A coffee-to-water ratio calculator for your wrist.

Set your brewing ratio once, then dial in coffee or water to get the matching amount instantly. Perfect for pour-over, when you weigh your beans freely and need the water calculated on the spot.

Adjust coffee weight or water amount — the other updates automatically
Press Select to switch between adjusting coffee or water
Long-press Select to change your ratio (supports 1:10 through 1:25)
Tap for precision (0.1g / 1ml), hold to move faster (1g / 10ml)
Your ratio and last coffee weight are saved between sessions
Defaults to 1:17 ratio, 20g coffee.