The Brew About The Brew Calculator
The Brew Calculator is a small collection of free coffee calculators and brewing guides. No accounts, no apps to install, no paywalls — just tools that answer "how much coffee do I need?" and guides that explain the why behind the numbers.
How the tools work
Every calculator on this site runs entirely in your browser. Your inputs never leave your device — there's no server collecting them, because there's nothing to collect them with. The math is deliberately transparent: each tool page explains the formula it uses, and the caffeine estimates are built on published averages from USDA FoodData Central and FDA analyses, not guesses.
That said, calculators are estimates, not lab equipment. Real coffee varies with the bean, the roast, and your technique. Use the numbers as a precise starting point, then let your taste buds make the final call.
How this site makes money
Straightforwardly: we plan to run display ads and recommend coffee gear we actually believe in through affiliate links. If you buy something through one of those links, we may earn a commission at no extra cost to you. It keeps the calculators free. We'll always mark affiliate content clearly — if a recommendation is paid, you'll know.
Who's behind it
The Brew Calculator is run by coffee people who got tired of "two scoops per cup" advice. We're also behind Raven Horse Co, a specialty coffee roaster — so when we talk about fresh beans mattering, it's because we roast them ourselves.
Get in touch
Found a bug in a calculator? Have a tool you'd like us to build? We read everything — reply to any newsletter email once it's live, or check back here for a contact address soon.