Most 1RM calculators are accurate within 5–10% when lifts are performed close to muscular failure between 3 and 8 repetitions. Accuracy depends on exercise type, lifting experience, fatigue level, and proper technique.
Factors Affecting Accuracy
- Exercise selection
- Training experience
- Rep range used
- Recovery condition
- Lifting form
Safe Alternative to Max Testing
Instead of risky maximal lifting, estimate strength instantly using: