Free1RM Calculator App
Calculate your one rep max using the Epley formula. Track personal records for 29+ exercises including snatch, clean & jerk, squat, and deadlift. All built into EVOX, free on iOS & Android.
Complete Strength Tracking
Everything you need to track and improve your lifts
Accurate 1RM Calculation
Calculate your estimated one rep max using the proven Epley formula. Input your weight and reps, get your estimated 1RM instantly.
PR Tracking
Log personal records for every lift. See your progress over time with clear history and improvement tracking.
Percentage Charts
Instantly see training percentages from 50% to 100% of your 1RM. Perfect for percentage-based programming and warm-up calculations.
29+ Exercises
All major lifts covered: snatch, clean & jerk, back squat, front squat, deadlift, bench press, overhead press, and many more.
Built for Serious Lifters
Whether you do CrossFit, Olympic weightlifting, or powerlifting
CrossFit Athletes
Know your numbers for WOD scaling. Quickly calculate percentages for prescribed weights and track PRs across all CrossFit movements.
Olympic Weightlifters
Track snatch, clean & jerk, and all variations. See percentage charts for training programs and monitor PR progression.
Strength Training
Perfect for powerlifting and general strength training. Track squat, bench, deadlift, and calculate working weights for any percentage-based program.
Calculate Your 1RM in Seconds
Simple, fast, accurate
Enter Your Lift
Select the exercise and enter the weight you lifted and how many reps you completed.
Get Your 1RM
The Epley formula calculates your estimated one rep max instantly. See percentages from 50-100%.
Save Your PR
Log the result as a personal record. Track your progress over time and celebrate new PRs.
1RM Calculator FAQ
Common questions about one rep max calculation
Still have questions?
Contact us →The Complete 1RM Calculator Guide: Epley Formula, Training Percentages & When to Test
Your one-rep max (1RM) is the foundation of intelligent strength training. It determines your working weights, guides your programming, and serves as the ultimate benchmark of strength progress. But testing a true 1RM is demanding and carries injury risk, which is why accurate estimation formulas like the Epley method exist. This guide explains everything you need to know about calculating, testing, and using your 1RM effectively.
What Is a 1RM and Why Does It Matter?
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 measurement of absolute strength and serves as the reference point for percentage-based training programs. When a program prescribes back squats at 75% for 5 sets of 3 reps, it means 75% of your 1RM back squat. Without knowing your 1RM — whether tested or estimated — you are essentially guessing your training loads, which leads to either undertraining (weights too light to stimulate adaptation) or overtraining (weights too heavy to maintain quality). In CrossFit, knowing your 1RM for key lifts is essential for scaling workouts appropriately. When the whiteboard says 135-pound power cleans and your 1RM power clean is 155 pounds, you know that workout is asking you to work at 87% of your max — which is extremely heavy for a conditioning workout and should likely be scaled. This kind of informed decision-making is only possible when you track your numbers accurately.
The Epley Formula: How It Works and When It's Accurate
The Epley formula is the most widely used and validated method for estimating 1RM from a submaximal lift. The formula is simple: 1RM = Weight x (1 + 0.0333 x Reps). For example, if you bench press 200 pounds for 5 reps, your estimated 1RM is 200 x (1 + 0.0333 x 5) = 200 x 1.1665 = 233 pounds. The formula is most accurate when using sets of 2-6 reps, where the relationship between weight and rep count is most linear. At 7-10 reps, accuracy decreases slightly because individual factors like muscular endurance and pain tolerance begin to influence the result. Above 10 reps, the formula becomes unreliable because you are testing endurance more than maximal strength. Other estimation formulas exist — Brzycki, Lander, Lombardi, and O'Conner — each with slightly different coefficients. The Epley formula is preferred in the CrossFit community because it performs well across both Olympic lifts and powerlifting movements. EVOX uses the Epley formula by default and shows you the estimated 1RM instantly when you log any submaximal set.
Testing vs Estimating: When to Attempt a True 1RM
There is an ongoing debate in strength training about whether to test a true 1RM or always rely on estimates. Both approaches have valid applications. Testing a true 1RM is valuable when you need precise numbers for competition preparation, when you have not tested in 3-6 months and estimates may have drifted from reality, or when you simply want the psychological experience of lifting a maximal load. A proper 1RM test requires careful preparation: warm up thoroughly with progressive sets (empty bar, 50%, 65%, 75%, 85%, 90%, then attempt), rest 3-5 minutes between heavy attempts, and always have a spotter for pressing movements. Never test 1RM when you are fatigued, underfed, or under time pressure. Estimating is more appropriate for day-to-day training, when you are in a high-volume training phase where a 1RM attempt would add unnecessary stress, or when you are an intermediate athlete whose 1RM is still climbing consistently. A practical approach used by many coaches is to test true 1RM once per quarter on core lifts and use estimates for everything in between.
Using Percentages for Training: Common Exercises and Rep Ranges
Once you know your 1RM, percentage-based training becomes your most powerful programming tool. Different percentages correspond to different training adaptations. At 50-65% of 1RM, you are in the speed and technique zone — ideal for warming up, practicing Olympic lift positions, and developing barbell velocity. At 70-80%, you are building muscle and work capacity with sets of 5-8 reps that stimulate hypertrophy and muscular endurance. At 80-90%, you are in the strength zone with sets of 2-5 reps that drive maximal strength adaptation. At 90-100%, you are peaking — singles and doubles that prepare you for competition or 1RM testing. Common exercises where 1RM tracking is most valuable include back squat, front squat, overhead squat, deadlift, bench press, strict press, power clean, squat clean, power snatch, squat snatch, clean and jerk, and push jerk. EVOX supports all of these with automatic percentage charts that instantly show you every training weight from 50% to 100%, eliminating mental math during workouts and ensuring you always train at the intended intensity.
Track Your Strength Progress
Calculate 1RM, track PRs, and see your percentage charts — all in one free app. Download EVOX now.