Regenerative Braking Torque Calculator

Regenerative braking turns a vehicle's motor into a generator. It helps slow the vehicle while sending energy back to the battery. The amount of braking torque depends on power and motor speed.

Our Regenerative Braking Torque Calculator makes this calculation simple. You can calculate regenerative torque from mechanical power, electrical power with efficiency, or wheel braking force.

Regenerative Braking Torque Formula

The main regenerative braking torque formula is:

Torque = Power ÷ Angular Speed

Angular speed is:

Angular Speed = (2 × π × RPM) ÷ 60

So, when power is in watts:

Torque (N·m) = Power (W) ÷ Angular Speed (rad/s)

For power in kilowatts and speed in RPM, you can use:

Torque (N·m) = 9550 × Power (kW) ÷ Speed (RPM)

This is the core formula for calculating torque from rotating power.

Calculating Torque from Electrical Power and Efficiency

When you know electrical regenerative power and system efficiency, the calculator first finds mechanical power:

Mechanical Power = Electrical Power ÷ Efficiency

Then:

Regenerative Torque = Mechanical Power ÷ Angular Speed

Calculating Torque from Wheel Braking Force

For wheel braking force, the calculator uses:

Wheel Torque = Braking Force × Wheel Radius

If a gear reduction and drivetrain efficiency are included, motor torque is:

Motor Torque = Wheel Torque ÷ (Gear Ratio × Drivetrain Efficiency)

These formulas let you calculate the required torque for a regenerative braking system from the available inputs.

How to Use Online Regenerative Braking Torque Calculator

1. Choose the calculation method. Select mechanical power, electrical power, or wheel braking force.
2. Enter the required values. For mechanical power, enter power and motor speed. For electrical power, enter electrical power, efficiency, and speed.
3. Choose the correct units. The calculator supports power in watts, kilowatts, or horsepower. Speed can use RPM or rad/s.
4. For wheel torque, enter braking force and wheel radius. You can also enable the gear option and enter the gear ratio and drivetrain efficiency.
5. Click calculate. The calculator converts the units, applies the correct torque formula, and shows the result in N·m.

This makes it useful for EV design, motor testing, braking studies, and basic regenerative braking system analysis.

Example Regenerative Braking Torque Calculation

Suppose an electric motor produces 66.67 kW of mechanical regenerative power at 3,000 RPM.

First, calculate angular speed:

Angular Speed = (2 × π × 3000) ÷ 60

Angular Speed = 314.159 rad/s

Now calculate torque:

Torque = 66,670 W ÷ 314.159 rad/s

Torque ≈ 212.21 N·m

Therefore, the regenerative braking torque is approximately:

212.21 N·m

Electrical Power Example

Suppose the regenerative electrical power is 60 kW. The regenerative efficiency is 90%, and motor speed is 3,000 RPM.

Mechanical Power = 60 ÷ 0.90

Mechanical Power = 66.67 kW

Now:

Torque = (66.67 × 9550) ÷ 3000

Torque ≈ 212.22 N·m

So the estimated regenerative braking torque is about 212.22 N·m.

Wheel Torque Example

Suppose braking force is 2,000 N and wheel radius is 0.30 m.

Wheel Torque = 2,000 × 0.30

Wheel Torque = 600 N·m

If the gear ratio is 4:1 and drivetrain efficiency is 95%:

Motor Torque = 600 ÷ (4 × 0.95)

Motor Torque ≈ 157.89 N·m

Final Verdict

The Regenerative Braking Torque Calculator gives a quick way to calculate motor or wheel torque during regenerative braking. Its core calculation uses the power-to-torque relationship, while its other modes account for electrical efficiency and wheel force.

It can help with EV calculations, motor sizing, regenerative brake analysis, and checking required torque. It should not be confused with brake caliper torque specifications, brake line torque specs, or automotive brake repair estimates. Those values depend on the specific vehicle and manufacturer.

FAQs

What is regenerative braking torque?

Regenerative braking torque is the opposing torque produced when an electric motor operates as a generator during vehicle deceleration.

How do you calculate rated torque?

Rated torque can be calculated from rated power and rated rotational speed using:

Torque = Power ÷ Angular Speed

For kW and RPM:

Torque (N·m) = 9550 × Power (kW) ÷ RPM

How do you calculate required torque?

Required torque depends on the system. From power, use Torque = Power ÷ Angular Speed. From wheel force, use Wheel Torque = Force × Radius.

How do you calculate torque from RPM?

First convert RPM to angular speed:

Angular Speed = 2 × π × RPM ÷ 60

Then divide power by angular speed.

Can this calculator calculate wheel braking torque?

Yes. Enter the regenerative braking force and wheel radius. The calculator uses Wheel Torque = Force × Radius.

What units does torque use?

The calculator reports torque in N·m. Power and force inputs are converted to compatible SI units before calculation.

Is regenerative braking the same as normal braking?

No. Regenerative braking uses the electric motor to create braking torque and recover energy. Conventional friction brakes use brake components such as pads, rotors, and calipers to create friction.

Can this calculator determine brake caliper torque specifications?

No. Brake caliper torque specs and brake rotor torque specifications are vehicle-specific service values. They should come from the vehicle manufacturer's repair information.

What affects regenerative braking torque?

Motor power, motor speed, regenerative efficiency, wheel force, gear ratio, and drivetrain efficiency can affect the calculated torque.