1 Rep Max Calculator (1RM)
Estimate your 1RM from any weight and rep count. The 1 rep max calculator runs the Epley, Brzycki, and Lander formulas in parallel and returns the average plus a full training percentage table.
How the 1 rep max calculator works
A 1 rep max calculator (also called a 1RM converter) estimates the heaviest weight you could lift for a single rep based on a submaximal set you have already completed. Instead of risking injury by attempting a true 1RM, you enter the weight you lifted and the number of reps you hit, and the formulas predict your ceiling. Use it to set training percentages, plan peaking blocks, or check your strength progress between meets.
The Epley formula for 1RM
The Epley formula is the most widely used 1 rep max equation. It scales linearly with rep count, which keeps the estimate conservative for high rep sets. The Epley formula for 1RM is:
1RM = w × (1 + r / 30)Where w is the weight you lifted and r is the number of reps you completed. Example: if you bench 100 kg for 5 reps, your Epley estimated 1RM is 100 × (1 + 5 / 30) = 116.7 kg.
The Brzycki formula
The Brzycki formula is more accurate in the 1 to 10 rep range and curves off sharply above 10 reps. It is the formula you want if your test set sits between a triple and a set of 8.
1RM = w × 36 / (37 - r)The Lander formula
The Lander formula is the third estimate this calculator runs. It sits between Epley and Brzycki across most rep ranges, which is why averaging all three gives the most reliable 1 rep max converter result.
1RM = (100 × w) / (101.3 - 2.67123 × r)1 rep max percentages and training table
Once you have a 1RM estimate, training percentages tell you how much weight to use for a given goal. The table below is the standard 1 rep max table used in powerlifting and strength programming.
| % of 1RM | Typical reps | Use case |
|---|---|---|
| 95% | 2 | Peak strength, meet openers |
| 90% | 3 to 4 | Heavy strength work |
| 85% | 5 to 6 | Pure strength block |
| 80% | 7 to 8 | Strength and hypertrophy mix |
| 75% | 9 to 10 | Hypertrophy main work |
| 70% | 11 to 12 | Volume hypertrophy |
| 60% | 16 to 20 | Endurance, conditioning |
| 50% | 25+ | Warmups, technique work |
How to calculate your one rep max
Your one rep max (1RM) is the maximum weight you can lift for a single repetition with proper form. This calculator uses three well known formulas: Epley, Brzycki, and Lander. Each formula takes the weight you lifted and the number of reps you performed, then estimates what you could lift for one rep. The average of all three formulas gives the most reliable estimate.
The percentage chart shows how much weight to use at various intensities. For example, 85% of your 1RM is typically a 5 to 6 rep range, ideal for strength training. Use 70 to 75% for hypertrophy work (8 to 12 reps). These percentages apply to any barbell or dumbbell lift, including bench press, squat, deadlift, overhead press, and rows.
1 rep max calculator by lift
1 rep max calculator for squat
Use this 1 rep max calculator for squat by entering a top set you recently completed: a heavy 3, 5, or 8 with full depth and a controlled tempo. The squat is the most accurate of the big three for the Epley formula because the rep speed stays consistent until the last rep. If your test set used a paused or tempo squat, the estimated 1RM is your competition style number, not your touch and go gym number.
1 rep max calculator for bench
For bench press, use the Brzycki estimate as your primary number when the test set is 1 to 8 reps and switch to Epley when reps climb above 8. Bench press has the largest gap between gym 1RM and paused competition 1RM (often 5 to 10 percent), so set your training percentages off a paused single if you compete in powerlifting.
1 rep max calculator for deadlift
The deadlift produces the noisiest 1 rep max estimates because grip, lower back, and central nervous system fatigue cap rep sets before true muscular failure. Use a 3 or 5 rep test for the cleanest deadlift 1RM estimate, and round the calculated number down by 5 to 10 pounds for programming. The Sumo Deadlift and conventional deadlift run on the same formulas, only the lift execution differs.