Enter the weight you lifted and how many reps you got. You get the estimated max and what to train with at every percentage.
Your one-rep max — the load you could lift exactly once — does not have to be attempted to be known. It is estimated from a set you already did. GiFit uses Epley: max = weight × (1 + reps ÷ 30). Brzycki (weight × 36 ÷ (37 − reps)) is shown for comparison: below 6 reps the two nearly agree, above that they drift apart.
Reps are capped at 12 even if you enter more, and that is deliberate: past that point the formula overstates strength, because a long set measures endurance more than a maximum. The app applies the same cap.
It stays an estimate. The real number moves with rest, technique, the lift and the day: use it to pick working loads, not to decide what to load on the bar without warming up.
Inside GiFit your max is recalculated after every set you log, lift by lift, and the coach uses it to propose the load for your next session. Works with no account and no connection.