FPS Calculator / Joule Calculator

How to Use

Use the above calculators to make sure your gun is within the necessary energy / fps limits set forth by your local airsoft field or any milsim you are planning to attend.

The left "Joule Calculator" will allow you to calculate the energy your gun will shoot if you've measured your FPS and know the ammunition (bb weight) that was used during the chrono.  This will allow you to ensure your gun is within the energy limit.

The right "FPS Calculator" will allow you to calculate the FPS of your gun if you've measured your energy and know the ammunition (bb weight) that you plan to use.  This will allow you to estimate the FPS of your gun using certain ammunition to ensure your gun is within the FPS limit.

BEWARE OF JOULE CREEP

All guns - though especially gas guns and HPA guns - experience joule creep.  It is important to always chrono your gun with the bb you plan to use, and calculate the joules from there.  You cannot simply take the joule output value on the left calculator, input it into the calculator on the right, and assume that your gun will be legal.  While it is a useful estimation, different weight bbs may affect the amount of energy your gun can output, especially if they are gas or HPA.

Be safe!  Have fun!  And always obey local field regulations.