Which One Rep Max Formula Is Most Accurate
There’s no single “official” 1RM formula — and that’s because different formulas suit different rep ranges and training styles. Whether you’re using 3 reps or 10, the right formula can make your 1RM estimate more accurate. In this post, we’ll break down the most popular 1RM formulas, how they work, and which one you should use.
Want to lift heavier, smarter? Use our One Rep Max Calculator to find your perfect load.
- Epley = best for general use (especially 3–10 rep ranges)
- Brzycki = best for low reps (1–5 reps)
- Differences are small, but each formula suits different lifters and rep schemes
Why Are There Different 1RM Formulas?
1RM calculators are based on studies, coaching data, and real-world lifting performance. Different researchers and coaches created their own formulas to reflect what they observed in training.
The Epley Formula (Most Versatile)
Formula: 1RM = weight × (1 + reps ÷ 30)
Works well for rep ranges between 3–10
Adjusts for fatigue and is great for general strength training
Slightly overestimates for very high reps
The Brzycki Formula (Low-Rep Focused)
Formula: 1RM = weight ÷ (1.0278 – 0.0278 × reps)
Best suited for 1–5 reps
Great for powerlifters or strength-focused lifters
May underestimate if used with higher reps
Other Common Formulas (Quick Overview)
Lander: Similar to Brzycki, focused on lower reps
Lombardi: Better with high-rep endurance sets
O’Conner/Wathan: More complex, often used in academic settings
Explore More Calculators
Which Formula Should You Use?
Use Epley if:
You’re lifting 3–10 reps
You want an easy, all-purpose estimate
You train for general strength or hypertrophy
Use Brzycki if:
You’re lifting 1–5 reps
You want a more precise low-rep prediction
You’re tracking progress in pure strength blocks
Final Thoughts
No 1RM formula is perfect, but choosing the right one for your rep range can give you more consistent and reliable results. Try a few out and see which matches your actual lifts best.
Try it for yourself:
Use the One Rep Max Calculator to estimate your max based on your current lifts.
Still have questions?
We’ve covered the most common ones below — and we’re adding more every month based on your feedback.
What is the most accurate 1RM formula?
There’s no single “most accurate” formula for everyone. That said, the Epley Formula is the most widely used for general training (especially in the 3–10 rep range), while Brzycki tends to be more precise for lower rep sets (1–5 reps). The best formula often depends on your experience level, goals, and how many reps you use to estimate.
Why do different formulas give different results?
Each formula uses its own equation based on rep range assumptions, training population data, and fatigue factors. For example, some scale more aggressively at high reps, while others stay conservative. This is why some calculators show multiple formula results side-by-side for comparison.
Which formula should I use if I train in higher rep ranges?
If you typically lift in the 8–12 rep range, formulas like O’Conner or Lombardi may give you a more realistic estimate. They account better for endurance-style strength and are less aggressive in their predictions compared to low-rep focused formulas like Brzycki.
Can I rely on just one formula for training progression?
It’s best to use 1RM formulas as guidelines, not absolutes. Comparing multiple formulas and averaging results — or checking them against how a lift feels — is a smarter approach than relying on just one method. Real progress happens in the gym, not just in a calculator.
How do I know if a formula is right for me?
Use your own training log and actual 1RM testing as reference. If a formula regularly overestimates your max, try one that’s more conservative. If it always underestimates, look at formulas better suited to your style. You’ll find the right fit by tracking results over time.
Take me to
