HERE is a little calculator I whipped up.
This calculator uses 7 different equations that are in use today to calculate a 1RM.
- Calculate your estimated One Rep Max based on how many repetitions you performed at a given weight.
- Calculate the weight to use on a Rep Max attempt.
I.e. You are progressively working up to a new 5 RM every week, this week you predict you can hit a 5RM that represents a 1RM of 440. Put in 5 reps and 440lbs, and smash ~380lbs for 5
- Calculate the number of reps you should be able to get at any given weight, knowing your 1RM. Note: Lombardi and O’Conner et al. are very high estimates for some weights given the nature of their equation. I would not consider these accurate.
Equations Used: Epley, Brzycki, Lander, Lombardi, Mayhew et al. , O’Conner et al. , and Wrathan