One-Rep Max (1RM) Calculator
Epley & Brzycki formulas · with a %-of-1RM rep table
Your one-rep max is the most weight you can lift for a single rep. From a set of several reps you can estimate it: Epley → 1RM = weight × (1 + reps ÷ 30) and Brzycki → 1RM = weight × 36 ÷ (37 − reps). Enter the weight you lifted and how many clean reps you got (use 10 or fewer for accuracy) to see both estimates and a loading table from 50% to 100% of your max.
Source: Epley (1985) & Brzycki (1993).
Your loading table
Weights for each percentage of your estimated 1RM (Epley estimate).
| % of 1RM | Weight | ~Reps | Typical use |
|---|---|---|---|
| 100% | — | 1 | True max; rarely trained to grind. |
| 95% | — | 2 | Peak strength / heavy singles & doubles. |
| 93% | — | 3 | Maximal strength work. |
| 90% | — | 4 | Strength; low-rep top sets. |
| 87% | — | 5 | Strength (classic 5×5 top end). |
| 85% | — | 6 | Strength to hypertrophy crossover. |
| 83% | — | 7 | Hypertrophy-leaning strength. |
| 80% | — | 8 | Hypertrophy; common working sets. |
| 77% | — | 9 | Hypertrophy. |
| 75% | — | 10 | Hypertrophy; volume work. |
| 70% | — | 12 | Hypertrophy / volume. |
| 67% | — | 14 | Higher-rep hypertrophy. |
| 65% | — | 15 | Muscular endurance crossover. |
| 60% | — | 18 | Muscular endurance. |
| 55% | — | 22 | Muscular endurance / conditioning. |
| 50% | — | 26 | Endurance; warm-up sets. |
The formulas
Epley: 1RM = weight × (1 + reps / 30)
Brzycki: 1RM = weight × 36 / (37 − reps)Reference: reps per percentage of 1RM
| % of 1RM | Reps ≈ | Typical training use |
|---|---|---|
| 100 | 1 | True max; rarely trained to grind. |
| 95 | 2 | Peak strength / heavy singles & doubles. |
| 93 | 3 | Maximal strength work. |
| 90 | 4 | Strength; low-rep top sets. |
| 87 | 5 | Strength (classic 5×5 top end). |
| 85 | 6 | Strength to hypertrophy crossover. |
| 83 | 7 | Hypertrophy-leaning strength. |
| 80 | 8 | Hypertrophy; common working sets. |
| 77 | 9 | Hypertrophy. |
| 75 | 10 | Hypertrophy; volume work. |
| 70 | 12 | Hypertrophy / volume. |
| 67 | 14 | Higher-rep hypertrophy. |
| 65 | 15 | Muscular endurance crossover. |
| 60 | 18 | Muscular endurance. |
| 55 | 22 | Muscular endurance / conditioning. |
| 50 | 26 | Endurance; warm-up sets. |
Source: Standard %1RM–rep relationship (NSCA-style guidance).
Use your 1RM with the TDEE calculator to fuel training properly. For how the math works and when each formula breaks down, read how 1RM formulas work.
Frequently asked questions
What is the Epley one-rep-max formula?
The Epley formula estimates your one-rep max as 1RM = weight × (1 + reps ÷ 30). For example, 100 kg for 5 reps gives 100 × (1 + 5/30) ≈ 116.7 kg. It assumes a linear relationship and tends to read slightly higher than Brzycki at moderate reps.
Epley vs Brzycki — which is more accurate?
Both are accurate enough for programming in the 1–10 rep range, and they agree closely at low reps. Brzycki (1RM = weight × 36 ÷ (37 − reps)) tends to read a little lower at higher reps, while Epley reads higher. Use a rep count of 10 or fewer for the best estimate.
How many reps should I use for the estimate?
Use a set taken close to failure with 1–10 reps; 3–6 reps usually gives the most reliable estimate. Above about 10–12 reps, fatigue and technique break down and the prediction becomes much less trustworthy.
What is a percentage-of-1RM table for?
It tells you roughly how much weight to load for a given number of reps. Strength work usually sits at 85–100% of 1RM, hypertrophy at 67–85%, and endurance below about 67%. Use it to pick working weights from your estimated max.