Calculate Your One-Rep Max (1RM)
Use the calculator below to estimate your one-rep max (1RM)—the maximum amount of weight you can lift for one full repetition of a specific exercise. Just enter the weight lifted and the number of reps performed (to failure) to calculate your estimated 1RM.
Why do you need to calculate your 1RM?
Understanding your 1RM helps you train smarter. Strength programs often use percentages of your 1RM to determine how much weight you should lift for a given rep range. For example:
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60% of your 1RM = light training or warm-up
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75–85% = muscle-building zone
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90–95% = max strength training
Most coaches and lifters don’t test their true 1RM every week (it’s intense and risky). That’s where a calculator comes in—it provides a safe estimate based on reps you can perform without reaching complete failure.
How It Works
The calculator uses established formulas (like the Epley or Brzycki equations) to estimate your 1RM:
1RM = Weight × (1 + Reps ÷ 30) (Epley Formula)
So if you lift 100 kg for 10 clean reps, your estimated 1RM is:
100 × (1 + 10 ÷ 30) = 133.3 kg
How to Use the 1RM Calculator Effectively
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Choose a lift you perform with good form (e.g., squat, bench press, deadlift).
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Enter a weight you can lift for 3–12 reps—going too high in reps decreases accuracy.
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Don’t sacrifice form to get more reps—only count clean reps.
Use this information to:
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Create custom strength programs
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Track progress over time
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Set realistic performance goals
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Avoid overtraining or injury
Pro Tips
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Re-calculate your 1RM every 4–6 weeks as you get stronger.
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Pair your 1RM with a structured training plan (like 5×5 or push/pull splits).
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If you’re a beginner, always work with a spotter or coach when testing max loads.
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Warm up properly before attempting any heavy lifts—even in testing.
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