Epley vs Brzycki Formula Comparison explains why the same set can produce two different one-rep-max estimates, where the equations meet, where they separate, and how to use that disagreement without pretending either estimate is a measured maximum.
Use a hard set with consistent technique. These equations estimate 1RM; they do not measure it directly.
At 5 reps, Epley reads higher than Brzycki.
Want one number for training? Use the full One Rep Max Calculator and keep the estimate in context.
The Epley vs Brzycki Formula Comparison is useful because both equations answer the same practical question with different mathematical assumptions: if you lifted a known weight for several hard repetitions, what single-repetition maximum might that performance imply?
Neither result is a direct strength test. A true one-repetition maximum is an actual successful single performed under specific conditions; an estimated 1RM is an extrapolation from a multi-rep set. Your technique, exercise selection, fatigue, rest, rep speed, proximity to failure, and individual endurance profile can all affect the relationship between a rep set and a true maximum. That is why a comparison is often more informative than a lone number.
The Epley vs Brzycki Formula Comparison also helps explain why two calculators may disagree even when both are functioning correctly. Epley increases the estimate in a linear way as reps rise. Brzycki uses a reciprocal relationship, so its curve behaves differently. For common lower-rep sets the difference is usually modest; as reps climb, the mathematical shapes matter more.
Both use the weight lifted and repetitions completed. The output stays in the same weight unit as the input.
1RM = weight × (1 + reps ÷ 30)
Every additional repetition adds one-thirtieth of the lifted weight to the multiplier. For 100 kg × 5 reps, the multiplier is 1.1667 and the estimate is about 116.7 kg.
1RM = weight × 36 ÷ (37 − reps)
The denominator shrinks as reps rise. For 100 kg × 5 reps, 36 ÷ 32 = 1.125, giving an estimate of 112.5 kg.
At 10 reps, Epley gives 1 + 10/30 = 4/3. Brzycki gives 36/(37 − 10) = 36/27 = 4/3. So both equations return the same estimate at exactly 10 reps.
The SEO title promises seven insights; these are the seven comparison points that matter most in actual use.
For rep counts from 2 through 9, the Epley estimate is greater than the Brzycki estimate for the same load. The gap is not a calculation error; it follows directly from the different multipliers built into the equations.
The Epley vs Brzycki Formula Comparison has a clean crossover at 10 reps. Both multipliers equal 1.3333, so a 75 kg set of 10 predicts 100 kg with either formula, before rounding.
At 11 and 12 reps, Brzycki overtakes Epley. This is where the reciprocal denominator starts to matter more. The live calculator still shows those values, but the widening gap should encourage caution rather than confidence.
When both equations land close together, you have two common models pointing to a similar region. That does not make the estimate a measured maximum, but it gives a more transparent range than presenting one formula as unquestionably correct.
The calculator shows a midpoint only as a descriptive reference between the two outputs. It is not presented as a research-derived prediction equation. Use it to visualize the center of the range, not as proof that the true 1RM sits there.
Rep endurance on a bench press, squat, deadlift, machine press, or isolation movement is not identical. The Epley vs Brzycki Formula Comparison should therefore be tracked exercise by exercise instead of using one lift to infer another.
If you monitor progress across training blocks, use the same equation, rep range, technique standard, and similar effort each time. Switching formulas can manufacture an apparent strength change even when the underlying performance is unchanged.
The table below fixes the lifted weight at 100 units, so the values also act as formula multipliers in percentage form. The Epley vs Brzycki Formula Comparison is easiest to understand when you can see the crossover rather than just read about it.
For example, at 5 reps the estimates are 116.7 and 112.5. At 8 reps they are much closer. At 10 reps they are identical. By 12 reps Brzycki has moved above Epley. This shape is why high-rep inputs should not be treated as if the equation choice were irrelevant.
For practical load planning after you estimate a maximum, use the Percentage of One-Rep Max Calculator rather than doing repeated percentage arithmetic by hand.
| Reps | Epley from 100 | Brzycki from 100 | Which is higher? |
|---|---|---|---|
| 2 | 106.7 | 102.9 | Epley |
| 3 | 110.0 | 105.9 | Epley |
| 5 | 116.7 | 112.5 | Epley |
| 8 | 126.7 | 124.1 | Epley |
| 10 | 133.3 | 133.3 | Equal |
| 11 | 136.7 | 138.5 | Brzycki |
| 12 | 140.0 | 144.0 | Brzycki |
Three calculations show how the same formulas behave at low, crossover, and slightly higher rep counts.
Epley is higher because this set is below the 10-rep crossover.
The Epley vs Brzycki Formula Comparison converges exactly at 10 reps.
Brzycki has moved higher; the high-rep estimate deserves more caution.
The most useful role for the Epley vs Brzycki Formula Comparison is not to declare a perfect max. It is to give you a reasonable strength-estimation range that can support load selection, progress tracking, and training decisions without requiring a maximal attempt every week.
Use a set performed with the same technique you normally train. A set stopped many reps before failure may understate your rep capacity, while a sloppy grinder may overstate what you can reproduce with good form. For consistent tracking, keep the exercise, range of motion, equipment, and effort standard as similar as practical.
A set of roughly 3–8 hard reps is often easier to interpret than a long endurance set because the equations stay relatively close and the performance is more strength-specific. Research comparing repetition-maximum prediction methods has also commonly emphasized lower rep counts; one 1997 analysis evaluated equations using 10 or fewer repetitions to fatigue.
If Epley says 116.7 kg and Brzycki says 112.5 kg, treat 112.5–116.7 kg as the formula-generated range rather than pretending 116.7 is automatically correct. If your program needs one training reference, choose a consistent method and keep using it. The One Rep Max Calculator can provide a broader calculation workflow, while the Strength Standards page can help place a number in context.
An estimated max is a planning anchor, not a command to load the bar to a percentage regardless of readiness. Use the Percentage of One-Rep Max Calculator for percentage targets, then adjust for the exercise, training phase, fatigue, and your actual repetition performance.
The Epley vs Brzycki Formula Comparison becomes more useful across time when the measurement process stays stable. If you compare a paused bench set this month with touch-and-go reps next month, the change may reflect technique rather than strength. Pair the estimates with a clear Progressive Overload Guide approach instead of chasing formula fluctuations.
A useful estimate does not mean every workout should be organized around a percentage of 1RM. Hypertrophy work, technique practice, speed work and recovery sessions can all use different loading decisions. The Epley vs Brzycki Formula Comparison is most valuable when it answers a specific question—such as whether a repeated 5-rep performance suggests progress—rather than becoming the only number that governs the entire program.
Prediction equations are useful because they simplify a real relationship. They are limited for the same reason.
A predicted maximum is not the same as a successful single. Day-to-day readiness, technique, psychological arousal, equipment and familiarity with heavy singles can all change the tested result.
The same athlete may have different repetition-to-maximum relationships on the squat, bench press, deadlift and machine exercises. Track each movement separately.
As repetitions rise, local endurance contributes more and formula curves diverge. Reynolds and colleagues reported that 5RM data predicted 1RM more accurately than 10RM or 20RM conditions in their sample.
If pain, unstable technique or unusual fatigue appears, a calculator should not override sensible training decisions. Use estimates to support programming, not to force a maximal effort.
The Epley vs Brzycki Formula Comparison should also be understood historically. Brzycki's 1993 article, Strength Testing—Predicting a One-Rep Max from Reps-to-Fatigue, is the source commonly associated with the Brzycki equation. A 1997 Journal of Strength and Conditioning Research paper compared seven prediction equations, including Epley and Brzycki, against achieved 1RM performance in bench press, squat and deadlift; the relationships were strong, but prediction error varied by lift and equation.
Later research continued to show that multiple-repetition testing can estimate maximum strength while also showing that accuracy depends on rep count and exercise. That supports a careful interpretation: the Epley vs Brzycki Formula Comparison is a practical estimation tool, not a universal physiological law.
Short answers to the practical questions that come up when the two formulas disagree.
There is no universal winner for every person and every lift. The Epley vs Brzycki Formula Comparison shows that the two equations are different models of the same relationship. For repeated tracking, consistency matters more than switching formulas whenever one gives the number you prefer.
Epley uses a linear multiplier: 1 + reps/30. Brzycki uses 36/(37 − reps). Between 2 and 9 reps, the Epley multiplier is mathematically larger, so the same weight and reps produce a higher estimate.
At 10 reps, Epley becomes 1 + 10/30 = 4/3, while Brzycki becomes 36/(37 − 10) = 36/27 = 4/3. The Epley vs Brzycki Formula Comparison therefore has an exact crossover at 10 reps.
Yes. Both formulas multiply the entered load by a unitless factor. If you enter pounds, the output is pounds; if you enter kilograms, the output is kilograms. The live calculator changes only the unit label, not the formula.
Longer sets become increasingly influenced by muscular endurance and the formula curves diverge more. This page keeps the Epley vs Brzycki Formula Comparison in a practical range and encourages lower-rep inputs for strength estimation rather than pretending high-rep extrapolation is precise.
You may use the midpoint as a descriptive reference, but it is not presented here as a validated third equation. A better habit is to record the two estimates, understand their range, and use one consistent method when tracking progress.
It can be useful as a planning reference when paired with sensible load selection and current readiness. It should not force you to attempt a maximal lift. Use the Percentage of One-Rep Max Calculator for target loads and adjust based on performance.
The arithmetic works for any load-and-rep input, but the prediction quality may vary by exercise and individual. Rep endurance on a bench press can differ from a squat or machine movement, so compare trends within the same exercise.
For a practical strength estimate, a hard lower-to-moderate rep set is generally easier to interpret than a long endurance set. This calculator allows 2–12 reps, while the discussion emphasizes that lower reps usually keep the two estimates closer.
Recalculate when you have a meaningful new performance under comparable conditions, not after every warm-up set. The Epley vs Brzycki Formula Comparison is most useful when it tracks a consistent exercise, technique and effort standard across time.
The equations can turn one hard set into a useful estimate, but your training log, technique, recovery and actual performance give that estimate meaning.
Educational strength-planning information only. Estimated 1RM values are predictions, not guaranteed maximal performance.