Enter a set you lifted and get your estimated one rep max, how much you can lift for 2 to 12
reps, and the loads for every training percentage. Works for bench press, squat, deadlift,
overhead press and any other lift, in kilograms or pounds.
How to use your one rep max
Your one rep max (1RM) is the most weight you can lift once with good form. Most programs
prescribe loads as a percentage of it: 5 sets of 5 at 80 percent, a top single at 90 percent,
back-off sets at 70 percent. Knowing the number turns a program on paper into the plates on
the bar.
You rarely need to test it. A hard set of 3 to 6 reps, stopped one or two reps short of
failure, gives an estimate that is close enough to program from and updates every time you
train. Test a true max only for a meet or a milestone, with safeties set or a spotter.
Getting an honest estimate
- Use a set taken close to failure. An easy set of 5 underestimates your max.
- Only count reps with full range of motion: below parallel, chest touch, lockout.
- Prefer 3 to 6 reps. Above 10, every formula gets less reliable.
- Track the estimate over weeks, not one session: daily strength swings by 5 percent.
Track it automatically
SigmaGains works this out for every set you log. Each exercise shows your estimated max over
time, flags a new personal record the moment you hit it, and warns you when a lift has stalled
for several sessions so you know to change something before you waste a month.
Questions
How is one rep max calculated?
From a set you actually did: the weight and how many reps you got. This calculator uses the Brzycki formula (weight × 36 / (37 − reps)) for sets of 2 to 10 reps and the Epley formula (weight × (1 + reps / 30)) for 11 or 12, the same split the SigmaGains app uses for your estimated max.
How accurate is a 1RM calculator?
Within a few percent for most people when the set was hard and had 10 or fewer reps. Accuracy falls as reps rise, which is why the estimate stops at 12 reps. Lifters with lots of slow-twitch endurance will see the estimate run high, explosive lifters low.
Which rep range gives the best estimate?
Sets of 3 to 6 reps taken close to failure. They are heavy enough to reflect max strength and short enough that fatigue and technique break down less than in long sets.
Should I test my 1RM or estimate it?
Estimate it for programming. A true max test is tiring, needs spotters or safeties, and only tells you about one day. A hard set of 3 to 5 every week or two gives a number that moves with you and carries less risk.
What percentage of 1RM should I train at?
For strength, most work sits between 75 and 90 percent (roughly 3 to 8 reps). For muscle growth, anywhere from 60 to 85 percent works when sets end close to failure. The percentage table on this page turns your max into the loads for each.
Does this work for bench press, squat and deadlift?
Yes. The formulas are not lift specific, so enter any barbell, dumbbell or machine set. Deadlift estimates tend to run slightly high on long sets because grip and lower back fatigue first; use sets of 5 or fewer for it.