{
  "slug": "email-subscriber-lifetime-value-calculator",
  "title": "Email Subscriber Lifetime Value Calculator",
  "heading": "Email Subscriber LTV Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/email-subscriber-lifetime-value-calculator",
  "summary": "What a new email signup is worth over its full life on your list, not just this month.",
  "description": "A monthly revenue-per-subscriber number understates what a signup is actually worth, because it ignores how long that person stays engaged before they unsubscribe or go inactive. This calculator takes your average monthly revenue per active subscriber and your monthly list churn rate (unsubscribes plus going permanently unengaged) to compute expected subscriber lifespan and total lifetime value, the same logic used for customer LTV but applied to the list itself. It also converts that into a maximum sustainable cost per new subscriber acquired, so you can set sane bids on lead-gen ads, giveaways, or co-registration deals without guessing. A list with 3% monthly churn has an expected lifespan of roughly 33 months, while a list bleeding 12% monthly churn only lasts about 8 months — the same monthly revenue per subscriber produces a completely different acquisition budget in each case. This matters because email is often the highest-margin channel a company has (no per-send platform tax, no auction pricing), so understating its per-subscriber value leads to under-investing in list growth relative to its real payback.",
  "formula": "Expected lifespan (months) = 1 ÷ monthly churn rate; LTV = monthly revenue per subscriber × expected lifespan × margin.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=email-subscriber-lifetime-value-calculator",
  "inputs": [
    {
      "id": "monthlyRevPerSub",
      "label": "Monthly revenue per active subscriber",
      "kind": "number",
      "hint": null,
      "default": 1.4,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "monthlyChurn",
      "label": "Monthly list churn (unsub + inactive)",
      "kind": "number",
      "hint": null,
      "default": 3.5,
      "unit": "%",
      "min": 0.1,
      "max": 50
    },
    {
      "id": "margin",
      "label": "Contribution margin on that revenue",
      "kind": "number",
      "hint": null,
      "default": 55,
      "unit": "%",
      "min": 1,
      "max": 100
    },
    {
      "id": "targetCacRatio",
      "label": "Target LTV:CAC ratio for signups",
      "kind": "number",
      "hint": null,
      "default": 3,
      "unit": null,
      "min": 0.5,
      "max": 10
    }
  ],
  "outputs": [
    {
      "id": "ltv",
      "label": "Subscriber lifetime value",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "lifespanMonths",
      "label": "Expected subscriber lifespan",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "maxCac",
      "label": "Max sustainable cost per new subscriber",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "annualValue",
      "label": "Contribution value per subscriber per year",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Monthly revenue per active subscriber: 1.4 $",
      "Monthly list churn (unsub + inactive): 3.5 %",
      "Contribution margin on that revenue: 55 %",
      "Target LTV:CAC ratio for signups: 3"
    ],
    "outputs": [
      "Subscriber lifetime value: $22.00",
      "Expected subscriber lifespan: 28.6",
      "Max sustainable cost per new subscriber: $7.33",
      "Contribution value per subscriber per year: $9.24"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter monthly revenue per active subscriber ($).",
      "Enter monthly list churn (unsub + inactive) (%).",
      "Enter contribution margin on that revenue (%).",
      "Enter target ltv:cac ratio for signups.",
      "Read your subscriber lifetime value 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": {
        "monthlyRevPerSub": 0.84,
        "monthlyChurn": 2.1,
        "margin": 33,
        "targetCacRatio": 1.7999999999999998
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "monthlyRevPerSub": 1.4,
        "monthlyChurn": 3.5,
        "margin": 55,
        "targetCacRatio": 3
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "monthlyRevPerSub": 2.2399999999999998,
        "monthlyChurn": 5.6000000000000005,
        "margin": 88,
        "targetCacRatio": 4.800000000000001
      }
    }
  ],
  "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": "How do I measure monthly list churn accurately?",
      "a": "Count unsubscribes plus anyone who goes from engaged to unengaged status (no opens or clicks in 90-120 days) in a given month, divided by active subscribers at the start of the month. Don't count hard bounces from list cleaning as churn if they were never truly active."
    },
    {
      "q": "Why include contribution margin instead of raw revenue?",
      "a": "Revenue per subscriber includes the cost of the product you're shipping. What you can actually afford to spend acquiring a subscriber is bounded by the profit that revenue generates, not the top-line number, same as any CAC calculation."
    },
    {
      "q": "What's a reasonable LTV:CAC ratio for list growth tactics?",
      "a": "3:1 is the common floor used across acquisition channels generally. Email list growth often supports lower ratios like 2:1 to 2.5:1 because the ongoing cost to serve a subscriber (ESP fees) is near zero, unlike paid customer acquisition with real cost of goods."
    },
    {
      "q": "Does this account for re-engagement campaigns extending lifespan?",
      "a": "Not directly — if you run active win-back flows that recover a meaningful share of about-to-churn subscribers, your effective churn rate should already reflect that recovery. Measure churn after re-engagement efforts, not before."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/seo-traffic-value-calculator",
    "https://www.revenuelab.fyi/toolbox/marketing-budget-payback-allocator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Email Subscriber Lifetime Value Calculator (https://www.revenuelab.fyi/toolbox/email-subscriber-lifetime-value-calculator)"
}