What This Calculator Does

This pour-over coffee ratio calculator helps you find the ideal water amount for any coffee dose, across the three most common pour-over ratios: 1:12, 1:15, and 1:18. Furthermore, it adjusts based on roast type, since lighter and darker roasts extract differently. As a result, you can find a starting point that matches the coffee you’re brewing.

If you’re new to pour-over brewing, start with a 1:15 to 1:17 ratio, a medium grind, and water at around 93 degrees Celsius. For the bigger picture, read our pillar guide on how to brew better coffee at home.

How Pour-Over Ratios Work

The coffee-to-water ratio is the relationship between the weight of dry coffee and the weight (or volume) of water used to brew it. Furthermore, because 1ml of water weighs roughly 1g, the maths is straightforward:

• 1:15 ratio. 1g of coffee per 15g of water. Furthermore, for a 500ml brew, that’s 33g of coffee.
• 1:16 ratio. 1g of coffee per 16g of water. For 500ml, use 31g.
• 1:17 ratio. 1g of coffee per 17g of water. For 500ml, use 29g.
• 1:18 ratio. 1g of coffee per 18g of water. For 500ml, use 28g.

To calculate any ratio quickly, divide the volume of water in millilitres by the second number in the ratio. For example, 500 divided by 16 equals 31g of coffee. As a result, you can dial in any cup size without memorising fixed recipes.

Which Ratio Should You Use?

Choosing the right ratio depends more on the cup you want than on the coffee itself. Furthermore, ratio shapes strength and clarity; grind size and brew time handle extraction. As a result, here is a simple guide:

• 1:15 (stronger). A fuller-bodied, more intense cup. Suits chocolatey, nutty, medium-roasted coffees where richness is the goal. Moreover, this is the Routes house default for Moccamaster brewing.
• 1:16 to 1:17 (balanced). The classic specialty coffee starting point. Works for most coffees and brewing methods. In addition, this range sits within the Specialty Coffee Association Golden Cup standard of 55 to 60 grams per litre.
• 1:18 (lighter). A cleaner, more delicate cup that preserves aromatic clarity. As a result, many drinkers prefer this ratio for light-roasted, fruit-forward, or experimentally processed coffees, where complexity matters more than body.

Note, this is subject to preference. There is no wrong way of brewing when you are starting out. Let taste and variety be your guide.

How Roast Type Affects Your Ratio

Roast level changes both how a coffee extracts and how it tastes. Furthermore, most specialty roasters and the SCA Golden Cup standard suggest the following starting points:

• Light roasts: 1:16 to 1:18. Dense and slower to extract. Use a finer grind, hotter water (94 to 96 degrees Celsius), and a lighter ratio to preserve aromatic clarity and let the delicate fruit and floral notes show through.
• Medium roasts: 1:15 to 1:17. The most forgiving. As a result, this is the safest starting range for most specialty coffees.
• Dark roasts: 1:14 to 1:16. Porous and quick to extract. Use a coarser grind and slightly cooler water (90 to 92 degrees Celsius) to avoid harshness. A stronger ratio also adds body to balance the roast’s natural bitterness.

In addition, these are starting points, not rules. Furthermore, your grinder, water, and personal taste will shape what works best in your cup.

Troubleshooting Your Pour Over

If your coffee doesn’t taste right, the cause is usually one of four things. Moreover, our flavour cluster covers each in detail:

• Sour, sharp, or thin. Under-extraction. Try a stronger ratio, finer grind, or hotter water. Read our guide on why coffee tastes sour.
• Bitter or harsh. Over-extraction. Try a lighter ratio, coarser grind, or slightly cooler water. Read our guide on why coffee tastes bitter.
• Flat or muted. Often water quality. Filtered or soft mineral water can transform your cup. Read our guide to water quality in coffee brewing.
• Missing sweetness. Usually freshness or roast level. Read our guide on what makes coffee sweet.

More Routes Coffee Calculators

• Interactive Brewing Ratio Calculator : for general brewing across methods.
• Interactive Espresso Calculator : for dialling in espresso shots.

Brewing Better Coffee with Routes

The right ratio matters most when paired with great beans. A Routes Coffee subscription delivers freshly roasted single origins and blends to your door, starting from £9 with free UK delivery. Furthermore, every bag arrives with detailed tasting notes and our recommended brewing approach.

Frequently Asked Questions

What is the best coffee-to-water ratio for pour over?

The best pour-over coffee ratio is between 1:15 and 1:17, meaning 1 gram of coffee per 15 to 17 grams of water. Furthermore, 1:15 produces a stronger, fuller-bodied cup, while 1:17 gives a lighter, more delicate brew. As a result, 1:16 is a balanced starting point for most coffees.

How much coffee do I use for 500ml of water?

For a 1:15 ratio, use 33g of coffee for 500ml of water. At 1:16, use 31g. At 1:17, use 29g. Furthermore, you can calculate any ratio by dividing the water amount in millilitres by the second number in the ratio.

Does roast type affect the coffee ratio?

Some, but grind size and brew time matter more. Lighter, denser roasts are slower to extract, which is usually solved with a finer grind or hotter water rather than changing the ratio. Many drinkers actually prefer a lighter ratio (1:17 to 1:18) on delicate light roasts because it preserves the clarity and aromatic detail that makes them special. Stronger ratios can mask those qualities. Furthermore, our Moccamaster house ratio of 1:15 is on the stronger side of the SCA standard (which sits around 1:16 to 1:18), and we use it because it suits the way we roast.

What is the golden ratio for coffee?

The Specialty Coffee Association golden ratio is 55g of coffee per litre of water, roughly 1:18. Furthermore, this is a guideline rather than a fixed rule. Most specialty roasters prefer slightly stronger ratios between 1:15 and 1:17 for pour-over brewing.

How do I know if my ratio is right?

Taste the coffee. If it tastes weak, thin, or sour, increase the coffee dose or use a stronger ratio. If it tastes bitter, harsh, or muddy, decrease the dose or use a lighter ratio. As a result, your palate is the most reliable guide.

Should I weigh coffee or measure by volume?

Always weigh coffee on a scale. Furthermore, scooping by volume is unreliable because grind size and bean density change how much fits in a spoon. As a result, a kitchen scale is one of the most worthwhile investments for home brewing.

Does grind size matter for ratio?

Grind size and ratio work together. A finer grind extracts faster, so it tends to work better with lighter ratios. On the other hand, a coarser grind extracts slower and often pairs better with stronger ratios. Moreover, getting both variables aligned produces the best cup.

Related Reading

• Routes Coffee, How to Brew Better Coffee at Home (pillar)
• Routes Coffee, Moccamaster Coffee Ratio: The Complete Brewing Guide
• Routes Coffee, Why Water Quality Is Important in Coffee Brewing
• Routes Coffee, Why Does Coffee Taste Bitter?
• Routes Coffee, Why Does Coffee Taste Sour?
• Routes Coffee, What Is Specialty Coffee and Why Is It Important?

Sources & Further Reading

• Specialty Coffee Association, brewing guidelines and the golden cup standard.
• Barista Hustle, ratio and extraction studies.
• Rivera, J. A. Roast Magazine, brewing chemistry.