{
  "slug": "blended-cac-mer",
  "title": "Blended CAC vs MER Calculator",
  "heading": "Blended CAC & MER Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/blended-cac-mer",
  "summary": "Total marketing spend against total revenue and new customers, not per-channel math.",
  "description": "Channel-level ROAS gets distorted by attribution — a customer who saw a Meta ad, searched on Google, then bought through email gets credited multiple times or not at all depending on the platform's model. Blended CAC and MER solve this by looking at total marketing spend across every channel against total revenue and total new customers for the same period, giving you a number that can't be gamed by attribution windows. This calculator takes your total marketing spend for a period, total revenue for that period, and total new customers acquired, and computes blended CAC (spend ÷ new customers) and MER (revenue ÷ spend). Enter total spend across all paid channels, total revenue including repeat customers, and new customer count for the same window. The output shows blended CAC, MER, and the implied average order value contribution needed to be profitable, which is the real health check for your marketing efficiency versus any single platform's self-reported ROAS.",
  "formula": "Blended CAC = total spend ÷ new customers; MER = total revenue ÷ total spend.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=blended-cac-mer",
  "inputs": [
    {
      "id": "spend",
      "label": "Total marketing spend (period)",
      "kind": "number",
      "hint": null,
      "default": 18000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "revenue",
      "label": "Total revenue (same period)",
      "kind": "number",
      "hint": null,
      "default": 72000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "newCustomers",
      "label": "New customers acquired",
      "kind": "number",
      "hint": null,
      "default": 450,
      "unit": null,
      "min": 1,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "blendedCac",
      "label": "Blended CAC",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "mer",
      "label": "MER (revenue ÷ spend)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "spendPctOfRevenue",
      "label": "Marketing spend as % of revenue",
      "format": "percent",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Total marketing spend (period): 18000 $",
      "Total revenue (same period): 72000 $",
      "New customers acquired: 450"
    ],
    "outputs": [
      "Blended CAC: $40.00",
      "MER (revenue ÷ spend): 4",
      "Marketing spend as % of revenue: 25.0%"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter total marketing spend (period) ($).",
      "Enter total revenue (same period) ($).",
      "Enter new customers acquired.",
      "Read your blended cac 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": {
        "spend": 11000,
        "revenue": 43000,
        "newCustomers": 270
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "spend": 18000,
        "revenue": 72000,
        "newCustomers": 450
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "spend": 29000,
        "revenue": 115000,
        "newCustomers": 720
      }
    }
  ],
  "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": "Why use MER instead of platform-reported ROAS?",
      "a": "Platform ROAS is self-attributed and inflated by overlapping attribution windows across Meta, Google, TikTok, and email. MER uses your actual total revenue and total spend from your own financial data, so it can't double-count a conversion the way multiple platforms claiming credit for the same sale can."
    },
    {
      "q": "What's a healthy MER for a growing DTC brand?",
      "a": "Most established brands run MER between 2.5 and 4.5 depending on margin structure; higher-margin categories like apparel or beauty can sustain lower MER (more spend relative to revenue) than thin-margin categories like food or low-cost commodities."
    },
    {
      "q": "Does blended CAC include organic and repeat customers?",
      "a": "This version only counts new customers in the denominator, which is standard for CAC. Revenue in the MER calculation typically includes total revenue (new plus repeat), which is intentional since a lot of paid spend indirectly drives repeat purchase behavior too."
    },
    {
      "q": "How often should I calculate blended CAC and MER?",
      "a": "Weekly for fast-moving paid social spend and monthly for a stable trend line. Daily numbers are too noisy given normal week-to-week conversion variance, but waiting a full quarter means you react to problems too late."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/break-even-roas",
    "https://www.revenuelab.fyi/toolbox/repeat-purchase-ltv",
    "https://www.revenuelab.fyi/toolbox/shopify-margin-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Blended CAC vs MER Calculator (https://www.revenuelab.fyi/toolbox/blended-cac-mer)"
}