How do I find my e-bike battery's watt-hour rating?

Multiply the battery's voltage (V) by its amp-hour (Ah) rating. A 48V 14Ah battery stores 672Wh. If your battery label only shows watt-hours, divide by voltage to get amp-hours: 500Wh ÷ 36V = 13.9Ah. Both numbers should be on the battery label or in the bike's spec sheet. If the label is unreadable, check the charger: its output voltage tells you the battery voltage, and the manufacturer's website will list the capacity.

Why doesn't this calculator ask for rider weight?

Because no maker and no test publisher prints a rule for how range changes with rider weight. What they do print is the weight their own figure was measured at: Aventon states its 60-mile range came from a 160 lb rider on flat ground in PAS 1. Weight does cost energy, most of it on climbs, but there is no published number to put on it, so this calculator asks for the watt-hours per mile you actually use instead. Ride your route once with the display showing watt-hours, and your own weight is already inside that figure.

How does cold weather affect e-bike battery range?

Lithium-ion cells release energy more slowly when they are cold, so a battery delivers less of its rated capacity on a freezing morning than on a mild one. The loss is real and it is temporary: the pack recovers once it warms up. Nothing published gives a single figure for it, because it depends on the cell, the pack's insulation and how hard you draw from it. Store the battery indoors overnight, fit it just before you ride, and check the watt-hours your display reports on a cold ride against a warm one; that number is your bike's answer.

Can I increase my e-bike's range without buying a new battery?

Yes, several habits help. Use the lowest assist that suits each stretch and save the higher modes for hills. Keep the tires at the pressure printed on the sidewall. Reduce cargo weight. Pedal more actively instead of relying on throttle-only mode. Keep your chain clean and lubricated. Avoid full-throttle starts from stops. Electric Bike Report rode the same 710 Wh bike 61.03 miles at its lowest assist and 23.42 miles at its highest, so the setting you choose moves range further than anything else on this list.

E-Bike Battery Range Calculator - Wh per Mile

6 min read

Enter your pack size and the watt-hours you use per mile, and this e-bike battery range calculator divides one by the other. Every rate offered below is one a manufacturer or an independent tester published, with the arithmetic shown, so you can see how far a maker's best case sits from a measured ride.

Electric bicycle frame with integrated battery pack, pedal assembly, and wheel hubs.

How to Find Your E-Bike Battery Specs

Check the battery label. Most e-bike batteries have a sticker showing voltage (V) and amp-hours (Ah). Common combinations: 36V 10Ah, 48V 14Ah, 52V 17.5Ah. Some labels show watt-hours (Wh) instead; divide Wh by voltage to get Ah.
Check the charger. The charger output voltage tells you your battery voltage. A charger rated at 42V output charges a 36V battery (10 cells × 4.2V max). A 54.6V charger means a 48V battery (13 cells × 4.2V).
Look up your bike model. If both the battery and charger labels are worn, search your bike manufacturer's spec sheet. Battery capacity is always listed in the original specs, and you can use our battery capacity calculator if the spec lists watt-hours only.
Multiply for watt-hours. Once you have V and Ah, multiply them: 48V × 14Ah = 672Wh. Watt-hours are the universal measure for comparing e-bike batteries, regardless of voltage.

Bar chart of a 710Wh e-bike: 90 miles claimed in eco mode against 61 and 23 miles measured in range testing. — Specialized prints 90 miles in eco mode for this 710Wh pack; Electric Bike Report measured 61.03 miles at the lowest assist and 23.42 at the highest.

What Makers Claim and What Testers Measure

Specialized prints that its Turbo Vado 2 4.0 can go up to 90 miles on its 710Wh battery in eco mode. Electric Bike Report, an independent test publisher, rode the same bike on the same 710Wh pack until the battery ran out: 61.03 miles at the lowest assist setting, averaging 11.51 mph, and 23.42 miles at the highest, averaging 18.9 mph. Its protocol is a fully charged bike pedalled on the paved trail system in St. George, Utah, and it says its own results should be considered a rough estimate.

Two things follow from those figures. The assist setting you choose moves range more than anything else: 61.03 ÷ 23.42 = 2.6 times the distance on the same battery. And a maker's figure is its best case: the tester's lowest-assist ride reached 61.03 ÷ 90 = 68% of the eco-mode claim. Bosch's own battery guide shows why, printing the conditions behind its range figures: a total weight of rider, bike and cargo of 232 lbs in favorable conditions against 254 lbs in difficult ones, hilly terrain against low mountain ranges, and slight wind against moderate wind. Its range falls in the difficult column, and it prints no factor for how much.

So the rate you type is where the conditions live. The best number is your own: ride your usual route with the display showing watt-hours, divide by the miles, and enter that. For general battery pack design including series-parallel cell configurations, the same voltage and capacity math applies.

Watt-Hours per Mile on Real Bikes

Each maker below prints both the pack energy and a range for one of its own bikes, so the watt-hours per mile follow by division. The conditions column is only what the maker prints next to its figure.

Bike	Pack	Range the maker prints	Conditions the maker prints	Implied Wh/mile
Aventon Level	672 Wh (48V × 14Ah)	Up to 60 miles	PAS 1, flat terrain, 160 lb rider	672 ÷ 60 = 11.2
Rad Power RadRunner	624 Wh (13Ah)	Up to 55 miles	None printed	624 ÷ 55 = 11.3
Specialized Turbo Vado 2 4.0	710 Wh	Up to 90 miles (145 km), 6.5 hours	Eco mode	710 ÷ 90 = 7.9

Electric Bike Report measured the same Specialized bike on the same 710 Wh pack:

Assist setting	Distance	Average speed	Implied Wh/mile
Lowest (ECO)	61.03 miles	11.51 mph	710 ÷ 61.03 = 11.6
Highest (TURBO)	23.42 miles	18.9 mph	710 ÷ 23.42 = 30.3

The calculator's voltage is a select, so the presets enter Specialized's printed 710 Wh pack as 48V × 14.8Ah = 710.4 Wh, which the result shows as 710. Our solar panel calculator can help you size a panel for mid-trip recharging if you carry a portable panel. The same Wh-based formula drives our drone battery flight time calculator, useful if you fly a drone on bike tours.

Worked Examples

A 36V 14Ah Commuter Pack at the Rad Power Rate

Context

Your commuter bike has a 36V 14Ah battery, and you want to know how far it goes at the rate Rad Power's own figures imply for its RadRunner: 624 Wh over up to 55 miles, which is 11.3 Wh per mile.

Calculation

Battery energy = 36V x 14Ah = 504 Wh

Range = 504 Wh ÷ 11.3 Wh/mile = 44.6 miles

In kilometres: 44.6 x 1.609344 = 71.8 km

Interpretation

44.6 miles is what this pack gives at a maker's best-case rate. Rad Power prints no conditions beside its figure, so treat it as a ceiling: at Electric Bike Report's measured lowest-assist rate of 11.6 Wh per mile the same pack would cover a little less.

Takeaway

If your battery label shows watt-hours instead of amp-hours, divide Wh by voltage, or check our watts in a battery guide for the full explanation.

Riding at Full Assist on a 52V 15Ah Pack

Context

You ride a 52V 15Ah pack in the highest assist mode for the whole trip. The only published full-assist rate is Electric Bike Report's measurement of a 710Wh Specialized Turbo Vado 4.0 in TURBO: 23.42 miles, so 710 ÷ 23.42 = 30.3 Wh per mile.

Calculation

Battery energy = 52V x 15Ah = 780 Wh

Range = 780 Wh ÷ 30.3 Wh/mile = 25.7 miles

In kilometres: 25.7 x 1.609344 = 41.4 km

Interpretation

25.7 miles is a full-assist figure measured on one bike on a flat paved trail. Your motor, speed and route will move it, which is why a rate you measure yourself beats any borrowed one.

Takeaway

Dropping to a lower assist setting is the largest change you can make: the same tester covered 2.6 times the distance at the lowest assist. For charge time planning between rides, check our battery charge time calculator.

Frequently Asked Questions

Glossary

Pedal Assist System

The sensor and controller that detect your pedaling and activate the motor. Cadence sensors detect whether you are pedaling; torque sensors detect how hard you are pedaling. Torque-based PAS matches motor output to your effort, so it spends less battery on the stretches where you are already doing the work.

Watt-Hours per Mile

A measure of energy efficiency for e-bikes, analogous to miles per gallon for cars. Lower numbers mean greater efficiency. Makers' own pairs imply 7.9 to 11.3 Wh/mi at their best-case settings; Electric Bike Report measured 11.6 at the lowest assist and 30.3 at the highest on one 710 Wh bike. This metric accounts for speed, terrain, rider weight, and assist level in a single number.

Regenerative Braking

A system that converts braking energy back into electrical energy stored in the battery. Common on hub-motor e-bikes but rare on mid-drive bikes. It returns a small part of your braking energy to the battery, useful on a long descent, not a factor over a flat ride. It adds drag when coasting, which some riders dislike.

Charging your e-bike from solar panels on a bike tour? Our solar battery charge time calculator shows how long a portable panel takes to top off your battery.

Range estimates are starting points, not guarantees. Real-world range varies with wind, tire pressure, road surface, temperature, and how much you pedal versus relying on the motor. Ride your usual route once with the display showing watt-hours consumed, then use that measured consumption rate in this calculator for a far more accurate prediction than any default value. Nothing is multiplied on top of it: the calculator divides your pack's watt-hours by the rate you enter, and stops. Our e-bike battery range guide covers everything that affects range and how to maximize miles per charge. If you also ride an electric scooter, the scooter range calculator handles the higher consumption rates and different speed modes.

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Last updated: October 25, 2026

Written and maintained by Dan Dadovic, Commercial Director at Ezoic Inc. & PhD Candidate in Information Sciences. On the energy side, Dan has hands-on experience with residential solar panel installation, DIY battery bank construction, off-grid power systems, wind power, and EV ownership/driving, all from building, maintaining, and operating his own systems.

Disclaimer: Calculator results are estimates based on theoretical formulas. Actual performance varies with temperature, battery age, load patterns, and equipment condition. For critical electrical work, consult a licensed electrician.

Methodology reviewed by Doc. dr. sc. Damir Topić, Assistant Professor, FERIT Osijek.