{
  "id": "churn-rate",
  "version": "c6c1d7752ca4",
  "status": "published",
  "name": "Churn Rate Calculator",
  "question": "What is my churn rate?",
  "summary": "Computes the customer churn rate for a period (customers lost ÷ customers at the start × 100) and the retention rate, from customers at the start, at the end and new, or from the customers lost.",
  "category": "finance",
  "subcategory": "business",
  "url": "https://www.acalculator.org/finance/churn-rate-calculator",
  "markdown": "https://www.acalculator.org/finance/churn-rate-calculator.md",
  "kind": "function",
  "method": "Customers kept = customers at the end − new customers (or customers at the start − customers lost); churn rate = customers lost ÷ customers at the start × 100; retention rate = customers kept ÷ customers at the start × 100.",
  "assumptions": [
    "The customers lost are customers from the start of the period; new customers gained during the period are all still customers at its end.",
    "Arithmetic is exact on the typed counts; the rates show to 2 decimals."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "from": {
        "title": "I know the",
        "description": "Whether you know the customers at the start, at the end and new, or the customers lost.",
        "type": "string",
        "enum": [
          "counts",
          "lost"
        ]
      },
      "start": {
        "title": "Customers at the start",
        "description": "Customers you had at the start of the period.",
        "type": "integer",
        "minimum": 1,
        "maximum": 1000000000000
      },
      "end": {
        "title": "Customers at the end",
        "description": "Customers you had at the end of the period.",
        "type": "integer",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "new": {
        "title": "New customers",
        "description": "Customers you gained during the period.",
        "type": "integer",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "lost": {
        "title": "Customers lost",
        "description": "Customers from the start of the period who left during it.",
        "type": "integer",
        "minimum": 0,
        "maximum": 1000000000000
      }
    }
  },
  "outputs": {
    "churn": {
      "label": "Churn rate",
      "description": "Customers lost ÷ customers at the start × 100.",
      "format": "percent"
    },
    "retention": {
      "label": "Retention rate",
      "description": "(Customers at the end − new customers) ÷ customers at the start × 100, which is 100 − churn rate.",
      "format": "percent"
    },
    "customersLost": {
      "label": "Customers lost",
      "description": "Customers at the start − customers kept.",
      "format": "integer"
    },
    "kept": {
      "label": "Customers kept",
      "description": "Customers from the start who are still customers at the end.",
      "format": "integer"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "from": "counts",
      "start": 400,
      "end": 410,
      "new": 30,
      "lost": 20
    },
    "outputs": {
      "churn": 5,
      "retention": 95,
      "customersLost": 20,
      "kept": 380
    },
    "text": "20 lost out of 400 at the start is a churn rate of 5% and a retention rate of 95%."
  },
  "examples": [
    {
      "given": {
        "from": "counts",
        "start": 400,
        "end": 380,
        "new": 0
      },
      "expect": {
        "churn": 5,
        "retention": 95,
        "customersLost": 20,
        "kept": 380
      },
      "source": "HubSpot, \"Customer Churn — What It Is And Why It Matters for Every Business\" (churn rate = customers lost in the period ÷ customers at the start; 400 at the start and 380 at the end is 20 ÷ 400 = 5%). https://blog.hubspot.com/service/what-is-customer-churn; HubSpot, \"7 Ways to Boost Your Customer Retention Rate\" (retention rate = (customers at the end − new customers) ÷ customers at the start × 100%). https://blog.hubspot.com/service/customer-retention-rate: (380 − 0) ÷ 400 × 100 = 95"
    },
    {
      "given": {
        "from": "counts",
        "start": 400,
        "end": 410,
        "new": 30
      },
      "expect": {
        "churn": 5,
        "retention": 95,
        "customersLost": 20
      },
      "source": "HubSpot, \"7 Ways to Boost Your Customer Retention Rate\" (retention rate = (customers at the end − new customers) ÷ customers at the start × 100%). https://blog.hubspot.com/service/customer-retention-rate; hand calculation in content.mdx: (410 − 30) ÷ 400 × 100 = 95; 20 ÷ 400 × 100 = 5"
    },
    {
      "given": {
        "from": "lost",
        "start": 1250,
        "lost": 75
      },
      "expect": {
        "churn": 6,
        "retention": 94,
        "kept": 1175
      },
      "source": "HubSpot, \"Customer Churn — What It Is And Why It Matters for Every Business\" (churn rate = customers lost in the period ÷ customers at the start; 400 at the start and 380 at the end is 20 ÷ 400 = 5%). https://blog.hubspot.com/service/what-is-customer-churn; hand calculation in content.mdx: 75 ÷ 1,250 × 100 = 6"
    },
    {
      "given": {
        "from": "lost",
        "start": 3,
        "lost": 1
      },
      "expect": {
        "churn": 33.333333333333336,
        "retention": 66.66666666666667
      },
      "source": "HubSpot, \"Customer Churn — What It Is And Why It Matters for Every Business\" (churn rate = customers lost in the period ÷ customers at the start; 400 at the start and 380 at the end is 20 ÷ 400 = 5%). https://blog.hubspot.com/service/what-is-customer-churn; hand calculation in content.mdx: 1 ÷ 3 × 100 = 33.33"
    }
  ],
  "sources": [
    "HubSpot, \"Customer Churn — What It Is And Why It Matters for Every Business\": churn rate = customers lost during the period ÷ customers at the start of it; 400 at the start and 380 at the end is 20 ÷ 400 = 5%. https://blog.hubspot.com/service/what-is-customer-churn (retrieved 2026-10-18)",
    "HubSpot, \"7 Ways to Boost Your Customer Retention Rate\": retention rate = (customers at the end − new customers acquired during the period) ÷ customers at the start × 100%. https://blog.hubspot.com/service/customer-retention-rate (retrieved 2026-10-18)"
  ],
  "related": [
    "nrr",
    "customer-lifetime-value",
    "csat",
    "cac"
  ],
  "changelog": []
}