What is your one-rep max?
Enter a weight and how many clean reps you did with it. You get an estimated one-rep max, a percentage table for planning sets, and the rep ranges each percentage suits.
Calculator
Average of Epley and Brzycki.
- Epley116.7 kg
- Brzycki112.5 kg
Percentage table
| % of 1RM | Weight | Reps | Best for |
|---|---|---|---|
| 100% | 112.5 kg | 1 | Strength |
| 95% | 107.5 kg | 2 | Strength |
| 90% | 102.5 kg | 3–4 | Strength |
| 85% | 95.0 kg | 5–6 | Strength |
| 80% | 90.0 kg | 7–8 | Muscle growth |
| 75% | 85.0 kg | 9–10 | Muscle growth |
| 70% | 80.0 kg | 11–12 | Muscle growth |
| 65% | 72.5 kg | 13–15 | Muscle growth |
| 60% | 67.5 kg | 16–20 | Endurance |
| 55% | 62.5 kg | 20–25 | Endurance |
| 50% | 55.0 kg | 25+ | Endurance |
Rep ranges
Strength
3–6 sets, 2–5 min rest. Heavy, low-rep work that trains your nervous system to produce force.
Muscle growth
3–4 sets, 1–3 min rest. Take sets close to failure; total weekly volume drives growth.
Endurance
2–3 sets, 30–90 s rest. Builds work capacity and is easy on the joints.
What a one-rep max is
Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with good form. Most strength programs are written as percentages of it — “5 sets of 5 at 80%” — so knowing it lets you load every session correctly instead of guessing.
Testing a true max is tiring and, without a spotter and good technique, risky. Estimating it from a heavier set of 3–8 reps gets you very close with a fraction of the fatigue, and you can re-estimate from any hard set you log.
How this calculator works
It runs two well-established formulas. Epley assumes each extra rep is worth about 3.3% of your max; Brzycki uses a slightly different curve that reads a little lower at higher reps. Both agree closely between 2 and 10 reps, and the calculator shows their average as the headline number.
The percentage table multiplies that estimate by 50–100% and rounds to a loadable weight (2.5 kg or 5 lb steps). The rep column shows roughly how many reps most people can do at each percentage, which is useful for choosing weights for any rep target.
Getting an accurate estimate
Use a set taken close to failure — one or two reps left in the tank at most — with the same technique and range of motion you would use for a single. Sets of 3–6 reps give the most accurate estimates; above 10 reps, endurance plays a bigger part and the formulas drift.
Estimates are exercise-specific. A 1RM for the squat tells you nothing about your bench press, and machine or dumbbell lifts behave differently from barbell lifts. Calculate each main lift separately and update them every few weeks as you get stronger.
The formulas
- Epley
1RM = weight × (1 + reps ÷ 30)- Brzycki
1RM = weight × 36 ÷ (37 − reps)- Training weight
weight = 1RM × percentageRounded down to the nearest 2.5 kg or 5 lb.
FAQ
How accurate is a one-rep max calculator?
From a hard set of 3–6 reps, the Epley and Brzycki formulas usually land within about 5% of a tested max. Accuracy drops above 10 reps, and it varies between people: those with more endurance-type muscle can do more reps at a given percentage, so the formula overestimates their max.
Which formula is better, Epley or Brzycki?
Neither is clearly better across the board. They give nearly the same result between 2 and 10 reps; Epley runs slightly higher at higher reps. Using the average, as this calculator does, smooths out the difference.
Should I test my real one-rep max?
You do not have to. For most training goals an estimated max is accurate enough and far less fatiguing. If you compete in powerlifting or simply want to know, test it after a proper warm-up, with a spotter or safety pins, and only on lifts where your technique is solid.
What percentage of my 1RM should I train at?
For strength, most work sits at 80–90% for sets of 2–6 reps. For muscle growth, 65–80% for 6–12 reps works well, as long as sets end close to failure. For muscular endurance, 50–65% for 15 or more reps. Most good programs mix several ranges across the week.
How often should I recalculate my 1RM?
Every 4–6 weeks, or at the end of each training block. Beginners get stronger quickly, so updating more often keeps the percentages honest; advanced lifters can go longer between updates.
Lifts to calculate your max for
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