[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"content-seo:oneRepMax":3},{"description":4,"seo":5,"faq":8},"Giggleus's 1RM calculator estimates your one-rep max from a lighter set. Enter the weight in kg or lb and the reps you completed (1 to 20) for squat, bench press, deadlift or overhead press, and it averages two standard formulas: Epley, weight × (1 + reps ÷ 30), and Brzycki, weight × 36 ÷ (37 − reps). For example, 100 kg for 5 reps gives 116.7 kg (Epley) and 112.5 kg (Brzycki), so an estimated 1RM of about 114.6 kg.\n\nYou also get a %1RM chart from 60% to 100% with the approximate reps for each load, and a rough strength level from beginner to elite based on your 1RM as a multiple of bodyweight. Estimates are most reliable for sets of 10 reps or fewer. You don't need to test a true max to use it; if you do, warm up gradually and use a spotter or safety bars.",{"ogTitle":6,"ogDescription":7},"1RM Calculator: Estimate Your One-Rep Max - Giggleus","Enter the weight and reps from one set to estimate your squat, bench, deadlift or overhead press 1RM, with a %1RM chart and a strength level by bodyweight. Free.",[9,12,15,18],{"question":10,"answer":11},"How do you calculate a one-rep max?","This calculator averages two formulas: Epley, weight × (1 + reps ÷ 30), and Brzycki, weight × 36 ÷ (37 − reps). For 100 kg × 5 reps that gives about 114.6 kg.",{"question":13,"answer":14},"How accurate is an estimated 1RM?","It is most reliable for sets of 10 reps or fewer; above that the two formulas drift apart and error grows. A single rep entered as 1 is treated as your actual 1RM.",{"question":16,"answer":17},"What weight should I use for a given number of reps?","The %1RM chart lists loads from 60% to 100% of your estimate with approximate reps, for example about 8 reps at 80% and about 5 to 6 at 85%. Individual results vary.",{"question":19,"answer":20},"Is it safe to test my real 1RM?","It carries injury risk, which is why estimating from a lighter set is popular. If you test it, warm up with gradually heavier sets and use a spotter or safety bars; beginners and anyone injured should skip max attempts."]