Join early access

Tesla charging kWh calculator

How many kWh does it take to charge a Tesla?

The useful answer is not one fixed battery number. It is the energy needed to move your Tesla from its current charge to your target — plus the extra electricity drawn from the wall during charging.

20% → 80%60%of the usable battery energy
60 kWh example36 kWhstored in the battery
+10% loss example40 kWhapproximately from the wall

The 60 kWh battery and 10% loss figures are examples, not specifications for every Tesla.

Calculate your kWhConvert kWh to cost

Calculator

Tesla kWh charging calculator

Tesla charging calculator →

Enter a battery-energy assumption, start and target charge, an estimated charging-loss percentage and your electricity rate. The calculator separates battery energy from wall energy.

Into the battery36.0 kWhUsable energy × SOC increase
From the wall40.0 kWhIllustrative loss-adjusted estimate
Electricity cost$7.26Wall kWh × electricity rate

Use this as an estimate. Battery-energy figures vary by vehicle and version, and real wall energy can change with temperature, battery conditioning, charging power and other vehicle loads. For actual spend, measured charging energy is better.

The calculator’s default 18.16¢/kWh rate is the U.S. residential average year-to-date through June 2026 from U.S. EIA Electric Power Monthly. Replace it with your own utility rate for a personal estimate.

The formula

Start with the percentage you actually need to add

If your Tesla moves from 20% to 80%, you are adding 60 percentage points — not a full battery.

Battery kWh= usable battery kWh × SOC increaseExample: 60 kWh × 0.60 = 36 kWh

Then estimate wall energy by allowing for charging losses:

Wall kWh≈ battery kWh ÷ charging efficiencyAt an illustrative 90% efficiency: 36 ÷ 0.90 = 40 kWh

Examples

The same 20% → 80% charge can mean different kWh

Example A

55 kWh assumption

33 kWh

into the battery for a 60-point SOC increase.

Example B

60 kWh assumption

36 kWh

into the battery for the same 20% → 80% charge.

Example C

75 kWh assumption

45 kWh

into the battery for the same percentage increase.

These are deliberately generic calculation examples. They are not claims about the usable capacity of a specific current Tesla trim.

kW vs kWh

Charging power tells you how fast. kWh tells you how much.

Energy needed40 kWhExample wall energy
÷
Charging power7.7 kWExample Tesla home power
=
Idealized time5.2 hbefore taper/loss effects

Tesla's current Wall Connector documentation lists power levels up to 11.5 kW / 48 A, while some Tesla variants are limited to 7.7 kW / 32 A. Your vehicle and electrical installation determine the actual maximum. Tesla Wall Connector specifications.

This matters for smart charging: once you know the kWh the car needs, you can estimate how many charging hours must fit inside the cheaper electricity window.

What changes the number?

Why the wall can deliver more kWh than the battery stores

Charging losses

Conversion and electrical losses mean charging is not perfectly lossless.

Battery conditioning

Heating or cooling the battery can use energy while the car is plugged in.

Cabin & vehicle loads

Preconditioning and other vehicle systems can consume electricity during a charging session.

Temperature & power

Real charging behavior changes with conditions and available charging power.

Cost

Convert charging kWh to dollars

For electricity cost, use the wall energy if you have it:

Charging cost = wall kWh × electricity rate40 kWh × $0.18/kWh = $7.20
Wall energy12¢/kWh18.16¢/kWh30¢/kWh
20 kWh$2.40$3.63$6.00
40 kWh$4.80$7.26$12.00
60 kWh$7.20$10.90$18.00

See the full Tesla charging cost guide and session-cost calculator →

FAQ

Tesla charging kWh questions

How many kWh does it take to charge a Tesla?

It depends on the battery-energy assumption and how far you raise the state of charge. For example, 20% to 80% adds 60% of the usable battery energy. With a 60 kWh assumption, that is about 36 kWh stored in the battery before charging losses.

How do I calculate Tesla charging kWh from battery percentage?

Multiply usable battery energy by the change in state of charge. For example: 60 kWh × (80% − 20%) = 36 kWh into the battery. Then allow for charging losses if estimating energy from the wall.

Why can wall kWh be higher than the kWh added to the battery?

Charging is not perfectly lossless. Battery conditioning and other vehicle systems can also use electricity while plugged in, so the wall can deliver more energy than the battery retains.

Where can I see actual Tesla charging energy?

Tesla Charge Stats can display Total Charged in kWh for the selected period. For actual cost tracking, measured charging energy is preferable to a nominal battery-capacity estimate.

What is the difference between kW and kWh when charging?

kW is power — how quickly energy can be delivered. kWh is energy — how much electricity is delivered. Tesla Wall Connector supports up to 11.5 kW where the vehicle and installation support it.

Know how many kWh the car needs. Then choose when to deliver them.

DriveQuery is being built to connect the Tesla's charging need with lower-cost electricity windows before departure.

Join early access