5 reps → 1RM
63lb
average estimate
8 reps → 1RM
69lb
10 reps → 1RM
73lb
3 reps → 1RM
59lb
Show the math
Epley (5 reps) = 55 lb × (1 + 5 ÷ 30) = 64 lb
Brzycki (5 reps) = 55 lb × 36 ÷ (37 − 5) = 62 lb
If you lifted 55 lb for…
| Reps | Epley | Brzycki | Average 1RM |
|---|---|---|---|
| 1 rep | 55 | 55 | 55 |
| 2 reps | 59 | 57 | 58 |
| 3 reps | 61 | 58 | 59 |
| 4 reps | 62 | 60 | 61 |
| 5 reps | 64 | 62 | 63 |
| 6 reps | 66 | 64 | 65 |
| 7 reps | 68 | 66 | 67 |
| 8 reps | 70 | 68 | 69 |
| 9 reps | 72 | 71 | 71 |
| 10 reps | 73 | 73 | 73 |
| 11 reps | 75 | 76 | 76 |
| 12 reps | 77 | 79 | 78 |
If 55 lb is your one rep max
| % of 1RM | Load (lb) | About this many reps |
|---|---|---|
| 95% | 52 | 2 |
| 90% | 50 | 4 |
| 85% | 47 | 6 |
| 80% | 44 | 8 |
| 75% | 41 | 10 |
| 70% | 38 | 12 |
| 65% | 36 | 15 |
| 60% | 33 | 20 |
How to use it
- Enter your numbers. Switch between US and metric units at any time.
- Results update as you type, and the formula is shown so you can check it.
- Copy the link, save the plan on this device, or print it for your next appointment.

Want a clinician to look at these numbers?We know licensed clinicians in every state. If you ask, one can reach out to you. Get matched
These are estimates, not a diagnosis. A clinician can account for your health history and medicines.
Other weights
Common questions
What is my 1RM if I lift 55 lb for 5 reps?
About 63 lb, averaging the Epley and Brzycki formulas.
What is my 1RM if I lift 55 lb for 10 reps?
About 73 lb. Estimates get less precise above 10 reps.