How accurate is the Brzycki formula?
Typically within 2-10% of actual 1RM when using 2-10 rep data.
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Bench Press 1RM Calculator
Calculate bench press 1rm with your details.
Personalized estimate
Use realistic inputs for the most useful results.
What this calculator does
One-rep max (1RM) is the maximum weight you can lift for a single rep. The Brzycki formula estimates 1RM from submaximal sets, allowing safe strength assessment without injury risk.
How it works
Brzycki uses weight lifted and reps completed. Most accurate with 2-10 reps at moderate-heavy weight.
Formula
1RM = Weight ÷ [1.0278 - (0.0278 × Reps)]. Example: 200 lbs × 5 reps ≈ 225 lbs 1RM.
Tips for using this calculator
- Use data from true muscular fatigue with good form
- 2-10 rep range gives best accuracy
- Test at 80-85% of calculated max first
- Retest every 4-6 weeks as strength improves
- Ratios vary between exercises
Frequently asked questions
Can I use this for other exercises?
Yes, it works for most barbell and dumbbell exercises.
Why estimate instead of testing actual 1RM?
Direct testing carries injury risk and requires significant recovery.