Tool · Scales and weighing
Espresso ratio calculator
Work out where to stop the shot for your dose and ratio, or the dose for a target yield. Plus why 1:2 is a starting point, not a rule.
Short answer
Multiply your dose by the ratio to get the espresso weight to stop at: 18 g of coffee at 1:2 means about 36 g of espresso. A 1:2 ratio is a common starting point, not a rule. Socratic Coffee's tamping study used 20 g in and 40 g out,[1] and Cafelat gives 16 g in and 32 g out as an example for its Robot.[2] The calculator below does the arithmetic in either direction.
Dose, yield and ratio
- Dose is the ground coffee in the basket, in grams. Your basket sets a sensible range: Breville gives an 18 g dose for the Bambino and Barista Express, and 22 g for the Dual Boiler.[3][4][5]
- Yield is the weight of espresso in the cup, also in grams. Weigh it on a scale under the cup rather than judging it by volume.
- Brew ratio is yield divided by dose, written coffee to espresso. 18 g in and 36 g out is 1:2; 18 g in and 27 g out is 1:1.5.
Why 1:2 is a starting point, not a rule
No source we checked sets a single correct ratio. A 1:2 ratio shows up as a reference in controlled work, such as Socratic Coffee's study, and in makers' examples, such as Cafelat's. Roast, grinder, basket and your own taste all move the best ratio for you.
The direction of each change is easy to predict. A shorter ratio, such as 1:1.5, means less espresso from the same coffee: a smaller and usually stronger drink. A longer ratio, such as 1:2.5 or 1:3, puts more water through the same coffee: a larger and usually lighter drink. Socratic Coffee's study found that brew weight drove the differences in strength (TDS) it measured, which is why the yield is the number to control.[1]
How to use the calculator
- Enter your dose in grams. Weigh it rather than relying on a scoop.
- Choose a ratio with the 1:1.5, 1:2, 1:2.5 or 1:3 buttons, or type your own.
- Read the target yield, then stop the shot when the scale under your cup reaches it.
- Working backward: enter the espresso weight you want, and the calculator gives the dose for the chosen ratio.
- Change one thing at a time. If you change the ratio, keep the dose and grind the same for that shot, and write down what you changed.
What it does not do
The calculator is plain arithmetic: yield equals dose times ratio, rounded to 0.1 g. It does not recommend a ratio, adjust for roast or know your basket's range. For the range, check your basket maker's figures in baskets and portafilters. For the weighing, use a scale that reads in 0.1 g steps; our scale shortlist has two.
Stop the shot at about 36 g of espresso (18 g × 2).
Questions
What is a good espresso ratio to start with?
1:2 is a common starting point: Socratic Coffee used 20 g in and 40 g out in its tamping study, and Cafelat gives 16 g in and 32 g out as an example for its Robot. Adjust from there by taste.[1][2]
Should I weigh the espresso or time the shot?
Weigh it, and note the time as well. In Socratic Coffee's tamping study, brew weight, not tamp force, drove the differences in strength (TDS).[1]
What dose should I use?
Start with your basket's stated dose. Breville gives 18 g for the Bambino and Barista Express and 22 g for the Dual Boiler, and basket makers such as IMS publish a dose range for each basket.[3][4][5][6]
What do ristretto and lungo mean in ratio terms?
A ristretto is a shorter, more concentrated shot and a lungo a longer one, but the names are used loosely. Go by the numbers instead: set your dose and the yield you want, and the calculator shows the ratio.