Calculate your one-rep max to determine the maximum weight you can lift for a single repetition.
Calculate your one-rep max to determine the maximum weight you can lift for a single repetition.
đź’ˇ This tool provides estimates as a guide. Individual results may vary.
Knowing your 1RM transforms your strength training from random workouts to strategic progress. Whether you're squeezing in a 20-minute session before work or hitting the gym during lunch, understanding your max strength lets you choose the right weights every time—no guessing, no wasting sets figuring it out. For busy professionals and parents with limited training time, this efficiency is everything.
Most effective strength programs prescribe weights as percentages of your 1RM (like "5 reps at 80%"). Without this number, you're either lifting too light and making no progress, or too heavy and risking injury or burnout. Once you know your 1RM, you can program intelligently, track progress objectively, and make every gym session count. Pair this with smart nutrition from our Protein Calculator and Maintenance Calorie Calculator to fuel your gains properly.
Your 1RM (one-rep max) is the absolute maximum weight you can lift for exactly one complete repetition of an exercise with proper form. It's the gold standard for measuring maximum strength in powerlifting and strength sports.
Knowing your 1RM is crucial because most effective strength training programs are based on percentages of your max. For example, a program might prescribe "5 sets of 5 reps at 80% of your 1RM." Without knowing your 1RM, you'd be guessing at the right weight.
The beauty of this calculator is that you don't have to actually test your 1RM (which can be risky, especially for beginners). Instead, you can lift a weight for multiple reps and use proven formulas to estimate your max.
Our calculator uses three scientifically validated formulas and averages them for accuracy:
Epley Formula (1977):
1RM = weight Ă— (1 + reps/30)
Most commonly used, simple and effective
Brzycki Formula (1993):
1RM = weight Ă— (36 / (37 - reps))
Slightly more conservative, good for higher reps
Lander Formula (1985):
1RM = (100 Ă— weight) / (101.3 - 2.67123 Ă— reps)
Research-backed, splits the difference
Example: If you bench press 185 lbs for 5 reps:
You'll notice the three formulas produce slightly different results. This happens because:
By averaging all three formulas, our calculator gives you a more balanced estimate that accounts for these variations.
Once you know your 1RM, you can program your training using percentages. Here's how different intensity zones affect your training:
90-100% of 1RM (1-3 reps):
Max Strength - Develops pure strength and neural adaptations. Heavy, challenging, requires long rest (3-5 min). Use sparingly, risk of injury is higher.
80-90% of 1RM (3-6 reps):
Strength Building - The sweet spot for getting stronger. Challenging but manageable. Most powerlifters train here regularly. Rest 2-4 minutes between sets.
70-80% of 1RM (6-10 reps):
Hypertrophy (Muscle Growth) - Best range for building muscle size. Moderate weight, moderate reps, shorter rest (1-3 min). Where bodybuilders spend most time.
60-70% of 1RM (10-15 reps):
Muscular Endurance - Develops work capacity and conditioning. Lighter weights, higher reps. Good for beginners and deload weeks.
Most effective programs cycle through these zones over time (periodization) rather than staying in one range year-round.
While our calculator estimates 1RM, you might eventually want to test your actual max. Here's how to do it safely:
⚠️ Safety First:
Proper Testing Protocol:
How often should I test my 1RM?
Every 6-12 weeks is plenty for most people. Testing too frequently can interfere with training progress and increase injury risk. Many experienced lifters only test 1-2 times per year before competitions. Use calculated estimates from your working sets the rest of the time.
Are these formulas accurate for all exercises?
They're most accurate for compound lifts (squat, bench, deadlift, overhead press, rows). For isolation exercises (bicep curls, leg extensions), the estimates are less reliable because these movements are more affected by muscular endurance than pure strength.
Should I use 1RM calculations as a beginner?
Yes, but don't test your actual 1RM. Use this calculator to estimate your max from sets of 5-8 reps, then program training at 60-75% of that estimate. As a beginner, focus on perfecting form with moderate weights rather than chasing heavy singles.
What if the calculator shows different results for each formula?
Small differences (5-10 lbs) are normal. Large differences suggest you might be better at certain rep ranges. If Epley is much higher, you're strong but tire quickly (neural strength). If Brzycki is higher, you have good muscular endurance. Use the average for programming.
Can I use this for bodyweight exercises?
Yes, for weighted variations (weighted pull-ups, dips, etc.). Enter the added weight, not your body weight. For unweighted bodyweight moves, 1RM concepts don't apply the same way—focus on rep maxes and progression schemes instead.
Why is my calculated 1RM different from my actual 1RM?
Several reasons: 1) You might have poor technique on max singles but good technique on sets of 5-8, 2) You might be better or worse at grinding through heavy singles than the average person, 3) Fatigue or inadequate rest before testing, 4) Mental factors—some people psych themselves out on max attempts.
How accurate are 1RM estimates from high reps (10+)?
Much less accurate. These formulas work best between 2-8 reps. Beyond 10 reps, muscular endurance and mental toughness play bigger roles than pure strength. If you can bench 135 lbs for 15 reps, the calculator might overestimate your true 1RM by 10-20 lbs.
Should my squat, bench, and deadlift 1RMs follow a certain ratio?
Rough guidelines: Deadlift > Squat > Bench. A common ratio is 3:2:1 (if you bench 200 lbs, you might squat 300 lbs and deadlift 400 lbs). But body proportions, training history, and genetics create huge variation—don't stress if your ratios are different.
Complete your fitness planning:
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