Free tools
The same calculators the Liftrung app uses. They run in your browser and nothing you type is stored or sent anywhere.
One-rep max calculator
Enter a set you did. Get an estimate of the most you could lift once.
How it works
Liftrung uses the Epley formula, weight × (1 + reps ÷ 30), and averages it with the Brzycki formula, weight × 36 ÷ (37 − reps), for sets of 6 to 10 reps. Above 12 reps, every formula gets unreliable, so the estimate stops at 12 reps and is marked approximate.
Plate calculator
Enter the total you want on the bar. See the plates for each side.
How it works
It assumes a standard set of plates: 25, 20, 15, 10, 5, 2.5 and 1.25 kg, or 45, 35, 25, 10, 5 and 2.5 lb, up to four of each per side. If the exact total can’t be loaded, it shows the nearest one that can.