Homemade Oat Milk Cost Calculator

Is Homemade Oat Milk Actually Cheaper?

Oat milk has become a pantry staple for millions of households, but brands like Oatly and Planet Oat typically run $4 to $6 per quart at grocery stores. The ingredients for homemade oat milk — rolled oats, filtered water, a pinch of salt, and a nut milk bag — cost a fraction of that.

What Goes Into a Quart of Homemade Oat Milk?

A standard recipe uses about 3/4 cup of rolled oats per quart of finished milk. Old-fashioned rolled oats cost roughly $0.10–$0.25 per cup when bought in bulk, making the oat ingredient cost per quart anywhere from $0.08 to $0.19. Add a one-time nut milk bag (amortized over 100+ uses at roughly $0.08 per batch) and a negligible pinch of salt, and your all-in cost per quart typically lands between $0.20 and $0.35.

Compare that to Oatly Original at $5.49/qt, Planet Oat at $4.79/qt, or a store-brand option at $3.49/qt, and homemade is 10 to 25 times cheaper per quart in many scenarios.

Tips to Get the Best Homemade Oat Milk

Use cold water. Warm or hot water activates the starch in oats and makes the milk slimy. Always blend with cold or ice water.
Don't over-blend. 30–45 seconds is enough. Over-blending breaks down more starch and creates a gummy texture.
Strain twice if you want a cleaner texture — once through the nut milk bag and once through a fine-mesh strainer.
Buy oats in bulk. A 25 lb bag of organic rolled oats from a co-op or warehouse club drops your per-cup cost dramatically, often below $0.08/cup.

Oatly vs. Planet Oat vs. Store Brand vs. Homemade

Oatly Original: ~$5.49/qt
Planet Oat Original: ~$4.79/qt
Store brand (Kirkland, Trader Joe's, etc.): ~$2.99–$3.49/qt
Homemade (bulk oats): ~$0.20–$0.35/qt

Even against the cheapest store brand, homemade oat milk costs roughly 10x less per quart. For a household going through 4 quarts a month, that's a potential savings of $120–$200 per year.

Hidden Costs and Trade-Offs

Homemade oat milk does require a few minutes of active prep and cleanup. It also lacks the fortification (added calcium, vitamin D, vitamin B12) that commercial brands include. If you rely on oat milk as a nutritional source for these vitamins, you may need to supplement separately. The nut milk bag is a true one-time cost — a quality reusable bag lasts years and hundreds of batches.

Frequently Asked Questions

How many cups of oats does it take to make one quart of oat milk?

Most recipes use about 3/4 cup (roughly 70 grams) of rolled oats per quart of water. You can adjust slightly for a thicker or thinner consistency, but the standard ratio is 1 cup oats to 4 cups (1 quart) of cold water.

Does homemade oat milk taste like Oatly?

Homemade oat milk has a milder, less sweet flavor than Oatly, which adds a small amount of oil and sometimes sugar. You can mimic the commercial taste by adding a teaspoon of neutral oil (like sunflower or canola) and a date or a little maple syrup per quart. Cold-processing with ice water also helps reduce the starchy, gummy quality that some homemade batches develop.

How long does homemade oat milk last in the fridge?

Homemade oat milk lasts 4 to 5 days when stored in a sealed glass jar or bottle in the refrigerator. It does not contain preservatives, so it will sour faster than commercial versions. Always shake or stir before using because the oat solids settle quickly.

Can I use instant oats or steel-cut oats instead of rolled oats?

Rolled oats (old-fashioned oats) give the best results. Instant oats break down too quickly and tend to produce a slimy, starchy milk. Steel-cut oats are too tough to blend properly without soaking overnight first, and the yield is lower. Stick with rolled oats for the most consistent texture and flavor.

Is homemade oat milk nutritionally equivalent to store-bought?

No — commercial oat milks are typically fortified with calcium, vitamin D, vitamin B12, and sometimes riboflavin. Homemade oat milk contains the natural nutrients found in oats (fiber, some B vitamins, iron) but lacks these added vitamins and minerals unless you fortify it yourself. If you rely on plant-based milk for calcium or vitamin D, you may want to supplement or occasionally buy fortified store-brand oat milk.