FermentoryConvert a beer recipe from gallons to litres
Most homebrew recipes online are American, written in US gallons. If you brew in litres, here's the quick way to convert the whole recipe, not just the water, plus a table and a free tool that does every ingredient for you.
Quick answer: 1 US gallon is 3.785 litres, so a standard 5 US gallon recipe is about 18.9 litres. A UK (imperial) gallon is larger at 4.546 litres, but almost every recipe you find online uses US gallons.
Gallons → litres
Convert the batch size first. Then use the full scaler for the ingredients.
Common batch sizes in litres
The batch sizes you'll see most often in American recipes, converted to litres:
| US gallons | Litres | Also known as |
|---|---|---|
| 1 gal | 3.8 L | Small test batch |
| 2.5 gal | 9.5 L | Half batch |
| 3 gal | 11.4 L | Stovetop batch |
| 5 gal | 18.9 L | The standard homebrew batch |
| 6 gal | 22.7 L | 5 gal into a keg, with losses |
| 10 gal | 37.9 L | Double batch |
How to convert the whole recipe, not just the water
Converting the batch volume is the easy part. The bit people get wrong is the ingredients. You can't convert the water to litres and leave the malt and hops sitting at their old amounts, because you've changed how much beer you're making.
The method is one idea, three steps:
- Decide the batch size you actually brew, in litres. Say 20 L.
- Work out the scale factor: your litres divided by the recipe's litres. A 5 gallon (18.9 L) recipe brewed as 20 L is 20 ÷ 18.9 = 1.06.
- Multiply every ingredient by that factor. 2.5 kg of malt becomes 2.65 kg, 30 g of hops becomes 32 g, and so on down the list.
Shortcut: a 5 gallon recipe is basically a 19 litre recipe. If you brew 19 L, the amounts are close enough to use as they are without touching a calculator.
Recipe also written in pounds and ounces? Convert those while you're at it: 1 lb = 0.454 kg, and 1 oz = 28.3 g.
What you don't need to worry about
- Your ABV won't change. Alcohol comes from the ratio of sugar to water, not the size of the batch. Scale everything together and a 5.5% beer stays a 5.5% beer.
- Bitterness stays about the same. As long as you scale the hops by the same factor as the volume, the IBU lands in roughly the same place.
- Only your equipment needs half an eye. A different kettle or mash efficiency can nudge your grain a little, but that's a small tweak, not a full recalculation.
Skip the maths on every recipe
The free Fermentory browser extension spots homebrew recipes on any blog or forum and rescales the whole thing to your batch size in litres, no copy-paste. It builds a shopping list from the recipe too.
＋ Add Fermentory to Chrome Free to install · optional one-time Pro upgradeGallons to litres FAQ
How many litres is a 5 gallon batch of beer?
A US 5 gallon batch is about 18.9 litres (5 × 3.785). If the recipe means UK gallons, which is rare online, it works out to 22.7 litres instead.
Are homebrew recipes in US or UK gallons?
Almost always US gallons, at 3.785 litres each, because most recipes online come from American brewers and sites. If a recipe clearly comes from a UK source it may use imperial gallons (4.546 litres), so check where it's from if the numbers look off.
Do I need to change the hops when I convert to litres?
Scale the hops by the same factor as the rest of the recipe and your bitterness stays about the same. You only need to rethink hops if you also change the batch size by a lot or brew at a different gravity, in which case re-check the IBU.
Does converting a recipe to litres change the ABV?
No. Alcohol depends on the ratio of fermentable sugar to water, not the batch size. If you scale every ingredient and the volume by the same amount, the ABV is unchanged.