There’s a famous claim in personal finance: skip your daily latte, invest the money instead, and you’ll retire with about a million dollars. That’s the latte factor, coined by David Bach, and it’s probably the most quoted — and most argued-about — idea about small spending ever written. The calculator above runs the honest version of it, with your numbers instead of his.
How it works
Two steps. First, scale the habit to a year: cost per time × times × frequency (365 days, 52 weeks, or 12 months). Second, run the what-if: that same yearly amount, invested at a rate you choose, compounding for as long as you keep the habit. The gap between spent and would have grown to is what the habit really costs — the cash plus the growth it never got to do.
The honest math
Take the classic example, already close to the defaults above: a $5 latte, once a day. That’s $1,825 a year. Over a forty-year working life you’ll hand over $73,000 — and at a sober 7% average return, investing it instead grows to about $364,000.
Not a million. Bach’s headline number needs 10–12% returns every single year for four decades, before taxes and inflation. At 11% the math does in fact reach seven figures — which is why the claim survives — but no honest plan assumes 11% forever. The real story is the smaller number, and the smaller number is still startling.
Now measure it the way this site likes to: in hours of your life. At a real hourly wage of $25, that $5 latte is 12 minutes of work every day — about 73 hours a year, almost two working weeks, for the coffee alone. The $73,000 lifetime spend is 2,920 hours on the clock: nearly a year and a half of full-time work.
Why you never notice
The latte factor is a psychology observation wearing a math costume. We judge a purchase by what it costs this time — five dollars, nothing, don’t even think about it — and we never see the flow: $1,825 a year, $73,000 a lifetime. Nobody puts that number in front of us, so the decision never actually gets made. It’s the same blind spot that keeps forgotten subscriptions alive for years: small one at a time, heavy as a sum.
Where the idea breaks — and where it’s right
Fair criticism first: for most households, coffee is not the problem. Housing, cars, and income dwarf every latte ever bought, and no amount of skipped espresso fixes a rent that’s too high. Treating small pleasures as a moral failing is bad advice, and the original math oversold the prize.
But the method survives the criticism: give the invisible flow a number, then decide on purpose. It works on any recurring spend, not just coffee — run yours through the cost of a habit tool, or check what a one-off purchase costs in growth with opportunity cost. And remember the return you type is an assumption, not a promise — the compound interest page shows how much the rate moves the result.
Change the values above to your own habit — the real price, the real frequency, the years you’d actually keep it up. If the lifetime number leaves you cold, enjoy the habit with a clear conscience. If it doesn’t, you just found money.