Calculate your one rep max (1RM) for any exercise. Estimate your maximum strength based on the weight you can lift for multiple reps. Useful for tracking progress and planning training.
Your one rep max is the maximum weight you can lift for a single repetition of a given exercise. It's a measure of maximum strength and is used to calculate training weights and track progress over time.
This calculator uses the Epley formula: 1RM = Weight × (1 + Reps ÷ 30). The formula is most accurate for reps between 4-10. For best accuracy, test with a weight you can lift for 5-8 reps with good form.
Never attempt a true 1RM test without proper warm-up, spotters, and experience with the movement. For most people, estimating 1RM from submaximal lifts (like this calculator does) is safer and just as useful for programming training.
1RM formulas provide reasonable estimates but have limitations. The Epley formula is most accurate for 4-8 reps; accuracy decreases significantly above 10 reps or below 3 reps. Individual variation matters enormously: some lifters excel at high-rep sets (better muscular endurance) whilst others are strong for low reps (better neuromuscular efficiency and power). The formula doesn't account for training history, fiber type distribution, or technique proficiency. A powerlifter who trains singles regularly will have a true 1RM closer to their calculated estimate than a bodybuilder who rarely lifts below 8 reps. Compound movements (squat, bench, deadlift) generally estimate better than isolation exercises (bicep curl, tricep extension) because isolation exercises involve more metabolic fatigue relative to maximal strength. The formula assumes perfect form throughout the rep range; if your form breaks down significantly after rep 5, your estimated 1RM will be inflated. For practical training purposes, being within 5-10% of true 1RM is sufficient for programming — you don't need exact numbers to make progress. Test your estimated 1RM periodically by attempting lifts in the 90-95% range with a spotter to verify accuracy. If your estimated 1RM is 100kg but you struggle with 90kg for a single, the estimate is likely too high.
Training directly at 1RM is counterproductive and risky. Maximal lifts create enormous neuromuscular fatigue, joint stress, and injury risk whilst providing minimal hypertrophy stimulus. Elite powerlifters attempting true 1RM lifts do so only at competitions, not in regular training. Instead, use your 1RM to calculate training percentages. For strength gains, work at 80-90% of 1RM for sets of 3-6 reps. For muscle growth (hypertrophy), train at 70-80% of 1RM for sets of 6-12 reps. For muscular endurance, use 60-70% of 1RM for sets of 12-20 reps. Periodization involves cycling through these ranges: spend 4-6 weeks at higher reps (70-75% of 1RM), then 4-6 weeks at moderate reps (80-85%), then 2-4 weeks at lower reps (85-90%), followed by a deload week at 60-70% before testing a new 1RM. This approach allows for progressive overload, adequate recovery, and reduced injury risk compared to constantly grinding near-maximal weights. Programs like 5/3/1, Texas Method, and GZCL use 1RM percentages to autoregulate training intensity across training cycles. As you get stronger, your 1RM increases, automatically increasing the absolute weight used at each percentage, ensuring continued progress without guesswork.
Beginner lifters (first 6-12 months training) can increase 1RM rapidly through neural adaptations and learning proper technique — adding 2.5-5kg monthly on major lifts like squat and deadlift, 1-2.5kg monthly on bench press and overhead press. Intermediate lifters (1-3 years training) see slower progress: 1-2kg monthly on lower body lifts, 0.5-1kg monthly on upper body. Advanced lifters (3+ years) might add 5kg annually to their squat/deadlift, 2.5kg to bench — progress is measured in kilograms per year, not per month. Factors affecting progress include genetics (muscle fiber types, limb lengths, insertion points), age (younger lifters progress faster), nutrition (surplus calories and adequate protein support strength gains), sleep quality (recovery happens during sleep), training consistency (missing workouts derails progress), and program quality (structured progression beats random training). Diminishing returns are inevitable: going from 60kg to 100kg bench press takes less time than going from 100kg to 140kg despite both being 40kg improvements. Unrealistic expectations lead to frustration and program-hopping. Focus on adding small increments consistently over years rather than chasing dramatic monthly jumps. A 2.5kg addition seems trivial but compounds to 30kg annually. Very few natural lifters reach elite standards (200kg+ squat, 150kg+ bench, 250kg+ deadlift for men) regardless of training, highlighting genetic limits.
Estimated 1RM = 80 × (1 + 6÷30) = 80 × 1.2 = 96kg. Training percentages: 90% = 86.4kg for 2-3 reps (strength), 80% = 76.8kg for 4-6 reps (strength-hypertrophy), 70% = 67.2kg for 8-12 reps (hypertrophy). Program week 1 might be 5 sets × 5 reps at 77kg, progressing to 80kg in week 4 before testing new 1RM.
Estimated 1RM = 120 × (1 + 3÷30) = 120 × 1.1 = 132kg. Less accurate than 5-8 rep ranges, so treat as rough estimate. If attempting 90% for testing (118.8kg), successfully completing 2-3 reps validates the estimate. If struggling with even 1 rep, the true 1RM may be closer to 125kg. Adjust training weights accordingly based on performance.
This is your actual 1RM, not an estimate. Use directly for programming: 90% = 126kg, 85% = 119kg, 80% = 112kg, 75% = 105kg, 70% = 98kg. A typical progression might be Week 1-4: 5×5 at 105kg, Week 5-8: 5×3 at 119kg, Week 9-11: 3×2 at 126kg, Week 12: retest 1RM expecting 145-147.5kg if training went well.
Retest your estimated 1RM every 8-12 weeks to ensure training percentages remain accurate as you get stronger. Don't test true 1RM more than 2-3 times yearly to avoid excessive fatigue and injury risk. Warm up properly before any heavy lifting: general cardio, dynamic stretching, then specific warm-up sets at 50%, 70%, and 85% of working weight. For example, if working sets are at 100kg, warm up with bar, 50kg, 70kg, 85kg before your first work set. Always use a spotter for barbell movements where you could be pinned (bench press, squat). Learn to fail safely: know how to dump the bar on squats, don't use collars when benching alone so you can tip plates off if stuck. Prioritize form over numbers — adding weight with deteriorating technique increases injury risk without equivalent strength gains. Track every workout recording weight, reps, and how the set felt (RPE - Rate of Perceived Exertion) to monitor progress objectively. Strength isn't linear — expect fluctuations day-to-day based on sleep, nutrition, and stress. A bad session doesn't mean you're weaker; you might PR the following week. Implement deload weeks (reducing volume and intensity by 40-50%) every 4-8 weeks to allow for recovery and supercompensation. Eat in a slight calorie surplus with adequate protein (1.6-2.2g per kg bodyweight) to support strength gains. Sleep 7-9 hours nightly as recovery and hormonal optimization occur during sleep. Finally, be patient: building serious strength takes years of consistent training, not months. Focus on adding small increments regularly, trust the process, and celebrate progress however modest rather than comparing yourself to others with different genetics, training history, and potential performance-enhancing substance use.