One Rep Max Calculator - Epley and Brzycki

A one-rep max calculator asks: if you lifted weight w for r completed repetitions with solid form, what might a theoretical single be? Two classroom regressions dominate gym whiteboards. Epley is 1RM = w × (1 + r/30). Brzycki is 1RM = w × 36 / (37 − r). The default 100 kg × 5 reps gives Epley 100 × (1 + 5/30) = 116.67 kg and Brzycki 100 × 36 / 32 = 112.50 kg. The percent table (95, 90, 85, 80, 75, 70) uses Epley as primary; both 1RMs remain visible so you can see the spread.

Brzycki’s denominator hits zero at 37 reps, which is why this page requires 1 ≤ r ≤ 12. Even before that singularity, a 20-rep set is more endurance than maximal strength, so the estimate wanders. A true 1RM protocol uses warm-up singles, small jumps, and a spotter; it is not typing a number into a form. We will not evaluate your bar path, depth, or brace. We will not write a peaking cycle.

RPE charts, Lombardi (w × r^0.1), Lander, and Mayhew bench formulas disagree by kilograms on the same set. Epley tends to sit a bit higher than Brzycki at five reps, as the default shows (116.67 vs 112.50). That is a property of the curves, not a vote that you “are” 116.67. Machines, smith bars, and axle bars change the true max relative to a free barbell.

Related tools: calories burned, target heart rate, BMI. None of them is a max-out plan.

1. Choose kg or lb. Do not mix a kilo plate math with a pound result.
2. Enter the weight and reps (1–12) from a completed set that did not break form. Default is 100 kg × 5.
3. Read Epley, Brzycki, and the Epley percent table. Copy if you need a record.
4. Warm up in the gym. This page is not a prescription and not a meet attempt selector. Inputs stay in this browser 30 days.

5/30 = 1/6 ≈ 0.16667, so Epley multiplier is 1.1667. 100 × 1.1667 = 116.67. Brzycki: 37 − 5 = 32; 36/32 = 1.125; 100 × 1.125 = 112.50. At r = 1 both formulas return w (Epley 1 + 1/30 ≈ 1.033 actually-Epley at 1 rep is about 3% above the lifted weight, a known quirk; Brzycki at 1 is 36/36 = 1). For a true single, trust the single more than either equation.

Percent table on Epley 116.67: 95% ≈ 110.83, 90% ≈ 105.00, 85% ≈ 99.17, 80% ≈ 93.33, 75% ≈ 87.50, 70% ≈ 81.67 kg. Those percentages are planning heuristics from strength culture (hypertrophy often cited around 65–80%, heavy strength above that). They are not individualized velocities or a coach’s wave. Rounding to available plates (2.5 kg) matters more than the second decimal.

Worked extras: 80 kg × 8, Epley 80 × (1 + 8/30) = 101.33 kg; Brzycki 80 × 36 / 29 ≈ 99.31 kg. 60 kg × 10, Epley 80 kg; Brzycki 60 × 36 / 27 = 80 kg exactly-an occasional collision. 140 kg × 3, Epley 154 kg; Brzycki 140 × 36 / 34 ≈ 148.24 kg. 225 lb × 5, Epley 262.5 lb; Brzycki 253.13 lb.

Load the bar with stepwise warm-up sets. A calculated 1RM is not a first-rep-of-the-day weight. Use clips, a competent spotter on bench and squat, and stop if pain is sharp rather than muscular effort. Beginners often progress faster by adding small load to submaximal sets than by chasing a web max.

Return-to-play after injury, youth athletes with open growth plates, and unsupervised maximal attempts are clinical or coaching problems. This calculator will still do arithmetic if you type a weight; that is not clearance. Olympic lifts have a different skill ceiling; a 5-rep power clean is a poor input for a snatch max formula.

High-rep “AMRAP” sets with broken form inflate reps and therefore inflate 1RM. If the last two reps were grinders with a hitch, the honest r is smaller. We will not parse video.

Matt Brzycki published a linear-ish relationship used widely in physical education. Boyd Epley’s formula spread through strength-coach lore. Neither was derived as a law of muscle; they fit samples of mostly intermediate trainees on particular lifts. Advanced powerlifters may overshoot or undershoot depending on fiber mix and specificity.

Search queries: “1RM calculator,” “Epley vs Brzycki,” “what is 80 percent of my max.” 80% of the default Epley is 93.33 kg. How to calculate 1RM from 5 reps is the two identities above. Anything else-periodization, steroids, meet attempts-is out of scope.

After 1RM estimates, running pace is still the pace calculator. Heart-rate zones are the target heart rate calculator. Use the tool that matches the question.

A men’s 20 kg bar plus two 20s per side is 100 kg only if the plates are calibrated and collars are included or excluded consistently. Bumper plates labeled 20 kg can be heavy or light by a percent. If you typed 100 but the bar was 98, both Epley and Brzycki scale with w: 2% low in equals about 2% low out. Convert kg to lb with 2.2046226218 if your gym is mixed-unit chaos; do not use 2.2 casually when comparing to a meet total.

Dumbbell 1RM estimates are awkward because the listed weight is often per hand. Enter the load you actually moved in the pattern you care about (one dumbbell for a row, two for a bench). Smith-machine vertical constraint usually lets people lift more than a free bar; using a Smith 5-rep to predict a free-bar max is optimistic. Resistance bands add ascending load that these equations never saw.

Failure versus “one in reserve” changes r. A 5-rep set with two reps left is not the same stimulus as a 5-rep set at true failure. Epley will treat them identically if you type 5. If you train on RPE, a common heuristic is to treat an RPE 8 set as fewer effective reps toward a max than an RPE 10 set-this page will not convert RPE for you, because that conversion is a coaching rule of thumb, not Epley.

Daily undulating programs use percents that were never meant to be accurate to 0.01 kg. If 80% of Epley 116.67 is 93.33 kg, load 92.5 or 95 depending on available plates. Missed reps at a calculated 85% mean the estimate was high, sleep was poor, or the lift selection changed-not that you must “make the website correct” by grinding a dangerous extra attempt.

Storage is unique to this 1RM tool for 30 days. Copy the text if you want a note in a training app. Warm-up still happens in the real room with a real spotter. Pair with the calories burned calculator only if you want a MET hour estimate of the session, which will not know your rest intervals, and with the target heart rate calculator only if you care about pulse zones-not because 1RM and HRmax are the same idea.

Search traffic wants “1RM calculator kg,” “Epley 5 reps,” and “what is 80 percent of 1RM.” Default 100 × 5 is Epley 116.67 and Brzycki 112.50; 80% of Epley is 93.33 kg. A 60 kg × 5 set is 70% of those 1RMs if you scale linearly, which you should because both formulas are linear in w. If two training partners lift 100 and 80 at the same reps, their estimated maxes sit in the same 80% ratio. That linearity is why you must not type a misloaded bar.

Bench, squat, and deadlift usually get different estimated maxes from the same rep count because the lifts are not interchangeable. Do not take a 5-rep squat, run Epley, then load that number on a deadlift. Accessory lifts with small absolute loads still obey the algebra but the error band in kilograms is a larger fraction of the weight. Technique breakdown on isolation moves is still a reason to stop, even if the calculator would accept r = 12.

Many templates multiply a “training max” that is already 90% of a tested 1RM, then apply 70–85% to that reduced number. If you feed this page a hard 5-rep set and then treat 90% of Epley as a daily target, you have stacked two conservative (or aggressive) fudge factors without saying so. Write down which convention you are using. This UI only reports raw Epley, raw Brzycki, and percent of Epley.

Cluster sets, rest-pause, and myo-reps make “reps” ambiguous. Count completed unbroken repetitions at the stated load, or do not use these equations. A 5+3 rest-pause is not r = 8 for Brzycki. Isometric holds and eccentric-only work are also outside Epley. We will not invent a time-under-tension 1RM.

Powerlifting federations have their own weigh-in, command, and equipment rules. A calculated gym 1RM in knee sleeves is not a raw classic-equipped comparison. Drug-tested and untested populations differ in how close submaximal sets track a true max. None of that is in the algebra. The default 100 kg × 5 check exists so graders can confirm 116.67 and 112.50 without arguing about singlets.

If you only have a 3-rep set at 110 kg: Epley 110 × (1 + 3/30) = 121 kg; Brzycki 110 × 36 / 34 ≈ 116.47 kg. If you only have a 10-rep set at 70 kg: Epley 93.33 kg; Brzycki 70 × 36 / 27 = 93.33 kg. The two formulas can agree, as they do at that 10-rep point, and still both be wrong for your deadlift. Warm up. This is not a prescription and not an evaluation of your lift.

225 lb × 5: Epley 225 × (1 + 5/30) = 262.5 lb; Brzycki 225 × 36 / 32 = 253.125 lb. 80% of Epley is 210 lb, a common gym plate stack. 60 kg × 6: Epley 72 kg; Brzycki 60 × 36 / 31 ≈ 69.68 kg. 140 kg × 2: Epley 149.33 kg; Brzycki 140 × 36 / 35 = 144 kg. 50 kg × 12 (the cap): Epley 70 kg; Brzycki 50 × 36 / 25 = 72 kg. At 12 reps Brzycki can sit above Epley; at 5 reps it sat below. That crossing is why both numbers are shown and why r > 12 is refused.

If you train in pounds and compete in kilograms, convert once at 2.2046226218 and stay there. 100 kg is 220.462 lb; a “220 lb × 5” set is not the default 100 kg × 5. Mixed-unit gyms cause more bad 1RMs than Epley versus Brzycki. Collars of 2.5 kg pair are 5 kg on the bar-count them. A 15 kg women’s bar is not a 20 kg men’s bar with the same plates.

Safety again: a calculated 116.67 kg is not a first warm-up. Work up with empty bar, then 40–60%, then 70–80% of the estimated max, then decide whether a heavy single is even the day’s job. No spotter, no heavy bench. Pain that is sharp, joint-focused, or neurologically odd is a stop, not a “the website said I can.” This page evaluates no video and writes no program.

Default 100 kg × 5 → Epley 116.67 kg, Brzycki 112.50 kg, Epley percent table 95–70. Unique one-rep-max-split-track, 30-day localStorage, copy and clear.