Why One-Rep Max Is Important

Knowing your 1RM is essential for:

• Setting Training Loads: Helps determine ideal weights for specific training goals (e.g., strength, hypertrophy, or endurance).

• Tracking Progress: Measures strength improvements over time.

• Avoiding Injury: Prevents lifting weights that are too heavy or too light.

• Personalized Programming: Allows athletes and coaches to structure workouts using percentages of 1RM (e.g., 70% of 1RM for moderate-intensity training).

Common One-Rep Max Formulas

These formulas estimate your 1RM based on the weight lifted and the number of repetitions performed before failure.

1. Epley Formula

A widely used and simple method that works best for sets between 1–10 reps.

$$\text{1RM}=\text{Weight}\times (1+0.0333\times \text{Reps})$$

Example: If you lifted 80 kg for 6 reps:

$$1RM=80\times (1+0.0333\times 6)=80\times 1.1998=95.98\text{ kg (approx.)}$$

2. Brzycki Formula

Accurate for moderate repetitions (up to 10–12 reps), and popular in strength testing.

1RM=Weight1.0278−0.0278×Reps\text{1RM} = \frac{\text{Weight}}{1.0278 – 0.0278 \times \text{Reps}}1RM=1.0278−0.0278×RepsWeight​

Example: If you lifted 80 kg for 6 reps:

1RM=801.0278−0.0278×6=800.861=92.9 kg (approx.)1RM = \frac{80}{1.0278 – 0.0278 \times 6} = \frac{80}{0.861} = 92.9 \text{ kg (approx.)}1RM=1.0278−0.0278×680​=0.86180​=92.9 kg (approx.)

3. Lombardi Formula

This formula uses a power relationship and is often used for experienced lifters who can handle higher loads with fewer reps.

1RM=Weight×(Reps0.10)\text{1RM} = \text{Weight} \times (\text{Reps}^{0.10})1RM=Weight×(Reps0.10)

Example: If you lifted 80 kg for 6 reps:

1RM=80×(60.10)=80×1.196=95.7 kg (approx.)1RM = 80 \times (6^{0.10}) = 80 \times 1.196 = 95.7 \text{ kg (approx.)}1RM=80×(60.10)=80×1.196=95.7 kg (approx.)

How to Improve Your One-Rep Max

Improving your 1RM involves both training strategy and recovery.

• Progressive Overload: Gradually increase weights over time to challenge your muscles.

• Proper Form: Focus on technique to maximize power and prevent injury.

• Accessory Exercises: Strengthen supporting muscles (e.g., triceps for bench press, hamstrings for deadlift).

• Adequate Recovery: Ensure rest between heavy sessions for muscle repair and growth.

• Nutrition: Eat sufficient protein and calories to support strength development.

• Consistency: Regular, structured training over weeks or months leads to sustainable gains.

Disclaimer

Estimating or testing your one-rep max should be done with proper supervision and safety precautions. Attempting a true 1RM without assistance can lead to injury, especially for beginners. Always warm up properly, use a spotter, and start conservatively when testing new strength limits. The calculator provides an estimate, not an exact measurement.