One-Rep Max Calculator | Sports Strength Training

One-Rep Max Calculator

Estimate your maximum strength for any lift using proven formulas and build training plans with ease.

Estimated 1 Rep Max (1RM)

Epley Formula:

Brzycki Formula:

Formulas Used

Epley: 1RM = weight × (1 + reps / 30)
Brzycki: 1RM = weight × (36 / (37 - reps))

Training Percentages Table

% 1RM	Weight	Target Reps*

* Typical reps possible at each percentage, actual numbers may vary by individual and exercise.

Strength Training Principles

Varying intensity (percentage of 1RM) allows for training different strength qualities, such as endurance, hypertrophy, or max strength.
Higher percentages (>85% 1RM) are primarily for low-rep strength work; moderate zones (~70-80%) target muscle growth and technique.
Track progress over time by periodically retesting your 1RM or using rep maxes (e.g., 3RM, 5RM).
Warm up properly, use spotters when appropriate, and never sacrifice form for heavier weights to avoid injury.

Safety Considerations

1RM attempts should be performed with supervision if possible, especially for beginners.
Online estimations are practical and safer alternatives for most lifters compared to actual max attempts.
If you have health issues or injuries, consult a medical professional before engaging in max strength testing.

About One-Rep Max (1RM) Calculators

Your one-rep max (1RM) is the maximum weight you can lift for a single repetition of an exercise with proper form. It serves as a benchmark for strength training progress and a reference for constructing effective workout plans.

Since performing actual 1RM tests can be risky (particularly for inexperienced athletes), prediction formulas like Epley and Brzycki are widely used. They allow you to estimate your maximum without having to perform single, maximal-effort lifts.

Useful References & Further Reading

One-Rep Max Calculator – Find Your Maximum Lifting Potential Instantly

Whether you’re chasing personal records or building strength intelligently, our One-Rep Max Calculator helps you estimate the maximum weight you can lift for one complete repetition of an exercise. No guesswork. No injury risk. Just precise numbers based on science.

💡 What Is One-Rep Max (1RM)?

Your One-Rep Max (1RM) is the maximum amount of weight you can lift once for a given exercise with proper form. It’s a key metric in:

🏋️ Powerlifting
🏃‍♂️ CrossFit
🧠 Strength programming
🧘 Personal fitness tracking

Whether it’s for a bench press, deadlift, or squat, knowing your 1RM allows you to set realistic and safe lifting goals.

📐 How the One-Rep Max Calculator Works

Instead of maxing out and risking injury, the calculator uses submaximal efforts (weights you’ve already lifted for reps) to estimate your 1RM using well-known formulas:

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

Brzycki Formula:
1RM = Weight × (36 ÷ (37 – Reps))

Lombardi Formula:
1RM = Weight × Reps^0.10

The calculator gives you an average from multiple formulas for a more accurate result.

🧮 Example Calculation

Let’s say:

You lifted 100 kg
For 5 reps

Epley formula result:
100 × (1 + 5 ÷ 30) = 116.6 kg

That means your estimated 1RM is about 116.6 kg

🔁 Why Calculate Your 1RM?

📈 Track strength gains over time
📊 Build personalized training percentages (like 75% of 1RM)
🧠 Avoid overtraining or injury
🔁 Optimize progressive overload plans
💪 Set accurate PR (personal record) targets

📋 1RM Training Zone Table

% of 1RM	Training Focus	Reps Possible
90–100%	Max Strength / PRs	1–2 reps
80–90%	Power Development	3–5 reps
70–80%	Muscle Growth (Hypertrophy)	6–8 reps
60–70%	Endurance & Volume	10–15 reps

🔥 Features Included

One rep max calculator
1RM calculator online
Estimate your max lift
Weightlifting 1 rep max
Strength training tool
Lifting calculator by reps
Max squat/bench press estimator
Gym PR calculator

🧭 Related Tools on Desmos Calculators

BMI Calculator – monitor your fitness baseline
Calories Burned Calculator – measure post-lift energy use
Target Heart Rate Calculator – balance lifting with cardio

🔗 External References

One rep max calculator,

1RM calculator online,

Estimate your max lift,
Weightlifting 1 rep max,

Strength training tool,

Lifting calculator by reps,

Max squat/bench press estimator,

Gym PR calculator,

✅ Final Thoughts

Lifting smart means lifting informed. With our One-Rep Max Calculator, you no longer need to risk injuries or guess your limits. Get real, data-backed insights to build strength safely and efficiently—every rep of the way.