1 Rep Max Calculator - Calculate Your One Repetition Maximum
Quick Answer
This calculator estimates your one-rep max (1RM) using seven proven formulas. Enter the weight you lifted and number of reps to instantly calculate your maximum strength potential.
- Uses 7 scientific formulas including Epley, Brzycki, and NSCA methods
- Provides accuracy within ±2-5% for trained athletes
- Includes sport-specific standards for powerlifting and Olympic weightlifting
Understanding Your 1RM Results
One repetition maximum tests (1-RM) are popular fitness tests for measuring muscle strength. It is a measure of the maximal weight a subject can lift with one repetition. According to research by Robert J. Wood, PhD in Exercise Physiology from the University of Western Australia and founder of Topend Sports, 1RM testing remains the gold standard for strength assessment in athletic populations.
Measuring 1RM has safety issues, so it is sometimes useful to estimate the 1RM using a calculator based on the number of times (greater than 1) that someone can lift a certain weight. This calculator applies for all exercises, and any measurement unit for weight.
The Science Behind 1RM Calculations
Our calculator uses seven different formulas to provide the most accurate estimate possible. The primary formula was derived by Boyd Epley in 1985:
1RM = weight × (1 + (reps / 30))
Each formula has been validated through different research populations. According to sports science expert Robert Wood, who has analyzed sports performance data for over 25 years, using multiple formulas and averaging the results provides the most reliable estimate for individual athletes.
Formula Accuracy
Most accurate with 2-10 reps. Accuracy decreases above 15 reps due to endurance factors.
Learn More →Training Application
Use percentage charts to program your training based on your goals.
Training Guide →How to Use the 1RM Calculator
Follow these simple steps to calculate your one rep max:
- Enter Your Lift Data - Input the weight you lifted and the number of repetitions completed. For example, if you bench pressed 225 pounds for 5 reps, enter those values.
- Select Your Units - Choose between pounds (lbs) or kilograms (kg). The calculator works with any unit of measurement.
- Optional Athletic Settings (for precision)
- Exercise type: Select your specific lift for sport-specific standards
- Body weight: Enter to see strength-to-weight ratios
- Gender: For accurate percentile rankings
- Get Your Athletic Results - Click "Calculate 1RM" for instant results showing all seven formula estimates, your average 1RM, and training percentages.
Pro Tip: For most accurate results, use a weight you can lift for 2-10 reps. The formulas lose accuracy above 15 reps as muscular endurance becomes a larger factor than pure strength.
1RM for Athletes and Sports
Sport-Specific Standards
Powerlifting (IPF Standards)
- Elite: Total (Squat + Bench + Deadlift) = 2.5-3x body weight
- Advanced: Total = 2x body weight
- Intermediate: Total = 1.5x body weight
- Competition weight classes: 52kg to 120+kg
Olympic Weightlifting (IWF Standards)
- Clean & Jerk: Elite males = 2x body weight, Elite females = 1.5x body weight
- Snatch: Approximately 80% of Clean & Jerk 1RM
- Weight classes: 49kg to 109+kg (women), 55kg to 109+kg (men)
CrossFit/Functional Fitness
- Benchmark standards vary by workout (Fran, Grace, Isabel)
- Regional qualifiers typically require: Squat 1.75x BW, Deadlift 2.25x BW, Press 1x BW
- Games athletes often exceed: Squat 2.5x BW, Deadlift 3x BW
"Understanding your true 1RM is crucial for effective strength programming. Most athletes should train at 70-85% of their 1RM for optimal strength and hypertrophy gains while minimizing injury risk."--- Robert J. Wood, PhD, Founder of Topend Sports
Professional Athlete Examples
- Eddie Hall (Strongman): 500kg (1,102 lbs) Deadlift world record - First human to deadlift half a ton
- Julius Maddox (Powerlifting): 355kg (782.6 lbs) Raw Bench Press world record
- Lasha Talakhadze (Weightlifting): 267kg (588 lbs) Clean & Jerk Olympic record
- NFL Combine Standards: 225 lbs bench press for maximum reps (record: 51 reps by Justin Ernest)
- NBA Combine: Bench press 185 lbs for reps (guards), 185-225 lbs (forwards/centers)
How to Improve Your 1RM
Based on your calculated 1RM, adjust your training to maximize strength gains:
Below Target Range:
- Increase training volume by 10-15% per week
- Focus on progressive overload - add 2.5-5kg per session
- Add supplementary exercises (pause reps, tempo work)
- Timeline: 4-6 week mesocycle with deload week
- Nutrition: Ensure adequate protein intake (0.8-1g per lb body weight)
At Target Range:
- Maintain current program with periodic testing
- Focus on technique refinement and consistency
- Monitor for overtraining signs (decreased performance, fatigue)
- Consider periodization: alternate intensity and volume phases
Above Target Range:
- Consider competition entry in your sport
- Increase training specificity for your goals
- Work with qualified strength coach for advanced programming
- Implement peaking cycles for competition
Training Percentage Guidelines
As Robert Wood, founder of Topend Sports, notes in his analysis, different training percentages serve different purposes:
Understanding the Different Formulas
Research by Robert J. Wood, PhD in Exercise Physiology from the University of Western Australia and founder of Topend Sports, indicates that each formula has specific strengths:
- Epley Formula: Most widely used in commercial gyms and fitness apps. Best for general population and 1-10 rep range.
- Brzycki Formula: Conservative estimates preferred in research settings. NCAA validated for college athletes.
- Lombardi Formula: Better for higher rep ranges (10-15 reps) where endurance plays a larger role.
- Mayhew Formula: Validated across diverse populations including trained and untrained individuals.
- O'Conner Formula: Provides conservative estimates, good for beginners to avoid overestimation.
- Wathen Formula: NSCA recommended, particularly accurate for explosive athletes.
- Lander Formula: Similar to Brzycki but provides slightly higher estimates for competitive athletes.
⚠️ Safety Note: Always warm up properly before attempting heavy lifts. Consider working with a qualified strength coach when testing actual 1RM, especially for complex movements like squats and deadlifts. Use spotters for bench press and squat attempts above 90% of estimated 1RM.
Frequently Asked Questions
What is the most accurate 1RM formula?
The Epley and Brzycki formulas are considered most accurate for reps under 10. For higher reps (10-15), the Mayhew formula is often more accurate. Our calculator uses 7 formulas and provides an average for the best estimate.
How accurate is a 1RM calculator compared to actual testing?
1RM calculators are typically accurate within 2-5% for trained athletes when using 2-10 reps. Accuracy decreases with higher reps and varies between individuals based on muscle fiber type and training experience.
What percentage of 1RM should I use for training?
For strength: 85-95% (1-5 reps). For hypertrophy: 70-85% (6-12 reps). For muscular endurance: 50-70% (12+ reps). Power training typically uses 30-60% with explosive movement.
Can I use this calculator for any exercise?
Yes, the 1RM calculator works for any resistance exercise including bench press, squat, deadlift, overhead press, and even isolation exercises. However, it's most accurate for compound movements.
Why do different formulas give different results?
Each formula was developed using different populations and rep ranges. Epley works best for 1-10 reps, Lombardi for higher reps, and Brzycki is conservative. Using multiple formulas provides a more reliable estimate.
How often should I test my 1RM?
For most athletes, testing estimated 1RM every 4-6 weeks is sufficient. Actual 1RM testing should be limited to 2-4 times per year to minimize injury risk and allow for proper peaking.
What's a good 1RM for my body weight?
For males: Bench 1.5x body weight, Squat 2x body weight, Deadlift 2.5x body weight is considered advanced. For females: Bench 1x body weight, Squat 1.5x body weight, Deadlift 2x body weight is advanced level.
References
- Epley, B. (1985). "Poundage Chart." In: Boyd Epley Workout. Lincoln, NE: Body Enterprises. p. 86.
- Brzycki, M. (1993). "Strength testing—predicting a one-rep max from reps-to-fatigue." Journal of Physical Education, Recreation & Dance, 64(1), 88-90.
- Lander, J. (1985). "Maximums based on reps." NSCA Journal, 6(6), 60-61.
- Lombardi, V. P. (1989). "Beginning Weight Training: The Safe and Effective Way." Dubuque, IA: Wm. C. Brown.
- Mayhew, J. L., et al. (1992). "Relative muscular endurance performance as a predictor of bench press strength in college men and women." Journal of Applied Sport Science Research, 6(4), 200-206.
- O'Conner, R., et al. (1989). "Weight Training Today." St. Paul, MN: West Publishing.
- Wathen, D. (1994). "Load assignment." In: Essentials of Strength Training and Conditioning. Champaign, IL: Human Kinetics. pp. 435-439.
- Wood, R. J. (2025). "Fitness Testing Protocols and Standards." TopEndSports.com.
- International Powerlifting Federation. (2025). "Technical Rules Book." IPF Official Documentation.
- National Strength and Conditioning Association. (2024). "NSCA's Guide to Tests and Assessments." Human Kinetics.
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