How it works
Enter a recent set of bench presses taken close to failure: the weight on the bar and the reps you completed. The calculator estimates the most you could press for a single rep, then works out training weights by percentage, the plates to load for each and your likely maxes for other rep counts.
The bench press is the lift most one-rep max research has used, so the equations behave best here. Sets of 3 to 6 reps taken close to failure give the tightest estimate.
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 bench 80 kg for 5 reps.
- Epley: 80 × (1 + 5 ÷ 30) = 93.3 kg.
- Brzycki: 80 × 36 ÷ (37 − 5) = 90 kg.
- The average of all seven equations is 92.4 kg.
- A working set at 80% is 73.9 kg, which rounds to 75 kg: 25 + 2.5 on each side of a 20 kg bar.
Getting a good bench press estimate
- Use a set where you had at most one or two reps left in the tank.
- Count only full reps: bar to the chest and locked out at the top.
- Estimate from the style you want to predict. Paused reps are harder than touch-and-go reps, so a touch-and-go set predicts a touch-and-go max.
- Grip width, arch and leg drive all change the numbers. Keep them the same as in the set you entered.
Questions
How accurate is a bench press 1RM estimate?
From a set of 3 to 6 reps close to failure, the seven equations usually agree within a few percent, and the range is shown under Equation spread. Above 10 reps they spread out quickly, so treat high-rep estimates as rough.
How often should I test my bench max?
Most training plans rarely test a true one-rep max and use estimates in between. Updating the estimate from a heavy set every few weeks is enough to keep training weights right.
What can I lift at 80% of my max?
The NSCA’s strength training textbook lists 80% of a one-rep max as roughly an 8-rep weight. That is why sets of 5 to 8 at 75 to 85% are a staple of strength programs. The rep max table shows your own estimates.
How do I read the plates column?
It lists the plates for one side of the bar, heaviest first. Load the same on the other side. With a 20 kg bar, 90 kg is 35 kg a side: 25 + 10.
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.