One Rep Max Calculator
Use the One Rep Max to track training progress. Enter your lifts, reps, or body stats to get personalised targets and performance benchmarks.
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy
One Rep Max Calculator Formula
Brzycki: 1RM = Weight × (36 / (37 - Reps))
The Brzycki formula estimates your one-rep max from a submaximal set. Epley uses: Weight × (1 + Reps/30). Lander uses: (100 × Weight) / (101.3 - 2.67123 × Reps). All formulas work best for sets of 1-10 reps.
One Rep Max Calculator — Worked Examples
Example 1: Bench Press 1RM Estimate
Problem:You bench pressed 225 lbs for 5 reps. What is your estimated 1RM?
Solution:Using Brzycki: 1RM = 225 × (36 / (37 - 5)) = 225 × 1.125 = 253 lbs\nTraining Max (90%): 253 × 0.90 = 228 lbs\n85% working weight: 253 × 0.85 = 215 lbs (3-4 reps)\n75% working weight: 253 × 0.75 = 190 lbs (6-8 reps)
Result:Estimated 1RM: 253 lbs | Training Max: 228 lbs
Example 2: Squat Programming
Problem:You squatted 315 lbs for 3 reps. What weights should you use for a 5/3/1 program?
Solution:Using Brzycki: 1RM = 315 × (36 / (37 - 3)) = 315 × 1.059 = 334 lbs\nTraining Max (90%): 334 × 0.90 = 300 lbs\nWeek 1 (5s): 65% = 195, 75% = 225, 85% = 255\nWeek 2 (3s): 70% = 210, 80% = 240, 90% = 270\nWeek 3 (1s): 75% = 225, 85% = 255, 95% = 285
Result:Estimated 1RM: 334 lbs | Training Max: 300 lbs
One Rep Max Calculator — Frequently Asked Questions
What is a one-rep max (1RM)?
A one-rep max is the maximum amount of weight you can lift for a single repetition with proper form. It's the gold standard for measuring absolute strength and is used to program training percentages. Rather than actually testing a true 1RM (which carries injury risk), most lifters estimate it using formulas based on submaximal sets. For example, if you can bench press 225 lbs for 5 reps, your estimated 1RM is approximately 253 lbs using the Brzycki formula.
What is a training max and why use 90%?
A training max is typically set at 90% of your estimated 1RM. Programs like 5/3/1 by Jim Wendler use the training max instead of your true max to calculate working weights. This provides a built-in buffer that ensures you can complete all prescribed reps with good form, allows room for progression over multiple cycles, and accounts for day-to-day strength fluctuations. Starting lighter and building up leads to more sustainable long-term strength gains.
How do I calculate my one-rep max for weightlifting?
The Epley formula estimates 1RM: weight x (1 + reps/30). For example, if you bench press 150 lbs for 8 reps, your estimated 1RM is 150 x (1 + 8/30) = 190 lbs. Use this for programming percentages without the risk of actual max attempts.