حاسبة 1RM

1RM calculators are most accurate when using 3-6 reps at a heavy weight. Accuracy decreases significantly above 10 reps. The Brzycki formula tends to be most accurate for low reps (1-6), while the Epley formula works better for moderate reps (6-10). For best results, test with a weight you can lift for 3-5 reps with proper form.

Only attempt a true 1RM if you have experience with heavy lifting, proper form, and a trained spotter. For most training purposes, using calculated percentages of your estimated 1RM is safer and equally effective for programming. Many successful strength programs never require true maximal attempts.

Recalculate your estimated 1RM every 4-8 weeks as you progress. This aligns with typical training cycles and ensures your working weights stay appropriately challenging. You can simply input your latest heavy set into the calculator rather than attempting a true 1RM test.

For maximum strength, train at 85-95% of 1RM for 1-5 reps. For strength and size, use 75-85% for 5-8 reps. For hypertrophy (muscle growth), use 65-75% for 8-12 reps. For muscular endurance, use 50-65% for 12-20 reps. Most people benefit from varying percentages across their training week.

Each formula was developed from different research populations and methodologies. The Epley, Brzycki, and Lander formulas all make slightly different mathematical assumptions about the relationship between weight and reps. The differences are usually small (within 5%) and all provide useful estimates for training purposes.