| Lifted Weight | Reps | Epley 1RM | Brzycki 1RM | Average 1RM |
|---|---|---|---|---|
| 80 kg | 6 | 96.00 kg | 95.29 kg | ≈ 95–97 kg |
| 185 lb | 5 | 215.83 lb | 207.00 lb | ≈ 208–216 lb |
| 60 kg | 10 | 80.00 kg | 80.93 kg | ≈ 79–83 kg |
This calculator estimates your one‑rep maximum (1RM) from a submax set using multiple published equations:
- Epley:
1RM = w × (1 + reps/30) - Brzycki:
1RM = w × 36 / (37 − reps) - Lombardi:
1RM = w × reps^0.10 - O'Conner:
1RM = w × (1 + reps/40) - Lander:
1RM = w × 100 / (101.3 − 2.67123×reps) - Mayhew:
1RM = w × 100 / (52.2 + 41.9×e^(−0.055×reps)) - Wathan:
1RM = w × 100 / (48.8 + 53.8×e^(−0.075×reps))
The displayed “Average” is the mean of valid formula outputs, optionally rounded.
- Warm up, then perform a clean set for 1–10 reps.
- Enter the lifted weight, completed reps, and your unit.
- Select a primary method (Average is a reliable default).
- Set rounding to match plate jumps in your gym.
- Use the Training Max for safer long‑term programming.
For best accuracy, repeat tests across several sessions and use consistent technique, rest, and equipment.
Strength estimation from submax sets
A one‑rep maximum estimate converts a completed set into a comparable strength metric. For example, 80 kg × 6 reps often predicts roughly 95–97 kg depending on method. This helps standardize progress tracking across different rep ranges and weeks, especially when you avoid heavy singles. It is most reliable when the set is controlled, the range of motion is consistent, and reps stop before form breaks.
Why multiple formulas are shown
Different equations respond differently as reps increase. Epley tends to rise steadily, while Brzycki can be slightly lower at moderate reps and may become unstable at very high reps. Mayhew and Wathan use exponential terms that often fit common training ranges well. By displaying several estimates plus an average, you get a practical range rather than a single fragile number. The spread and standard deviation highlight when your chosen reps are increasing uncertainty.
Training max and load planning
Most lifters program from a training max instead of a true max. Using 85–95% of the chosen estimate reduces fatigue and keeps technique clean. If your estimated 1RM is 100 kg, a 90% training max is 90 kg; working sets can then be derived from that anchor. A common progression is adding 2.5 kg to upper‑body lifts and 5 kg to lower‑body lifts when your estimate trend supports it. If performance drops, hold the training max and improve recovery.
Rounding and gym reality
Plates, dumbbell jumps, and machine stacks rarely match decimal outputs. Rounding to the nearest 0.5, 1, 2.5, or 5 aligns the plan with available equipment. Consistent rounding improves comparability when you export results and review past sessions. In small gyms, 2.5 kg steps may be the practical minimum; in lb plates, 5 lb rounding often matches loading options.
Using the export report effectively
The CSV is useful for logging, spreadsheets, and trend charts, while the PDF is a quick session summary for coaching notes. Record the lift variation, rest time, and perceived effort alongside the estimate. Over time, stable estimates at lower effort indicate real strength gains. Use notes to explain equipment changes or pain.
FAQs
1) What rep range gives the best estimate?
Most lifters get the steadiest results from 1–10 reps. Sets above that can magnify endurance and technique effects, so the estimate may drift higher or vary more between formulas.
2) Which method should I pick?
If you are unsure, choose the Average option. It blends valid formulas into one value and reduces the chance that a single equation underestimates or overestimates your max for your rep count.
3) How often should I calculate again?
Recalculate whenever your working sets change meaningfully, or every 4–8 weeks for a consistent program. Use similar exercise variation, rest, and tempo so changes reflect strength, not testing conditions.
4) Why are kg and lb results different?
They are not different in principle. The estimate is computed in your chosen unit, and conversions are shown only as a reference. Small differences can appear from rounding steps you select for your equipment.
5) What is a training max?
A training max is a conservative anchor, often 85–95% of an estimated 1RM. It lets you train hard with better technique and recovery, while still supporting long‑term progression.
6) Can I use this for dumbbells or machines?
Yes, as long as the load and reps are accurate and the movement is repeatable. For machines with stack jumps, use rounding that matches the increments, and compare estimates only within the same machine.