One Rep Max Calculator
Enter any set you have already done. Get your estimated max and the exact loads to train at, without risking a true max attempt.
Use a hard set you took close to failure. Sets of 3 to 8 give the tightest estimate.
Fill in the fields above and your number appears here instantly.
What your numbers mean
Your estimated max
The load you could move once with clean technique today. It is a programming anchor, not a target to chase every week.
The percentage table
This is where the number becomes useful. Strength blocks live at 80 to 92 percent, growth work at 65 to 80. Pull your working weights straight off this table.
When to recalculate
Every four to six weeks, or any time a working set moves faster than it should. Strength drifts up quietly, and stale percentages leave gains on the floor.
How to adjust after two weeks
- 1Weigh in the same way every morningAfter the bathroom, before food or water, same clothing. One day means nothing. The seven day average is the number you read.
- 2Compare week two's average to week one'sLosing fat: you want a half pound to one percent of bodyweight down per week. Building: a quarter to half pound up. Holding steady inside those ranges means the numbers are right, so leave them alone.
- 3Move calories, not everything at onceOff target for two straight weeks? Change calories by roughly 150 to 200 and hold protein exactly where it is. Protein is what protects the muscle you already built.
- 4Recheck the calculator when your weight moves 10 lbA lighter or heavier body burns a different amount. Ten pounds in either direction is the trigger to run these numbers again.
Numbers are the easy part.
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Start my free 7 day kickstartCommon questions
How do you calculate your one rep max?
Take a weight you can lift for a known number of reps, then run it through a validated formula. This calculator averages Epley, Brzycki, and Lombardi, because averaging the three tracks real lifters better than any single equation. Use a set of 3 to 8 reps for the most accurate estimate.
How accurate is a 1RM calculator?
Very close inside 8 reps, and it drifts the further out you go. A set of 5 will estimate within a few percent. A set of 20 tells you more about your conditioning than your strength, so the estimate loosens.
Should I actually test a true one rep max?
Rarely. A max attempt costs recovery and carries injury risk, and the estimate from a hard set of 3 to 5 gives you the same programming information. Test true maxes at the end of a strength block, not on a random Tuesday.
What percentage of my max should I train at?
Strength work lives at 80 to 92 percent for 1 to 5 reps. Hypertrophy sits at 65 to 80 percent for 6 to 12. Technique and speed work stays at 50 to 65 percent. The table under your result gives you the exact loads.
Does the formula work for every lift?
Best on squat, bench, deadlift, and overhead press. On small isolation movements like curls or lateral raises the estimate is far less reliable, and there is no reason to max those out anyway.