One Rep Max Calculator
Estimate your one rep max and training weights from any set
| % of 1RM | Weight (kg) | Loadable (kg) | Typical reps | Used for |
|---|---|---|---|---|
| 100% | 69.3 | 67.5 | 1 | Your estimated max |
| 95% | 65.9 | 65 | 2 | Heavy strength work |
| 90% | 62.4 | 60 | 3–4 | Strength |
| 85% | 58.9 | 57.5 | 5–6 | Strength |
| 80% | 55.5 | 55 | 7–8 | Strength and size |
| 75% | 52.0 | 50 | 9–10 | Muscle building |
| 70% | 48.5 | 47.5 | 11–12 | Muscle building |
| 65% | 45.1 | 45 | 13–15 | Muscle building, endurance |
| 60% | 41.6 | 40 | 15–20 | Endurance, technique |
| 55% | 38.1 | 37.5 | 20+ | Warm-up, technique |
| 50% | 34.7 | 32.5 | 20+ | Warm-up |
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For general information only, not medical advice. Talk to a doctor or a qualified professional about your health. Terms of use
How to Use
- Choose kg or lb, whichever your gym's plates use.
- Enter the Weight lifted: the full load, including the bar (a standard Olympic bar is 20 kg).
- Enter the Reps done in that set, from 1 to 12. A hard set of 3 to 6 reps gives the most reliable estimate.
- Your estimated one rep max appears straight away, with the Epley, Brzycki and Lombardi results side by side.
- Use the table below to pick training weights from 50% to 95% of your max. The "Loadable" column rounds down to weights you can make with 2.5 kg (or 5 lb) steps.
How the one rep max calculator works
Your one rep max (1RM) is the most you can lift for a single rep. Testing it directly is tiring and carries some risk, so most lifters estimate it from a heavier set of a few reps. This one rep max calculator does that with three well-known formulas and then turns the result into a table of training weights you can use in the gym.
The three formulas
Brzycki: 1RM = weight × 36 ÷ (37 − reps)
Lombardi: 1RM = weight × reps ^ 0.10
All three are rules of thumb from strength-training research. They give similar answers for 3 to 6 reps and spread out as reps go up, because muscular endurance varies a lot from person to person. For a single rep, each one simply returns the weight you lifted.
A worked example
Say you bench pressed 100 kg for 5 reps.
- Epley: 100 × (1 + 5 ÷ 30) = 116.7 kg
- Brzycki: 100 × 36 ÷ 32 = 112.5 kg
- Lombardi: 100 × 5^0.10 = 117.5 kg
The average is 115.5 kg, and the tool shows that as your estimated 1RM. At 85% you'd train with about 98 kg; on a gym bar with 2.5 kg steps that means loading 97.5 kg.
Using percentages to plan training
| % of 1RM | Typical reps | Main use |
|---|---|---|
| 90–95% | 2–4 | Maximum strength |
| 80–85% | 5–8 | Strength |
| 70–75% | 9–12 | Muscle size |
| 60–65% | 13–20 | Endurance and technique |
| 50–55% | 20+ | Warm-up sets |
These rep counts are a rough guide. A lifter who is strong for one rep but has less endurance will manage fewer reps at 70%, and the reverse is also common. The reps you can do at a given percentage also differ from one exercise to another.
Progress carefully
An estimated max is a planning number, not a target to chase every week. Add weight in small steps (2.5 kg at a time is plenty for most upper-body lifts), keep a log, and leave a rep or two in reserve on most sets. If you're new to lifting, spend the first months on technique with a coach or an experienced friend before working near your max. Stop and see a doctor if you feel sharp pain, chest pain or dizziness while lifting.
Many Indian gyms still use plates in both kg and lb, and fixed dumbbells may be marked in either. Check before you load the bar, since 20 lb is only about 9 kg.