Free Tool

One Rep Max Calculator

Estimate your 1RM from any weight and rep combination. Get a full percentage chart for programming your training.

Your Results

Enter a weight and rep count to estimate your one rep max.

Tips for accuracy

- Use a recent lift (last 1-2 weeks)
- Lower rep sets (1-6) are most accurate
- Take the set close to failure
- Compare multiple formulas

How to Use Your 1RM

Your One Rep Max (1RM) is the maximum weight you can lift for a single repetition with good form. It's a key metric for programming your training.

Training Zones

90-100% 1RM: Maximal strength (1-3 reps) - for peaking or testing
80-90% 1RM: Strength (3-6 reps) - primary strength work
70-80% 1RM: Strength-hypertrophy (6-10 reps) - size and strength
60-70% 1RM: Hypertrophy (10-15 reps) - muscle building
Below 60%: Muscular endurance (15+ reps) - conditioning

About the Formulas

Different formulas have different strengths. Epley and Brzycki are most commonly used. For best results with low reps (1-6), use Brzycki. For moderate reps (6-10), Epley tends to be accurate. The average of all formulas provides a balanced estimate.

Important Notes

These are estimates - your true 1RM may vary
Accuracy decreases significantly above 10 reps
Don't attempt a true 1RM without proper warmup and spotters
Your 1RM changes as you get stronger - recalculate every 4-8 weeks

Ready to get stronger? Check your macros and TDEE to make sure your nutrition supports your strength goals.