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Endowment Spending Policy Calculator

Annual distribution, real growth, and corpus purchasing power over time.

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Rex says

Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.

Try a scenario

Click to load — tweak from there.

Inputs

Result

First-year distribution

$225,000

Corpus at horizon (nominal)

$10,591,283

Corpus in today's dollars

$5,575,252

Purchasing power vs today

111.5%

Total distributed over the period

$8,430,771

Annual real growth rate

-0.95%

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How to use this

  1. 1Enter endowment corpus ($).
  2. 2Enter spending rate (%).
  3. 3Enter expected nominal return (%).
  4. 4Enter inflation (%).
  5. 5Enter investment & admin fees (%).
  6. 6Enter new gifts to corpus per year ($).
  7. 7Enter years to project.
  8. 8Read your first-year distribution on the right — it updates as you type.
  9. 9Hit Share to keep the scenario or send it to someone.

About this calculator

A spending policy is a bet that returns exceed payout plus inflation plus fees. Project the annual distribution under a rolling-average policy and see whether the endowment's purchasing power grows, holds, or erodes across decades.

FormulaPayout = corpus × rate; real growth = return − payout − inflation − fees.

Worked example

Using the values the calculator loads with:

Inputs

  • Endowment corpus: 5000000 $
  • Spending rate: 4.5 %
  • Expected nominal return: 7 %
  • Inflation: 2.6 %
  • Investment & admin fees: 0.85 %
  • New gifts to corpus per year: 100000 $
  • Years to project: 25

Results

  • First-year distribution: $225,000
  • Corpus at horizon (nominal): $10,591,283
  • Corpus in today's dollars: $5,575,252
  • Purchasing power vs today: 111.5%
  • Total distributed over the period: $8,430,771
  • Annual real growth rate: -0.95%

What each field means

Inputs

Endowment corpus ($)
The endowment corpus used in the calculation, measured in $. Starts at 5000000 $ so you have a working example on load.
Spending rate (%)
The spending rate used in the calculation, measured in %. Starts at 4.5 % so you have a working example on load. Accepted range: 0–12 %.
Expected nominal return (%)
The expected nominal return used in the calculation, measured in %. Starts at 7 % so you have a working example on load. Accepted range: -5–20 %.
Inflation (%)
The inflation used in the calculation, measured in %. Starts at 2.6 % so you have a working example on load. Accepted range: 0–15 %.
Investment & admin fees (%)
The investment & admin fees used in the calculation, measured in %. Starts at 0.85 % so you have a working example on load. Accepted range: 0–5 %.
New gifts to corpus per year ($)
The new gifts to corpus per year used in the calculation, measured in $. Starts at 100000 $ so you have a working example on load.
Years to project
The years to project used in the calculation. Starts at 25 so you have a working example on load. Accepted range: 1–75.

Results

First-year distribution
Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Corpus at horizon (nominal)
Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Corpus in today's dollars
Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Purchasing power vs today
Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Total distributed over the period
Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Annual real growth rate
Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.

FAQ

Why is 4–5% the standard spending rate?

It is roughly what a diversified portfolio can distribute while still covering inflation and fees. Push past 6% and the endowment usually shrinks in real terms across a full market cycle.

What is a rolling-average policy?

Applying the spending rate to the trailing 12- or 20-quarter average market value rather than the current value. It smooths distributions so a bad market year does not force a sudden program cut.

Accuracy and 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.

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Cite this calculator

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APA
RevenueLab. (2026). Endowment Payout Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/endowment-payout
HTML
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/endowment-payout" target="_blank" rel="noopener">Endowment Payout Calculator — RevenueLab</a> (2026).</p>
Markdown
Source: [Endowment Payout Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/endowment-payout) (2026).
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