One-Rep Max Calculator

Estimate your one-rep max (1RM) from a set of several reps with the Epley and Brzycki formulas, plus a training-load table.

Most accurate with 2–10 reps taken close to failure.

Estimated 1RM (Epley)
215.8
Training loads by % of 1RM
020406080100100% (≈1) — Load: 97.9100% (≈1)95% (≈2) — Load: 93.00595% (≈2)90% (≈3) — Load: 88.1190% (≈3)85% (≈5) — Load: 83.21585% (≈5)80% (≈8) — Load: 78.3280% (≈8)75% (≈10) — Load: 73.42575% (≈10)70% (≈13) — Load: 68.5370% (≈13)65% (≈16) — Load: 63.63565% (≈16)60% (≈20) — Load: 58.7460% (≈20)
Brzycki
208.1
Average of both
212
Training loads (based on Epley 1RM) 
100%    97.9 kg   215.8 lb  ≈ 1 rep
 95%    93.0 kg   205.0 lb  ≈ 2 reps
 90%    88.1 kg   194.3 lb  ≈ 3 reps
 85%    83.2 kg   183.5 lb  ≈ 5 reps
 80%    78.3 kg   172.7 lb  ≈ 8 reps
 75%    73.4 kg   161.9 lb  ≈ 10 reps
 70%    68.5 kg   151.1 lb  ≈ 13 reps
 65%    63.6 kg   140.3 lb  ≈ 16 reps
 60%    58.7 kg   129.5 lb  ≈ 20 reps
Show the working
  1. Epley: 83.9 kg × (1 + 5 ÷ 30) = 97.9 kg
  2. Brzycki: 83.9 kg × 36 ÷ (37 − 5) = 94.4 kg

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Formula

Epley: 1RM = w × (1 + reps ÷ 30)Brzycki: 1RM = w × 36 ÷ (37 − reps)

How it works

Your one-rep max is the heaviest weight you can lift once with good form. Testing it directly is tiring and carries some injury risk, so most lifters estimate it from a heavier set of several reps instead. Many strength programs then prescribe training weights as a percentage of that number.

The Epley and Brzycki equations are the two most widely used estimators. They agree closely at around 10 reps and differ slightly below that, with Brzycki giving a more conservative figure at low rep counts. Both are most accurate when the set is taken close to failure with 2–10 reps.

The table shows roughly how many reps you could expect at each percentage of your estimated max — useful for picking working weights. Individuals vary: people with more slow-twitch muscle often manage more reps at a given percentage. Always lift with a spotter or safety bars when working near your limit.

Frequently asked questions

Which formula should I use?

Either is fine for programming. Epley is the default here; Brzycki is a little more conservative for low-rep sets. Track the same formula over time so changes reflect real progress.

Does this work for every lift?

It works best for compound barbell lifts like squat, bench press and deadlift. For small isolation exercises and machines the rep-to-max relationship is less consistent.

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