Training

How to calculate your one-rep max (1RM) safely

You don't need to max out to know your 1RM. Here is how to test it properly, how to estimate it from a set of reps, and how to use it in training.

Your one-rep max (1RM) is the heaviest weight you can lift for a single clean repetition. You can find it in two ways: test it directly with a structured warm-up, or estimate it from a heavier set of 2–10 reps using a formula such as Epley or Brzycki. For most lifters, estimating is safer, faster and accurate enough to plan training.

Option 1: estimate your 1RM from a set of reps

Pick a weight you can lift for roughly 3–8 good reps, perform one hard set with solid technique, and plug the numbers into a formula:

• Epley: 1RM = weight × (1 + reps / 30)


• Brzycki: 1RM = weight × 36 / (37 − reps)

• Epley: 80 × (1 + 6/30) = 80 × 1.2 = 96 kg


• Brzycki: 80 × 36 / 31 ≈ 92.9 kg

Option 2: test your 1RM directly

A true test makes sense for experienced lifters, before a competition, or at the end of a training block. Do it when you are fresh, with a spotter or safety pins.

A sample progression if you expect a 100 kg max:

• Empty bar for 8–10 reps


• 50 kg × 5


• 70 kg × 3


• 80 kg × 2


• 90 kg × 1


• 95 kg × 1


• 100 kg × 1, then 102.5–105 kg if it moved well

Is testing 1RM dangerous for beginners?

A max single with good technique under supervision is not inherently dangerous, but beginners gain little from it. Their strength rises quickly, technique under maximal load is still unstable, and an estimate from a set of five tells them just as much. In the first months, track your best sets of 3–8 reps instead.

How to use your 1RM in a program

Many programs prescribe weights as a percentage of 1RM. Typical rough relationships:

• 90% of 1RM: about 3–4 reps


• 85%: about 5–6 reps


• 80%: about 7–8 reps


• 75%: about 9–10 reps


• 70%: about 11–12 reps

Re-estimate your 1RM every four to eight weeks from your best recent sets. A training log makes this easy, because every heavy set becomes a data point instead of a guess.

FAQ

Which formula is the most accurate?
None is perfect for everyone. Epley and Brzycki are both widely used and give similar results for 3–6 reps. Pick one and use it consistently so your numbers stay comparable.

Can I use a 15-rep set to estimate 1RM?
You can, but the estimate becomes unreliable. Use a heavier set of 10 reps or fewer.

How often should I test a true max?
Two to four times a year is plenty for most lifters. More often adds fatigue and injury risk without improving your training.

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