For performance, the regex101 site shows number of steps and that is most of the time enough.
But, from my time in Windows, I used the RegexBuddy and is an excellent (paid) tool to measure performance. I have no relation to it, and I am not recommending anyone to buy it, but it is nice to know it exists since it can convert from one regex type to another and is the only tool I know that has BRE and ERE regexes.