One Rep Max Calculator

Calculate your one-rep max (1RM) for bench press, squat, deadlift, and any lift. Uses Epley, Brzycki, and Lombardi equations with personalized training zones.

Lift Parameters

lbs
Formulas are most accurate between 2 and 10 reps.
reps
Estimated One Rep Max
214lbs (Composite Average)

Calculated from 185 lbs performed for 5 repetitions.

Peak Capacity100% 1RM

Epley

216 lbs

Brzycki

208 lbs

Lombardi

217 lbs

Prescribed Training Zones

Working Load (lbs)
Max Strength90–100%
193 lbs1–3 reps

Peak neurological adaptation

Strength Power80–90%
171 lbs3–5 reps

Heavy myofibrillar strength

Hypertrophy65–80%
139 lbs8–12 reps

Muscle growth & volume

Endurance50–65%
107 lbs15–25 reps

Work capacity & stamina

Always use spotters and safety pins when testing or lifting near maximum intensity. For regular training, calculate your working weights using these sub-maximal formulas rather than attempting frequent true 1RM testing.

What Is a One Rep Max (1RM)?

Your one rep max (1RM) is the maximum weight you can lift for a single repetition of an exercise with proper form. It is the fundamental measure of absolute muscular strength and the basis for calculating training loads in virtually every structured periodization program.

1. Epley Formula (Gold Standard for < 10 Reps)
1RM=Weight×
1+
Reps30
2. Brzycki Formula (Hypertrophy & Higher Reps)
1RM=Weight×
3637 − Reps
Step-by-Step Calculation Breakdown (Bench Press: 185 lbs for 5 Reps)
Step 1: Compute Epley 1RM Estimate
Multiplier = 1 + (5 ÷ 30) = 1 + 0.1667 = 1.1667
Epley 1RM = 185 × 1.1667 = 215.8 lbs (≈ 216 lbs)
Step 2: Compute Brzycki & Lombardi Estimates
Brzycki 1RM = 185 × (36 ÷ 32) = 185 × 1.125 = 208.1 lbs
Lombardi 1RM = 185 × 5^0.1 = 185 × 1.1746 = 217.3 lbs
Step 3: Multi-Formula Composite 1RM
Composite 1RM=214 lbs (97 kg)

Training Zones Based on Your 1RM

Zone% of 1RMRep RangePrimary Training Adaptation
Max Strength90–100%1–3 repsPeak neurological motor unit recruitment
Strength Power80–90%3–5 repsHeavy myofibrillar hypertrophy & power
Hypertrophy65–80%8–12 repsMuscle cross-sectional area & sarcoplasmic volume
Muscular Endurance50–65%15–25 repsLactate buffering & work capacity

Frequently Asked Questions

What is a one rep max (1RM)?
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise with proper form. It is the gold standard for measuring absolute strength in weightlifting. Knowing your 1RM helps you calculate training loads for different goals: 90-100% for max strength, 75-85% for hypertrophy, and 50-65% for muscular endurance.
Which 1RM formula is most accurate?
The Epley formula is the most widely used and validated for experienced lifters. The Brzycki formula tends to be more accurate for higher rep ranges (8-12+ reps). The Lombardi formula gives slightly higher estimates for low reps. Our calculator uses all three and provides the average, which gives you the most reliable estimate regardless of your rep range.
Can I calculate my 1RM from any rep range?
Yes, 1RM formulas work best with rep ranges between 2-10 reps. For reps above 10 (especially above 15), the formulas become less accurate because muscular endurance becomes a limiting factor. For the most reliable estimate, use a weight where you can complete 3-8 reps with good form.
How often should I test my 1RM?
Most lifters should test their 1RM every 4-8 weeks. Beginners can make progress faster and may retest every 4 weeks. Intermediate and advanced lifters should limit max testing to every 8-12 weeks because heavy max attempts are neurologically demanding and increase injury risk.
What training zone should I use for muscle growth?
The hypertrophy zone is 65-80% of your 1RM, typically performed in sets of 8-12 reps. This rep range maximizes muscle growth by combining mechanical tension with metabolic stress. Aim for 3-5 sets per exercise with 60-90 seconds of rest between sets.

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