1RM Strength

One-rep-max (1RM) estimator from a sub-maximal set.

Formulas

• Brzycki: 1RM = w · 36 / (37 − r)
• Epley: 1RM = w · (1 + r/30)
• Lombardi:1RM = w · r^0.10

At exactly 1 rep the three formulas trivially agree, so the lifted weight is shown directly as the 1RM. The estimated range is the spread across the three formulas, not a confidence interval — beyond about 10 reps it widens quickly and the result is flagged as an extrapolation. Reps above 20 are rejected, since Brzycki's denominator (37 − r) approaches zero and the formula breaks down.

Also shows a percentage table (50–100 %) for programming sets. Switching kg/lb converts the entered weight instead of just relabeling it.