One Rep Max Calculator

One Rep Max (1RM) Calculator
Estimate your maximum lift capacity for a single repetition using this calculator. Input the weight you can lift for 1–10 reps, and select your preferred formula for the most accurate 1RM prediction. Adjust values and click “Calculate” to update results.

Calculator Inputs

• Weight Lifted: 100 kg
• Repetitions: 5 (1–10 range)
• Formulas: Epley, Brzycki, Lombardi (toggle in settings)

What is a One Rep Max?

A 1RM is the maximum weight you can lift once with proper form for a specific exercise (e.g., bench press, squat). It’s a key metric in strength training and competition.

Why Track Your 1RM?

• Program Design: Tailor workout intensity to your goals (strength, endurance, hypertrophy).
• Progress Tracking: Quantify strength gains over time.
• Motivation: Set and achieve measurable targets.

How to Calculate Your 1RM

Direct Measurement

Safely test your true max with these steps:

1. Warm Up: Prepare relevant muscle groups.
2. Use a Spotter: Essential for safety near max effort.
3. Progressive Loading: Start with a weight you can lift 5–10 times, then increase incrementally with rest between sets.
4. Stop at Failure: Your 1RM is the heaviest weight lifted once with proper form.

Pros: Accurate.
Cons: Time-consuming; higher injury risk.

Estimation Formulas

Input a weight you can lift 3–10 times into these equations:

• Epley: 1RM = Weight × (1 + Reps/30)
• Brzycki: 1RM = Weight × 36 / (37 – Reps)
• Lombardi: 1RM = Weight × Reps^0.10

Pros: Quick, safe, beginner-friendly.
Cons: Less accurate for novices; varies by formula.

Using Your 1RM in Training

Adjust workout intensity based on your goals:

• Explosive Power: 50–60% of 1RM for 3–5 reps (short rests).
• Muscle Endurance: ~70% of 1RM for 10–15 reps.
• Hypertrophy: 70–80% of 1RM for 7–12 reps.
• Strength/Power: 80–100% of 1RM for 1–3 reps (use a spotter).

Tips to Improve Your 1RM

1. Safety First: Use spotters and prioritize form over ego-lifting.
2. Train Consistently: Focus on progressive overload.
3. Vary Workouts: Incorporate supersets, pyramids, or compound sets.
4. Strengthen Supporting Muscles: Balance training to avoid plateaus.
5. Rest and Recover: Avoid overtraining; muscles grow during recovery.

Disclaimer: Consult a fitness professional or healthcare provider before attempting maximal lifts or new programs. Safety is paramount.

Save & Track Progress: Use the calculator’s save feature to monitor 1RM changes over time and adjust your training plan accordingly.