1. Enter a real set
Use a challenging, controlled set from the lift you want to estimate.
Epley + Brzycki strength estimate
Free One Rep Max Calculator
A one rep max calculator estimates the heaviest weight you could lift once from a completed set. Enter your lifted weight and reps to compare two common 1RM formulas and build a practical training-percentage table.
Strength estimate
Enter a completed set
Use a challenging set performed with consistent technique. Sets of 10 reps or fewer give the most practical estimate.
This calculator estimates capacity; it does not recommend attempting a maximum lift. Use safe technique, appropriate spotting, and qualified coaching.
Estimated one-rep max
258lb
Best estimate range: sets of 1-10 controlled reps.
Epley formula
262.5 lb
Brzycki formula
253 lb
Training percentage table
Rounded to the nearest 0.5 lb. Choose loads you can control with good form.
100%
258 lb
95%
245 lb
90%
232 lb
85%
219 lb
80%
206.5 lb
75%
193.5 lb
70%
180.5 lb
65%
167.5 lb
60%
154.5 lb
55%
142 lb
50%
129 lb
How the 1RM estimate works
2. Compare formulas
Epley and Brzycki respond differently as reps rise, so the calculator shows both.
3. Plan conservatively
Use the percentage table as a starting point and adjust for technique, fatigue, and experience.
One rep max calculator FAQ
What is a one rep max calculator?
A one rep max calculator estimates the heaviest weight you could lift once from a completed submaximal set. It applies established formulas to the weight and repetitions you enter.
Which 1RM formula does this calculator use?
It calculates both Epley and Brzycki estimates and averages them for a practical headline result. The two formula results remain visible so you can compare them.
How accurate is a one rep max estimate?
Accuracy varies by lift, technique, training experience, fatigue, and rep count. Estimates are usually more useful from hard, controlled sets of 10 repetitions or fewer.
Do I need to test a true one rep max?
No. A submaximal estimate can support training decisions without attempting a maximal lift. Choose conservative loads and prioritize safe technique and appropriate spotting.
Can I use kilograms or pounds?
Yes. Select pounds or kilograms before entering the set. The estimate and every training percentage stay in the selected unit.
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