{
  "slug": "endowment-spending-rate",
  "title": "Endowment Spending Rate Calculator",
  "heading": "Endowment Spending Rate Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/endowment-spending-rate",
  "summary": "Find a sustainable spending rate that preserves purchasing power.",
  "description": "Most institutional endowments spend 4-5% annually, a rate designed to balance current program funding against preserving the endowment's real purchasing power for future generations. This calculator checks whether your proposed spending rate is sustainable given your expected long-term investment return and inflation assumption: if your spending rate exceeds expected return minus inflation minus fees, the endowment will erode in real terms even if the nominal balance grows. It applies the rate to a trailing average balance (commonly 12 or 20 quarter rolling average) rather than the current point-in-time balance, which is standard practice because it smooths spending through market volatility and avoids overspending after a single strong year or panicking after a single bad one.",
  "formula": "Sustainable rate ≈ expected return − inflation − fees; spending $ = rate × trailing avg balance.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=endowment-spending-rate",
  "inputs": [
    {
      "id": "balance",
      "label": "Trailing average endowment balance",
      "kind": "number",
      "hint": null,
      "default": 5000000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "spendingRate",
      "label": "Proposed spending rate",
      "kind": "number",
      "hint": null,
      "default": 4.5,
      "unit": "%",
      "min": 0,
      "max": 15
    },
    {
      "id": "expectedReturn",
      "label": "Expected long-term nominal return",
      "kind": "number",
      "hint": null,
      "default": 7,
      "unit": "%",
      "min": 0,
      "max": 20
    },
    {
      "id": "inflation",
      "label": "Expected inflation",
      "kind": "number",
      "hint": null,
      "default": 2.5,
      "unit": "%",
      "min": 0,
      "max": 10
    },
    {
      "id": "fees",
      "label": "Investment/admin fees",
      "kind": "number",
      "hint": null,
      "default": 0.6,
      "unit": "%",
      "min": 0,
      "max": 5
    }
  ],
  "outputs": [
    {
      "id": "spendAmount",
      "label": "Annual spending amount",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "sustainableRate",
      "label": "Sustainable spending rate",
      "format": "percent",
      "hint": null,
      "primary": false
    },
    {
      "id": "gap",
      "label": "Cushion (or deficit) vs proposed rate",
      "format": "percent",
      "hint": null,
      "primary": false
    },
    {
      "id": "realGrowthDollars",
      "label": "Real dollar growth (or erosion) per year",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Trailing average endowment balance: 5000000 $",
      "Proposed spending rate: 4.5 %",
      "Expected long-term nominal return: 7 %",
      "Expected inflation: 2.5 %",
      "Investment/admin fees: 0.6 %"
    ],
    "outputs": [
      "Annual spending amount: $225,000",
      "Sustainable spending rate: 3.90%",
      "Cushion (or deficit) vs proposed rate: -0.60%",
      "Real dollar growth (or erosion) per year: -$30,000"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter trailing average endowment balance ($).",
      "Enter proposed spending rate (%).",
      "Enter expected long-term nominal return (%).",
      "Enter expected inflation (%).",
      "Enter investment/admin fees (%).",
      "Read your annual spending amount 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": {
        "balance": 3000000,
        "spendingRate": 2.6999999999999997,
        "expectedReturn": 4.2,
        "inflation": 1.5,
        "fees": 0.36
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "balance": 5000000,
        "spendingRate": 4.5,
        "expectedReturn": 7,
        "inflation": 2.5,
        "fees": 0.6
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "balance": 8000000,
        "spendingRate": 7.2,
        "expectedReturn": 11.200000000000001,
        "inflation": 4,
        "fees": 0.96
      }
    }
  ],
  "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 a trailing average balance instead of today's balance?",
      "a": "A rolling 12- or 20-quarter average smooths out market swings so program spending doesn't spike after a great year and doesn't get slashed after a downturn. Most college and foundation endowment policies specify this explicitly in their spending policy documents."
    },
    {
      "q": "Is 4-5% the right rate for every organization?",
      "a": "It's the common range (NACUBO surveys show average rates near 4.5-5% for institutional endowments), but a smaller endowment with a shorter time horizon, or one supporting a program that can flex spending down in bad years, might sustainably run higher. Perpetual endowments meant to fund an operation forever should stay conservative."
    },
    {
      "q": "What happens if my gap is negative?",
      "a": "A negative gap means you're spending faster than the endowment can regenerate after inflation and fees, so real purchasing power shrinks every year even while the nominal dollar balance might still rise. That's sometimes an intentional decision (e.g., a term-limited endowment meant to spend down), but it should be a board decision, not an accident."
    },
    {
      "q": "Does state UPMIFA law affect what I can spend?",
      "a": "Yes. Most states have adopted the Uniform Prudent Management of Institutional Funds Act, which generally prohibits spending below 'historic dollar value' preservation in most cases and requires a documented prudent process for setting the spending rate, not just picking a number."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/donor-advised-fund-payout",
    "https://www.revenuelab.fyi/toolbox/restricted-fund-drawdown"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Endowment Spending Rate Calculator (https://www.revenuelab.fyi/toolbox/endowment-spending-rate)"
}