🏋️ One Rep Max Calculator

What is One Rep Max (1RM)?

One rep max (1RM) is the maximum amount of weight you can lift for a single repetition of an exercise with proper form. It is the gold standard for measuring strength in exercises like bench press, squat, and deadlift.

Formula Used (Epley)

1RM = Weight × (1 + Reps / 30). This is the most widely used formula for estimating 1RM from submaximal lifts.

How to Use Training Percentages

• 90–100% — Maximum strength, 1–3 reps
• 80–90% — Strength and power, 3–5 reps
• 70–80% — Hypertrophy (muscle building), 6–12 reps
• 60–70% — Muscular endurance, 12–20 reps
• Below 60% — Warm-up and recovery

Safety Note

Never attempt a true 1RM without a spotter and proper warm-up. Use submaximal testing (e.g. 5 reps) and calculate your estimated 1RM instead.