{
  "id": "pi-attenuator",
  "slug": "pi-attenuator-calculator",
  "url": "https://electronics.tools/tools/pi-attenuator-calculator/",
  "name": "Pi Attenuator Calculator",
  "group": "rf",
  "summary": "A 10 dB pi attenuator for 50 Ω uses R1 = 96.25 Ω (shunt) and R2 = 71.15 Ω (series).",
  "formulas": [
    {
      "id": "k",
      "label": "Voltage ratio",
      "plain": "K = 10^(A/20)",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"K = 10^(A/20)\"><mrow><mi>K</mi><mo>=</mo><msup><mn>10</mn><mrow><mi>A</mi><mo>/</mo><mn>20</mn></mrow></msup></mrow></math>",
      "symbols": [
        "K",
        "A"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "parasitics",
      "label": "High attenuation",
      "plain": "A above 60 dB: parasitics dominate; values are theoretical",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"A above 60 dB: parasitics dominate; values are theoretical\"><mrow><mi>A</mi><mo>&gt;</mo><mn>60</mn><mspace width=\"0.167em\"></mspace><mtext>dB</mtext></mrow></math>",
      "symbols": [
        "A"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "e96",
      "label": "Preferred values",
      "plain": "E96 nearest preferred values",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"E96 nearest preferred values\"><mrow><msub><mi>R</mi><mtext>E96</mtext></msub><mo>=</mo><mtext>nearest</mtext><mspace width=\"0.167em\"></mspace><mi>E</mi><mn>96</mn><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math>",
      "symbols": [
        "RshE96",
        "RseE96"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "net",
      "label": "Pi Attenuator Calculator",
      "plain": "Rsh = Z0 (K+1)/(K−1); Rse = Z0 (K²−1)/(2K)",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"Rsh = Z0 (K+1)/(K−1); Rse = Z0 (K²−1)/(2K)\"><mrow><msub><mi>R</mi><mtext>sh</mtext></msub><mo>=</mo><msub><mi>Z</mi><mn>0</mn></msub><mfrac><mrow><mi>K</mi><mo>+</mo><mn>1</mn></mrow><mrow><mi>K</mi><mo>-</mo><mn>1</mn></mrow></mfrac><mo>,</mo><mspace width=\"0.278em\"></mspace><msub><mi>R</mi><mtext>se</mtext></msub><mo>=</mo><msub><mi>Z</mi><mn>0</mn></msub><mfrac><mrow><msup><mi>K</mi><mn>2</mn></msup><mo>-</mo><mn>1</mn></mrow><mrow><mn>2</mn><mi>K</mi></mrow></mfrac></mrow></math>",
      "symbols": [
        "Rsh",
        "Z0",
        "K",
        "Rse"
      ],
      "sources": [
        "itt"
      ]
    }
  ],
  "variables": [
    {
      "symbol": "A",
      "name": "Attenuation",
      "unit": "dB",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0,
        "note": "A must be > 0"
      },
      "default": 10,
      "urlParam": "a"
    },
    {
      "symbol": "Z0",
      "name": "Characteristic impedance",
      "unit": "Ω",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0
      },
      "default": 50,
      "urlParam": "z0"
    },
    {
      "symbol": "Pin",
      "name": "Input power (optional)",
      "unit": "W",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0
      },
      "default": "",
      "urlParam": "pin"
    },
    {
      "symbol": "K",
      "name": "Voltage ratio",
      "unit": "1",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Zin",
      "name": "Input impedance",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "AdB",
      "name": "Ideal attenuation",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "AE96",
      "name": "E96 attenuation",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RL",
      "name": "Return loss",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Rsh",
      "name": "Shunt resistor",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Rse",
      "name": "Series resistor",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RshE96",
      "name": "Shunt E96",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RseE96",
      "name": "Series E96",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "PshIn",
      "name": "Input shunt dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Pse",
      "name": "Series dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "PshOut",
      "name": "Output shunt dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Pload",
      "name": "Load power",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    }
  ],
  "examples": [
    {
      "id": "10db-50",
      "title": "10 dB / 50 Ω",
      "input": [
        {
          "symbol": "A",
          "value": 10,
          "unit": "dB",
          "display": "10 dB"
        },
        {
          "symbol": "Z0",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        }
      ],
      "output": [
        {
          "symbol": "K",
          "value": 3.1622776601683795,
          "unit": "1",
          "display": "3.162"
        },
        {
          "symbol": "AdB",
          "value": 10,
          "unit": "dB",
          "display": "10 dB"
        },
        {
          "symbol": "AE96",
          "value": 10.049258899998236,
          "unit": "dB",
          "display": "10.05 dB"
        },
        {
          "symbol": "Zin",
          "value": 50.000000000000014,
          "unit": "Ω",
          "display": "50 Ω"
        },
        {
          "symbol": "Rsh",
          "value": 96.24752955742645,
          "unit": "Ω",
          "display": "96.25 Ω"
        },
        {
          "symbol": "Rse",
          "value": 71.15124735378855,
          "unit": "Ω",
          "display": "71.15 Ω"
        }
      ],
      "computedBy": "compute"
    },
    {
      "id": "6db-50",
      "title": "6 dB / 50 Ω",
      "input": [
        {
          "symbol": "A",
          "value": 6,
          "unit": "dB",
          "display": "6 dB"
        },
        {
          "symbol": "Z0",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        }
      ],
      "output": [
        {
          "symbol": "AdB",
          "value": 6,
          "unit": "dB",
          "display": "6 dB"
        },
        {
          "symbol": "K",
          "value": 1.9952623149688795,
          "unit": "1",
          "display": "1.995"
        }
      ],
      "computedBy": "compute"
    }
  ],
  "sources": [
    {
      "title": "Attenuator (electronics)",
      "url": "https://en.wikipedia.org/wiki/Attenuator_(electronics)",
      "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/tee-attenuator-calculator/",
    "https://electronics.tools/tools/bridged-tee-attenuator-calculator/",
    "https://electronics.tools/tools/dbm-to-watts/"
  ]
}