SYNCT tools
1 Rep Max Estimator
How do I estimate my one-rep max? Enter a recent set and this free calculator estimates your 1RM with Epley and Brzycki, then places it on ExRx strength standards for your bodyweight — untrained through elite, plus a world-record reference. No sign-up.
How to use the 1 rep max estimator
Enter weight and reps (up to 12), bodyweight, sex, and lift. We estimate your one-rep max with Epley and Brzycki, average them, and compare that number to ExRx.net absolute strength standards by bodyweight class (Kilgore), including a world-record line.
Use a hard but honest set — grinders inflate estimates. Treat the level (untrained through elite) as a classification guide, not a coaching programme. Log the same lifts in SYNCT and the app can keep estimated maxes up to date from every set you train.
Frequently asked questions
Epley (weight × (1 + reps/30)) and Brzycki (weight × 36 / (37 − reps)). We show both and the average. Reps are capped at 12 because estimates beyond that are unreliable.
ExRx.net weightlifting performance standards for ages 18–39, provided by Dr. Lon Kilgore, PhD. They are absolute 1RM targets by bodyweight class, not SYNCT user data. We interpolate between published classes for your exact bodyweight.
Bench press, squat, deadlift, overhead press, power clean, and power snatch — the lifts covered by the ExRx absolute tables.
No. Estimates only. If you test a true max, use a spotter and sensible loading.
Your 1RM for every lift, without the maths.
SYNCT works this out automatically from every set you log, estimated maxes for every exercise, how they’re trending, and exactly how far off your next PB you are.
