What Is a One-Rep Max?
A one-rep max is the most weight you can lift once with solid form. Lifters use it as a strength benchmark for exercises like bench press, squat, deadlift, and overhead press.
How the 1RM Calculator Works
Enter weight and reps from one hard set. The calculator estimates your 1RM, rounds it to practical gym loading, and shows training percentages you can use for warm-ups, strength work, and volume.
Epley vs Brzycki
Epley and Brzycki are common one-rep max formulas. Epley is Bazu's default and often estimates a bit higher. Brzycki can be slightly more conservative, especially as reps climb.
Is an Estimated 1RM Accurate?
An estimated 1RM is useful for planning, but it is not a guarantee. Form, range of motion, rest, equipment, fatigue, and practice with heavy singles all affect your true max.
Best Rep Range for Estimating 1RM
For most lifters, 3-10 clean reps is the best range. Higher-rep sets can still be useful, but fatigue and conditioning make the estimate less precise.
How to Use Your 1RM in Training
Use percentages of your estimated 1RM to choose loads. Heavy singles and doubles often sit near 90-95%, working strength sets near 80-90%, and volume or technique work often below that.
Why Track 1RM Over Time?
Your estimated 1RM gives you a simple trend line for strength. If your estimated max rises across months, your training is moving in the right direction even when day-to-day sessions vary.
Track Your 1RM Automatically With Bazu
Bazu is a strength training tracker for iPhone and Apple Watch. Log your sets, track PRs, and see estimated 1RM progress without maintaining a spreadsheet.
Related reading
Go deeper on the training ideas behind this calculator.
How Bazu Calculates Personal Records
See how Bazu handles load PRs, rep PRs, bodyweight PRs, and estimated 1RM.
Read guideProgressive Overload 101
Learn when to add reps, increase weight, hold steady, or deload.
Read guideHow to Spot PRs and Training Trends Faster
Use weekly top sets and simple checkpoints to make progress easier to see.
Read guideBest Free Workout Tracker for Strength Training
See how Bazu tracks PRs, 1RM estimates, history, and training trends.
Read guideFAQ
What is a one-rep max?
A one-rep max, or 1RM, is the most weight you can lift for one complete rep with good form on an exercise.
How do I calculate my 1RM?
Enter the weight and reps from one hard set. The calculator applies a proven 1RM formula to estimate the heaviest single you could likely lift.
Which formula does Bazu use?
Bazu defaults to the Epley formula for this calculator and lets you compare it with the Brzycki formula.
What is the difference between Epley and Brzycki?
Epley tends to estimate slightly higher as reps increase. Brzycki is a common alternative that can be more conservative for many sets.
What rep range is best for estimating 1RM?
For most lifters, a challenging set of 3-10 clean reps gives a more useful estimate than very high-rep sets.
Is this the same as testing a true 1RM?
No. This is an estimate based on a submaximal set. A true 1RM test depends on skill, fatigue, warm-up, equipment, and safety setup.
Can beginners use this calculator?
Yes, but beginners should treat the result as a rough guide and prioritize clean technique over testing heavy singles.
Can I use this for bench, squat, and deadlift?
Yes. You can use the calculator for bench press, squat, deadlift, overhead press, and most weighted strength movements.
How does Bazu track 1RM automatically?
When you log workouts in Bazu, the app can estimate 1RM from your completed sets and show strength progress over time.
Is the calculator free?
Yes. The calculator is free, runs in your browser, and does not require a login.
Make the next number easier to beat.
Bazu tracks your workouts, PRs, estimated 1RM, history, and progressive overload targets so each session has a clear next step.
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