{
  "id": "measuring-cups",
  "version": "dd7113cfccac",
  "status": "published",
  "name": "Measuring Cups Calculator",
  "question": "Which measuring cups do I use?",
  "summary": "Finds the fewest measuring cups and spoons from a standard US set that add up to an amount, such as ¾ cup or ⅝ cup, with the total in milliliters.",
  "category": "food",
  "subcategory": "recipes",
  "url": "https://www.acalculator.org/food/measuring-cups-calculator",
  "markdown": "https://www.acalculator.org/food/measuring-cups-calculator.md",
  "kind": "function",
  "method": "Turn the amount into quarter teaspoons (1 cup = 192, 1 tbsp = 12, 1 tsp = 4), rounded half up to a whole number. Find the fewest measures that add up to it; among equal counts, use the largest measure as often as possible, then the next largest, and so on.",
  "assumptions": [
    "US customary measures: 1 cup = 16 tbsp = 48 tsp; 1 tsp = 4.92892159375 mL.",
    "The basic set is 1, ½, ⅓ and ¼ cup with 1 tbsp, 1 tsp, ½ tsp and ¼ tsp spoons. The extended set adds ⅔ and ¾ cup. You can fill a measure more than once.",
    "An amount that is not a whole number of quarter teaspoons is measured to the nearest quarter teaspoon."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "amt": {
        "title": "Amount",
        "description": "The amount to measure, as a whole number, fraction, mixed number or decimal: 3/4, 1 2/3, 0.5.",
        "type": "string",
        "pattern": "^-?\\d+( \\d+)?(/\\d+)?$"
      },
      "unit": {
        "title": "Unit",
        "description": "The unit the amount is in.",
        "type": "string",
        "enum": [
          "cup",
          "tbsp",
          "tsp"
        ]
      },
      "set": {
        "title": "Your cups",
        "description": "Which cup sizes your set has. Both sets have 1 tbsp, 1 tsp, ½ tsp and ¼ tsp spoons.",
        "type": "string",
        "enum": [
          "basic",
          "extended"
        ]
      }
    }
  },
  "outputs": {
    "combo": {
      "label": "Use",
      "description": "The fewest measures that add up to the amount, largest first.",
      "format": "text"
    },
    "count": {
      "label": "Number of scoops",
      "description": "How many times you fill a measure.",
      "format": "integer"
    },
    "tsp": {
      "label": "Total (teaspoons)",
      "description": "The measured total in teaspoons.",
      "format": "number"
    },
    "ml": {
      "label": "Total (mL)",
      "description": "The measured total in milliliters.",
      "format": "number"
    },
    "off": {
      "label": "Short (−) or over (+), tsp",
      "description": "Measured total minus the amount, in teaspoons; 0 when it is exact.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "amt": "3/4",
      "unit": "cup",
      "set": "basic"
    },
    "outputs": {
      "combo": "½ cup + ¼ cup",
      "count": 2,
      "tsp": 36,
      "ml": 177.441177375,
      "off": 0
    },
    "text": "Use ½ cup + ¼ cup."
  },
  "examples": [
    {
      "given": {
        "amt": "3/4",
        "unit": "cup",
        "set": "basic"
      },
      "expect": {
        "combo": "½ cup + ¼ cup",
        "count": 2,
        "tsp": 36,
        "ml": 177.441177375,
        "off": 0
      },
      "source": "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz; 1 gal = 128 fl oz = 3.785411784 L), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c; hand calculation in content.mdx: ¾ cup = 144 quarter teaspoons = 96 + 48"
    },
    {
      "given": {
        "amt": "2/3",
        "unit": "cup",
        "set": "basic"
      },
      "expect": {
        "combo": "2 × ⅓ cup",
        "count": 2,
        "tsp": 32
      },
      "source": "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz; 1 gal = 128 fl oz = 3.785411784 L), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c; hand calculation in content.mdx: ⅔ cup = 128 = 64 + 64"
    },
    {
      "given": {
        "amt": "5/8",
        "unit": "cup",
        "set": "basic"
      },
      "expect": {
        "combo": "½ cup + 2 × 1 tbsp",
        "count": 3,
        "tsp": 30
      },
      "source": "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz; 1 gal = 128 fl oz = 3.785411784 L), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c; hand calculation in content.mdx: ⅝ × 192 = 120 = 96 + 12 + 12"
    },
    {
      "given": {
        "amt": "1 1/3",
        "unit": "cup",
        "set": "extended"
      },
      "expect": {
        "combo": "1 cup + ⅓ cup",
        "count": 2
      },
      "source": "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz; 1 gal = 128 fl oz = 3.785411784 L), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c; hand calculation in content.mdx: 256 = 192 + 64 = 128 + 128; the rule picks 1 cup first"
    },
    {
      "given": {
        "amt": "0.3",
        "unit": "cup",
        "set": "basic"
      },
      "expect": {
        "combo": "¼ cup + 2 × 1 tsp + ½ tsp",
        "count": 4,
        "tsp": 14.5,
        "off": 0.1
      },
      "source": "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (1 cup = 8 fl oz; 1 tablespoon = 1/2 fl oz; 1 teaspoon = 1/6 fl oz; 1 gal = 128 fl oz = 3.785411784 L), https://www.nist.gov/document/2026-nist-handbook-44-appendix-c; hand calculation in content.mdx: 0.3 × 192 = 57.6, rounded to 58 = 48 + 4 + 4 + 2",
      "tolerance": 1e-12
    }
  ],
  "sources": [
    "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement (US customary: 1 cup = 8 fluid ounces, 1 tablespoon = 1/2 fluid ounce, 1 teaspoon = 1/6 fluid ounce; 1 gallon = 128 fluid ounces = 3.785411784 liters). https://www.nist.gov/document/2026-nist-handbook-44-appendix-c (cited from the copy already in this repo; retrieved 2026-10-01)",
    "NIST Office of Weights and Measures, Metric Kitchen: Culinary Measurement Tips (US customary cups and spoons differ from metric ones; dry and liquid measuring cups). Retrieved 2026-10-18. https://www.nist.gov/pml/owm/culinary-measurement-tips"
  ],
  "related": [
    "recipe-scaler",
    "rice-water-ratio",
    "cups-to-oz"
  ],
  "changelog": []
}