Energy
Check whether an EV trip is likely reachable with a chosen arrival reserve.
Enter your numbers to see the answer.
EV trip feasibility calculator guide
Before setting off on a trip that might stretch your battery, this calculator gives a yes-or-no verdict and shows the margin behind it. Enter usable battery, the percentage you are starting with, the trip distance in kilometres, your consumption in kWh per km, and the reserve you want to arrive with. It subtracts the reserve from the starting charge to find the energy you are willing to spend, converts that into reachable kilometres, and compares it with the distance. A positive margin reads Feasible; a negative one reads Not feasible. The reserve matters: 15% on a 75 kWh pack is 11.25 kWh, about 56 km at the default consumption, which is the difference between a relaxed arrival and hunting for a charger at 3%. Use your trip computer’s recent average for consumption, and raise it for cold weather, motorway speeds, headwinds, or a loaded car.
Spendable energy (kWh) = usable battery (kWh) × (starting charge % − arrival reserve %) ÷ 100. Reachable distance (km) = spendable energy ÷ consumption (kWh/km). Margin (km) = reachable distance − trip distance; Feasible when margin ≥ 0.
Worked example: 75 kWh usable, starting at 80%, a 180 km trip, 0.2 kWh/km, and a 15% arrival reserve. Spendable percentage = 80 − 15 = 65 points. Spendable energy = 75 × 65 ÷ 100 = 48.75 kWh. Reachable distance = 48.75 ÷ 0.2 = 243.8 km. Margin = 243.8 − 180 = +63.8 km, so the verdict is Feasible. The trip itself consumes 180 × 0.2 = 36 kWh, leaving 60 − 36 = 24 kWh, or 32%, on arrival. Push consumption to 0.27 kWh/km for a cold, fast run and reachable distance falls to 48.75 ÷ 0.27 = 180.6 km, a margin of just 0.6 km—technically Feasible but with no room for a detour.
Battery is kWh with a Wh/MWh menu. Distance is kilometres with a miles option converted at 1.609344 km per mile. Consumption is kWh per kilometre, so divide a kWh/100 km figure by 100, or use 1 ÷ (mi/kWh × 1.609344) for miles per kWh; 3.5 mi/kWh is about 0.178 kWh/km. Starting charge and reserve are whole-number percentages of the same usable capacity; do not enter the reserve in kWh or kilometres.
This is a modelled estimate, not a meter reading. Real consumption moves with weather, occupancy, appliance age, standing charges, and tariff structure, and equipment rarely runs at its nameplate rating. Use the figure to compare options against each other, then confirm against your own bill and the manufacturer's specification before committing to a purchase. On this page the figure rests entirely on usable battery, starting charge, trip distance, consumption, arrival reserve, market / jurisdiction, effective date, data source, update owner and review date, so start there if the ev trip feasibility calculator returns something you did not expect.
Good to know: a Feasible verdict with a margin under about 10% of the trip distance is a coin toss once weather, elevation, or a closed road intervene, so treat +63.8 km as comfortable and +6 km as a warning. Entering rated consumption instead of a real recent average is the most common way to get a false Feasible. Also check that the starting charge is what the car will show when you actually leave: a car that finished charging at midnight and sat in a −5 °C car park can lose 1–3% overnight and more warming the battery on departure.
Energy results depend on tariffs, equipment behavior, region, weather, and installation assumptions. Verify rates and electrical decisions with the utility, manufacturer, or qualified professional.
Sources
How it works
Check whether an EV trip is likely reachable with a chosen arrival reserve. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Usable battery = 75 kWh · Starting charge = 80 % · Trip distance = 180 km · Consumption = 0.2 kWh/km · Arrival reserve = 15 % → Feasible (trip feasibility verdict). Change an input above and this example updates with your numbers.
Common questions
A 75 kWh usable pack at 80% holds 60 kWh. Keeping a 15% reserve leaves 48.75 kWh to spend, which at 0.2 kWh/km reaches 243.8 km, so a 180 km trip is feasible with 63.8 km to spare. A smaller 40 kWh car under the same rules reaches only 130 km and would need a stop.
Plan for 10–20%. Below 10% the car may limit power, and one occupied or faulty charger becomes a problem. The default 15% on a 75 kWh pack is 11.25 kWh, about 56 km at 0.2 kWh/km—enough to reach a backup charger. Raise it to 20% in winter or on routes with sparse charging.
Treat the charger as your destination, set the arrival reserve to what you want left when you plug in, and enter the distance from a mapping app. If the margin is positive by at least 10–15% of the distance, go; if not, slow down (dropping from 120 to 100 km/h can cut consumption 15–20%) or charge earlier.
At 0.2 kWh/km it uses 36 kWh, which at a home rate of $0.16 per kWh costs about $5.76 plus roughly 10% charging losses. At 0.25 kWh/km in winter the same trip needs 45 kWh. The calculator’s “energy for this trip” row shows this figure for your own inputs.
Yes, more than in a petrol car. Aerodynamic drag grows with the square of speed, so 100 km/h instead of 120 km/h typically cuts consumption by 15–20%, turning 0.24 kWh/km into about 0.20. On a marginal trip that is the single most effective lever you have.