Estimate your true one-rep max (1RM) for bench press, squat, deadlift or any lift — using Epley, Brzycki and Lombardi formulas, averaged for accuracy.
| % of 1RM | Weight | Typical use |
|---|
| Reps | Estimated weight |
|---|
Your one rep max, or 1RM, is the heaviest weight you can lift for exactly one complete repetition of an exercise with correct technique. It is the reference point strength coaches use to program training intensity, track long-term progress and compare strength across lifters of different sizes.
Testing a true 1RM — loading a bar until you fail on a single rep — carries real injury risk, especially on the bench press and squat. Most lifters, including competitive powerlifters between meets, instead estimate their 1RM from a submaximal set they can perform safely, then use a validated formula to project the theoretical maximum.
This calculator applies three peer-reviewed regression formulas built from real strength-training data, then averages them so no single formula's bias dominates:
The three formulas agree closely for 1–5 reps and diverge more as reps climb. Epley tends to read slightly higher and is generally most reliable for 6–10 rep sets; Brzycki is often tighter for 1–6 reps but becomes unstable above 10; Lombardi sits between the two across most rep ranges. Averaging them smooths out the difference into a single practical estimate.
Once you know your estimated 1RM, percentages of it define the training zone for different goals. This is how most evidence-based strength programs (5/3/1, linear periodization, powerlifting peaking blocks) prescribe load:
| % of 1RM | Typical rep range | Primary goal |
|---|---|---|
| 90–100% | 1–3 reps | Maximal strength, competition peaking |
| 80–89% | 3–6 reps | Strength & power development |
| 70–79% | 6–10 reps | Strength-hypertrophy (most common training zone) |
| 60–69% | 10–15 reps | Hypertrophy (muscle growth) |
| Below 60% | 15+ reps | Muscular endurance, technique work, deloads |
The calculator above generates your exact training weight for each percentage automatically, rounded to a practical loading increment.
The same math applies to every exercise, but real-world accuracy differs by movement:
Your one rep max is the maximum weight you can lift for a single complete repetition of an exercise with correct form. It is the standard reference point for programming strength training intensity, comparing strength over time, and setting competition or testing goals.
1RM formulas are typically accurate within about 5-10% when based on a set of 1 to 10 reps performed close to failure. Accuracy drops for sets above 12 reps, for beginners with inconsistent technique, and for exercises with a strong technique component like the deadlift.
No single formula is best for everyone. Epley tends to run slightly higher and works well for 6-10 rep sets. Brzycki is often more accurate for 1-6 rep sets but becomes unstable above 10 reps. Lombardi sits between the two. This calculator averages all three so no single formula's bias dominates your estimate.
Only if you have solid technique, a spotter or safety pins, and experience with the lift — true 1RM testing carries injury risk, especially for the bench press and squat. Most lifters, including advanced ones, estimate 1RM from a submaximal set instead of testing to failure every few weeks.
Once you know your 1RM, use percentages to target specific adaptations: 85-100% for maximal strength (1-5 reps), 67-85% for hypertrophy and strength (6-12 reps), and below 67% for muscular endurance (12+ reps). This calculator generates the exact weight for each percentage automatically.
Formulas assume consistent effort and technique across rep ranges, but real performance is affected by fatigue, nervous system readiness, technique breakdown at high reps, and individual muscle fiber type. Fast-twitch dominant lifters tend to underperform formula estimates at high reps; endurance-oriented lifters tend to overperform them.
The math is identical, but real-world accuracy varies by lift. Deadlift estimates from higher-rep sets tend to run high because grip and lower-back fatigue limit reps before true muscular failure. Bench press and overhead press estimates are usually the most reliable across formulas.
Recalculate your estimated 1RM every 4-8 weeks, or at the end of a training block, using a recent top set. Beginners can see meaningful strength gains monthly; intermediate and advanced lifters should expect smaller, slower increases and may only need to retest every 8-12 weeks.
Sets of 3 to 6 reps performed close to failure give the best balance of accuracy and safety. Very low reps (1-2) risk technical failure rather than muscular failure; very high reps (12+) let fatigue and pacing distort the estimate more than actual strength does.