📊IPI
CALCULATOR · DCF GATEWAY

How Much Are You Worth?

Warren Buffett's thought experiment from his Omaha High School lecture — turned into a calculator. The same logic as chapter 13 of «Marathon», applied not to a company but to a person: future cash flows, discounted to today.

Buffett sets the scene like this: «Imagine I came to you and wanted to buy 10% of your financial future. I'll write you a check today — from this day forward, you give me 10% of everything you earn. How much would you charge me?» He says: minimum $50,000. Which means the whole person is worth at least $500,000 today — and that's «the main financial asset you own».

«Far more important is what you do with that $500,000 asset you own today than whether you decide to buy stocks or bonds, put your money in a mutual fund, or start your own business.»
Step 1. Your Gut Price
What you'd charge for 10% of your future
$20 000
A gut number — before any calculation. Change it on the right.
Step 2. DCF Calculation
NPV of all your future earnings
$319 400
The discounted value of everything you'll earn until retirement. That's your fair value today.
Value of 10%
$31 940
Buffett's deal price
Undiscounted
$1 026 250
Sum of all earnings, raw
Real value in 1959 dollars
Slight underestimate. You're asking $20 000 for 10%, the math gives $31 940. A 37% difference — Buffett gets a decent margin of safety on this deal.

Cash Flow by Year

Dark column — nominal annual income. Light — same, discounted to today. Time eats future earnings.

Sensitivity to Assumptions

How much your NPV changes when one parameter shifts. The analog of «how assumptions break DCF» from chapter 13.

ScenarioNPVChangeValue of 10%
Base scenario$319 400$31 940
Discount rate +2 pp$237 526-25.6%$23 753
Discount rate −2 pp$448 593+40.4%$44 859
Peak income +25%$385 363+20.7%$38 536
Peak income −25%$253 437-20.7%$25 344
Years working +10$341 582+6.9%$34 158
Years working −10$279 674-12.4%$27 967

Why IPI as a discount rate?

The discount rate is your alternative real return — what your money would earn if you didn't have the income stream. IPI tracks the real growth of the US investment portfolio (stocks + real estate + bonds + cash), so IPI CAGR is a defensible long-run real rate. CPI-based real Treasury yields understate this because CPI tracks consumer goods, not investable assets.

Read methodology →

What This Experiment Shows

1. The main asset isn't your portfolio — it's you. For most people the PV of future salary is 5–20× larger than their current securities portfolio. The decision «how to use your own 200 hp engine» weighs more than the choice «stocks or bonds».

2. Current earnings ≠ fair value. A student with zero income today is worth $500,000+ if they have a career ahead. Same way Amazon with zero profit in 2000 wasn't worth zero — it was worth future cash flows.

3. Discount rate decides everything. A 2 pp shift in rate changes your fair value by multiples. The same sensitivity breaks any company DCF when the Fed moves rates.

4. Time is a double-edged sword. Every «frozen» year early in your career is a year when the investor (Buffett) gets nothing. But he's buying the trajectory, not the current flow. Same as the market does with Tesla, NVDA, Eli Lilly: paying for the trajectory, not TTM.