What percentage of 1RM should I train at?

For strength: 85-100% (1-5 reps). For hypertrophy: 67-85% (6-12 reps). For endurance: below 67% (12+ reps). Use our 1RM calculator to get exact percentages for each zone.

Strength Training Guide

How to Calculate Your 1 Rep Max: Complete Guide (Epley & Brzycki Formulas)

Q: What is the most accurate 1RM formula?

The Epley formula is the most commonly used and validated for most lifters. Use weight × (1 + reps/30). The Brzycki formula tends to be slightly more conservative at higher rep ranges.

Q: Can I test my 1RM directly?

Yes, but only with proper warm-up, a spotter, and good form. Most lifters should estimate using a sub-maximal set of 3-5 reps rather than testing a true max to reduce injury risk.

Q: How accurate are 1RM calculators?

1RM estimates are most accurate between 2-10 reps. Above 10 reps, neuromuscular fatigue makes estimates less reliable. Always treat calculator results as estimates.

July 8, 2026 · By ProAthletica Team

Knowing your one-rep max (1RM) is the foundation of any serious strength program. It tells you exactly how much weight to load for strength, hypertrophy, or endurance work — no more guessing, no more stalled progress.

In this guide, you'll learn the two most accurate formulas for estimating your 1RM, how to use training percentages, and when it's safe to test your true max.

Use our free 1 Rep Max Calculator — enter your weight and reps, get your estimated max plus a full training chart instantly.

Calculate Your 1RM Now

The Two Best 1RM Formulas

Epley Formula (Most Common)

Developed by Dr. Matt Brzycki at Princeton, this formula is simple and widely validated:

1RM = Weight × (1 + Reps / 30)

Example: If you bench press 185 lb for 5 reps: 1RM = 185 × (1 + 5/30) = 185 × 1.167 = 216 lb

Brzycki Formula (Conservative)

More conservative at higher rep ranges, often preferred by experienced lifters:

1RM = Weight × 36 / (37 - Reps)

Example: Same 185 lb for 5 reps: 1RM = 185 × 36 / (37 - 5) = 185 × 1.125 = 208 lb

How to Use Training Percentages

Once you know your estimated 1RM, use these zones to structure your training:

Strength Zone (85-100%): 1-5 reps per set. Builds maximal strength and neural adaptation.
Hypertrophy Zone (70-85%): 6-12 reps per set. Stimulates muscle growth and size.
Endurance Zone (50-70%): 12+ reps per set. Improves muscular endurance and work capacity.

Tips for Accurate 1RM Testing

Warm up thoroughly — 5-10 minutes of light cardio, then ramp up to your working weight over 3-4 sets.
Use a spotter — especially for bench press and squats above 90% of your estimated max.
Test at 3-5 reps — sub-maximal testing is safer and nearly as accurate as a true 1RM attempt.
Rest 3-5 minutes between heavy sets for full ATP replenishment.

When NOT to Test Your 1RM

Avoid max testing if you're new to lifting (less than 6 months of consistent training), recovering from an injury, or running a high-volume program. Use estimation formulas instead — they're safe and accurate enough for program design.

Ready to calculate your 1RM? Our free tool uses both formulas and gives you a complete percentage chart.

Use 1RM Calculator

Frequently Asked Questions

What is the most accurate 1RM formula?
The Epley formula is the most common and validated. Brzycki is more conservative at higher rep ranges.

Can I test my 1RM directly?
Yes, but only with a proper warm-up, spotter, and good form. Most lifters should estimate using 3-5 reps.

How accurate are 1RM calculators?
Most accurate between 2-10 reps. Above 10 reps, fatigue makes estimates less reliable.

What percentage should I train at?
Strength: 85-100%. Hypertrophy: 67-85%. Endurance: below 67%.