Calculator
Example data
These samples show typical outputs for different rep ranges.
| Units | Weight | Reps | Displacement (m) | Time/rep (s) | Estimated 1RM (avg) | Avg power (W) |
|---|---|---|---|---|---|---|
| kg | 80 | 5 | 0.45 | 2.0 | ~92 kg | ~177 W |
| kg | 60 | 10 | 0.40 | 2.2 | ~80 kg | ~107 W |
| lb | 185 | 3 | 0.45 | 1.8 | ~200 lb | ~210 W |
Values are approximate and depend on your selected settings.
Formula used
- Force: F = m · g
- Work per rep: W = F · d
- Total work: Wtotal = W · reps
- Average power: P = Wtotal / t
- 1RM estimates: Epley, Brzycki, Lander, Lombardi, Mayhew, and O'Conner formulas
- Working weights: w% = (percent/100) · 1RM, then rounded
- Plate plan: per-side load = (target − bar)/2, filled with common plates
This tool models the barbell's mechanical work against gravity.
How to use this calculator
- Select your preferred units.
- Enter the total weight you lifted on the bar.
- Enter the reps completed with good technique.
- Adjust displacement and time per rep if known.
- Set a rounding increment that matches your plates.
- Press Calculate to view results above the form.
- Download CSV or PDF for logs and coaching notes.
If reps exceed 15, treat 1RM values as rough guidance.
Bench press load analysis article
1) What this calculator measures
This tool links practical bench press planning with mechanical physics. It estimates one-rep max using several strength equations, then converts your set into force, work, and average power so you can compare sessions with consistent inputs.
2) Inputs that control the outcome
The lifted weight and repetitions drive the one-rep max estimates. Bar weight affects the plate plan, while displacement and time per rep shape work and power. Units can be kilograms or pounds, and the outputs are shown in your selected units.
3) Force on the barbell
The primary mechanical load is the barbell’s weight under gravity. Force is computed as F = m·g. With standard gravity 9.80665 m/s², a 100 kg system corresponds to about 981 N. This value helps compare sessions even when tempo changes, because force depends mainly on load.
4) Work per repetition from bar travel
Mechanical work depends on how far the bar moves against gravity: W = F·d. Typical bench displacement is roughly 0.30–0.60 m depending on grip and anatomy. Using 981 N and 0.45 m gives about 441 J per rep. Increasing range of motion increases work even if the same weight is lifted.
5) Average power and training tempo
Power summarizes how quickly work is performed: P = Wtotal / t. If you complete five reps in ten seconds, the average power is the set’s total work divided by ten. Faster intent and tighter pauses can change power without changing load.
6) One-rep max estimates and reliability
Different 1RM equations respond differently to repetition count and fatigue. The calculator reports multiple models (Epley, Brzycki, Lander, Lombardi, Mayhew, and O’Conner) and provides an average as a practical reference. Estimates tend to be most stable from 1–10 reps and become less reliable above 15.
7) Working weights by percentage
After selecting a rounded 1RM, the tool generates working loads from 50% to 100% in 5% steps. Many plans use moderate percentages for volume and higher percentages for strength. Rounding keeps targets realistic for available plates.
8) Plate planning and data logging
Plate math is per side: (target − bar)/2, then filled with common plate sizes for your unit system. The remainder highlights when exact loading is not possible with typical plates. Export results to maintain a consistent log.
FAQs
1) Is this a true bench press max calculator?
It provides a best-estimate 1RM from common equations, not a guaranteed max. Use it to guide training targets and monitor trends, then validate with safe testing and good technique.
2) Why do results change when I edit displacement?
Displacement affects work and power because W = F·d. A longer bar path increases mechanical work for the same load. It does not change the 1RM estimate, which is based on weight and reps.
3) What should I enter for bar weight?
Enter your bar’s actual mass: commonly 20 kg in many gyms or 45 lb in others. This value is used for the plate loading plan so per-side plates match your target.
4) Are 1RM estimates accurate for high reps?
Accuracy drops as reps rise because fatigue and endurance vary widely. Above about 15 reps, treat 1RM numbers as rough guidance. Consider using a heavier set with fewer reps for a clearer estimate.
5) What does the efficiency factor do?
It scales the estimated muscular power from mechanical power. Mechanical power is output at the bar, while the body’s internal effort can be higher. Use 1.0 if you want a direct mechanical-only view.
6) How should I pick the rounding increment?
Choose the smallest practical change you can load consistently. Many kilogram sets use 0.5 kg or 1.0 kg steps with microplates, while pound setups often use 2.5 lb increments.
7) Why does the plate plan show a remainder?
The plan uses common plate sizes. If your gym lacks a specific plate, the exact target may not be achievable. The remainder highlights what is left per side after loading typical plates.