Enter the maximum RPM of your converter and the maximum torque of the engine into the calculator to determine the k-factor.

K Factor Formula

The following formula is used to calculate the k-factor of a stall converter.

K = RPM * Sqrt (T)

  • Where K is the k-factor of the torque converter
  • RPM is the converters stall RPM
  • T is the engine torque output (lb-ft)

Stall Converter Definition

A stall converter is a device used in an internal combustion engine that produces a maximum torque multiplication at stall RPM.

Example Problem

How to calculate k-factor?

  1. First, determine the converters stall RPM.

    For this example, the stall RPM of the torque converter is found to be 4000RPM.

  2. Next, determine the maximum engine torque output.

    For this example, the engine can output a maximum of 400 lb-ft of torque.

  3. Finally, calculate the k factor.

    Using the formula above, the k factor is found to be:
    K = RPM * Sqrt (T)
    K = 4000 * Sqrt (400)
    K = 80,000