What's the difference between battery capacity and battery life?

Battery capacity often plays into battery life, but an impressive capacity stat doesn't translate to excellent battery life.

Battery capacity often plays into battery life, but an impressive capacity stat doesn&#39;t translate to excellent battery life.<p><img src="https://www.engadget.com/img/gallery/whats-the-difference-between-battery-capacity-and-battery-life/intro-1790703244.jpg" /></p>