EV & Energy Calculators

Running an electric car comes down to a few numbers

Owning an EV turns a handful of recurring questions into simple arithmetic: how long a charge takes, what it costs, how far the car actually goes, and how to keep the battery healthy over the years. None of it needs guesswork. Once you know your battery capacity in kilowatt-hours, your charger power in kilowatts, and your local electricity rate, every other figure follows from there.

Charging speed depends almost entirely on the connection, not the car. A standard home socket trickles in 1 to 2 kW; a dedicated wallbox delivers 7 to 22 kW; a motorway rapid charger pushes 50 to 350 kW. The same 60 kWh battery that needs most of a day on a socket reaches 80% in under half an hour on a DC charger. The mechanics behind those numbers, including why fast charging slows down near full, sit in the battery and charging section below.

Energy cost is usually where an EV wins. Charging at home on an overnight tariff is typically 3 to 4 times cheaper per kilometre than petrol, while leaning on public rapid chargers narrows that gap. Real-world range rarely matches the brochure figure: cold weather, motorway speed, and a loaded roof rack each take a measurable bite, so trip planning works best from the consumption your car actually shows rather than its official WLTP rating.

Battery longevity is the last piece. For most lithium-ion chemistries, keeping daily charge between roughly 20% and 80% slows capacity loss, with a full charge saved for the days you need the range. The calculators on this page turn each of these questions into a concrete answer for your own car, tariff, and journey.

EV battery and charging basics

An EV battery is rated in kilowatt-hours (kWh), the same unit on your electricity bill. A 60 kWh battery stores the energy of running a 1 kW appliance for 60 hours. In driving terms, a car consuming 16 kWh/100 km will cover about 375 km from that 60 kWh pack. In practice, manufacturers keep 5 to 15% of capacity in reserve at each end to protect the cells, so usable capacity is typically 90 to 95% of the rated figure.

Charging levels explained

For most European homes, a 7.4 kW (32 A single-phase) wallbox is the practical choice: it charges a 60 kWh battery in about 8 hours overnight. Going above 11 kW requires three-phase supply, which not all homes have. See the Home Charger Wiring planner to confirm what your installation can support.

Why fast charging stops at 80%

DC fast chargers use CC/CV charging: full rated power up to about 80% state of charge, then tapering current to protect cell chemistry. That last 20% takes nearly as long as the first 80%. On a long trip, it is almost always faster to charge to 80% and continue than to wait at the charger for 100%. The Charging Time calculator models this taper, so you get realistic session estimates rather than a flat linear projection.

What each tool does

When to use these tools

• Before a road trip, estimate how long to charge and what the electricity will cost
• Comparing home charging vs public charging tariffs
• Calculating monthly charging cost based on your driving habits
• Checking whether your EV range covers a planned route
• Estimating charging time when using a slower home outlet vs fast charger

What actually affects your real-world range

The WLTP figure on a manufacturer's spec sheet is a standardised test result. Real-world range varies considerably based on conditions you can and cannot control.

For trip planning: use the figure your car currently shows on its energy screen (often in kWh/100 km or miles/kWh) rather than the WLTP claim. If the display shows 19 kWh/100 km in current conditions, enter that, not the manufacturer's 15 kWh/100 km. The EV Trip Planner accepts current battery level and real consumption to show whether a charge stop is needed before you leave.

EV charging cost in context

Where you charge determines how much cheaper an EV is to run compared to a petrol car. Home charging at standard tariff gives the biggest saving; public rapid charging narrows the gap considerably.

At Dutch home tariffs, an EV costs roughly 3 to 4 times less per km than petrol. Charging exclusively at public rapid chargers narrows that advantage to about 1.5 to 2 times. The EV vs Petrol calculator takes your actual driving distance, local tariff, and current petrol price to show the real annual saving for your specific situation.

Putting the numbers together for a trip

A single journey usually pulls in several of these figures at once. Start from the energy your car needs: distance divided by 100, multiplied by your real consumption in kWh/100 km, gives the kilowatt-hours the trip will draw. Compare that against the usable capacity left in the battery, and you know immediately whether a charge stop is unavoidable or merely convenient.

If a stop is needed, the cost and timing follow directly. At a known charger power, the time to add a given number of kilowatt-hours is straightforward, and at a known tariff so is the price. Planning a longer route is just this calculation repeated for each leg, with an 80% target at each rapid charger rather than a full charge, since the final 20% is the slowest and rarely worth the wait mid-trip.

Run the EV Trip Planner for the route check, the Charging Time calculator for each stop, and the EV vs Petrol calculator when you want the running-cost picture over a full year of driving.

For EV charging infrastructure by region, the EV charging in Asia-Pacific guide and the EV charging in Southeast Asia guide cover connector standards, apps, and country-level charging notes. For conventional vehicle fuel economy, tyre sizing, and ICE-to-EV comparisons, see the automotive converters hub.