Thread:StrawberryMaster/@comment-35795256-20190919193224/@comment-11987506-20190919205326

Here's how it works:

In this case, you have a 250 mph (should be roughly 217kts) storm. As ACE is calculated by summing the squares of the estimated maximum sustained velocity of every active tropical storm, you should just do 217 x 217, which should be 47089. To make it more manageable, just divide the number by 10,000, which should lead to 4.7089, and that's the amount of ACE that storm produced in a six-hour interval.

This page may help you greatly when making an ACE table.