French Press Calculator
Size a brew to your press, not a guess. Enter your press capacity, how full you fill it, and your ratio to get the coffee dose and water — plus the real cup yield once the grounds soak up their share.
Leave room for the plunger and grounds — around 90% is typical.
French press runs stronger — 1:12 to 1:15 is common. Grounds hold about 2× their weight in water.
Formula & how it works
Water is press size × fill% (1 mL ≈ 1 g). Coffee is water ÷ ratio. Grounds retain about twice their weight, so retained water is coffee × absorption and the poured yield is water − retained.
Ounces are converted with 1 fl oz ≈ 29.57 mL.
Worked example
A 1000 mL press filled to 90% holds 900 g of water. At 1:15 that is 60 g of coffee. The grounds keep about 120 g of water, so you pour roughly 780 g of coffee — a little over three 8-ounce cups.
Better French press
Coarse and even
Immersion brewing is forgiving on timing but unforgiving on grind. A coarse, even grind keeps fines from slipping through the mesh and over-extracting, which is the usual cause of a muddy, bitter press. If your cup is silty, grind coarser before anything else.
Mind the yield, not just the water
Because the grounds soak up roughly twice their weight, the coffee you actually pour is noticeably less than the water you added. Sizing a brew to the number of cups you want means starting from the yield and working back — which is exactly what the yield figure here helps you do.
Press and decant
Steep around four minutes, press the plunger down slowly and steadily, and then pour it all out. Coffee left sitting on the grounds keeps extracting and grows bitter, so decanting into a carafe or your cups right away keeps the last cup as good as the first.