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flowchart TD
TotalWealth(["Your Total<br>Economic Wealth"]) --> HumanCapital("Human Capital:<br/>Future Earning Potential")
TotalWealth --> FinancialCapital("Financial Capital:<br/>Investments & Savings")
HumanCapital --> EarlyCareer("Early Career:<br/>Human Capital is HUGE")
FinancialCapital --> EarlyCareer2("Early Career:<br/>Financial Capital is small")
EarlyCareer --> Implication["Implication:<br>Invest in Skills,<br/>Education &<br>Career Growth"]
EarlyCareer2 --> Implication2("Implication:<br>Take More Stock<br>Market Risk When Young")
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style FinancialCapital fill:#0e9aa7,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
style EarlyCareer fill:#0e9aa7,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
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style Implication fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
style Implication2 fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
1 Income
Building wealth doesn’t start with picking the right stock or finding a hot investment; it starts with how you manage the money flowing in and out of your life. Let’s break down the foundational principles.
One thing to know before your first paycheck: your salary (gross pay) isn’t what lands in your bank account. Your employer first takes out federal and state income tax, Social Security and Medicare (7.65% combined), and anything you contribute to a 401(k) or health plan. What’s left is your take-home pay, the number you should plan around. On a $45,000 salary, take-home pay is often around $2,700 to $3,000 a month, depending on your state and benefits. The Taxes chapter explains each of these deductions.
1.1 Some Core Truths
Here’s a counterintuitive insight from Morgan Housel1:
“Wealth is the nice cars not purchased. The diamonds not bought. The watches not worn, the clothes forgone and the first-class upgrade declined. Wealth is financial assets that haven’t yet been converted into the stuff you see.” (Morgan Housel)
The person driving the flashy car isn’t necessarily wealthy; they just spent their money on a car. True wealth is the income you didn’t spend, quietly compounding in the background.
Ben Felix reinforces this with hard data. Research consistently shows that conspicuous consumption (signaling wealth through purchases) is negatively correlated with actual wealth.2 People who look rich usually aren’t, while the truly rich typically live below their income level.
1.2 Your Human Capital
One of Felix’s most powerful contributions is reframing how we think about income itself. He encourages investors to view themselves as having two forms of capital: human capital (your ability to earn money in the future) and financial capital (the money you’ve already saved and invested). When you’re young, your single biggest asset is your future earning potential.
During this time, investing in skills, education, and career mobility will return more than any portfolio decision. Income growth, especially early in your career, is one of the most powerful wealth-building levers available. Time and energy spent developing valuable skills can pay off in later years (when these resources are less readily available).
1.3 Spending and Happiness
The academic research on money and well-being tends to show some practical conclusions:
- Experiences beat possessions. Research shows experiential purchases generate more lasting happiness than material ones.3 Choose a vacation or night out over new clothes or toys.
- Buying time is one of the highest-return uses of money. Outsourcing tasks you dislike (cleaning, lawn care, commuting time) correlates strongly with life satisfaction.4 Real wealth should be measured in not doing things you don’t like to do (and more time spent doing things you like to do).
- Lifestyle inflation is the silent killer. Hedonic adaptation means each lifestyle upgrade quickly becomes the new baseline, but the financial commitment remains permanent.5 This is the classic “keeping up with the Joneses” trap: avoid external comparisons of material wealth. Instead, focus on where you were last year (and where you’d like to be in the next year).
- Housing is the biggest lever. Housing is usually your biggest expense, so choosing how much to spend on it greatly affects your wealth. Renting can be as good as (or better than) buying when you crunch the numbers.6
1.4 Three Anchoring Rules
1. Sethi: “Spend on What You Love, Cut on What You Don’t”
Love coffee? Buy the $6 latte. But maybe buy a reliable used car instead of leasing a luxury one. The goal isn’t deprivation; it’s intentionality.7
2. Housel: “Build a Gap Between Ego and Income”
The wider the gap between what you earn and what your ego demands you spend, the wealthier you become. Lifestyle creep silently kills financial freedom.8
3. Bogle: “Keep It Simple”
Bogle’s philosophy applies to spending, too: complexity is the enemy. The more complicated your financial life, the easier it is to lose track. Automate, simplify, repeat.9
1.5 Wealth vs Income
Scott Galloway, an NYU Stern professor and host of the Prof G podcasts, distills the whole problem into a single equation in his 2024 book The Algebra of Wealth:10
The Wealth Formula:
Wealth = Focus + (Stoicism × Time × Diversification)
The four variables are the four levers you actually control:
Focus: pick something economically valuable and become great at it. Career, geography, and skill choice compound harder than any single early financial decision. This is Galloway’s version of Felix’s human capital; you build your earning engine first.
Stoicism: your willingness to live below your means, without needing to signal otherwise, will keep you from spending money you don’t have on things you don’t really need. Galloway, Housel, and Sethi all agree here; spending discipline is a character trait before it’s a budget.11
Time: the most powerful financial variable is how many years of compounding you still have. The earlier you start, the more time you have.
Diversification: don’t bet on a single stock, sector, or career outcome. Spread risk across asset classes, geographies, and time.
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flowchart TD
Wealth(["<strong>Wealth</strong>"]) --> Focus("Focus is <br><em>ADDITIVE</em>")
Wealth --> SecondTerm("Second term is<br/><em>MULTIPLICATIVE</em><br>")
SecondTerm --> Stoicism("<strong>STOICISM</strong><br>Living Below Means")
SecondTerm --> Time("<strong>TIME</strong><br>Years Compounding")
SecondTerm --> Diversification("<strong>DIVERSIFICATION</strong><br>Smart Allocation")
Focus -.Standalone Contribution.-> SomeWealth(["<strong>FOCUS</strong><br>builds some wealth<br>even if others<br>fail"])
Stoicism --> Multiply{"Multiply<br>Together"}
Time --> Multiply
Diversification --> Multiply
Multiply --> Compounding(["<strong>Compounding<br>Wealth Engine</strong>"])
style Wealth fill:#48a56a,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
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style Compounding fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
style SomeWealth fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
style Multiply fill:#f0cfcf,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
The arithmetic does a lot of the teaching on its own. Focus is additive, meaning that even with poor execution on the other three, a strong income engine still builds wealth.
However, stoicism, time, and diversification are multiplicative, so a zero on any one of these collapses the whole second term.
In plain language: spending above your means while not saving or investing for forty years compounds to nothing.
The chart below illustrates this arithmetic.
Focus contributes in a straight line (additive), while stoicism, time, and diversification compound exponentially.
After 40 years, the multiplicative term dominates the total.
The illustration uses concrete assumptions: median income of $62,400, saving 15% yearly ($9,360, stoicism), and earning 8% annually (diversification). The red area grows linearly. The green area curves upward, eventually dwarfing the red. This is the power of compound growth.
1.6 As Your Income Grows
This is where most people fail. A raise feels like permission to upgrade everything. Instead, focus on Felix’s research-backed advice: the extra happiness from each lifestyle upgrade is much smaller than people expect, while the extra financial security from saving raises is enormous.
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flowchart TD
Raise(["Pay Raise"]) --> Split{"<strong>Split the Raise</strong>"}
Split --> HalfInvest["50% to<br>Investing/Savings"]
Split --> HalfLifestyle["50% to<br>Lifestyle"]
HalfInvest --> WealthGrows(["Wealth Compounds"])
HalfLifestyle --> EnjoyNow(["Enjoy the Win"])
style Raise fill:#48a56a,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
style Split fill:#f0cfcf,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
style HalfInvest fill:#0e9aa7,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
style HalfLifestyle fill:#0e9aa7,color:#F5F2E8,stroke:#1C1C1E,stroke-width:2px
style WealthGrows fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
style EnjoyNow fill:#86ddcd,color:#1C1C1E,stroke:#1C1C1E,stroke-width:2px
This way, you reward yourself and accelerate freedom, without falling into the trap of inflating your lifestyle to match every dollar.
1.7 Math for Income
This chapter is mostly about behavior, but I’ll cover some numbers below that can turn the behaviors into something you can track. Each calculation below is also written as an R and Python function, which are covered in the callout box below.
The Wealth Formula
Galloway’s wealth formula captures the essence of wealth building. To turn it into numbers, picture someone earning $62,400 a year, about the median for full time workers in 2025 (BLS: $1,204 a week). Your first paycheck will probably be smaller; think of this as an average over a career. They save 15% ($9,360) every year and earn 8%. Each bar below is their savings at a checkpoint, split into what they put in and what it grew into.
The blue layer grows in a straight line, one $9,360 deposit per year. The green layer is every deposit growing at 8% for the years it has left, and it passes the blue layer after about year 18. Adding up all those growing deposits is what the formula’s second term does. Each piece of Galloway’s formula has a place in the math: your income and savings rate set the yearly deposit (stoicism), the number of years is time, and the return is what diversified investing earns.
Formula: Wealth after n years = Yearly savings × [((1 + r)^n − 1) ÷ r]
- Where: Yearly savings = Income × Savings rate, r = the yearly return, and n = the number of years.
Example: $62,400 × 15% = $9,360 a year. $9,360 × [((1.08)^40 − 1) ÷ 0.08] = about $2,424,769 after 40 years.
Check: you put in $9,360 × 40 = $374,400, so growth did most of the work.
In Excel, we can break this into two columns for clarity. Let’s say we have:
A2: median income ($62,400)
B2: savings rate (0.15)
C2: annual return (0.08)
D2: years (40)
For the total contributed (the additive focus) in cell E2:
=A2*B2*D2
For total wealth, contributions plus growth, in cell F2:
=(A2*B2)*(((1+C2)^D2-1)/C2)F2 already includes everything in E2, so don’t add the two together.
The Python version of wealth_formula() works the same way:
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def wealth_formula(median_income, savings_rate, annual_return, years):
# future value of saving a fixed amount every year (contributions plus growth)
annual_savings = median_income * savings_rate
return annual_savings * (((1 + annual_return)**years - 1) / annual_return)After 40 years with median income, 15% savings rate, 8% return:
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wealth_formula(
median_income=62400,
savings_rate=0.15,
annual_return=0.08,
years=40
)
#> 2424769.0151255885In R, wealth_formula() returns the future value of saving a fixed amount every year.
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wealth_formula <- function(median_income, savings_rate, annual_return, years) {
# future value of saving a fixed amount every year (contributions plus growth)
annual_savings <- median_income * savings_rate
annual_savings * (((1 + annual_return)^years - 1) / annual_return)
}After 40 years with median income, 15% savings rate, 8% return:
show/hide
wealth_formula(
median_income = 62400,
savings_rate = 0.15,
annual_return = 0.08,
years = 40
)
#> [1] 2424769The result is approximately $2.4 million after 40 years, of which only $374,400 is money you contributed. This is a powerful demonstration of how modest, consistent saving paired with compound growth transforms modest income into substantial wealth.
The Fixed-Cost Ratio
Fixed costs (rent, loan payments, insurance, utilities) are the commitments you can’t easily change month to month. Take-home pay is what actually lands in your bank account after taxes and other deductions. Picture a first job with $3,200 of take-home pay a month and $1,760 of fixed costs. The bar below is that paycheck cut into 10 equal pieces of $320 (each piece is 10%), with the fixed costs shaded and the 60% ceiling that keeps the rest of the budget healthy marked.
The red section covers 5 and a half of the 10 pieces, so fixed costs take 55% of the paycheck. The formula does the same thing: divide the red section by the whole bar, then multiply by 100.
Formula: Fixed-Cost Ratio = Fixed Costs ÷ Take-Home Pay × 100
- Where: Fixed Costs = the monthly commitments you can’t easily change (rent, loan payments, insurance, utilities), and Take-Home Pay = what lands in your bank account after taxes and other deductions.
Example: $1,760 ÷ $3,200 × 100 = 55%.
Check: the ceiling is 60% of $3,200 = $1,920, and $1,760 is below it.
In Excel there’s no function to define: you put the numbers in cells and write the formula once. Enter the fixed costs in cell A2 and take-home pay in B2, then in C2:
=A2/B2That gives 0.55.
Format C2 as a percentage (Home → %, or Ctrl+Shift+5) and it displays 55%.
To produce the percent string directly (the analog of R’s paste0(..., "%") and Python’s f-string), use TEXT() instead:
=TEXT(A2/B2, "0.0%")
TEXTThe same formula in Python:
show/hide
def fixed_cost_ratio(fixed_costs, take_home):
return (fixed_costs / take_home) * 100$1,760 of fixed costs on $3,200 take-home pay
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fixed_cost_ratio(fixed_costs=1760, take_home=3200)
#> 55.00000000000001Below is an implementation of this function in R:
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fixed_cost_ratio <- function(fixed_costs, take_home) {
(fixed_costs / take_home) * 100
}$1,760 of fixed costs on $3,200 take-home pay
show/hide
fixed_cost_ratio(fixed_costs = 1760, take_home = 3200)
#> [1] 55This results in a 55% fixed-cost ratio, just under the ceiling!
What a Raise Is Really Worth
Say you get a raise that adds $400 a month to your take-home pay, and you follow the split from the diagram above: $200 goes to your lifestyle and $200 gets invested. $200/month doesn’t sound like much. The chart below shows what that single habit produces when invested at 7% over 25 years, split into the money you put in and what it grew into.
Each bar is the previous total plus another year of $200/month contributions and their growth; the future value formula adds up all those monthly deposits, each with its own growth, in one calculation.
Formula: FV = PMT × [((1 + r)^n − 1) ÷ r]
- Where: PMT is the amount invested each month, r is the monthly return, and n is the number of months.
We will revisit this future-value-of-contributions formula in the Investing Basics chapter.
Example: $200 × [((1 + 0.07 ÷ 12)^300 − 1) ÷ (0.07 ÷ 12)] = about $162,014 after 25 years (300 months).
Check: you put in $200 × 300 = $60,000, so growth added about $102,000.
Excel actually has a built-in FV() (future value) function, so we don’t have to write the formula ourselves. The arguments are FV(rate, nper, pmt):
rateis the return per period (monthly here):7%/12
nperis the number of periods:25*12
pmtis the amount invested each period, entered as a negative number because it’s cash leaving your pocket:-200
=FV(7%/12, 25*12, -200)
This returns $162,014.34, the same result as the R and Python functions above. (Excel reports a positive number because the contributions were entered as negative cash flows.)
Below is the same function in Python:
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def raise_invested_value(monthly_raise, invest_share, rate, years):
contribution = monthly_raise * invest_share
monthly_rate = rate / 12
periods = years * 12
return contribution * (((1 + monthly_rate) ** periods - 1) / monthly_rate)Half of a $400/month raise, invested for 25 years at 7%
show/hide
raise_invested_value(monthly_raise=400, invest_share=0.5, rate=0.07, years=25)
#> 162014.33860462217Here is an example of this function in R:
show/hide
raise_invested_value <- function(monthly_raise, invest_share, rate, years) {
contribution <- monthly_raise * invest_share
monthly_rate <- rate / 12
periods <- years * 12
contribution * (((1 + monthly_rate)^periods - 1) / monthly_rate)
}Half of a $400/month raise, invested for 25 years at 7%
show/hide
raise_invested_value(
monthly_raise = 400,
invest_share = 0.5,
rate = 0.07,
years = 25)
#> [1] 162014.3We can see this results in over $160K!
1.8 Recap
Invest in your human capital: your career is your biggest asset early on, and it’s the focus part of the wealth equation.
Track your fixed costs: aim to keep them under 60% of your take-home pay. Stoicism aligns with Housel’s “gap between ego and income.” Living within your means isn’t about restriction; it’s about control and intention.
Spend the rest without guilt on what genuinely brings you joy: prioritize experiences and time over possessions. As Housel puts it, the highest form of wealth is the ability to wake up and say, “I can do whatever I want today.”
Keep it simple: Bogle’s philosophy is portfolio-level diversification, and time is on the side of compounding (which we will return to in Investing).
Wealth comes from growing your income, protecting your savings, and spending money on what actually makes you happy.
The next chapter turns to the other side of income: tracking where your money actually goes.
The Psychology of Money. Housel, Morgan. 2020.↩︎
Social class, social self-esteem, and conspicuous consumption. Oh, Ga-Eun (Grace). 2021.↩︎
To do or to have? That is the question. Van Boven, Leaf and Gilovich, Thomas. 2003.↩︎
Buying time promotes happiness. Whillans, Ashley V. and Dunn, Elizabeth W. and Smeets, Paul and Bekkers, Rene and Norton, Michael I. 2017.↩︎
If money doesn’t make you happy, then you probably aren’t spending it right. Dunn, Elizabeth W. and Gilbert, Daniel T. and Wilson, Timothy D. 2011.↩︎
Lessons from over 30 years of buy versus rent decisions: Is the American dream always wise?. Beracha, Eli and Johnson, Ken H. 2012. See also Ben Felix’s analysis at PWL Capital and the Rational Reminder podcast.↩︎
I Will Teach You to Be Rich (2nd ed.). Sethi, Ramit. 2019. The phrase “spend extravagantly on the things you love, and cut costs mercilessly on the things you don’t” is the core of Sethi’s “Conscious Spending Plan” (see Chapter 4, Conscious Spending). More at https://www.iwillteachyoutoberich.com/.↩︎
The Psychology of Money: Timeless Lessons on Wealth, Greed, and Happiness. Housel, Morgan. 2020. The “gap between your ego and your income” framing appears in Chapter 10, Save Money. The chapter draws on Housel’s earlier essay of the same name at Collaborative Fund.↩︎
The Little Book of Common Sense Investing (10th Anniversary ed.). Bogle, John C. 2017. Bogle’s recurring mantra (“Simplicity is the master key to financial success”) runs throughout the book and his earlier Common Sense on Mutual Funds. The investor community he inspired distills these ideas at https://www.bogleheads.org/wiki/Bogleheads%C2%AE_investment_philosophy.↩︎
The Algebra of Wealth: A Simple Formula for Financial Security. Galloway, Scott. 2024. See profgalloway.com for his writing, podcasts, and the weekly No Mercy / No Malice newsletter.↩︎
Stoicism. Durand, Marion and Shogry, Simon and Baltzly, Dirk. 2023.↩︎