How it works
Enter a recent set of squats to depth, taken close to failure. The calculator estimates your one-rep max, then works out training weights by percentage, the plates for each and your likely maxes for other rep counts.
Squat estimates are most reliable from sets of 3 to 6 reps. Longer sets often end because of breathing and fatigue rather than leg strength, which makes estimates from them less dependable.
The formula
w = weight lifted, r = reps completed
Epley 1RM = w × (1 + r ÷ 30)
Brzycki 1RM = w × 36 ÷ (37 − r)
Average the mean of 7 published equations: Epley, Brzycki,
Lander, Lombardi, Mayhew, O'Conner and Wathen
With 1 rep, the one-rep max is the weight lifted.Worked example
You squat 100 kg for 5 reps.
- Epley: 100 × (1 + 5 ÷ 30) = 116.7 kg.
- Brzycki: 100 × 36 ÷ (37 − 5) = 112.5 kg.
- The average of all seven equations is 115.5 kg.
- A working set at 80% is 92.4 kg, which rounds to 92.5 kg: 25 + 10 + 1.25 on each side of a 20 kg bar.
Depth, bar position and equipment
An estimate only carries over to the same kind of squat. Keep these the same as in the set you entered:
- Depth. For a competition-style estimate, the hip crease should drop below the top of the knee. Partial reps inflate the result.
- Bar position. Most lifters squat more with a low bar than a high bar.
- Equipment. A set done with a belt and knee sleeves predicts a belted max.
Questions
Should I use a belted or beltless set?
Either, as long as you compare like with like. A belted set predicts your belted max, and a beltless set predicts your beltless max.
How deep does a rep need to be to count?
For an estimate that would hold up in a powerlifting meet, the hip crease must pass below the top of the knee. Stopping higher lets you use more weight and gives a flattering number.
How accurate is a squat 1RM estimate?
From 3 to 6 reps close to failure, the equations usually agree within a few percent, shown as the Equation spread. From 10 or more reps, treat the estimate as rough.
How do I use the rep max table?
It estimates the heaviest weight you could squat for each rep count, from the same set. Programs that prescribe, for example, a heavy triple or a 5-rep max can use these as starting points.
Add this calculator to your site
Gym, coach or blog? You can put this calculator on your own site for free. Copy the code below into your page’s HTML. The calculator updates itself whenever we improve it.
The short script lets the frame grow to fit the calculator on your page. Please keep the credit line underneath it.
Sources
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation and Dance. 1993;64(1):88-90.
- Mayhew JL, Ball TE, Arnold MD, Bowen JC. Relative muscular endurance performance as a predictor of bench press strength in college men and women. Journal of Applied Sport Science Research. 1992;6(4):200-206.
- LeSuer DA, McCormick JH, Mayhew JL, Wasserstein RL, Arnold MD. The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift. Journal of Strength and Conditioning Research. 1997;11(4):211-213.
- Haff GG, Triplett NT, eds. Essentials of Strength Training and Conditioning. 4th ed. Human Kinetics; 2016. Percentage of 1RM and repetitions allowed.