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Estimate 1RM from weight & reps using Epley & Brzycki formulas
This calculator estimates your one-rep max (1RM) โ the heaviest weight you could lift for a single repetition โ without having to attempt a risky all-out effort. Enter the weight you used and how many reps you completed, and the Epley and Brzycki formulas instantly give you a reliable estimate. Use it to set training zones, track strength progress, and program your lifts more effectively.
Lifting 100 kg for 5 reps means an estimated max of about 114.6 kg. The table below covers 40 to 160 kg and 1 to 12 reps.
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| Weight \ Reps | 1 | 2 | 3 | 4 | 5 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|---|---|
| 40 kg | 40.0 | 41.9 | 43.2 | 44.5 | 45.8 | 47.2 | 50.2 | 53.3 | 56.8 |
| 50 kg | 50.0 | 52.4 | 54.0 | 55.6 | 57.3 | 59.0 | 62.7 | 66.7 | 71.0 |
| 60 kg | 60.0 | 62.9 | 64.8 | 66.7 | 68.8 | 70.8 | 75.2 | 80.0 | 85.2 |
| 70 kg | 70.0 | 73.3 | 75.6 | 77.8 | 80.2 | 82.6 | 87.8 | 93.3 | 99.4 |
| 80 kg | 80.0 | 83.8 | 86.4 | 89.0 | 91.7 | 94.5 | 100.3 | 106.7 | 113.6 |
| 90 kg | 90.0 | 94.3 | 97.1 | 100.1 | 103.1 | 106.3 | 112.9 | 120.0 | 127.8 |
| 100 kg | 100.0 | 104.8 | 107.9 | 111.2 | 114.6 | 118.1 | 125.4 | 133.3 | 142.0 |
| 120 kg | 120.0 | 125.7 | 129.5 | 133.5 | 137.5 | 141.7 | 150.5 | 160.0 | 170.4 |
| 140 kg | 140.0 | 146.7 | 151.1 | 155.7 | 160.4 | 165.3 | 175.6 | 186.7 | 198.8 |
| 160 kg | 160.0 | 167.6 | 172.7 | 177.9 | 183.3 | 188.9 | 200.6 | 213.3 | 227.2 |
Enter the weight in kilograms and the rep count into the calculator above. It converts the set into an estimated single with two formulas, Epley and Brzycki, and shows their average: 100 kg for 5 reps gives 117 kg and 113 kg, so about 115 kg. Treat the output as an estimate rather than a fixed number.
Enter the weight and the rep count into the calculator above โ the formulas convert a multi-rep set into an estimated single. Different formulas (Epley, Brzycki, Lombardi) give slightly different results, so treat the output as a range rather than a fixed number.
Roughly a set of ten reps for most trained lifters, though the exact figure depends on the exercise and your muscular endurance. Percentage-to-rep tables are averages, so some lifters hit more reps at that load and some fewer.
It's your estimated one-rep max multiplied by zero point eight, which is a common working load for strength sets of about eight reps or fewer. Calculate your 1RM first, then apply the percentage to get the training weight.
It's uncommon among general gym-goers but fairly routine for men who have trained the bench press seriously for a few years. Bodyweight matters a lot: the same load is a much stronger effort for a lighter lifter.
Most lifters manage around five reps at that intensity before form breaks down. Endurance, exercise choice and training history shift this up or down, so use it as a starting estimate and adjust from your own sets.
Whether you're a seasoned powerlifter or just getting serious about strength training, knowing your one rep max (1RM) is essential. Our free 1RM Calculator helps you estimate the maximum weight you can lift for a single repetition โ without the risk of actually maxing out every session.
Your one rep max is the heaviest weight you can lift for exactly one complete repetition with proper form. It's the gold standard for measuring raw strength in exercises like the squat, bench press, deadlift, and overhead press. Coaches and athletes use 1RM values to structure training programs, set progressive overload targets, and track long-term progress.
Testing your true 1RM in the gym carries injury risk, especially without a spotter or when you're fatigued. That's why using a 1RM calculator based on submaximal lifts is a safer and highly practical alternative.
Our calculator uses well-established strength estimation formulas to predict your one rep max from a weight you've already lifted for multiple reps. Simply enter:
The calculator then applies two proven formulas, Epley and Brzycki, shows both results and uses their average, rounded to whole kilograms (or pounds), as your estimated 1RM. For 100 kg ร 5 reps that is 117 kg (Epley), 113 kg (Brzycki) and 115 kg on average. A table below lists 100% down to 65% of that value in 5% steps, each with a typical rep count.
One of the most widely used equations in strength sports: 1RM = Weight ร (1 + Reps / 30). It works best for moderate rep ranges (around 3โ10 reps) and slightly overestimates for very high rep sets.
A favorite among powerlifters: 1RM = Weight ร (36 / (37 โ Reps)). This formula is considered very accurate for rep ranges between 2 and 10 and tends to be more conservative than Epley.
Further estimation formulas exist, for example by Lander or O'Conner. This calculator does not use them; its result is the average of Epley and Brzycki.
Once you know your 1RM, you can structure every workout around training percentages. This method, used by elite coaches worldwide, ensures you're training at the right intensity for your goals:
The calculator's table covers 65% to 100% of your estimated 1RM in 5% steps, so you can plan the heavier zones without doing the math yourself; lighter percentages you work out from the 1RM.
This tool is valuable for anyone involved in resistance training, including:
For the best results with your 1RM calculation, keep these tips in mind:
1RM calculators provide a reliable estimate rather than a guaranteed exact number. Accuracy depends on your rep range, fatigue levels, and individual physiology. Most formulas are within 5โ10% of your true max when used correctly with moderate rep ranges.
Research consistently shows that 3 to 6 repetitions yield the most accurate 1RM predictions. As rep count increases beyond 10, accuracy decreases because fatigue becomes a bigger factor than pure strength.
Yes โ the 1RM formula applies to any barbell or dumbbell exercise, including squats, bench presses, deadlifts, rows, and overhead presses. Keep in mind that isolation exercises like curls tend to have more variability, so results may be less precise.
If you're following a consistent training program, recalculating every 4 to 8 weeks is a good practice. This aligns with typical mesocycle lengths and gives your strength enough time to meaningfully progress between measurements.
Testing your actual 1RM can be motivating and gives you a definitive number, but it should only be done when you're well-rested, properly warmed up, and have an experienced spotter. For most recreational lifters, calculator estimates are more than sufficient for programming purposes.