1 rm for 21's...how to calculate

[gratefuldog]

How do you calculate your reps when doing 21's? For example the standing barbell front press I used 30lbs. In the workout manager the reps only go as high as 20. Should I just put it at 20? Or am I figuring this wrong.
Help! I am a newbie as you can see!
Thanks
Carolyn

 

[marazoe]

Carolyn , i put down 20 because the counter doesn't go to 21.

Jean