Brzycki Formula
A precise one rep max formula tuned for sets of 10 reps or fewer.
The equation
1RM = weight × 36 ÷ (37 − reps)
Worked example
Say you squat 140 kg for 5 reps. Plugging into the formula:
1RM = 140 × 36 ÷ 32
1RM ≈ 157.5 kg
Strengths and limits
Brzycki is one of the most precise formulas for low-to-moderate rep sets, which is why it's a default in many strength calculators. Its main weakness is at high rep counts — as reps approach 37, the formula mathematically breaks down. Stick to sets of 10 reps or fewer for a trustworthy estimate.
Try it yourself
Enter your lift
Your estimated one rep max
Squat · estimated 1RM
112.5 kg
Raw estimate: 112.5 kg · 248.0 lb
Epley
116.7 kg
Brzycki
112.5 kg
Lombardi
117.5 kg
Training percentages
| % | Weight | Reps |
|---|---|---|
| 100% | 112.5 kg | 1 rep |
| 95% | 106.9 kg | 1-2 reps |
| 90% | 101.3 kg | 2-3 reps |
| 85% | 95.6 kg | 3-5 reps |
| 80% | 90.0 kg | 4-6 reps |
| 75% | 84.4 kg | 6-8 reps |
| 70% | 78.8 kg | 8-10 reps |
| 65% | 73.1 kg | 10-12 reps |
| 60% | 67.5 kg | 12-15 reps |
| 50% | 56.3 kg | 15-20 reps |
| 40% | 45.0 kg | 20+ reps |
Estimated weight for 1–12 reps
1 rep
112.5 kg
2 reps
105.5 kg
3 reps
102.3 kg
4 reps
99.3 kg
5 reps
96.4 kg
6 reps
93.8 kg
7 reps
91.2 kg
8 reps
88.8 kg
9 reps
86.5 kg
10 reps
84.4 kg
11 reps
82.3 kg
12 reps
80.4 kg
Brzycki formula FAQ
Who created the Brzycki formula?+
Strength and conditioning expert Matt Brzycki published this formula, which became popular through fitness textbooks and NSCA-affiliated coaching materials.
Why does Brzycki break down above 10 reps?+
The formula divides by (37 − reps). As reps approach 37, the denominator approaches zero and the estimate grows without bound — so results above roughly 10-12 reps become unreliable.
Is Brzycki more accurate than Epley?+
For sets under 10 reps the two formulas are very close. Brzycki is often considered slightly more precise in the 1-10 rep range, while Epley is simpler and holds up a bit better outside that window. We average both by default to reduce either formula's individual bias.
Compare it directly with the Epley formula or see a full formula comparison.