Calculate brake pedal force, master cylinder pushrod force, or pedal ratio from any two values in lb-f, kg-f, or N, with step-by-step results.

Brake Pedal Force Calculator

Enter any 2 values to calculate the missing variable

Brake Pedal Force Formula

The following equation is used to calculate the Brake Pedal Force from the pedal ratio and the force at the master cylinder pushrod (pedal output force).

F_{pedal} = F_{pushrod} / BPR
  • Where Fpedal is the brake pedal force (lb-f, N, or kg-f)
  • Fpushrod is the force transmitted from the pedal into the master cylinder pushrod (lb-f, N, or kg-f)
  • BPR is the brake pedal ratio (unitless, X:1)

To calculate the brake pedal force, divide the master cylinder pushrod force by the brake pedal ratio.

Note: Brake pedal ratio relates pedal force to master cylinder pushrod force. Converting pedal force to caliper clamping force, brake torque, or tire/road braking force requires additional information (master cylinder area, caliper piston area, brake geometry, friction, effective radius, etc.).

What is a Brake Pedal Force?

Definition:

The brake pedal force is the input force a driver applies to the brake pedal. It is a force (commonly expressed in pound-force (lb-f), newtons (N), or kilogram-force (kg-f)), not a pressure.

For example, if a vehicle requires about 50 lb-f at the brake pedal for a given braking demand, the driver would need to apply about 50 lb-f of force at the pedal. The actual stopping distance still depends on vehicle speed, road conditions, tire grip, and brake system design.

How to Calculate Brake Pedal Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Brake Pedal Force.

First, determine the required master cylinder pushrod force. In this example, the master cylinder pushrod needs to see a force of 600 lb-f.

Next, determine the brake pedal ratio. In this case, the brake pedal ratio is measured to be 8:1.

Finally, calculate the brake pedal force using the formula above:

Fpedal = Fpushrod / BPR

Fpedal = 600 / 8

Fpedal = 75 lb-f