Estimate Your One-Rep Max (1RM)
Use the Epley equation to estimate your one-rep max from a submaximal set:
1RM = Weight × (1 + Reps ÷ 30)
What Is the Epley Formula?
The Epley formula is a popular strength-training equation used to estimate your one-rep max (1RM) from a set you can do for multiple reps. Instead of testing a true max lift, you perform a challenging set and use that result to predict your maximum.
The formula is simple:
Estimated 1RM = weight lifted × (1 + reps / 30)
Example: If you bench press 80 kg for 6 reps, your estimated 1RM is:
80 × (1 + 6/30) = 96 kg
Why Lifters Use 1RM Estimation
Testing a true max every week is fatiguing and can increase injury risk, especially for beginners. A calculator gives you a practical way to track progress and set training loads while staying safer.
- Set percentage-based workouts (e.g., 75%, 80%, 85% of 1RM)
- Monitor strength trends over time
- Plan deloads and peak phases
- Compare progress across lifts consistently
How to Use This Calculator Correctly
1) Use a quality working set
Choose a set performed with solid technique and close effort (without grinding to complete form breakdown).
2) Enter exact reps and load
Accuracy depends on your input. Small differences in reps can noticeably shift the estimate.
3) Keep reps in a useful range
The Epley method tends to work best with lower to moderate reps (often 1-10). At very high reps, prediction error grows.
Epley vs Other 1RM Formulas
Epley is one of several formulas. Others include Brzycki, Lombardi, and O'Conner. They all estimate max strength slightly differently. In practice, consistency matters more than finding a "perfect" equation.
If you always use Epley for your logging, your trend data remains comparable over time—even if absolute values vary a little from another method.
When to Trust the Number (and When Not To)
- Trust it more: controlled sets, stable technique, normal sleep/recovery, reps under ~10.
- Trust it less: very high reps, inconsistent depth/range of motion, poor recovery, or technique breakdown.
Think of the result as a planning tool, not an absolute truth. Use it to guide training, then adjust based on bar speed, fatigue, and performance.
Practical Programming Tips
Use a Training Max
Many lifters use 90-95% of estimated 1RM as a training max to keep sessions productive and sustainable.
Recalculate every 2-6 weeks
Update your estimate from recent rep sets rather than chasing all-out max attempts too often.
Track by lift
Squat, bench, deadlift, overhead press, and Olympic lifts all adapt at different rates. Keep separate estimates for each.
Safety Note
Always prioritize proper warm-ups, controlled technique, and appropriate progression. If you are new to resistance training or returning after injury, consult a qualified coach or healthcare professional.