Spike's Calculators

Fuel and Distance Calculators

Convert RPM to MPH

Spike VM

Converting revolutions per minute to a speed of miles per hour.

Sample Calculation

Like you need to know this we will make this calculation about a skill saw.

If you look at the specs of your skill saw, among other things, it will state the no-load speed given in revolutions per minute the saw can operate at. This is the speed your saw blade will run at when you pull the trigger and of course the instance you cut into a material the RPM's will be reduced.

To be able to calculate the speed in miles per hour in addition to the RPM's, you need to know the diameter of the saw blade and convert this to its circumference.
 Formula : circumference = 2 * radius * pi or circumference = diameter * pi.
 pi = 3.14159...........
7 1/4" saw blade
no-load speed = 5900 RPM

7 1/4 = 7.25 * 3.14159 = 22.7765467
The circumference of the blade = 22.7765467 inches

RPM is the number of times the blade spins around in a minute.

To get the distance in inches per minute:
22.7765467 * 5900 = 134381.6257 inches

Convert this to inches per hour:
1 hour = 60 minutes--134381.6257 * 60 = 8062897.545438 inches per hour

Convert this to miles per hour:
one mile = 63360 -- 8062897.545438 ÷ 63360 = 127.255

The speed at which this saw blade runs is 127.255 miles per hour.


Revolutions per Minute rpm
Diameter in Inches in


Circumference in
Miles per Hour mph


  1. enter the revolutions per minute
  2. the diameter


  1. circumference
  2. speed in miles per hour
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