🏋️ One-Rep Max Estimator
Plug in any lift’s weight and reps to see one-rep max predictions, compare formulas, and plan training loads across intensity zones.
Best accuracy between 1–10 reps.
Selected Formula (1RM)
347 lb
157.2 kg
Average of Formulas
344 lb
156.3 kg
Input Session
315 lb × 3 reps
Formula Comparison
| Formula | Description | Estimated 1RM (lb) |
|---|---|---|
| Epley | Popular all-purpose strength formula. | 347 lb |
| Brzycki | Favours moderate rep ranges (≤10). | 334 lb |
| Lombardi | Uses power curve; suits higher reps. | 352 lb |
| Mayhew et al. | Bench press study; accurate for 2–10 reps. | 359 lb |
| O'Conner | Slightly conservative; useful for programming. | 339 lb |
| Lander | Derived from collegiate data; mid-range reps. | 338 lb |
Training Load Guide (using selected formula)
| Zone | Percent of 1RM | Recommended Weight |
|---|---|---|
| Maximal Strength | 90–100% | 330 lb |
| Strength | 80–90% | 295 lb |
| Hypertrophy | 70–80% | 260 lb |
| Power (Dynamic) | 50–60% | 190 lb |
| Endurance | 40–50% | 155 lb |
How to Use This Calculator
Enter set data
Use your heaviest quality set (1–10 reps) for the best estimate.
Pick formula
Select a formula or compare multiple to dial in a training max.
Apply training zones
Use the load guide to program strength, hypertrophy, or power work.
Re-test regularly
Update numbers each mesocycle or when you hit new rep PRs.
Formula
Epley: 1RM = weight × (1 + reps ÷ 30)
Brzycki: 1RM = weight × (36 ÷ (37 − reps))
Lander: 1RM = (100 × weight) ÷ (101.3 − 2.67123 × reps)
All formulas assume technical proficiency and consistent tempo. Adjust down 5% if reps were grindy or paused.
Choose the formula that aligns with your sport or coach’s guidance. Averaging or selecting a conservative formula helps manage fatigue while still progressing.
Programming Notes
Use 1RM estimates to establish training maxes for programs like 5/3/1, DUP, or percentage-based Olympic lifting cycles. Combine with velocity or RPE to refine load selection.
Best Practices
- Keep 1–2 reps in reserve (RIR) during the test set to preserve technique.
- Record video to audit bar speed; very slow reps skew estimates upward.
- Use lower percentages after hard training blocks or during peaking phases.
Frequently Asked Questions
Are 1RM calculators as good as actual max testing?
They’re safer and consistent for programming. Actual max testing captures neural drive but needs spotters and good conditions.
Which formula should I trust?
Use the one aligned with your coach or average several. Brzycki and Epley are widely accepted for general strength training.
What if my reps were paused or tempo controlled?
Adjust estimated 1RM down 2–5% to account for slower bar speed or longer time under tension.
Can I use kilograms?
Yes—enter weights in pounds and convert results using the metric values shown. Future updates may add direct metric input.
How often should I update my numbers?
Each time you log a rep PR or at least every mesocycle (4–6 weeks) to keep training loads relevant.