How long does it take to charge an electric car? Maths and examples

The short answer is “it depends”, but the basic maths is simple. You need two numbers: how much energy you want to put into the battery and how much power you are charging with.

The formula

Time (hours) ≈ energy to add (kWh) ÷ charging power (kW). Add around 10% for losses, especially when charging slowly.

Example: a 60 kWh usable battery charged from 10% to 80% takes in 42 kWh.

• Regular socket, ~2.3 kW: about 20 hours.
• Single-phase wallbox, 7.4 kW: about 6 hours.
• Three-phase wallbox, 11 kW, if the car accepts it: about 4 hours.
• 50 kW fast charger: close to an hour.
• 150 kW or faster charger: usually 20–40 minutes, depending on the car.

Why it slows down towards the end

When fast charging, the car only takes peak power in a certain window, usually when the battery is around half full. As it fills, the system cuts the power to protect the cells. That is why 80% to 100% can take almost as long as 10% to 80%.

What else affects charging time

• The on-board charger: on AC, the car charges no faster than it allows.
• Temperature: a cold battery accepts less power. Preconditioning before a fast charger helps.
• Battery condition: a battery with unbalanced cells may charge more slowly or stop early.
• The station: some chargers split power between two cars plugged in at once.

What about plug-in hybrids?

A plug-in hybrid has a small battery, so it usually charges in a few hours even from a regular socket. Many plug-ins do not accept DC fast charging at all.

How to charge in a way that protects the battery is in our charging tips.