The British imperial system invades other countries, makes them use pounds and feet, and then leaves.

Also, I want it to go to people outside my org that I email back, not random spammers and salespeople.

For some reason, the only option is to use people in my addressbook which doesn’t auto populate and I never use.

BMI works quite well for typical people.

Either you do so much more exercise than everyone around you that it’s not a good fit for you, or you should take it as a warning sign.

If you think it’s muscle and not fat, there’s another test that you might like to try instead which is the waist to hip ratio. https://www.healthline.com/health/waist-to-hip-ratio

But if you want an honest appraisal of your fitness, just do a fun run. The shortish runs round a park with a bunch of normal people. Either you can keep up without killing yourself and everything is fine, or you’re not as fit as you think.