 112 mi | 68 to 80 mi | 42 to 50 mi | High-speed trail |
|
52V, 20Ah (1,040Wh) 1 KWH PACK: 80 TO 120+ MILES REAL RANGE | 1040.0 Wh | 115 to 130 mi | 80 to 94 mi | 48 to 58 mi | 1 Kilowatt-Hour battery pack |
| 52V, 22Ah (1,144Wh) | 1144.0 Wh | 125 to 142 mi | 88 to 104 mi | 52 to 64 mi | Ultra-endurance explorer |
The Real Range Formula
Calculating your battery range requires two numbers: total stored energy in Watt-hours, and your average rate of consumption.
Step 1: Calculate Total Watt-Hours
Amp-hours measure electrical capacity, but voltage determines actual power. To find the total energy stored inside the battery pack, multiply nominal voltage by amp-hours:
- 36V 14Ah: 36 × 14 = 504 Watt-hours. The standard Bosch PowerPack 500 class.
- 48V 15Ah: 48 × 15 = 720 Watt-hours. The benchmark pack for fat tyre bikes and trail cruisers.
- 52V 20Ah: 52 × 20 = 1,040 Watt-hours. A high-capacity pack containing over 1 full kilowatt-hour of energy.
Step 2: Divide by Real Pedal-Assist Consumption
Do not use the generic 20 Wh/mile figure unless you are riding on pure throttle without pedalling. Use the rate that matches your assist mode:
- Eco Mode (Level 1): Consumes 7 to 10 Watt-hours per mile (average 8.5 Wh/mi). The motor offsets the bike weight while your legs carry the pace.
- Tour Mode (Levels 2 to 3): Consumes 11 to 14 Watt-hours per mile (average 12 Wh/mi). The motor and your legs share the work evenly. This is the realistic daily standard.
- Sport Mode (Level 4): Consumes 14 to 18 Watt-hours per mile. The motor provides strong torque for headwinds and brisk acceleration.
- Turbo Mode (Level 5): Consumes 20 to 25+ Watt-hours per mile. The motor delivers maximum power for steep gradients.
Worked Example: 48V 15Ah Battery on a Fat Tyre Bike
1. Total Energy: 48V × 15Ah = 720 Watt-hours.
2. Tour Mode Consumption on a Fat Bike: Roughly 13 Watt-hours per mile.
3. Real Range: 720 Wh ÷ 13 Wh/mi = 55.3 miles.
4. Eco Mode on Flat Tarmac: 720 Wh ÷ 9 Wh/mi = 80 miles.
The old charts reported 36 miles because they divided 720 by 20, assuming zero human effort.
Why Fat Tyres Increase Consumption
Four-inch fat tyres provide grip over sand, mud, and broken paths, but they extract an efficiency penalty on road surfaces:
- Contact Patch: A 4.0-inch tyre run at 15 to 20 PSI deforms under load, producing quadruple the contact area of a 38mm hybrid tyre. This added hysteresis costs roughly 2 to 3 extra Watt-hours per mile.
- Curb Weight: Wider rims, heavier rubber, and reinforced frames push total bike weight to between 28kg and 34kg.
- Net Reality: Even with this 20 percent rolling resistance penalty, a standard 48V 15Ah pack will still carry a rider 50 to 60 miles in Tour mode because 720 Watt-hours is a substantial fuel tank.
Five Mechanical Factors That Reduce Range
When an e-bike falls short of expected mileage, check these five physical factors before blaming the cells:
- Under-inflated tyres. Low pressure increases the contact patch and rolling drag, wasting up to 20 percent of your energy. Maintain 45 to 60 PSI on hybrid tyres, and 18 to 22 PSI on fat tyres for road riding.
- Low pedalling cadence. Electric motors operate at peak electrical efficiency when pedals rotate between 70 and 90 RPM. Grinding in high gears forces the motor controller to supply maximum current through hot windings at low efficiency. Shift down and spin.
- Winter cold. Lithium-ion electrolyte stiffens in low temperatures, raising internal cell resistance. At 0°C (32°F), available capacity drops by 15 to 20 percent. Always store and charge the battery inside your home before fitting it to the bike.
- Headwinds. Aerodynamic drag increases with the square of speed. Pushing into a 20 mph headwind can increase battery draw by more than 35 percent.
- Drivetrain friction. A dry, grimy chain robs mechanical efficiency on every revolution. Cleaning and lubricating the chain recovers 5 to 8 percent of range.
Frequently Asked Questions
How far will a 48V 15Ah e-bike battery travel?
A 48V 15Ah battery holds 720 Watt-hours. In standard Tour mode, expect 50 to 60 miles per charge on a fat-tyre bike, and 55 to 65 miles on a road hybrid. In Eco mode on flat tarmac, range extends beyond 80 miles. It only drops to 35 miles if you ride on pure throttle or climb steep hills in Turbo mode.
Why did an online calculator report 52 miles for a 52V 20Ah battery?
That calculation assumed a consumption rate of 20 Watt-hours per mile, which only occurs under full throttle with zero pedalling. A 52V 20Ah battery holds 1,040 Watt-hours. With normal pedalling in Tour mode, it covers 80 to 95 miles. In Eco mode, it easily clears 120 miles.
Does pedal assist use less battery than a throttle?
Yes. A throttle forces the battery to supply 100 percent of the energy required to move the bike and rider. With pedal assist, your legs contribute between 40 and 70 percent of total forward propulsion, effectively doubling your total range per charge.
How many years will an e-bike battery last?
Quality lithium-ion packs from Samsung, LG, Panasonic, and Bosch are rated for 500 to 1,000 full charge cycles before dropping to 75 to 80 percent of original capacity. For riders charging once or twice a week, that represents 3 to 5 years of daily service before noticeable range loss.
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