Is there lactose in buttermilk?
High per cup — but rarely drunk straight.
Cultured buttermilk contains lactose at a level similar to milk, trimmed slightly by its cultures. You rarely drink it by the glass — it's mostly a baking ingredient, and a lactose-free swap is easy.
“Buttermilk” sounds like it should be low-lactose. It isn’t butter, though. Modern cultured buttermilk is milk that’s been fermented, so it carries lactose at roughly the same level as regular milk, with only a small reduction from the cultures. The saving grace is that you almost never drink it straight — it’s a baking staple, spread across a whole batch of pancakes or a loaf of soda bread.
Handy trick: you don’t need to buy buttermilk at all. A tablespoon of lemon juice or vinegar stirred into a cup of lactose-free milk makes a perfect stand-in for baking.
How much lactose is in buttermilk?
Cultured buttermilk contains about 3.5–4.5 g of lactose per 100 mL — roughly 9–11 g in a 250 mL cup, similar to milk.
| Food | Lactose per 100 mL | Per typical serve |
|---|---|---|
| Buttermilk | 3.5–4.5 g | ~9–11 g (250 mL cup) |
| Regular milk | 4.8 g | ~12 g (250 mL) |
| Lactose-free milk + lemon | <0.1 g | ~0.1 g |
Figures compiled from food-composition databases — see the full lactose chart & sources.
When you can still enjoy it
Since it’s spread across a whole recipe, per serve buttermilk is often modest — but the DIY lactose-free version (milk + acid) is so easy there’s little reason not to use it.
If buttermilk isn't handy, reach for…
Common questions
Is buttermilk high in lactose?
Can I make a lactose-free buttermilk?
Does buttermilk in pancakes matter?
Want the full picture? Grab our free Living Lactose-Free in Australia cheat sheet — it sorts 60+ foods like this one so you never have to guess at the supermarket again.