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The One Rep Max Calculator — also known as a 1 Rep Max Calculator, 1RM Calculator, or Single Rep Max Calculator — helps you estimate the maximum amount of weight you can lift for one full repetition of an exercise. Whether it's bench press, squat, or deadlift, this tool gives you an idea of your true strength potential without actually needing to risk injury by attempting your max every time.

In simpler terms, your “one rep max” is the heaviest load you can move just once with proper form. This number becomes the foundation for structured training — helping you set weight targets for different rep ranges, track progress, and understand your overall power.

Knowing your one rep max is more than bragging rights — it’s a way to train smarter, not just harder. Coaches, athletes, and gym-goers use it to fine-tune workouts, ensuring each session is challenging but not over the line.

• Progress tracking

  Measure your true strength gains over time.

• Workout programming

  Design your lifts at specific percentages (like 70%, 80%, or 90% of your 1RM).

• Safety and recovery

  Avoid overtraining by keeping intensity within healthy limits.

The 1RM Calculator estimates your maximum lift using formulas developed by strength researchers. You enter the amount of weight you lifted and how many reps you performed, and the calculator predicts your one-rep maximum.

The most common formulas include:

Each formula gives a slightly different result, but all are close enough to guide your training intensity. Think of them as educated estimates — not absolute truth.