{
  "slug": "subscription-box-unit-economics",
  "title": "Subscription Box Unit Economics Calculator",
  "heading": "Subscription Box Unit Economics Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/subscription-box-unit-economics",
  "summary": "CAC payback period and LTV for recurring box subscriptions.",
  "description": "Subscription boxes live and die on payback period and churn, not just gross margin on the box itself. A box that's profitable on paper can still bankrupt a company if it takes eight months to recover acquisition cost and average customers churn at month five. This calculator takes your monthly subscription price, cost per box (product + packaging + shipping), customer acquisition cost, and monthly churn rate, and computes contribution margin per box, expected customer lifetime in months, total lifetime value, and CAC payback period in months. Enter subscription price, cost per box, CAC, and monthly churn rate as a percentage. The output shows months to recover CAC and total LTV, which together tell you whether your growth is sustainable or whether you're funding growth by burning cash faster than subscriptions replace it, a common failure mode in box subscription businesses that scale acquisition before fixing retention.",
  "formula": "Expected lifetime (months) = 1 ÷ monthly churn%; CM/box = price − cost per box; LTV = CM/box × lifetime; Payback months = CAC ÷ CM/box.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=subscription-box-unit-economics",
  "inputs": [
    {
      "id": "price",
      "label": "Monthly subscription price",
      "kind": "number",
      "hint": null,
      "default": 39,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "costPerBox",
      "label": "Cost per box (product+pack+ship)",
      "kind": "number",
      "hint": null,
      "default": 22,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "cac",
      "label": "Customer acquisition cost",
      "kind": "number",
      "hint": null,
      "default": 45,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "churnRate",
      "label": "Monthly churn rate",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0.5,
      "max": 100
    }
  ],
  "outputs": [
    {
      "id": "paybackMonths",
      "label": "CAC payback period",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "ltv",
      "label": "Lifetime value",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "lifetimeMonths",
      "label": "Expected customer lifetime",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "cmBox",
      "label": "Contribution margin per box",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "ltvCacRatio",
      "label": "LTV : CAC ratio",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Monthly subscription price: 39 $",
      "Cost per box (product+pack+ship): 22 $",
      "Customer acquisition cost: 45 $",
      "Monthly churn rate: 10 %"
    ],
    "outputs": [
      "CAC payback period: 2.6",
      "Lifetime value: $170",
      "Expected customer lifetime: 10",
      "Contribution margin per box: $17.00",
      "LTV : CAC ratio: 3.78"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter monthly subscription price ($).",
      "Enter cost per box (product+pack+ship) ($).",
      "Enter customer acquisition cost ($).",
      "Enter monthly churn rate (%).",
      "Read your cac payback period on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "price": 23,
        "costPerBox": 13,
        "cac": 27,
        "churnRate": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "price": 39,
        "costPerBox": 22,
        "cac": 45,
        "churnRate": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "price": 62,
        "costPerBox": 35,
        "cac": 72,
        "churnRate": 16
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "What's a safe CAC payback period for a subscription box?",
      "a": "Under 3 months is strong, 3-6 months is workable if you have cash reserves to fund the gap, and over 6 months is risky unless you have outside funding, since you're financing growth from your balance sheet rather than from the subscriptions themselves."
    },
    {
      "q": "How does churn rate affect LTV so dramatically?",
      "a": "Expected lifetime is the inverse of churn rate, so dropping monthly churn from 10% to 7% extends expected lifetime from 10 months to over 14 months, a 40%+ LTV increase from a change that often costs less to achieve than acquiring more customers."
    },
    {
      "q": "Is 1 ÷ churn rate an accurate lifetime estimate?",
      "a": "It's a standard approximation assuming constant (geometric) churn each month, which is reasonably accurate for many subscription businesses after the first couple of months, though early cancellation spikes in month one or two can make real average lifetime a bit shorter than this formula suggests."
    },
    {
      "q": "What's a good LTV:CAC ratio for a box subscription?",
      "a": "3:1 or higher is the standard healthy benchmark. Below 2:1 usually means you need to either raise price, cut churn, or lower acquisition cost before scaling ad spend further, since growth just accelerates the cash burn."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/repeat-purchase-ltv",
    "https://www.revenuelab.fyi/toolbox/blended-cac-mer",
    "https://www.revenuelab.fyi/toolbox/packaging-cost-per-order"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Subscription Box Unit Economics Calculator (https://www.revenuelab.fyi/toolbox/subscription-box-unit-economics)"
}