How Switch Operating/Actuation Force is Measured

Operating force refers to the amount of force applied to the switch’s actuation mechanism to cause the contacts to change state. More simply put: how hard you have to press a switch to make it work. The amount of distance the actuator moves before changing state is called Travel, or Pretravel.

In most cases in the switch industry, you’ll see actuation force measured in grams or gf (gram force). However, it can be measured in any force unit — newtons (N), ounces (oz), pounds (lb), etc. It all depends on the final application and what number is easiest to read.

For example, one newton roughly equates to 102 grams, specifically 101.9716213g. So for larger switches like anti-vandals or regular pushbutton switches, you might see an actuation force in the datasheet written as four newtons (4N), but for smaller tact switches you might see it written as 350gf±100gf. The 350gf is the nominal actuation force and the plus/minus 100gf means there’s a tolerance of 100 grams in either direction. Because every part might be slightly different, it may function at 250 or 450 grams.

DigiKey operating force filter snippet:

Sometimes the datasheet has to be referenced as operating force isn’t always readily listed:

Source - E-Switch - What is Actuation or Operating Force? How is it Measured?