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- Your one rep max (1RM) is the most weight you can lift once with good form.
- Estimate it from a lighter set: Epley 1RM = weight × (1 + reps ÷ 30); Brzycki 1RM = weight × 36 ÷ (37 − reps).
- A set of 185 lb for 5 reps gives an estimated 1RM of about 212 lb.
- Estimates are most reliable at 10 reps or fewer. Lift heavy only with good technique and safety in place.
How to use the one rep max calculator
Pick the exercise
Bench press, squat, deadlift, overhead press or another lift.
Enter the weight
The weight on the bar for your set, in pounds or kilograms.
Enter the reps
How many reps you completed with good form, ideally close to failure and 10 or fewer.
Read your 1RM
You get the Epley and Brzycki estimates, their average and training weights from 70% to 100% of your 1RM.
One rep max formulas
Estimating 1RM
Epley: 1RM = weight × (1 + reps ÷ 30)
Brzycki: 1RM = weight × 36 ÷ (37 − reps)
The two formulas agree exactly at 10 reps. Below 10 reps Brzycki is a little lower, and above 10 it is higher. Research has found Brzycki most valid for the bench press when the set is 10 reps or fewer.
1RM multipliers by reps
Multiply the weight you lifted by these factors (Epley / Brzycki).
- 2 reps 1.067 / 1.029
- 3 reps 1.100 / 1.059
- 4 reps 1.133 / 1.091
- 5 reps 1.167 / 1.125
- 6 reps 1.200 / 1.161
- 8 reps 1.267 / 1.241
- 10 reps 1.333 / 1.333
With 1 rep, the weight lifted is your 1RM.
How to calculate your one rep max
Do a hard set
After a warm-up, lift a weight you can manage for about 3 to 6 good reps.
Apply Epley
185 × (1 + 5 ÷ 30) = 215.8 lb.
Apply Brzycki
185 × 36 ÷ 32 = 208.1 lb.
Average them
(215.8 + 208.1) ÷ 2 = about 212 lb.
Worked examples
Bench press: 185 lb for 5 reps
A common working set.
- Epley 215.8 lb
- Brzycki 208.1 lb
- Estimated 1RM 212.0 lb
- 80% of 1RM 169.6 lb (about 8 reps)
Many programs use 70 to 85% of 1RM for strength sets.
Deadlift: 100 kg for 10 reps
A higher-rep set.
- Epley 133.3 kg
- Brzycki 133.3 kg
- Estimated 1RM 133.3 kg
At exactly 10 reps the two formulas match.
Percentage of 1RM chart
Training weights for a 212 lb 1RM
Percent of 1RM, weight and the approximate reps (Brzycki).
- 100% 212.0 lb (1 rep)
- 95% 201.4 lb (about 3 reps)
- 90% 190.8 lb (about 5 reps)
- 85% 180.2 lb (about 6 reps)
- 80% 169.6 lb (about 8 reps)
- 75% 159.0 lb (about 10 reps)
- 70% 148.4 lb (about 12 reps)
The calculator builds this chart for your own lift.
Is it safe to test a one rep max?
A true 1RM test is safe for most experienced lifters with good technique, a thorough warm-up and a spotter or safety bars, but it adds risk for beginners. Estimating from a set of 3 to 6 reps gives a useful number with less strain. If you have a heart condition, high blood pressure or an injury, ask a doctor before heavy lifting.
Where a one rep max calculator helps
Programming
Set training weights as percentages of your 1RM.
Tracking strength
See your estimated max rise without testing a true single.
Bench, squat, deadlift
Estimate your PR for the main lifts.
Safer testing
Use a heavy set of 3 to 6 reps instead of a max attempt.
Track body composition with the FFMI calculator and body fat calculator, and fuel training with the protein intake calculator. This is general information, not medical or coaching advice.
One rep max calculator FAQ
How do I calculate my one rep max?
Lift a weight for a hard set of 10 reps or fewer, then use Epley, weight × (1 + reps ÷ 30), or Brzycki, weight × 36 ÷ (37 − reps). The calculator shows both and their average.
Which 1RM formula is most accurate?
Both are estimates. They agree at 10 reps, and Brzycki has been found most valid for the bench press when the set is 10 reps or fewer. Fewer reps give a closer estimate.
How do I estimate my bench press max?
Bench a weight for 3 to 6 good reps, then enter the weight and reps. 185 lb for 5 reps gives about 212 lb.
Does it work for squat and deadlift?
Yes. The same formulas are used for most barbell lifts, though accuracy varies by lift and by person.
Why are high-rep estimates less accurate?
Endurance plays a bigger part as reps rise, so a set of 15 or 20 says less about maximal strength.
What percentage of 1RM should I train with?
Many programs use about 70 to 85% for strength work, and lighter loads for higher-rep muscle-building sets.