What is an E1RM (Estimated One Rep Max)?

An estimated one rep max (1RM) is the theoretical maximum weight you can lift for a single repetition of a given exercise. It's a common metric used in strength training and weightlifting to gauge an individual's maximum strength for a particular lift.

We offer a free E1RM calculator here at Strength Journeys:

https://www.strengthjourneys.xyz/calculator

Estimating a 1RM is helpful for:

• Program design: Setting appropriate working weights for different exercises. Your coach or program may designate 5 reps at 70% of your current one rep max or similar.
• Tracking individual progress over time: You can use the Strength Journeys Strength Visualizer to see a chronological chart of your e1rm progress for each lift.
• Comparing strength levels: If you know you own 5 rep max bench and your buddy only knows his 3 rep max bench - you can use an e1rm estimate to see who is the alpha of the gym.

The one rep max is typically estimated rather than directly tested because attempting to lift an actual maximum can be risky, especially for inexperienced lifters. The most common method is to use one of the exercise science formulae which models an estimate max based on a certain reps and weight combination.

For a deep dive into the maths behind e1RM estimation, see our article: How do I calculate my E1RM (estimated one rep max)? It covers all the major one rep max formulas — including the Epley formula, Brzycki formula, Lombardi, Mayhew, Wathan and O'Conner equations — with the exact calculations so you can see how each formula produces a different 1RM estimate from the same reps and weight. Or jump straight to the Strength Journeys One Rep Max Calculator to compare all 7 e1RM formulas side-by-side instantly.