{
  "id": "one-rep-max-calculator",
  "version": "2.0.0",
  "name": "One Rep Max Calculator",
  "shortName": "One Rep Max",
  "description": "Estimate one-repetition maximum with seven established formulas or their average and generate a percentage-based training table.",
  "category": "Health & Fitness",
  "categorySlug": "health-fitness",
  "keywords": [
    "one rep max",
    "1RM",
    "Epley",
    "Brzycki",
    "strength training percentages"
  ],
  "status": "live",
  "workStatus": "pending",
  "reviewStatus": "pending",
  "migrationStatus": "migrated",
  "migratedDate": "2026-08-25",
  "engine": "native",
  "creator": null,
  "reviewer": null,
  "quality": {
    "availability": "live",
    "technicalReviewRecord": "/reviews/one-rep-max-calculator.json",
    "qualifiedReview": "pending",
    "qualifiedReviewer": null,
    "qualifiedReviewDate": null,
    "formulaVersion": "2.0.0",
    "referenceCoverage": "references-listed",
    "releaseTestScope": "Catalog and regression checks are not a professional formula audit; consult release evidence.",
    "historicalMetadataDate": "2026-08-25",
    "historicalMetadataNotice": "The imported date is not evidence of a completed human review."
  },
  "notice": "Estimated 1RM is not a recommendation to attempt a maximal lift. Use appropriate technique, supervision, and load progression.",
  "urls": {
    "page": "/calculator/one-rep-max-calculator/",
    "definition": "/calculator/one-rep-max-calculator/definition.json",
    "schema": "/calculator/one-rep-max-calculator/schema.json",
    "llms": "/calculator/one-rep-max-calculator/llms.txt",
    "legacyDefinition": "/calculator/one-rep-max-calculator.json"
  },
  "queryExample": "https://askcalculators.com/calculator/one-rep-max-calculator/?unitSystem=lb&liftedWeight=135&repetitions=5&formula=average",
  "queryParameters": {
    "unitSystem": {
      "label": "Weight units",
      "type": "select",
      "required": true,
      "default": "lb"
    },
    "liftedWeight": {
      "label": "Weight lifted",
      "type": "number",
      "required": true,
      "default": 135
    },
    "repetitions": {
      "label": "Repetitions completed",
      "type": "number",
      "required": true,
      "default": 5
    },
    "formula": {
      "label": "Formula",
      "type": "select",
      "required": true,
      "default": "average"
    }
  },
  "inputs": [
    {
      "id": "unitSystem",
      "label": "Weight units",
      "type": "select",
      "required": true,
      "defaultValue": "lb",
      "options": [
        {
          "label": "Pounds",
          "value": "lb"
        },
        {
          "label": "Kilograms",
          "value": "kg"
        }
      ],
      "width": "full"
    },
    {
      "id": "liftedWeight",
      "label": "Weight lifted",
      "type": "number",
      "required": true,
      "defaultValue": 135,
      "min": 0.1,
      "max": 5000,
      "step": 0.5,
      "width": "half"
    },
    {
      "id": "repetitions",
      "label": "Repetitions completed",
      "type": "number",
      "required": true,
      "defaultValue": 5,
      "min": 1,
      "max": 20,
      "step": 1,
      "width": "half"
    },
    {
      "id": "formula",
      "label": "Formula",
      "type": "select",
      "required": true,
      "defaultValue": "average",
      "options": [
        {
          "label": "Average of formulas",
          "value": "average"
        },
        {
          "label": "Epley",
          "value": "epley"
        },
        {
          "label": "Brzycki",
          "value": "brzycki"
        },
        {
          "label": "Lombardi",
          "value": "lombardi"
        },
        {
          "label": "Lander",
          "value": "lander"
        },
        {
          "label": "Mayhew",
          "value": "mayhew"
        },
        {
          "label": "O’Conner",
          "value": "oconner"
        },
        {
          "label": "Wathan",
          "value": "wathan"
        }
      ],
      "width": "full"
    }
  ],
  "outputs": [
    {
      "id": "oneRepMax",
      "label": "Estimated one-rep max",
      "format": "number",
      "primary": true,
      "digits": 1
    },
    {
      "id": "epley",
      "label": "Epley estimate",
      "format": "number",
      "digits": 1
    },
    {
      "id": "brzycki",
      "label": "Brzycki estimate",
      "format": "number",
      "digits": 1
    },
    {
      "id": "formulaSpread",
      "label": "Formula range",
      "format": "text"
    }
  ],
  "formula": {
    "expression": "Examples: Epley 1RM = w(1+r/30); Brzycki 1RM = 36w/(37−r); other selected equations apply published repetition coefficients."
  },
  "examples": [
    {
      "label": "Reproducible default-input example (not a personal recommendation)",
      "inputs": {
        "unitSystem": "lb",
        "liftedWeight": 135,
        "repetitions": 5,
        "formula": "average"
      }
    }
  ],
  "sources": [
    {
      "label": "Calculator.net reference calculator",
      "url": "https://www.calculator.net/one-rep-max-calculator.html"
    }
  ]
}