Free 1-Rep Max Tool
One Rep Max Calculator
Estimate your one-rep max for any barbell lift. Enter the weight you lifted and how many reps you hit, and get your 1RM, training percentages, rep targets and the plates to load, without ever testing a true max under the bar.
Your One Rep Max Calculator Rep-Max Targets
The weight you should be able to lift for a given number of reps.
Your estimated one-rep max converts into target weights for every rep range. Use these to pick a working weight: if your program calls for a set of five, the 5-rep row is your starting load. The table updates with your estimate above.
| Reps | Estimated weight | % of 1RM |
|---|---|---|
| 1 rep (max) | 260 lb | 100% |
| 2 reps | 243 lb | 94% |
| 3 reps | 236 lb | 91% |
| 4 reps | 229 lb | 88% |
| 5 reps | 223 lb | 86% |
| 6 reps | 216 lb | 83% |
| 8 reps | 205 lb | 79% |
| 10 reps | 195 lb | 75% |
| 12 reps | 185 lb | 71% |
How the Calculator Works
Five established formulas, averaged for a steadier estimate.
The calculator estimates your one-rep max by working backwards from a set you already completed. The more reps you do at a given weight, the further that weight sits below your true max, and prediction formulas model that relationship. This tool runs your input through five equations at once, then averages them so no single formula's bias skews the result. Estimates are most reliable at five reps or fewer.
These are long-established one-rep-max prediction equations from strength-training research. For training and coaching standards, the recognized professional body is the National Strength and Conditioning Association (NSCA). Estimates are guidance, not a substitute for coaching or medical advice, and a true max should only be attempted with proper warm-up and a spotter.
Specific Examples
Common rep sets and the max they estimate.
What's my one-rep max if I lift 225 for 5 reps?
Lifting 225 for 5 reps estimates a one-rep max of about 260 lb. A mid-range set that estimates reliably.
What's my one-rep max if I lift 135 for 10 reps?
Lifting 135 for 10 reps estimates a one-rep max of about 179 lb. A higher-rep set, so treat this as a ballpark and retest heavier.
What's my one-rep max if I lift 185 for 3 reps?
Lifting 185 for 3 reps estimates a one-rep max of about 201 lb. A low-rep set like this gives the most accurate estimate.
What's my one-rep max if I lift 315 for 1 rep?
Lifting 315 for 1 rep estimates a one-rep max of about 315 lb. A single is your max, so this figure is exact.
What's my one-rep max if I lift 155 for 8 reps?
Lifting 155 for 8 reps estimates a one-rep max of about 194 lb. A higher-rep set, so treat this as a ballpark and retest heavier.
What's my one-rep max if I lift 275 for 2 reps?
Lifting 275 for 2 reps estimates a one-rep max of about 289 lb. A low-rep set like this gives the most accurate estimate.
What's my one-rep max if I lift 95 for 12 reps?
Lifting 95 for 12 reps estimates a one-rep max of about 133 lb. A higher-rep set, so treat this as a ballpark and retest heavier.
What's my one-rep max if I lift 245 for 4 reps?
Lifting 245 for 4 reps estimates a one-rep max of about 275 lb. A mid-range set that estimates reliably.
Want a specific number? Type your weight and reps into the calculator at the top and it will estimate any combination instantly.
Calculators for Every Lift
The same method, tuned for each barbell movement.
A Percentage-Based Program Built on Your Max
A training program that plugs straight into the one-rep max you just calculated. Not available yet, check back soon.
Recommended Gear
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Lifting Belt
A stiff belt helps you brace and stay tight on your heaviest attempts across every lift.
Shop on AmazonLifting Chalk
Better grip on the bar means fewer missed reps from your hands giving out first.
Shop on AmazonFrequently Asked Questions
Answers to the most common one-rep-max questions.
How do you calculate a one rep max?
You calculate a one rep max by taking a set you completed and applying a prediction formula. Enter the weight and reps you did above and the calculator projects the single heaviest weight you could lift for one rep, averaged across five formulas.
How accurate is a one rep max calculator?
A one rep max calculator is most accurate at low rep counts. At one to five reps the estimate is usually within a few percent of a true max. Above about ten reps accuracy drops because muscular endurance varies more between people.
Which one rep max formula is best?
No single formula is best for everyone. Epley and Brzycki are the most widely used and agree closely at low reps. This tool averages Epley, Brzycki, Lombardi, Lander and Wathan so no single equation dominates.
What is a one rep max?
A one rep max, or 1RM, is the most weight you can lift for a single repetition of an exercise with good form. It is the standard reference point coaches use to set training loads by percentage.
Can I calculate my 1RM without testing it?
Yes. Do a set to near failure at a known weight, ideally five reps or fewer, then enter the weight and reps above. The calculator estimates your max so you never have to attempt a true one-rep max.
Does this work for bench, squat and deadlift?
Yes. The prediction formulas apply to any barbell lift. For lift-specific strength standards and examples, use the dedicated bench press, squat, deadlift and overhead press calculators.
What are training percentages for?
Training percentages let you program by intensity. Most strength work sits between 70 and 90 percent of your one-rep max, with heavy sets near 85 to 90 percent and higher-rep volume near 65 to 75 percent.
Is it safe to test a true one rep max?
A true max attempt carries more injury risk than submaximal work, especially without a spotter or experience. Estimating from a rep set avoids that risk, which is why most coaches program from estimates.
Does the calculator work in kilograms?
Yes. Switch the unit toggle to kg and the input, results, training percentages and plate math all convert to kilograms using a 20 kg Olympic bar.
How often should I recalculate my max?
Recalculate whenever you hit a new rep record on a working set, which for most lifters is every few weeks. Rebasing your percentages on a fresh estimate keeps your training aligned with your current strength.