Calculate your estimated 1RM from any weight and rep range
Your one rep max (1RM) is the most weight you can lift for a single repetition. Instead of testing your max, this calculator estimates it from submaximal sets using three proven formulas:
The result shown is the average of all three, giving a well-rounded estimate.
This tool estimates your one-repetition maximum, the heaviest single lift you could perform for a given exercise, without an actual max attempt. It uses three established formulas, Epley, Brzycki, and Lander, and averages them for a more stable result than any single formula alone. Knowing your estimated 1RM lets you program training loads as precise percentages of your strength, which is the backbone of most structured strength plans.
These formulas convert a submaximal set into a projected single. The Epley formula is one-rep max equals weight times (1 plus reps divided by 30). The Brzycki formula is weight divided by (1.0278 minus 0.0278 times reps), which is another way of scaling the load up as reps rise. Lander uses a similar structure with its own coefficients. All three share the same logic: the more reps you complete at a given weight, the higher your true single must be, so each formula inflates the lifted weight by an amount that grows with reps. Averaging the three smooths out the quirks of any one equation.
Suppose you bench press 100 kg / 220 lb for 5 reps. Using Epley, one-rep max equals 100 times (1 plus 5 divided by 30), which is 100 times 1.1667, giving about 117 kg / 257 lb. Using Brzycki, it is 100 divided by (1.0278 minus 0.0278 times 5), which is 100 divided by 0.8888, giving about 113 kg / 249 lb. Lander lands nearby. Averaging the three yields an estimated 1RM around 115 kg / 253 lb. From there, if you want to train at 80 percent, you would load about 92 kg / 203 lb.
Enter the weight you lifted, the number of reps you completed, and select your unit, pounds or kilograms. Press Calculate 1RM to see your estimated maximum. The page also displays a percentage table showing recommended weights across common rep ranges, which you can use directly to program your working sets for the weeks ahead.
This is an estimate built from a formula, not a tested maximum. Accuracy is highest with rep counts between 2 and 10, because very high-rep sets bring in endurance and fatigue, which the equations do not model well. Results also vary by exercise, technique, and how close to failure your set was. Do not use an estimate to justify loading a bar beyond what you can safely control. If you are new to training or returning from injury, work with a qualified coach.
How accurate is the estimate? Accuracy is highest with rep counts between 2 and 10. Sets beyond 12 reps introduce more variability because fatigue becomes a larger factor relative to raw strength.
Should I test my actual 1RM? Submaximal estimation is safer for most training. Reserve true max attempts for competition or structured testing under appropriate supervision.
Why average three formulas? Each formula was derived from different data and drifts in different directions. Averaging Epley, Brzycki, and Lander reduces the chance that one formula's bias skews your number.
Can I use this for any lift? It works best for compound barbell lifts like squat, bench, and deadlift. Isolation movements and machines can behave differently, so treat those estimates more loosely.