Strength calculators
Numbers for the training floor: what a set says about your max, what to load, and lean mass for your height.
FFMI calculator
Fat-free mass for your height, with the 1995 height adjustment labelled.
168 cm · 76 kg · 14% → 23.9Barbell plate calculator
Which plates go on each side, in kg or lb.
140 kg → 25 + 25 + 10 a sideRPE and RIR calculator
Estimated max from a set’s effort, and back-off sets.
100 kg × 5 @ RPE 8 → 123.3One-rep max calculator
Seven formulas side by side, and the spread.
100 kg × 5 → 112.5–119.0How these calculators work
Each one runs in your browser, shows the formula and its source, and works in kilograms or pounds. Results are estimates for planning training: a formula can’t know your technique or the day you are having.
Which one do I need?
- Planning a top set? Use the one-rep max calculator on a recent set of 2–10 reps, or the RPE calculator if you stopped short of failure.
- Loading the bar? The plate calculator lists the plates for each side, in kg or lb.
- Tracking lean mass? The FFMI calculator shows fat-free mass for your height, adjusted to 1.80 m.
Every page shows a worked example with the numbers filled in, so you can check the arithmetic yourself. The seven one-rep max formulas disagree by a few kilograms for the same set; we show the average and the spread rather than pick one silently.