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Max Load Capacity · Brzycki 1RM

Brzycki 1RM estimate plus recovery / hypertrophy / strength loads.

Brzycki (1993) is the most accurate sub-max 1RM estimator in the 1–10 rep range: 1RM = weight × 36 / (37 − reps). Training percentages flow from the estimate — 60% recovery, 75% hypertrophy, 85% strength.

Part of: Structural Output

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Fields marked optional can be skipped; results update as you type
Max Load Capacity · Brzycki 1RM
Load Stress Indicator
1 rep5 reps · strength zone10 reps · upper bound
Estimated Structural Limit (1RM)
253.1 lb
Recovery · 60%
151.9 lb
Hypertrophy · 75%
189.8 lb
Strength · 85%
215.2 lb
Brzycki: 1RM = weight × 36 / (37 − reps). Validated 1–10 reps. Accuracy degrades past 10 reps; testing actual 1RM above 85% carries chassis-damage risk.

How to use

  1. Enter the weight you lifted and the reps you completed (≤ 10 for accuracy).
  2. Read estimated 1RM and the three training-zone loads.
  3. Re-test every 4–6 weeks at the same rep count.

Examples

225 lb × 5 reps
1RM ≈ 253 lb · recovery 152 · hypertrophy 190 · strength 215.

Before you act on the result

Health-related tools are educational planning aids. They can make a number or assumption visible, but they do not diagnose, treat, prescribe, or replace clinician guidance.

If the result points to risk, symptoms, medication questions, or urgent changes, use it as a note for a qualified professional rather than a final decision.

Next up

Max known. Now measure rep efficiency.Strength-to-Weight Efficiency · Wilks → Load set. Check the growth signal you're triggering.Anabolic Trigger · MPS Bolus →

Frequently asked questions

› Why cap at 10 reps? Troubleshooting

Above 10, endurance starts to dominate strength and Brzycki systematically under-estimates 1RM. Use a different formula (Epley, Lombardi) or a true 3-rep-max test.

› Is testing actual 1RM worth the risk? Trust & accuracy

Rarely. Structural injury risk rises sharply above 85% for untrained lifters. Estimates from a well-executed 3–5 rep set are within 3%.

Tips & related reading

See the Structural Output hub →

Tips & how-tos

Relevant links

Related tools

Strength-to-Weight Efficiency · Wilks

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Operational Heart Rate Zones · Karvonen

Calculate the five training zones using Karvonen (heart-rate reserve) method. More accurate than %HRmax alone.

Anabolic Trigger · MPS Bolus

Per-meal protein bolus that maximises muscle protein synthesis. 0.25-0.40 g/kg per feeding, 1.6-2.2 g/kg daily.