Compare your e1RM trend over time.
The main benefit is not knowing a theoretical maximum to the nearest kilogram. Use the same formula, exercise, and comparable execution to observe the trend over several weeks.
An estimate is still an estimate.
Technique, range of motion, fatigue, and proximity to failure affect the result. A long set or one performed far from failure is more likely to overestimate or underestimate your actual level.
Frequently asked questions
What is e1RM?
e1RM estimates the maximum load you could lift for one rep. It is calculated from a set you actually performed, without requiring a true max attempt.
Which formula does the calculator use?
The calculator uses the Epley formula: load × (1 + reps ÷ 30). ShapeVision uses the same formula to track e1RM trends in the app.
How many reps should you enter?
Use a challenging set of 1 to 12 reps performed with consistent technique. The longer the set or the farther it is from failure, the more the estimate may differ from your true maximum.