Where Your EV Range Actually Goes: Speed, Cold, and Cargo
EV range figures are quoted as single numbers and behave as ranges, and the largest variables are not the ones people expect.
The arithmetic is simple
The range calculator divides usable energy by consumption. A 75 kWh battery at 18 kWh/100 km gives 416.7 km (258.9 miles). The same battery at 80% state of charge gives 333.3 km.
| Battery | Consumption | Range |
|---|---|---|
| 60 kWh | 16 kWh/100 km | 375 km |
| 75 kWh | 18 kWh/100 km | 416.7 km |
| 100 kWh | 22 kWh/100 km | 454.5 km |
| 60 kWh | 25 kWh/100 km | 240 km |
Notice the last row against the first: the same 60 kWh battery gives 375 km or 240 km depending only on consumption. Consumption is the variable that decides range, and it is the one that moves most in real driving.
What moves consumption
Speed, more than anything. Aerodynamic drag rises with the square of speed, so motorway cruising is disproportionately expensive. This is the opposite of a combustion car, which is least efficient in town — and it is why EV range figures look pessimistic in traffic and optimistic on a motorway.
Cold. Battery chemistry is less efficient cold, and cabin heating draws from the same pack — a resistive heater in particular is a meaningful continuous load. Winter range is genuinely lower, and the effect is largest on short trips where the car never warms through.
Terrain. Climbing costs energy; regenerative braking returns some of it descending, but not all.
Load and tyres. Weight, roof boxes and underinflated tyres all raise consumption, and a roof box in particular is an aerodynamic penalty at exactly the speeds where drag already dominates.
Nameplate versus usable
The calculator takes nameplate capacity and applies a state-of-charge figure. Most vehicles also hold a buffer at both ends that is not available to you, so real usable capacity is somewhat below the headline number — another reason to treat a computed range as an upper bound.
Planning against it
The practical habit is to plan on consumption you have measured rather than the manufacturer's figure, and to plan arrivals at a state of charge rather than at zero. Arriving at 10–20% leaves margin for a diversion, a closed charger, or a headwind — all of which happen.
The 80% figure in the table is there for a reason too: DC fast charging slows considerably above it, so the last fifth of the battery costs disproportionate time to add. On a long trip, two stops to 80% is usually faster than one to 100%.
The cost comparison
The trip cost calculator uses one formula for both. Six hundred kilometres in a petrol car at 7 L/100 km and £1.60/L is 42 litres — £67.20, or £11.20 per 100 km. The same distance in an EV at 18 kWh/100 km and £0.30/kWh is 108 kWh — £32.40, or £5.40 per 100 km.
That gap is entirely dependent on the energy price, which is the input that varies most — home overnight rates and motorway rapid chargers can differ by a factor of three or four, and a trip charged entirely on rapid chargers looks very different from one charged at home.
Measuring your own consumption
Most EVs report lifetime and trip consumption directly, and that figure is the one to plan with. It already contains your speeds, your climate, your terrain and your driving.
Expect it to be worse than the official rating and to vary seasonally by a noticeable margin. Recording a winter figure and a summer figure separately makes range planning far more reliable than a single annual average.
Preconditioning while plugged in
Heating or cooling the cabin while still connected uses grid power rather than battery, which preserves range on the first leg — the leg where cold-weather losses are largest because neither cabin nor pack has warmed.
Some vehicles also precondition the battery on the way to a rapid charger, which improves charging rate rather than range. Both are small habits with a measurable effect in winter.