Which 1RM formula is most accurate?

It depends on your training background. Epley is popular for general fitness, Brzycki is often used in research, and Lander is preferred for strength athletes.

Can I use kilograms or pounds?

Yes, the tool supports both kilograms (kg) and pounds (lb) for all inputs and outputs.

Is it safe to test a real 1RM in the gym?

Not always. Testing actual 1RMs can increase injury risk. Estimating using submaximal lifts is safer and widely recommended.

How is the rep-to-weight chart created?

The chart uses the estimated average 1RM and applies inverse Epley logic to show projected weight at different rep ranges (1–15).

Can I track strength progress over time?

Yes, by inputting your regular lifts over time, you can use the tool to monitor improvements in your 1RM.

Why do formulas give slightly different results?

Each formula uses a different mathematical model. We display all three so you can compare and choose what's most relevant to your training.

Who should use this 1RM Calculator?

Athletes, strength coaches, gym-goers, and rehab professionals can all benefit from safe and effective max strength estimation.

1RM Calculator – Estimate Your One-Rep Max with Epley, Brzycki & Lander

Q: What is a 1RM (One-Rep Max)?

1RM, or One-Rep Max, is the maximum weight you can lift for a single full repetition of a specific exercise with proper form.

Reps vs. Estimated Weight Chart

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🏋️ Overview: 1 Rep Max (1RM) Estimator

The 1RM Estimator helps lifters and coaches estimate the maximum amount of weight an individual can lift for a single repetition (known as the One-Rep Max) based on submaximal lifts.

Simply input the weight lifted and the number of reps performed (1–15), and this tool will calculate your estimated 1RM using three popular formulas:

Epley Formula
Brzycki Formula
Lander Formula

The tool also generates a rep-to-weight table and an interactive chart to visualize your strength across rep ranges.

🧠 Formulas & Methodology

The tool calculates three separate estimates and then averages them to provide a reliable result.

📐 1RM Estimation Formulas:

Epley:
  1RM = Weight × (1 + Reps / 30)

Brzycki:
  1RM = Weight × (36 / (37 − Reps))

Lander:
  1RM = (100 × Weight) / (101.3 − 2.67123 × Reps)

🔍 Formula Comparison:

Epley: Best suited for general fitness and strength training. Most popular among coaches.
Brzycki: Commonly used in academic or testing settings due to its simplicity.
Lander: Slightly more aggressive, preferred in some strength-based sports or competition predictions.

All formulas assume proper lifting form and no assistance. The average value gives a balanced estimate.

🧪 Example Calculation

Weight Lifted: 200 lb
Reps Performed: 8

Results:

Epley: 253.33 lb
Brzycki: 246.15 lb
Lander: 245.87 lb
Average 1RM: 248.45 lb

The rep-to-weight table below shows how much weight you could lift for different reps based on this estimate.

💡 Use Cases

🏋️‍♂️ Track progress in strength training programs
📊 Set realistic goals for max effort lifts
🧮 Estimate lifting capacity without performing a max rep
📈 Visualize strength output across various rep ranges
💪 Compare multiple formulas for training insights

❓ Frequently Asked Questions

🔢 What is a 1RM (One-Rep Max)?

1RM, or One-Rep Max, is the maximum amount of weight you can lift for one complete repetition of a given exercise.

📏 Which formula is most accurate?

Each formula serves different needs. Epley is common for general training, Brzycki is simple and reliable, and Lander is ideal for competitive scenarios. We show all three so you can compare.

⚖️ Should I use kilograms or pounds?

Choose the unit you're most familiar with. The results are calculated using your selected unit and consistent throughout the chart and table.

📉 How is the rep-to-weight table calculated?

Based on the average 1RM, we reverse-calculate estimated liftable weight for 1 to 15 reps using the Epley formula.

👥 Who should use this tool?

Athletes, gym-goers, personal trainers, and physical therapists can all benefit from accurate 1RM estimation.

🚫 Is it safe to test a real 1RM directly?

Not always. Testing actual 1RM carries injury risk. Estimating 1RM from submaximal lifts (like 3–10 reps) is a safer and widely accepted alternative.

📈 Can I use this tool to track my progress?

Absolutely! Use it periodically with your training data to monitor strength improvements over time.

💬 Why are there small differences between formulas?

Each formula is based on different research populations and mathematical assumptions. Comparing them offers a broader view of your potential.