Smith Machine Bench Press Calculator
Estimate Smith machine bench press 1RM from your completed repetitions and load.
Exercise image: free Pexels photograph. See Sources for image credits.
Show the formula, not just the number
Smith machines vary in bar path, counterbalance and friction. Because of that equipment variation, this tool estimates from the actual Smith-machine set you enter and should not be treated as a direct barbell conversion.
For this site, the 1RM estimate is calculated from five established prediction equations: Epley, Brzycki, Lander, Lombardi and O’Conner. The page shows the individual estimates and their arithmetic mean.
Core equations:
- Epley: 1RM = weight × (1 + reps ÷ 30)
- Brzycki: 1RM = weight × 36 ÷ (37 − reps)
- Lander: 1RM = 100 × weight ÷ (101.3 − 2.67123 × reps)
- Lombardi: 1RM = weight × reps0.10
- O’Conner: 1RM = weight × (1 + 0.025 × reps)
Sources & methodology
- Brzycki, E. and related repetition-to-failure prediction work are represented in the published 1RM literature.
- LeSuer et al. (1997). Bench press research comparing prediction equations and repetition performance. PubMed record.
- Recent validation literature. Contemporary studies continue to compare 1RM prediction equations and report that accuracy varies by exercise, population and repetition range. PubMed example.
- NSCA. Bench press testing and performance context from the National Strength and Conditioning Association. NSCA education.
The equations are estimates, not direct measurements of a lifter’s verified maximum.
What the result can and cannot tell you
A repetition-based 1RM is an estimate. Research shows that prediction equations can be useful, but their accuracy is not identical across exercises, populations and repetition ranges. For this reason, the tool accepts 1–12 reps, shows several equations, and avoids presenting a single formula as universally correct.
Use a completed set that represents your normal technique. A set performed with unusual range of motion, assistance, momentum, a machine-specific setup or substantial fatigue can change the relationship between repetitions and maximal strength.
Continue with another bench press calculation
Smith Machine Bench Press Calculator FAQs
How does the smith machine bench press calculator work?
Enter the load you completed and the number of repetitions. The tool applies the documented calculation method and shows the resulting estimate.
Is the calculated 1RM exact?
No. It is a prediction from a submaximal set. A measured 1RM and a predicted 1RM are not the same thing.
Why are several formulas shown?
Different prediction equations can produce different estimates. Showing them makes the spread visible instead of hiding it behind one unexplained number.
What should I do if the result looks wrong?
Check the units, load, repetition count and exercise setup first. If the calculation still appears incorrect, use the Corrections page to report it.