Estimated 1RM (Epley).
These calculators use established formulas (such as Mifflin-St Jeor for calorie needs or the Devine formula for ideal weight) to provide general estimates. They're built for a general population and don't account for individual medical conditions, medications, or circumstances. They aren't a substitute for advice from a doctor, registered dietitian, or other qualified healthcare provider — especially for anything related to pregnancy, chronic conditions, or medication dosing.
Epley formula estimates 1RM from a lighter set: 1RM ≈ Weight × (1 + Reps/30).
Most accurate for 2–10 reps. Above 10, endurance dominates and the estimate drifts high.
Estimated 1RM is what most programming actually uses to set training percentages (like '80% of 1RM for 5 reps') — you rarely need to test a true maximal lift to train effectively.
100 kg × 5 reps: 1RM ≈ 100 × (1 + 5/30) = 116.7 kg.
Epley and Brzycki are the most-used, both within a few kg in the 3–8 rep range.
Only if experienced with a spotter and fully warmed up. Estimated 1RM is enough for most programming.
It's most reliable for compound barbell lifts like squat, bench, and deadlift — accuracy drops for exercises with more technical variability like Olympic lifts.