Tesla Charging Time Estimator
Updated .
This estimator divides the energy you want to add by the charging power to give the shortest time a charge could take. You can enter the energy directly in kWh, or give a start percent, an end percent and your usable pack size. You can enter the power in kW, or give volts and amps and let the tool compute kW. Real charging slows as the battery fills and in the cold, so treat the answer as a minimum.
How it works
Charging time is energy divided by power, which is the same idea as distance divided by speed:
- Energy to add (kWh) is either the number you enter, or usable pack size × (end % − start %) ÷ 100. The pack size is yours to supply; read it from your owner’s manual or the car, because it differs between models and battery types.
- Charging power (kW) is either the number you enter, or volts × amps ÷ 1000. The helper suits a single-phase supply; if your supply is different, or the charger or car shows a kW figure, enter that instead.
- Time (hours) = energy ÷ power. The tool shows it as hours and minutes.
Why the answer is a minimum. The formula assumes the power stays constant. In practice the car, the charger and the supply can each limit it: the current may be set below what the wiring allows, charging commonly slows as the battery fills, and a cold battery usually charges more slowly. Each of these only ever lengthens the time. The most reliable check is to look at the estimated time the car itself shows once charging starts, and compare.
The energy is the amount added to the battery. If you want to know what that costs once losses are included, use the charge cost calculator.
Worked example
Suppose a hypothetical pack of 60 kWh usable, charged from 20% to 80% on a 240 V supply at 32 A. The kWh and kW boxes are left blank.
Energy: 60 × (80 − 20) ÷ 100 = 36 kWh. Power: 240 × 32 ÷ 1000 = 7.68 kW. Time: 36 ÷ 7.68 = 4.69 hours, which is 4 hours 41 minutes at the very least.
Drop the current to 30 A and the power becomes 7.2 kW, so the same 36 kWh takes exactly 5 hours. Extend the end point from 80% to 90% and the energy rises to 42 kWh, which the formula prices at 5 hours 28 minutes at 7.68 kW, but that top stretch is where real charging is usually slowest, so the true figure would be longer. These numbers are illustrative arithmetic, not data for any Tesla model or charger.
Frequently asked questions
Why is the result called a minimum?
The formula assumes constant power. Real charging power tapers as the battery fills, can be limited by the charger or supply, and is usually lower when the battery is cold, so the actual time is the same or longer.
Where do I find my usable pack size?
Check your owner’s manual or the car itself, and use the usable figure rather than the total if both are given. This site does not state a pack size for any model because it varies.
How do volts and amps give kW?
Multiply volts by amps and divide by 1000. For example, 240 volts at 32 amps is 7,680 watts, or 7.68 kW. This suits a single-phase supply; if yours is different, use the kW shown by the charger or the car.
Can I enter kWh and percentages together?
If you enter kWh, the tool uses it and ignores the percentage boxes. If you leave kWh blank, it uses the usable pack size and the start and end percentages.
Should I charge to 100% to be safe?
That is a battery-care and planning question rather than a time one. Charge Limit advice depends on your battery type, so see the charge limit guide and your owner’s manual.
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