{
  "id": "year-over-year",
  "version": "c40e28f133b6",
  "status": "published",
  "name": "Year Over Year Growth Calculator",
  "question": "What is my year over year growth?",
  "summary": "Finds year over year growth in percent from a value last year and the same value this year, with the change in units.",
  "category": "math",
  "subcategory": "arithmetic",
  "url": "https://www.acalculator.org/math/year-over-year-calculator",
  "markdown": "https://www.acalculator.org/math/year-over-year-calculator.md",
  "kind": "function",
  "method": "Growth = (this year − last year) ÷ |last year| × 100.",
  "assumptions": [
    "Growth is measured against the size of last year’s value, so a rise from −50 to 25 is +150%.",
    "Last year’s value must not be 0.",
    "Both values cover the same length of time, such as the same quarter one year apart."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "from": {
        "title": "Last year",
        "description": "The value for the earlier period, such as last year’s sales. Not 0.",
        "type": "number"
      },
      "to": {
        "title": "This year",
        "description": "The value for the same period one year later.",
        "type": "number"
      }
    }
  },
  "outputs": {
    "growth": {
      "label": "Year over year growth",
      "description": "The change from last year to this year as a percent of the size of last year’s value.",
      "format": "percent"
    },
    "difference": {
      "label": "Change",
      "description": "This year minus last year.",
      "format": "number"
    },
    "direction": {
      "label": "Growth or decline",
      "description": "Whether the value went up, went down, or stayed the same.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "from": 2500000,
      "to": 2875000
    },
    "outputs": {
      "growth": 15,
      "difference": 375000,
      "direction": "Growth"
    },
    "text": "From 2,500,000 to 2,875,000 is a change of 15% year over year."
  },
  "examples": [
    {
      "given": {
        "from": 2500000,
        "to": 2875000
      },
      "expect": {
        "growth": 15,
        "difference": 375000,
        "direction": "Growth"
      },
      "source": "hand calculation in content.mdx: 375,000 ÷ 2,500,000 = 15%; OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and percent decrease: the change as a percent of the original amount; $26 to $36 is 38.5%, $3.71 to $3.64 is 1.9%), https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications (retrieved 2026-11-01)"
    },
    {
      "given": {
        "from": 26,
        "to": 36
      },
      "expect": {
        "growth": 38.46153846153846,
        "difference": 10,
        "direction": "Growth"
      },
      "source": "OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and percent decrease: the change as a percent of the original amount; $26 to $36 is 38.5%, $3.71 to $3.64 is 1.9%), https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications (retrieved 2026-11-01); Python 3 in docs/progress/WP-149/crosscheck.py"
    },
    {
      "given": {
        "from": 3.71,
        "to": 3.64
      },
      "expect": {
        "growth": -1.8867924528301887,
        "difference": -0.07,
        "direction": "Decline"
      },
      "source": "OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and percent decrease: the change as a percent of the original amount; $26 to $36 is 38.5%, $3.71 to $3.64 is 1.9%), https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications (retrieved 2026-11-01); Python 3 in docs/progress/WP-149/crosscheck.py"
    },
    {
      "given": {
        "from": -50,
        "to": 25
      },
      "expect": {
        "growth": 150,
        "difference": 75,
        "direction": "Growth"
      },
      "source": "hand calculation in content.mdx: 75 ÷ |−50| = 150%; OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and percent decrease: the change as a percent of the original amount; $26 to $36 is 38.5%, $3.71 to $3.64 is 1.9%), https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications (retrieved 2026-11-01)"
    },
    {
      "given": {
        "from": 80,
        "to": 80
      },
      "expect": {
        "growth": 0,
        "difference": 0,
        "direction": "No change"
      },
      "source": "hand calculation in content.mdx; OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and percent decrease: the change as a percent of the original amount; $26 to $36 is 38.5%, $3.71 to $3.64 is 1.9%), https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications (retrieved 2026-11-01)"
    }
  ],
  "sources": [
    "OpenStax, Elementary Algebra 2e, section 3.2 Solve Percent Applications (percent increase and decrease are the change as a percent of the original amount; $26 to $36 is 38.5%; $3.71 to $3.64 is 1.9%). Retrieved 2026-11-01. https://openstax.org/books/elementary-algebra-2e/pages/3-2-solve-percent-applications"
  ],
  "related": [
    "percentage-change",
    "percentage-increase",
    "percentage"
  ],
  "changelog": []
}