E-Bike Range Calculator
An e-bike’s range is one division: the battery’s watt-hours divided by how thirstily the motor drinks them at your assist level. Manufacturers quote the rosiest version of that division; this calculator runs it at each assist level’s typical consumption, so you can see the whole spread — eco to turbo — before the ride, not at the roadside.
Watt-Hours: The Tank's True Size
Batteries are sold in three dialects — amp-hours, volts, watt-hours — and only one of them measures energy: watt-hours = volts × amp-hours. A 36V 14Ah pack and a 48V 10.4Ah pack both hold about 500 Wh, which makes them the same size of fuel tank whatever the marketing emphasises; a 250 Wh city pack holds half of either. The capacity also ages: lithium packs typically retain around 80% of their original watt-hours after some hundreds of full charge cycles, so a three-year-old 500 Wh battery is honestly a 400 Wh battery for planning purposes. Enter the current capacity where you know it; where you don't, the label figure minus a humility discount is the number this page's division deserves.
Worked Example: The 500 Wh All-Rounder
The defaults run today's commonest serious battery through all four assist levels, and the spread is the lesson. At Tour's typical 11 Wh/km: 500 ÷ 11 ≈ 45.5 km (28.2 miles). Eco stretches it to about 71 km; Sport trims it to about 31; Turbo — the mode that flattens hills and empties batteries — delivers 500 ÷ 24 ≈ 20.8 km (12.9 miles). One bicycle, one battery, a three-and-a-half-fold range swing decided entirely by the mode button. This is why single-number range claims ("up to 120 km!") are technically true and practically meaningless: they are the Eco row of this table, quoted for a rider the Turbo row's owner will never meet.
What Actually Eats Range
The consumption figures assume a rider pedalling on mixed terrain in mild weather. Reality reprices every term. Climbing is the hungriest: lifting rider plus bike against gravity is raw watt-hours, and a mountainous route can double consumption. Wind is climbing's invisible twin — a stiff headwind at speed taxes like a grade. Cold temporarily shrinks lithium capacity (a winter battery may offer 20–30% less, recovering as it warms). Mass — rider, cargo, child seats — pays on every acceleration and climb. Tyres and pressure are the cheap win: soft knobbly tyres at low pressure can cost a fifth of the range that firm, properly inflated ones return. The calculator's planning note applies the standard 10% reserve; stack your own discounts on hostile days in the same spirit.
The Market's Battery Sizes, Priced
Run the division across the sizes on sale and the shopping conversation clarifies. A 250 Wh lightweight city pack at Tour consumption: about 22.7 km — a commuter tool, honestly sold for short hops. The 625 Wh mid-size: about 56.8 km, the long-ride threshold. A 750 Wh trekking battery: about 68.2 km. The 1,000 Wh dual-battery expedition rigs: about 90.9 km at Tour, over 140 at Eco — touring range that starts to rival a day's ambition rather than the battery's. The pattern for buyers: range scales linearly with watt-hours and inversely with thirst, so a 50% bigger battery buys exactly 50% more kilometres in the same mode — no more, and (the manufacturers' tables notwithstanding) no less.
Reading the Claim on the Box
Every range figure in e-bike marketing carries the same invisible footnote, and this page's table is the decoder. "Up to" numbers are measured at the lowest assist, on the flat, in still mild air, by a light rider on a new battery — the Eco row with every dial turned favourable. The honest shopper's translation is the one performed here: find the watt-hours, divide by the consumption of the mode you will actually ride, and discount for your weather and hills. Brands are not lying, exactly; they are quoting a different row of the table than the one your commute lives in, and the calculator exists so the row can be chosen by the rider instead.
The Rider's Contribution, Priced in Watt-Hours
The assist levels' consumption figures hide a conservation law worth seeing once. At Tour's cruising conditions the system draws on the order of 275 watts altogether — 11 Wh/km at typical speeds — split between motor and legs in whatever proportion the rider's effort sets. A rider contributing a genuine 100 of those watts cuts the battery's share to roughly 175 watts, and consumption falls toward 7 Wh/km — the Eco row, arrived at from the Tour row by pedalling. This is the arithmetic inside the calculator's note that strong pedalling beats the table: the table's modes are not motor settings alone but treaties between a battery and a pair of legs, and the legs' signature on the treaty is worth kilometres — 500 Wh at 7 Wh/km against 11 is the difference between 71 and 45 km on the same charge.
Extenders and Second Batteries
Range anxiety has an engineering answer, and its arithmetic is this page's division with a bigger numerator. Range-extender bottles (typically about 250 Wh) and dual-battery frames simply add watt-hours: the 500 Wh bike carrying a 250 Wh extender is a 750 Wh machine, priced by the market section's row at about 68 km of Tour riding — the sum is exact because watt-hours are energy, and energy is the one quantity in the whole system that merely accumulates. The practical footnotes are weight (extenders ride in a bottle cage and add a kilogram and a half or so) and charge management (two packs, two charging habits). But for the tourer deciding between a bigger frame battery and an extender, the calculator's verdict is purely arithmetic: buy watt-hours wherever they are cheapest per unit, and the division will not know the difference.
Charging Habits and the Range You Keep
Range is also a function of how the battery is kept. Lithium packs age fastest at the extremes — stored full in a hot garage, or stored empty in a freezing one — and a battery habitually charged to 100% and drained to the cutoff can lose noticeable capacity within a couple of seasons, silently repricing every figure on this page. The gentle regime (charge to around 80% for daily use, full only before long rides, store near half in mild temperatures) preserves the watt-hours the calculator divides. None of this appears in the division itself, which is exactly why it belongs on the page: the range you compute is the range your habits have left you.
Related Tools
More from the Sports Calculators hub: the Cycling Heart Rate Zone Calculator for pricing the rider's effort alongside the battery's, and the MET Minutes Calculator for logging assisted miles in the training week.
Frequently Asked Questions
How far can a 500 Wh e-bike really go?
Between about 21 and 71 km in this calculator's four modes — with the Tour figure (~45 km, 28 miles) the honest middle for a pedalling rider on mixed ground. Manufacturer claims above that band assume the lightest rider, the lowest assist, the flattest route and a new battery simultaneously. Treat the spread as the product and any single number as advertising, which is precisely the conversion this page exists to perform — before purchase, when the figure is a promise, and before any long ride, when it becomes a plan with a reserve built in.
How do I find my battery's watt-hours?
Multiply the volts and amp-hours printed on the battery or in the spec sheet (36V × 13.4Ah ≈ 482 Wh). Many modern packs print Wh directly. If neither figure is available, the bike's model and year plus "battery Wh" finds the factory specification — then discount for age and hard use as the watt-hours section advises before trusting the division with a long ride.
Why does my range drop in winter?
Lithium chemistry slows in the cold: internal resistance rises, usable capacity falls (20–30% at freezing is a fair planning figure), and the rider's own consumption rises too — heavier clothing, worse aerodynamics, softer winter tyres. The loss is mostly temporary (capacity returns with warmth), which is why storing and charging the battery indoors, then riding it warm, is the standard winter counsel.
Does pedalling harder actually extend range?
Yes — at a given speed, every watt the legs supply is a watt the battery doesn't, and consumption per kilometre can fall by a third or more for a fit rider working honestly at low assist. The extreme cases prove the rule by inversion: throttle-only riding with no pedalling posts the worst consumption figures of all, well above even the Turbo row here, because the motor does 100% of the work the Eco rider splits with their legs.
Do bigger motors drain batteries faster?
At the same assist level and speed, not necessarily by much — a 500W-rated motor cruising at 150W of assistance consumes 150W, like any other. What bigger motors change is temptation and capability: they make Turbo living easy, and their riders' consumption rises accordingly. Range lives in the right hand and the mode button far more than in the motor's nameplate — the division on this page never asks the motor's size.
Should I run the battery to empty to maximise range?
No — plan on the reserve this calculator applies. Deep discharges shorten lithium pack life, controllers cut power abruptly near empty (stranding you at the worst moment), and the last 10% of any battery delivers its kilometres at fading assistance. The range that matters is the range to 10% remaining; ride plans, like flight plans, are filed on usable fuel.