Yogurt Milk Ratio Calculator

The short version: a litre of milk becomes about a litre of plain yogurt, and straining that yogurt is what turns it into Greek yogurt. How much you end up with depends entirely on how long you strain. At a classic Greek thickness, roughly four hours of draining, a litre of whole-milk yogurt leaves you around 600 to 650 grams. The rest, roughly 400 millilitres, pours off as whey.

That is the part most people are not ready for the first time. Greek yogurt costs you volume. Straining to a firm, scoopable texture roughly halves the amount you started with, and pushing toward labneh cuts it further. The calculator above turns your batch size and target thickness into an actual weight so you can plan the milk purchase around the yogurt you want to end up with, not the yogurt you started with.

2 hours: about 770 g, thick and spoonable

4 hours: about 620 g, classic Greek

Overnight: about 390 g, heading toward labneh

Traditional Greek yogurt is ordinary set yogurt with a large share of its whey strained away. Removing that liquid concentrates the protein and the milk solids, which is why Greek yogurt is thicker, tangier, and higher in protein per spoon than the yogurt it started as. Nothing is added; something is taken away.

This matters because a lot of supermarket "Greek-style" yogurt is not strained at all. Instead it is thickened with milk powder, cream, or stabilisers to imitate the texture. That is not wrong, but it is a different product. When you strain your own yogurt at home you are making the real thing, and this calculator estimates the yield of that traditional straining method rather than the shortcut version.

Straining time is the single biggest lever you have. In the first hour or two, the loose whey drains quickly and the yogurt firms up fast. After that the losses slow down but never quite stop, which is why an overnight strain keeps creeping toward labneh territory. Choose the target that matches what you are cooking: pourable for drinking yogurt, spoonable for breakfast, firm for dips, or fully strained for a spreadable cheese.

The practical windows are easy to remember. Two hours gives a thick, spoonable yogurt that still feels like yogurt. Four hours is the classic Greek texture most recipes mean. Six to eight hours produces a dense, almost cream-cheese-like yogurt. Push past a day and you are making labneh, which you can roll into balls and store under olive oil.

Fat is part of what stays behind when the whey drains, so richer yogurt gives a higher yield and a creamier result. Whole-milk yogurt strains to the thickest, most luxurious Greek yogurt and keeps the most weight. Low-fat yogurt yields a little less and feels slightly leaner. Nonfat yogurt gives the smallest yield because there is less fat to hold in the curd, and more of the batch leaves as whey.

None of these are wrong choices — plenty of people strain nonfat yogurt specifically to boost protein without the fat. Just set your expectations with the calculator: the same straining time will leave you with noticeably less nonfat Greek yogurt than whole-milk Greek yogurt, so buy accordingly if you have a target weight in mind.

The setup is simple: line a sieve or colander with a few layers of cheesecloth, a clean cotton tea towel, or a dedicated nut-milk bag, and set it over a bowl deep enough that the draining whey never touches the bottom of the sieve. Spoon in your chilled, fully set yogurt, cover it, and put the whole rig in the fridge. Straining cold keeps everything safe and lets you judge the thickness honestly.

Check it on the schedule the calculator suggests rather than by guesswork. If you overshoot and it gets too thick, you can stir a little of the reserved whey back in to loosen it. Resist the urge to squeeze the cloth hard for speed — gentle pressing is fine, but forcing it can push milk solids through and cloud your whey. Patience in the fridge beats muscle every time.

The whey figure surprises people: a firm Greek strain leaves you holding several hundred millilitres of pale, protein-rich liquid for every litre you started with. It is not waste. Yogurt whey is acidic and full of useful protein, so it earns its keep in the kitchen. Swap it for some of the water in bread and pizza dough for a subtle tang and a better crumb, or blend it into smoothies for extra body.

Beyond baking, whey cooks rice, oats, and polenta beautifully, enriches soups and stocks, and makes a reliable starter liquid for lacto-fermenting vegetables. If you genuinely have more than you can use, diluted whey is a gentle feed for acid-loving plants. Knowing the volume in advance, which the calculator gives you, means you can have the right jar ready instead of pouring it down the drain.

These three are cousins on a straining spectrum. Greek yogurt is set yogurt strained to a firm but still yogurt-like texture. Labneh is simply Greek yogurt strained further, often overnight or longer and usually salted, until it is thick enough to spread or roll into balls. Both come from the same pot; the only difference is how much whey you removed.

Skyr is the odd one out. Technically an Icelandic fresh cheese, it is made from skim milk with its own cultures and then strained, giving a very thick, high-protein, low-fat result. You can approximate a skyr-like texture by straining nonfat yogurt for a long time, but the culture and the milk differ, so it is a lookalike rather than the real thing. The calculator handles the yield for any of them — the number that changes is the straining time.

Work backwards from the finished weight. If a recipe wants 500 grams of thick Greek yogurt, the calculator tells you to start with a bit under a litre of whole-milk yogurt and strain it to the classic four-hour mark. Want a full kilo for a big batch of tzatziki or a cheesecake? Start with roughly a litre and a half to two litres of yogurt, depending on how thick you are going.

Because straining losses grow with time, always give yourself a little headroom when you are aiming for the thicker end. A batch destined for overnight labneh needs noticeably more starting yogurt than the same target weight of two-hour yogurt. Plug both the amount and the strain time into the calculator before you buy the milk, and you will stop ending up with half as much Greek yogurt as the recipe assumed.