1RM Calculator – One Rep Max Calculator
Enter the weight you lifted and the reps you completed. You get your estimated one rep max from seven formulas, plus the weights to train at.
Results by formula
| Formula | Estimated 1RM |
|---|
Training percentages
Based on the 1RM shown above. Rep ranges are typical guides, not fixed rules.
| % of 1RM | Weight | Typical reps |
|---|
Training plan from your 1RM
Pick a goal to see the sets, reps and working weights that fit your max.
Plate calculator
See what to load on each side of the bar for a percentage of your 1RM.
What is a 1RM?
Your one rep max is the heaviest load you can lift once with good form. It is the standard way to measure strength and to set training weights, for example 8 reps at 75% of your max.
Testing a true max is tiring and risky, so most lifters estimate it from a lighter set of several reps.
How to get an accurate result
Use a set of 3 to 6 reps taken close to failure. Estimates get less reliable above 10 reps. Results work best on big lifts like bench press, squat and deadlift. Treat the number as an estimate: sleep, fatigue and technique all change it.
The complete guide to your one rep max
Why 1RM matters
A number for your max lets you set every working weight as a percentage instead of guessing. It also shows progress clearly: if your estimated max rises from 90 to 100 kg, you got stronger, even if you never tested a single rep.
How to test with a submaximal set
- Warm up with 2 to 3 lighter sets that build up gradually.
- Pick a weight you can lift for about 3 to 6 reps.
- Lift with strict form and stop when you cannot do another clean rep.
- Enter the weight and reps above. Use the same lift, same form and same range of motion each time you retest.
Which formula fits which rep range?
| Formula | Best for | Note |
|---|---|---|
| Epley | Most sets of 2 to 10 reps | Common default, reads a little above the average of all seven |
| Brzycki | Sets of 2 to 8 reps | Becomes unreliable past about 10 reps |
| Lander | Sets of 2 to 10 reps | Close to Brzycki |
| Lombardi | Sets of 3 to 10 reps | Higher than Brzycki at low reps, lower than Epley at high reps |
| Mayhew | Bench press style lifts | Developed on bench press data |
| O'Conner | Quick mental math | Simple linear formula |
| Wathan | Sets of 3 to 10 reps | Curved fit, close to the average |
Common mistakes
- Stopping far from failure. A set with 4 reps left in the tank will give a max that is too low.
- Using high reps. A set of 15 says more about endurance than maximal strength.
- Mixing lifts or form. Bounced reps, partial depth and different grips make results incomparable.
- Testing when tired. Poor sleep or a hard previous session can drop the result by several percent.
- Treating the estimate as fixed. Retest every 4 to 8 weeks and update your weights.
Using your 1RM in a program
A simple approach for beginners and intermediates: work at 70 to 80% for 3 to 4 sets of 5 to 8 reps, add a small amount of weight when all sets are done cleanly, and use 90 to 95% for heavy singles or doubles once every week or two. Deload to about 60% every fourth to sixth week.
FAQ
Which formula is the most accurate?
None is best for everyone. Epley and Brzycki are the most common. That is why this page shows seven and averages them.
How do the main formulas work?
Epley: weight × (1 + reps / 30). Brzycki: weight × 36 / (37 − reps).
Is it safe to test my true 1RM?
It can be if you warm up well, use a spotter or safety bars, and have solid technique. Beginners are better off using this calculator instead.
Can I use pounds?
Yes. Switch the unit to lbs. The formulas work the same in either unit.
Looking for a specific lift? Try our Bench Press Calculator, Squat Calculator or Deadlift Calculator.