日課・習慣の費用・節約シミュレーター（コーヒー・煙草・サブスク） - 無料オンライン計算ツール

How much can a small daily habit really cost over time? This calculator is based on a well-known personal-finance idea called the "Latte Factor", introduced (and trademarked) by financial author David Bach in his book "The Automatic Millionaire." The idea is simple: a small, often unconsidered daily purchase (coffee, tea, cigarettes, a subscription) looks trivial on its own, but if that same amount had been invested instead, compound returns could have turned it into a much larger sum.

This calculator shows two numbers: what you actually spent out of pocket, and what that same money could have grown to if invested instead (the opportunity cost).

This calculator carries two big assumptions that don't always hold true in real life.

First, it assumes the entire saved amount is invested immediately and consistently - in reality, most people just stop spending without actually investing, unless the process is automated (which is actually David Bach's real core message - the "Latte Factor" alone doesn't work; the "automatic" part is what matters).

Second, it assumes the return rate (e.g. 12%) stays constant across the years - markets fluctuate, and no return is guaranteed.

Third, some financial critics (such as the White Coat Investor site) point out that willpower is a limited resource - restricting small daily pleasures can cause fatigue, and the biggest real difference usually comes from cutting large expenses (housing, cars), not just daily coffee. Treat this calculator as motivation, not a guaranteed forecast.