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The 1-Rep Max (1RM) Calculator with Rep Range Ratios is designed to help athletes, trainers, and fitness enthusiasts determine the maximum weight they can lift for one repetition across various exercises, as well as understand the percentage of their 1RM they should be lifting to hit specific rep ranges according to their training goals. Here's how it works:

Step 1: Input Your Lift Details

  • Weight Lifted: Enter the weight you have lifted in kilograms or pounds. This should be a weight you can perform with correct form for the number of reps entered next.

  • Reps Performed: Input the number of repetitions you successfully completed with the weight entered above. Typically, this is a submaximal effort (not a single rep) that accurately reflects your current strength level.

Step 2: Calculate Your 1-Rep Max (1RM)

  • After entering the weight lifted and the reps performed, press the "Calculate 1RM" button. The calculator uses a well-regarded formula to estimate your 1RM, which is the maximum weight you could lift for a single repetition. This formula is: 1RM=Weight Lifted×(1+Reps Performed30)1RM=Weight Lifted×(1+30Reps Performed​)

Step 3: Input Desired Rep Range

  • Desired Rep Range: If you have a specific rep range target for your workouts (e.g., 10 to 15 reps for endurance, 5 to 7 reps for strength), you can enter that number here to see what percentage of your 1RM you should be lifting to achieve those reps.

Step 4: See the Percentage of 1RM for Desired Reps

  • The calculator will then display the percentage of your 1RM that corresponds to the desired rep range you entered. This is based on common strength training guidelines:

    • 70% for 10 to 15 reps

    • 75% for 8 to 12 reps

    • 80% for 6 to 10 reps

    • 85% for 5 to 7 reps

Additional Features:

  • The calculator is styled for ease of use, with clear input fields and buttons.

  • A small logo and a footer are included for branding and copyright purposes.

  • The calculator is responsive, designed to work on both desktop and mobile devices, ensuring accessibility no matter where you are.

This tool is invaluable for planning your workouts more effectively, ensuring you're lifting the appropriate amount of weight to meet your strength, hypertrophy, or endurance training goals. Whether you're looking to max out safely, understand your strength levels, or plan your training loads, this calculator provides the insights needed to inform your training decisions.

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