One Rep Max Calculator
Find your maximum strength for any exercise — instantly
What is 1RM? Your One Rep Max (1RM) is the maximum weight you can lift for a single repetition of any exercise. It is the gold standard measure of strength in weightlifting. Use it to set training weights, track progress, and compare your strength over time.
Calculate Your 1RM
How to Use the 1RM Calculator
- Choose a weight you can lift for multiple reps — ideally between 3 and 10 reps
- Perform the exercise with good form and note the weight and reps completed
- Enter those numbers above and click Calculate
- Your estimated 1RM and training percentages are calculated instantly
Important: Never attempt a true 1RM without proper warmup, a spotter, and experience with the movement. Use this calculator to estimate your 1RM safely from submaximal lifts.
Which Formula is Most Accurate?
Our calculator uses multiple validated formulas and shows you all of them. The most commonly used are:
| Formula | Best For | Accuracy |
|---|---|---|
| Epley | General use — most widely used | ✅ Very good |
| Brzycki | Best for lower rep ranges (1–10) | ✅ Very good |
| Lander | Good for higher rep ranges | ✅ Good |
| Lombardi | Higher rep ranges | ⚠️ Moderate |
| O’Conner | Simple estimation | ⚠️ Moderate |
Strength Standards — How Do You Compare?
Once you know your 1RM use these general strength standards to see where you stand. Based on bodyweight ratio:
| Level | Bench Press | Squat | Deadlift |
|---|---|---|---|
| Beginner | 0.5× bodyweight | 0.75× bodyweight | 1× bodyweight |
| Intermediate | 1× bodyweight | 1.5× bodyweight | 1.75× bodyweight |
| Advanced | 1.5× bodyweight | 2× bodyweight | 2.5× bodyweight |
| Elite | 2× bodyweight | 2.5× bodyweight | 3× bodyweight |
Want to Know Your Calorie Needs Too?
Use our free TDEE Calculator to find your exact daily calorie target for muscle gain or fat loss.
Calculate My Calories Free →Frequently Asked Questions
How accurate are 1RM formula estimates?
Formulas like Epley, Brzycki and Lander are reasonably accurate when your input reps are in the 1-10 range, typically within a few kilograms of your true max. Accuracy decreases noticeably above 10-12 reps, since these formulas were validated primarily on lower rep ranges. Treat estimates above that range as a rough guide rather than a precise number.
Should I actually test my true 1RM in the gym, or just use the estimate?
For most lifters, using a submaximal estimate is safer and sufficient for programming training percentages. Testing a true 1RM carries higher injury risk, especially for beginners, and is generally only necessary for competitive powerlifters or specific testing purposes.
Why do different 1RM formulas give me slightly different numbers?
Each formula (Epley, Brzycki, Lander) was derived from different research datasets and mathematical approaches, so small variations between them are normal and expected. The differences are usually minor at lower rep counts and grow larger as rep count increases.
How often should I retest my one rep max?
Every 4 to 8 weeks is reasonable for tracking progress, depending on your training programme. Retesting too frequently doesn’t allow enough time for strength adaptations to occur, while waiting too long makes your training percentages less accurate to your current strength level.
Disclaimer: This calculator provides estimates only. Results may vary based on individual factors. Always train safely with proper supervision and technique.