{
  "id": "capacitor-energy",
  "slug": "capacitor-energy-calculator",
  "url": "https://electronics.tools/tools/capacitor-energy-calculator/",
  "name": "Capacitor Energy Calculator",
  "group": "cap-ind",
  "summary": "E = ½ C V². 4700 µF at 50 V stores 5.875 J.",
  "formulas": [
    {
      "id": "energy",
      "label": "Stored energy",
      "plain": "E = ½ C V²",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"E = ½ C V²\"><mrow><mi>E</mi><mo>=</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mi>C</mi><msup><mi>V</mi><mn>2</mn></msup></mrow></math>",
      "symbols": [
        "E",
        "C",
        "V"
      ],
      "sources": [
        "energy"
      ]
    },
    {
      "id": "charge",
      "label": "Charge",
      "plain": "Q = C V",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"Q = C V\"><mrow><mi>Q</mi><mo>=</mo><mi>C</mi><mi>V</mi></mrow></math>",
      "symbols": [
        "Q",
        "C",
        "V"
      ],
      "sources": [
        "energy"
      ]
    }
  ],
  "variables": [
    {
      "symbol": "C",
      "name": "Capacitance",
      "unit": "F",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0
      },
      "default": 0.0047,
      "urlParam": "c"
    },
    {
      "symbol": "V",
      "name": "Voltage",
      "unit": "V",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "default": 50,
      "urlParam": "v"
    },
    {
      "symbol": "R",
      "name": "Resistance (optional τ)",
      "unit": "Ω",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "default": "",
      "urlParam": "r"
    },
    {
      "symbol": "E",
      "name": "Stored energy",
      "unit": "J",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "EWh",
      "name": "Stored energy",
      "unit": "Wh",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Q",
      "name": "Charge",
      "unit": "1",
      "role": "output",
      "precision": {
        "sig": 4
      }
    }
  ],
  "examples": [
    {
      "id": "4700u-50v",
      "title": "4700 µF at 50 V",
      "input": [
        {
          "symbol": "C",
          "value": 0.0047,
          "unit": "F",
          "display": "4.7 mF"
        },
        {
          "symbol": "V",
          "value": 50,
          "unit": "V",
          "display": "50 V"
        }
      ],
      "output": [
        {
          "symbol": "E",
          "value": 5.875,
          "unit": "J",
          "display": "5.875 J"
        },
        {
          "symbol": "EWh",
          "value": 0.0016319444444444445,
          "unit": "Wh",
          "display": "0.001632 Wh"
        },
        {
          "symbol": "Q",
          "value": 0.23500000000000001,
          "unit": "1",
          "display": "0.235"
        }
      ],
      "computedBy": "capacitorEnergy"
    },
    {
      "id": "100u-5v",
      "title": "100 µF at 5 V",
      "input": [
        {
          "symbol": "C",
          "value": 0.0001,
          "unit": "F",
          "display": "100 µF"
        },
        {
          "symbol": "V",
          "value": 5,
          "unit": "V",
          "display": "5 V"
        }
      ],
      "output": [
        {
          "symbol": "E",
          "value": 0.00125,
          "unit": "J",
          "display": "1.25 mJ"
        },
        {
          "symbol": "Q",
          "value": 0.0005,
          "unit": "1",
          "display": "0.0005"
        }
      ],
      "computedBy": "capacitorEnergy"
    }
  ],
  "sources": [
    {
      "title": "Electric energy stored in a capacitor (Wikipedia, textbook identity)",
      "url": "https://en.wikipedia.org/wiki/Capacitor#Energy_storage",
      "retrieved": "2026-11-02"
    }
  ],
  "datePublished": "2026-11-02T00:00:00+08:00",
  "dateModified": "2026-11-02T00:00:00+08:00",
  "author": {
    "name": "Jasper",
    "url": "https://electronics.tools/about/#jasper"
  },
  "relatedTools": [
    "https://electronics.tools/tools/rc-time-constant-calculator/",
    "https://electronics.tools/tools/capacitor-discharge-calculator/",
    "https://electronics.tools/tools/series-parallel-capacitor-calculator/"
  ]
}