AeroPress Ratio Calculator

Formula used

The AeroPress uses a coffee-to-water ratio like other immersion brewers:

Water (g) = Coffee (g) × N
Coffee (g) = Water (g) ÷ N

Two popular approaches: a full-cup ratio of about 1:14–1:16 brewed straight, or a concentrate ratio of about 1:8–1:10 that you top up with hot water (the ‘bypass’ method) to taste. The plastic chamber limits total water to roughly 250 ml per brew, so large servings use a concentrate plus bypass water.

Worked examples

Standard cup. 15 g of coffee at 1:14 uses 210 g of water for a clean, balanced mug.

Concentrate + bypass. 18 g at 1:9 makes a 162 g concentrate; add ~100 ml hot water afterwards for a fuller mug without overfilling the chamber.

Two small cups. Start from 16 g at 1:15 for 240 g of water, near the chamber limit.

How to use this calculator

1. Choose whether you start from coffee or water.
2. Enter the amount in grams (water in millilitres ≈ grams).
3. Pick a ratio: 1:14–1:16 for a straight cup, or 1:8–1:10 for a concentrate.
4. Press Calculate to get coffee and water weights.
5. Brew, press gently, and add bypass water if you used a concentrate ratio.

AeroPress ratio quick guide

Common doses and the water they need at each strength.

*Exceeds the ~250 ml chamber — brew as a concentrate and add bypass water.

Who should use this calculator

AeroPress users at home, at the office, or travelling. It suits both the standard upright method and the inverted method, and it is especially handy for the concentrate-plus-bypass approach where the chamber cannot hold a full mug of water at once.

What each input means

• Start from — coffee dose or water amount, whichever you prefer to fix first.
• Amount — grams of coffee or millilitres of water.
• Brew ratio — water per gram of coffee. Concentrate ratios are much lower because you dilute later.

How to read your result

You get the coffee and water to weigh plus an estimate of the liquid pressed out. If your water figure is above ~250 ml, treat the recipe as a concentrate: brew it strong in the chamber, then add bypass water to reach your mug size.

Common mistakes to avoid

• Overfilling the chamber. Keep total water under ~250 ml; go concentrate-plus-bypass for bigger servings.
• Pressing too hard. A slow, gentle press for 20–30 seconds avoids a harsh, over-extracted cup.
• Ignoring grind. Medium-fine works for most recipes; very fine grinds make the press difficult.

Limitations of this calculator

This calculates weights only. The AeroPress is sensitive to grind, water temperature (anything from 80–96 °C depending on recipe), steep time and press speed. Use the result as a starting recipe and adjust to taste.