Latte Factor Calculator
Set your daily spend, how many days a week you buy it, and the annual price increase — then see what investing that money at compound interest would build over time.
63% of the 30-year value is compound growth — you only contribute 37% in cash. Time does the heavy lifting.
$202K
30-year invested value of a $6/day weekday habit at 7% return with 3%/yr price growth
63%
Of that $202K, 63% is compound growth — you only contributed $74K in cash
5 vs 7
Days per week matters — 5 days is ~29% less than 7, compounding over decades
Why small habits have outsized cost
Frequency, price inflation, and compound interest make $6/day worth six figures.
Compound interest does most of the work
At default settings, you contribute ~$74K over 30 years. Compound interest adds ~$128K on top — 63% of the final value. The longer the horizon, the more extreme this ratio becomes. Time is the multiplier.
Frequency is the hidden variable
Most latte factor calculators assume 365 days/year. In reality, most coffee purchases happen on workdays. The days-per-week slider lets you model your actual habit — and it makes a 29% difference between 5 and 7 days.
Half the habit, half the regret
You don't have to go cold turkey. Cutting the habit in half and investing the rest still builds ~$101K over 30 years. The calculator shows this 'invest half' scenario so you can see the middle ground between keeping everything and cutting everything.
How the Latte Factor Calculator Works
Formula
Annual Spend (Year 1) = Daily Spend × Days/Week × 52
Annual Spend (Year y) = Year 1 Spend × (1 + Price Growth)^y
Total Spent = Σ Annual Spend for each year
Invested Value (growing annuity FV):
= Year 1 Spend × [((1 + Return)^Years − (1 + Growth)^Years) / (Return − Growth)]
Compound Gain = Invested Value − Total SpentSet your daily spend
The price of one occurrence — a $6 coffee, a $4 snack, a $3 energy drink.
Set days per week
How often you actually do it. Workdays only (5) vs every day (7) is a 29% difference.
Set annual price increase
Coffee CPI averages ~3%/yr. This inflates your spend each year, making the true lifetime cost higher.
Set investment return
The S&P 500 has returned ~7%/yr after inflation over the long run. Adjust up or down based on your risk tolerance.
See the opportunity cost
The gap between total spent and invested value is pure compound growth — money you'd earn just by redirecting the habit.
This calculator uses the growing-annuity future value formula, not a flat annuity. That means each year's contribution grows by the price inflation rate — reflecting the fact that your $6 coffee today will cost $6.18 next year and $14+ in 30 years. Both the total spent and the opportunity cost are higher than a naive flat calculation.
The key insight is the growth ratio. At default settings (7% return, 30 years), 63% of the final value is compound growth — you only put in 37% as cash. Over 40 years that ratio shifts even further. This is why starting early matters far more than the daily amount.
Frequently Asked Questions
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