STP Calculator

STP Online Calculator

STP Conversion Calculator is a web-based tool (with a downloadable option) that simplifies fractional horsepower motor and gearmotor selection for engineers and product designers. Quickly calculates Speed, Torque and Power and accurately converts units of measurement. The STP Online Conversion Calculator provides a fast, easy way to calculate speed, torque or power. The most commonly used units can be selected and conversions are automatically and accurately generated. You enter two of the three variables – speed, torque or power – and STP calculates the remaining value.

    •   Speed & Torque
    •   Speed & Power
    •   Torque & Power
  • rpm

STP Downloadable Desktop Calculator

The MOTORTEC™™ STP conversion calculator provides a fast, easy way to calculate speed, torque, or power. Conversions of the most commonly used units are selectable, automatically generated and can be printed out.

  • Calculate Speed, Torque and Power
  • Calculate Estimated Electrical Current and Losses for Optimum Motor Selection
  • Easily and Accurately Convert Units of Measurement
  • Customizable, Printed Report Function
  • Calculate Operating Costs.

Windows 7 installation instructions

STP Calculator FAQs

STP Reports

STP reports are detailed and comprehensive, as well as customizable.STP report example

Speed, Torque and Power Calculations:

Rotational devices such as motors and gearmotors are given specifications in relationship to speed, torque and horsepower. The relationship between these variables follows the equation below.

power equation

There are a number of web sites that give additional information on the history of Horsepower and its calculation by searching the key word “horsepower”.

Converting Units:

STPe can also be used simply as a tool to reliably and accurately convert units.

Calculating Electrical Input and Losses

STP has an added feature to calculate estimated input power and losses. Based on the power requirements determined in the STP calculation, additional information can be entered in the Electrical Input and Loss calculator, to estimate electrical values based on the efficiency of the system.

Calculating Annual Operating Cost:

To calculate the annual operating cost, it is first necessary to enter the following operational parameters:

  • Hours/Day
  • Days/Week
  • Weeks/Year

STP uses this data to calculate total Hours/Year operation. The button marked “Get KWh Rate” links to the U.S. Department of Energy website for electrical power rates by location. The selected kWh rate should be entered into the $/kWh data field for final calculation of annual operating cost.


Conversions used in the program are listed below (STP calculations are accurate to nine decimal places)

  • pi = 3.141…
  • 1 Pound = 16 Ounces
  • 1 Foot = 12 Inches
  • 1 Inch = 2.54 Centimeters
  • 1 Meter = 100 Centimeters
  • 1 rpm = 2 pi / 60 radians
  • 1 Newton = 100,000 Dynes
  • 1 Newton = 0.2248… Pounds Force
  • 1 hp = 745.6998… Watts


How to use the Motor Search Tool

Narrow your search by selecting motor type, gearbox, voltage, and phase options for your desired motor.

Select a dominant variable: choose one of the three parameters to narrow your search. The selected variable determines which slider bar you will be able to manually move.

Use the slider corresponding to your dominant variable to further narrow your motor selection. The other sliders will automatically move to show available ranges based on the range of your selected variable.

Results will upload as your search criteria changes. If you have any questions regarding your results or how to use the search tool, you can chat with us using the green tab on the left-hand side of your screen.

Note: Groschopp Universal motors are custom built to fit your application so no additional options are available to narrow the search. Selecting the Universal motor type will prompt a message taking you to the Universal product page.

Not sure what you need?

One of our team members would be happy to help. Contact us at 800-829-4135 or by email at You can also chat with us using the green tab on the left side of your screen.

send us an email

Universal Motors

Groschopp Universal motors are custom built to fit your application so no additional options are available to narrow the search. Standard frame sizes and motor features can be found on the Universal page.

go to Universal page