Estimate your one-rep max (1RM) from a set using Epley, Brzycki, or Lombardi – and derive appropriate training weights for 1 to 15 reps.
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Estimate 1RMCalculate one-rep max from a set
Performed Set
Weight, reps, and formula.
kg
The weight used in the set.
reps
Clean reps to exhaustion.
Load example
For illustration only – your own calculation is what counts.
Explanation
How 1RM Calculator works
The 1RM calculator estimates your one-rep max from a submaximal set and derives training weights for different rep counts. The basis is three established formulas from strength training research.
The Three Estimation Formulas
Epley1RM = Weight × (1 + Reps ÷ 30)
The most widely used approach; robust at low to medium rep counts.
Brzycki1RM = Weight × 36 ÷ (37 − Reps)
Only defined for fewer than 37 reps; provides different values at high reps.
Lombardi1RM = Weight × Reps ^ 0.10
Power approach that gives somewhat more conservative estimates at very high rep counts.
Practice
Practical examples
For illustration only – your own calculation is what counts.
1RM from 5 reps with 100 kg
Bench press succeeds five times cleanly with 100 kg; the calculated one-rep max is sought.
Result: According to Epley, estimated 1RM is around 116.7 kg. For 8 reps, about 92 kg would be appropriate.
Training weight for 5 reps
The 1RM for squats is 120 kg; the weight for clean 5 reps is sought.
Result: For 5 reps, around 102.9 kg result – about 86% of one-rep max.
Notes
Common mistakes
Estimating 1RM from very many reps
A set with 20 reps significantly overestimates max weight.
Use a heavy set with three to five clean reps as a basis.
Switching formulas between training sessions
Those who switch estimation formulas compare values that don't match.
Stick with one formula for progress tracking.
FAQ
Frequently asked questions
What is 1RM?
The one-rep max (1RM, one-rep max) is the highest weight you can handle for one rep cleanly and with full range of motion. It is the reference from which training weights for higher rep counts are derived.
Which formulas does the calculator use?
Three established estimation formulas are available: Epley (1RM = Weight × (1 + Reps ÷ 30)), Brzycki (1RM = Weight × 36 ÷ (37 − Reps)), and Lombardi (1RM = Weight × Reps to the power of 0.10). For a single rep, all provide the entered weight.
Which formula is best?
There is no generally best approach. Epley and Brzycki provide very similar values at low rep counts; Brzycki deviates more strongly from about ten reps and is only defined for fewer than 37 reps. For comparisons, stick with one formula.
How accurate is the estimate?
Most reliable are estimates from sets with about three to five reps. Above ten to twelve reps, deviations grow significantly because endurance and technique factors play a stronger role.
What do I need the percentage values for?
Training plans often state intensities as a percentage of 1RM, for example 5 sets of 5 reps at 85%. The calculator translates your 1RM into concrete weights for common rep counts.
Should I test my 1RM instead?
A true 1RM test is demanding and injury-prone. For most trainees, the calculated estimate from a submaximal set is safer. A real test, if at all, belongs only with warm-up, spotting, and experience.
Limits
Limitations
All values are estimates; actual maximum strength may vary.
Above ten to twelve reps, accuracy decreases noticeably.
Sources
Sources and references
Epley, B. (1985): Poundage ChartBoyd Epley Workout, Body Enterprises
Origin of the formula 1RM = Weight × (1 + Reps ÷ 30).
Retrieved: 09/23/2026 · Verified on: 09/23/2026
Brzycki, M. (1993): Strength Testing – Predicting a One-Rep Max from Reps-to-FatigueJOPERD 64(1):88–90
Documents the formula 1RM = Weight × 36 ÷ (37 − Reps).
Retrieved: 09/23/2026 · Verified on: 09/23/2026
Lombardi, V. P. (1989): Beginning Weight TrainingWm. C. Brown, Dubuque
Documents the power approach 1RM = Weight × Reps to the power of 0.10.
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