Examples retain the currency, units and country rules stated in each example. Use your own local inputs in the calculator above.
How does the EV range calculator work?
The calculator converts your usable battery charge into distance using your vehicle's efficiency, after setting aside any reserve you'd rather not drive below. It works in kilometres or miles, and accepts efficiency in any of the six units EVs are rated and displayed in worldwide.
- Range = usable battery energy × efficiency. Usable energy is your battery's kWh × (charge % − reserve %).
- Use your dashboard's own efficiency figure, not the WLTP, EPA or CLTC rating — the rated numbers assume gentler driving than almost anyone does.
- Cold weather costs 10–40% of your range, and sustained motorway speed another 10–20%. Together they can take a third of it.
- Keep 10% in reserve. Planning to arrive at 0% leaves nothing for a detour or an occupied charger.
Enter battery & charge
Set your battery capacity in kWh — the same unit in every market — and your current charge percentage.
Pick your unit & efficiency
Choose the unit your dashboard shows, then enter your real-world efficiency in it.
View your estimated range
See how far you can drive now in km or miles, plus your full-charge range for comparison.
Which efficiency unit does your car use?
Battery capacity is quoted in kilowatt-hours everywhere in the world, but efficiency is not. The unit your car displays depends on where it was sold, and a calculator that only speaks one of them is useless in most markets. This tool accepts all six, preselects the one that matches your region, and converts between them when you switch.
| Unit | Direction | Where it is standard |
|---|---|---|
| kWh/100 km | Lower is better | Europe, China, Australia — the WLTP and CLTC standard |
| mi/kWh | Higher is better | United States and United Kingdom |
| km/kWh | Higher is better | India, Japan, South Korea and much of South-East Asia |
| Wh/km | Lower is better | Tesla and many European dashboards |
| Wh/mi | Lower is better | Tesla and Rivian dashboards in the US |
| kWh/100 mi | Lower is better | US EPA window stickers |
Converting between efficiency units
Consumption units (kWh/100 km, Wh/km, Wh/mi, kWh/100 mi) count energy per unit of distance, so a lower number means a more efficient car. Distance-per-energy units (km/kWh, mi/kWh) work the other way round. Converting between the two families means taking a reciprocal as well as changing units, which is why the arithmetic catches people out. These are the figures the calculator itself uses:
| kWh/100 km | Wh/km | km/kWh | mi/kWh | Wh/mi |
|---|---|---|---|---|
| 13 | 130 | 7.69 | 4.8 | 209 |
| 15 | 150 | 6.67 | 4.1 | 241 |
| 16 | 160 | 6.25 | 3.9 | 257 |
| 18 | 180 | 5.56 | 3.5 | 290 |
| 20 | 200 | 5.00 | 3.1 | 322 |
| 22 | 220 | 4.55 | 2.8 | 354 |
| 25 | 250 | 4.00 | 2.5 | 402 |
As a rough mental check: mi/kWh ≈ 62 ÷ (kWh/100 km), and Wh/km = 10 × (kWh/100 km). A car using 20 kWh/100 km is doing roughly 3.1 mi/kWh, or 200 Wh/km.
Why a reserve matters
Planning to arrive at exactly 0% leaves no margin for a detour, unexpected traffic, or a charging stop that turns out to be occupied or out of order. This calculator sets aside a reserve percentage — 10% by default — before converting the rest of your charge into range, so the estimate reflects charge you'd actually be comfortable using rather than every last kilowatt-hour in the battery. In markets where the rapid-charging network is still sparse, a larger reserve is worth the lost range.
Usable charge is your current charge minus your reserve. Your efficiency is converted to a common internal unit first, so the same formula holds whichever unit you entered; the conditions adjustment is applied as a change in range, not as a change in the number you typed.
Worked example: checking a motorway trip on a cold day
A 77 kWh EV at 62% charge, cold weather and motorway driving
Suppose your EV has a 77 kWh battery, you're at 62% charge, and your normal consumption is 17 kWh/100 km — a typical real-world figure for a mid-size European electric car. You're about to drive 150 km on the motorway on a cold day, and want to keep a 10% reserve. Cold temperatures and sustained motorway speed together are cutting your real-world range by roughly 25% today.
- Usable charge: 62% − 10% reserve = 52%.
- Usable energy: 77 kWh × 0.52 = 40.0 kWh.
- Efficiency in distance terms: 17 kWh/100 km = 5.88 km/kWh.
- Adjusted for conditions: 5.88 km/kWh × (1 − 0.25) = 4.41 km/kWh — the same as 22.7 kWh/100 km.
- Estimated range: 40.0 kWh × 4.41 km/kWh ≈ 177 km.
With an estimated 177 km available above your reserve and a 150 km trip ahead, you'd arrive with roughly a 27 km cushion on top of your reserve — comfortable, but tight enough that a charging stop partway would be a reasonable precaution rather than cutting it close on a cold day.
Result: about 177 km (110 miles) available now, versus 306 km (190 miles) if the same battery were charged to 100% in normal conditions.
WLTP, EPA and CLTC: why the same car has three different ranges
Electric cars are rated on different test cycles depending on where they are sold, and the numbers are not interchangeable. WLTP is used across Europe, the UK, India, Australia and much of Asia. The US EPA procedure is harsher and typically returns a figure 10–20% lower for the same vehicle. China's CLTC cycle is the mildest of the three and usually reads highest. A car advertised at 500 km WLTP might be rated near 430 km by the EPA and above 550 km on CLTC without a single component changing.
None of them is a prediction of your own driving — they are standardised comparisons between vehicles, run at controlled temperatures with the climate control off. That is why this calculator asks for a real-world efficiency figure from your dashboard rather than starting from a rated range: your own average already includes your speeds, your climate, and your right foot.
What changes your real-world range
Five things account for almost all of the gap between a rated range and the one you actually get. The figures below are the ranges the calculator's condition presets are built on.
| Factor | Typical effect | Why |
|---|---|---|
| Cold weather | −10% to −40% | Cabin heating draws directly from the battery, and a cold pack delivers less. Heat pumps lose less than resistive heaters. |
| Motorway speed | −10% to −20% | Aerodynamic drag rises with the square of speed, so 130 km/h costs far more than 100 km/h. |
| Hot weather with air-con | −5% to −15% | Cooling is cheaper than heating, but continuous air-con above 35 °C still shows up. |
| Elevation gain | −5% to −20% | Climbing costs energy; regenerative braking returns some of it on the way back down. |
| Payload, towing, tyres | −2% to −30% | A full car costs a few percent. Towing is the single most expensive thing you can do to an EV's range. |
City driving is the exception that runs the other way: frequent stops let regenerative braking recover energy, which is why many EVs are more efficient in town than on an open road — the reverse of a petrol or diesel car.
How to find your real-world efficiency
Most EVs display a lifetime or trip efficiency figure on the dashboard — in kWh/100 km across most of the world, in mi/kWh in the US and UK, and in Wh/km on many Teslas and European models. Whichever it shows, that figure beats the rated WLTP, EPA or CLTC number for planning, because it already reflects your driving rather than a standardised test cycle.
If you drive a mix of city and motorway, use your dashboard's overall lifetime average. If the trip ahead is mostly one or the other, either enter that specific efficiency or leave your average in place and use a conditions preset. If you cannot find the figure at all, pick your car from the model list in the calculator — it loads an indicative real-world consumption you can then adjust.
Common ways to use this calculator
Compare your estimated range against a specific trip distance before you leave.
See how far you can go before you'd want to stop, keeping a comfortable reserve.
Estimate how much cold weather is likely to cut your usual range.
Convert a WLTP consumption figure into mi/kWh, or an EPA rating into kWh/100 km, to compare like with like.
Privacy and appropriate use
Your inputs are processed directly in your browser and are not sent to a database. The result is a planning estimate; always keep a safety margin on unfamiliar routes, and rely on your vehicle's live range estimate once you're driving.