Range calculatorMethodology v1.0 · planning band, not a promise
Ebike Range Calculator: Estimate Miles From Voltage, Ah, Terrain and Riding Style
Enter your battery and your route, and get a planning band rather than a single mileage promise. Range is not a property of a battery — it is what happens when a given amount of energy meets your weight, your terrain and your right hand.
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PLANNING BAND, NOT A PROMISEMETHODOLOGY V1.0UK MARKET
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THE SHORT ANSWER
Range comes from four steps: multiply voltage by amp-hours to get nominal watt-hours, subtract a reserve to get usable energy, estimate your watt-hours per mile from terrain, weight, speed and assist, then divide. The result is a band because the last step legitimately varies by a factor of five.
So a 52V × 20Ah pack holds 1,040Wh nominal and roughly 936Wh usable after a 10% reserve — which is anywhere from about 19 miles ridden hard off-road to about 94 miles on the flat at low assist. Both figures are correct. That is why we return a range and not a number.
What the Calculator Asks, and What It Returns
Stage
Inputs
What it produces
Basic
Voltage, amp-hours, units, total weight, terrain, assist style
A first band in under thirty seconds
Advanced
Cruising speed, elevation gain, surface, tyre type, wind, temperature, stop-start frequency, drive type
A narrower, better-conditioned band
Calibration
Your own measured Wh per mile, if you have it
A band based on your riding rather than our assumptions
Basic inputs give a rough plan; advanced inputs narrow the band; your own consumption figure beats both. The usable-energy reserve is editable at every stage.
Outputs are nominal watt-hours, usable energy after reserve, an estimated consumption band, best-case, typical and conservative planning ranges, trip-ready range, the battery percentage a planned trip would need, and a plain-language note on the biggest range penalties in your particular setup.
How Ebike Range Is Calculated
Step one: convert voltage and amp-hours into watt-hours. Nominal energy is voltage times amp-hours, so 52V × 20Ah is 1,040Wh. Amp-hours are meaningless across different voltages, which is why watt-hours are the only capacity figure worth comparing.
Step two: apply a usable-energy reserve. No pack delivers every nominal watt-hour. The battery management system reserves headroom to protect the cells, capacity fades with age, and cold weather reduces what is available on the day. A 10% reserve is a sensible default and this calculator lets you change it.
Step three: estimate consumption in watt-hours per mile. This is where terrain, total weight, speed, assist level, tyres, surface, wind and temperature all land. Step four: divide usable energy by consumption to produce a low, typical and high range. Our BMS amps guide covers why capacity and current capability are separate questions.
Why This Calculator Returns a Band, Not a Number
The same 1,040Wh pack across four riding conditions, using this calculator’s planning bands and a 10% reserve. The spread is roughly fivefold, and every figure in it is defensible.
A single watt-hours-per-mile figure hides too much. It conceals whether you pedalled, how much you climbed, what the wind did and how often you stopped — the difference between 19 miles and 94 from one battery. A tool returning one number is choosing an assumption on your behalf without telling you which.
Two related points. A manufacturer maximum range is a best-case figure under favourable conditions, not a trip guarantee, and should never be used as a planning number. And planning with a reserve is different from running a pack to cut-off: arriving at 5% repeatedly ages a battery faster and leaves nothing for a headwind or a detour. Government guidance is clear that battery condition and correct use matter for safety as well as longevity (GOV.UK).
Nominal Watt-Hours vs Usable Watt-Hours
Battery
Nominal energy
Usable at 10% reserve
Typical commuting range
36V × 10Ah
360Wh
324Wh
About 13–22 miles
48V × 20Ah
960Wh
864Wh
About 35–58 miles
52V × 20Ah
1,040Wh
936Wh
About 37–62 miles
52V × 25Ah
1,300Wh
1,170Wh
About 47–78 miles
52V × 30Ah
1,560Wh
1,404Wh
About 56–94 miles
Commuting range assumes 15–25Wh per mile. Arithmetic from planning bands, not measured results.
Nominal energy is still not fully usable even after the reserve. Cells age, cold reduces available capacity temporarily, and voltage sag under heavy load means the system reaches its low-voltage cut-off with energy still nominally in the pack. Treat the usable figure as the planning number and the nominal figure as a comparison number.
Watt-Hours per Mile: The Number That Sets Your Range
Everything else in this calculator exists to estimate one value. Lower watt-hours per mile means more range, higher means less, and the figure changes continuously during a single ride — a climb might cost 60Wh per mile while the descent afterwards costs almost nothing.
If you already know your own consumption, enter it. A figure derived from your own rides on your own routes beats any model, and the calculator will use it in place of our assumptions. Most displays and apps that show total watt-hours consumed let you work it out: divide watt-hours used by miles ridden. Our wattage and speed guide explains why gradient dominates the demand.
Terrain, Weight and Speed
Variable
Low consumption
High consumption
Why
Terrain
Flat
Very hilly or off-road
Climbing is work that must be paid for
Total weight
Light rider, no cargo
Heavy rider plus cargo
Mass matters most on climbs
Cruising speed
Low assisted speed
High-speed riding
Drag rises steeply with speed
Terrain and weight interact: added mass costs far more on hills than on flat cruising.
Speed deserves attention because riders underestimate it. Drag rises sharply with speed, so a modest increase in cruising speed costs disproportionately more energy. It is also why a bike assisted to 15.5mph is more efficient than a high-power build ridden at 30mph, quite apart from the legal difference.
Wind, Temperature, Tyres and Surface
Wind is the variable riders forget until it costs them a ride. A strong headwind can raise consumption dramatically, a tailwind can lower it substantially, and the same round trip is not symmetrical because you spend longer riding into the wind than with it.
Cold reduces available capacity temporarily, and the effect compounds with battery age — an older pack in winter is noticeably worse than either factor alone suggests. Tyres and surface change rolling resistance: narrow commuter tyres on smooth tarmac are the efficient end, MTB tyres cost more, fat tyres on tarmac more again, and gravel, sand or snow can raise consumption sharply. Tyre pressure matters as much as tyre type, and correct pressure depends on the tyre and rim combination (Schwalbe).
Assist, Throttle and Stop-Start Riding
Higher assist levels use more battery for the same distance, because the motor does more of the work. Throttle-heavy riding generally uses more than pedal assist, since the motor often supplies everything.
Sensor type changes the picture too. A torque sensor scales assistance to your effort, so easing off genuinely reduces consumption. A cadence sensor delivers the selected level whenever the pedals turn, including where you did not need it. And PAS 3 on one controller is not PAS 3 on another — assist levels are manufacturer-defined, which is why entering your own measured consumption is always better than describing your riding style.
Stop-start riding costs energy because every acceleration from standstill is expensive and that energy is then lost to the brakes. Few stops is the efficient case; frequent junctions in traffic is the costly one; and a heavy cargo build in stop-start use is the most expensive combination in this calculator.
Hub Motor vs Mid-Drive Range
Neither wins outright, because efficiency depends on where the motor is operated. A hub motor is efficient on flat and rolling routes at moderate speed. A mid-drive uses the bicycle gears, so it keeps the motor in a better operating range on steeper routes and is usually more efficient there. A direct-drive hub grinding slowly under heavy load is the least efficient case in this tool. Controller tuning and gearing change the result as much as motor position does — our layout comparison and guide to hub motor internals cover why.
Worked Examples
Setup
Usable energy
Consumption
Planning range
36V 10Ah commuter, flat, light assist
324Wh
10–15Wh/mi
22–32 miles
52V 20Ah, mixed commuting
936Wh
15–25Wh/mi
37–62 miles
52V 25Ah, hilly with cargo
1,170Wh
25–35Wh/mi
33–47 miles
52V 30Ah, high-power off-road
1,404Wh
35–50Wh/mi
28–40 miles
All figures arithmetic from planning bands with a 10% reserve. Not measured results.
Note what the last two rows show: a larger battery ridden harder returns less range than a smaller one ridden gently. Capacity is only one term in the division, and usually the one riders can do least about on the day.
Battery Presets You Can Load
Four reference presets, listed alphabetically. Two are OEM packs included because many riders have them; two are conversion packs. Voltage and amp-hours are what the calculator needs, and any pack can be entered manually.
1. Bosch PowerTube 750
A 750Wh frame-integrated pack widely fitted to complete e-bikes, included here as a reference value because a great many riders own one and want a range estimate. Worth being clear that it is not a conversion option: Bosch drive systems are designed to work only with Bosch batteries, and the pack mounts to frames with Bosch-specific fittings. Use it as a preset to estimate range on a Bosch-equipped bike, not as a pack to buy for a conversion build.
2. Generic Cased Conversion Packs
The large category of Hailong-style and similar cased packs sold for conversions, in a wide spread of voltages and capacities. For the calculator, only voltage and amp-hours matter, so any of them can be entered directly. Two cautions when using a claimed capacity as an input: verify the cell brand and model rather than accepting a label, and check the BMS continuous rating separately, because a pack that cannot supply your controller’s current will cut out long before the calculated range is reached.
3. KirbEbike Battery Range
Our conversion packs across three families, all of which can be entered by voltage and amp-hours: the entry lithium range at 36V, 48V and 52V, Taishan at 52V 25Ah for 1,300Wh, and HS-II at 52V 30Ah for 1,560Wh. Enter the voltage and capacity of the exact variant rather than a product-page range figure — a maximum range claim is a best case, not a planning number, and this calculator deliberately does not use one.
Enter the exact variant. Voltage × Ah is all the calculator needs.
4. Shimano BT-EN806 630Wh
A 630Wh pack used with Shimano STEPS drive systems, included as a preset for the same reason as the Bosch: it is common enough that riders will want to estimate range with it. It is an OEM component supplied with complete bikes rather than a conversion pack, and compatibility is tied to the Shimano system it was designed for. As a calculator input it behaves like any other 630Wh battery, which is exactly the point — energy is energy, whatever badge is on the case.
Preset
Nominal energy
Type
Use in this tool
Bosch PowerTube 750
750Wh
OEM, frame-integrated
Reference for Bosch-equipped bikes
Generic cased pack
Varies
Conversion
Enter voltage and Ah directly
KirbEbike range
540–1,560Wh
Conversion
Enter the exact variant
Shimano BT-EN806
630Wh
OEM, STEPS systems
Reference for STEPS-equipped bikes
Listed alphabetically. OEM packs are reference values, not conversion purchase options.
What This Calculator Will Never Claim
That a battery "will go" an exact number of miles. It returns a planning band and always will
That amp-hours alone determine range. Capacity means nothing without voltage, and watt-hours nothing without consumption
That motor wattage determines range. A bigger motor does not extend range; how you use it decides consumption
That a product-page maximum is a result. Manufacturer best-case figures are never used as outputs
That the reserve is hidden. The usable-energy reserve is always shown and always editable
That battery age, cold and headwind can be ignored. Advanced mode accounts for all three
That a high-power setup is road-legal because a range estimate is shown. Classification depends on the motor, not on this tool
Calculation Logic and Methodology Version
For transparency, and for anyone rebuilding or auditing the tool, the sequence is: compute nominal energy as voltage × amp-hours; apply the user-selected reserve to get usable energy; select a base consumption band by broad ride type; apply modifiers for terrain, total weight, speed, surface, tyre type, wind, temperature, stop-start frequency and drive type; produce low, typical and high consumption figures; divide usable energy by each to give three ranges; then compare against a planned trip distance to report the battery percentage required.
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METHODOLOGY V1.0 — PLANNING ASSUMPTIONS, NOT MEASURED DATA
Every consumption band on this page is a planning assumption derived from arithmetic and general riding experience, not from instrumented testing. We have not published first-party route logs, so we are not going to present these figures as measured or as an industry standard. They are a defensible starting point and they will be replaced with measured values once repeatable route testing is complete, at which point the methodology version will change. If your own figures differ from ours, yours are the better input — enter them.
To calibrate this properly we need repeatable logs: a fixed route ridden multiple times, recording rider and cargo weight, tyre type and pressure, assist level, average speed, elevation gain, temperature, wind and watt-hours consumed — with full-charge runs compared only against other full-charge runs. Until those exist, treat this tool as a planning aid. It is honest about being one.
Planning assumptions used by the calculator (v1.0)
Input
How it changes consumption or energy
Terrain (base, mixed assist, 100kg, 15mph)
Flat 12 · rolling 18 · hilly 27 · off-road 36 Wh per mile
Best case = typical ÷ 0.83 consumption · conservative = typical × 1.30 consumption
Climbing (trip check)
Weight × 9.81 × elevation gain ÷ 3,600 ÷ 0.75, times the motor’s share for your riding style
Planning assumptions, not measured data. Your own measured Wh per mile replaces all of them.
Why Your Actual Range May Differ
Higher than estimated, usually because you pedalled more than the model assumed, rode slower, had a tailwind, or your route was flatter than the terrain setting implied. Lower than estimated, usually because you rode faster, climbed more, faced a headwind, rode in the cold, carried more weight, or your battery has aged.
None of those are calculator failures — they are the variables the band exists to accommodate. The most useful thing you can do is log one real ride, work out your own watt-hours per mile, and enter it. That single number does more for accuracy than every advanced input combined. And keep the electrical side matched properly too: capacity is not current, and a pack that cannot supply your controller will underperform its calculated range regardless of watt-hours — see our battery-to-motor matching guide.
Legal Note
A range estimate says nothing about legality. In Great Britain a converted cycle is an Electrically Assisted Pedal Cycle only when it has pedals capable of propelling it, a motor whose continuous rated power does not exceed 250W, and assistance that cuts off at 15.5mph (GOV.UK). Higher-power builds are outside that classification and are treated as motor vehicles (GOV.UK EAPC standards). Riding at higher assisted speeds also consumes energy faster, so the fastest configuration is rarely the one with the best range.
Product touchpoint
Get a better estimate than any model can give you
Log one ride, divide watt-hours consumed by miles covered, and enter that figure. It beats every assumption on this page. If you are still choosing a pack, compare watt-hours rather than amp-hours across the battery range, and check the BMS continuous rating against your controller with our BMS amps guide — a pack that cannot supply the current will never reach its calculated range.
Range is watt-hours divided by watt-hours per mile, and the second term varies by a factor of five across legitimate riding conditions. That is why this calculator returns a low, typical and high figure rather than a single mileage, shows the reserve it applied, and lets you change it.
Use the typical figure for planning, the conservative figure for routes with no charging option, and always leave a reserve for a headwind or a detour. Enter your own measured consumption if you have it. And treat every figure here as a planning assumption until we publish calibrated route data — which is a limitation we would rather state than disguise. Charge with the authorised charger only (GOV.UK).
A band you can plan with, not a number you cannot trust
Enter your battery, your route and your own consumption if you have it.
Multiply battery voltage by amp-hours for nominal watt-hours, subtract a usable-energy reserve, then divide by your watt-hours per mile. Terrain, weight, speed and assist all set that last figure.
How far will a 52V 20Ah battery go?
It holds 1,040Wh nominal, around 936Wh after a 10% reserve. That is roughly 37 to 62 miles in mixed commuting, but under 30 ridden hard off-road and over 90 on the flat at low assist.
What is a good Wh per mile figure for an ebike?
Roughly 10 to 15Wh per mile on flat ground at low assist, 15 to 25 in mixed commuting, 25 to 35 when hilly or loaded, and 35 or more for high-power off-road riding.
Why is my actual range lower than advertised?
Manufacturer maximum figures are best-case results under favourable conditions. Speed, climbing, headwind, cold, weight and stop-start riding all raise consumption above those assumptions.
Does a bigger battery always mean more range?
More watt-hours raise potential range, but consumption matters equally. A larger pack ridden hard can return less range than a smaller pack ridden gently.
Does cold weather reduce ebike range?
Yes, temporarily. Cold reduces available capacity, and the effect compounds with battery age, so an older pack in winter performs noticeably worse than either factor alone suggests.
Do fat tyres reduce ebike range?
Generally yes on tarmac, because rolling resistance is higher. Tyre pressure matters as much as tyre type, and correct pressure depends on the tyre and rim combination.
Does using the throttle use more battery than pedal assist?
Usually, because throttle riding often means the motor supplies all the power. Pedal assist shares the work, and a torque sensor reduces consumption further when you ease off.
Is a mid-drive more efficient than a hub motor?
On steeper routes, usually, because it uses the bicycle gears to keep the motor in a better operating range. On flat and rolling routes at moderate speed the difference is small.
How accurate is this ebike range calculator?
It returns a planning band from stated assumptions rather than measured test data, so treat it as a planning aid. Entering your own measured watt-hours per mile makes it substantially more accurate.
Sources
Safety and legal claims are cited inline; the authoritative, non-competitor references follow. Battery specifications are published manufacturer figures and are referenced in the body only.
A note on safety & legality. This tool produces planning estimates, not guarantees. Do not plan a route with no reserve, and do not run a battery repeatedly to cut-off, which shortens pack life and leaves nothing for a headwind or detour. Use only a charger supplied or authorised for your battery, charge in a dry ventilated place away from escape routes, and stop using any pack showing damage, swelling, unusual smell or heat. A range estimate has no bearing on legality: in Great Britain a converted cycle is an EAPC only when it has working pedals, a motor rated no higher than 250W continuous and assistance stopping at 15.5mph; above that it is outside EAPC classification and may be used on private land with the landowner’s permission and subject to site rules, or on roads only with the relevant motor-vehicle approval, registration, tax, insurance, licence and equipment (GOV.UK).
About this tool
Author: KirbEbike Editorial. Technical review: KirbEbike conversion-support team. Methodology version 1.0. Last reviewed: October 2026. Methodology: all range figures are arithmetic from nominal watt-hours, a user-selected usable-energy reserve and stated consumption bands. Those consumption bands are planning assumptions derived from arithmetic and general riding experience; they are not measured test data and are not presented as an industry standard. No first-party route logs have been published, so the tool is uncalibrated at version 1.0 and will be reissued with a new methodology version once repeatable route testing is complete. Manufacturer maximum-range claims are never used as calculator outputs. Riders entering their own measured watt-hours per mile will get a materially more accurate result than any modelled estimate. Battery preset values are the manufacturers’ published figures; OEM packs are included as reference values and are not conversion purchase options. Legality is cited to GOV.UK and Department for Transport guidance current at the time of review.
