Question 1

What formulas does the 1RM calculator use?

Accepted Answer

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.

Question 2

Where do the strength standards come from?

Accepted Answer

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.

Question 3

Which lifts are supported?

Accepted Answer

Bench press, squat, deadlift, overhead press, power clean, and power snatch — the lifts covered by the ExRx absolute tables.

Question 4

Is this medical or coaching advice?

Accepted Answer

No. Estimates only. If you test a true max, use a spotter and sensible loading.

1 Rep Max Estimator

Your 1RM for every lift, without the maths.