Why is the oil amount less than the butter amount?

Butter is around 80% fat and 20% water and milk solids (UK butter is a minimum 80% milkfat under the Spreadable Fats Marketing Standards), while oil is nearly 100% fat. So you need less oil to provide the same fat. This converter matches by fat content: oil weight = butter weight × 0.80. As a quicker kitchen rule of thumb, many bakers use ¾ (use ¾ cup of oil per cup of butter, i.e. × 0.75) — at 200 g butter that is 150 g of oil versus 160 g here, so both are within the normal range.

Will switching from butter to oil change the texture?

Yes. Butter gives bakes a firmer texture and richer flavour, while oil produces a moister, more tender crumb. Oil-based cakes tend to stay moist longer. The choice depends on the style of bake you want.

Can I use any type of oil?

For neutral flavour, use sunflower or vegetable oil. Olive oil adds a fruity note that works well in citrus cakes and Mediterranean bakes. Coconut oil gives a subtle coconut flavour and solidifies when cool, making it a closer substitute for butter's texture.

Do I need to adjust other ingredients?

Generally no adjustment is needed for a simple swap. However, since butter contains water, you might find oil-based versions slightly richer. If the batter seems too wet, reduce any additional liquid by 1-2 tablespoons.

Will the texture be the same when substituting oil for butter?

Not exactly. Butter is about 80% fat and 20% water and milk solids, which contribute to flavour, colour, and structure. Oil-based cakes tend to be moister and denser, while butter-based cakes are lighter and more flavourful. Oil works best in recipes where moisture is important, such as carrot cake or chocolate cake.

BakeCalcs

Butter to Oil Converter

Convert between butter and oil quantities in baking recipes.

Conversion DirectionButter to Oil converts a butter quantity into the equivalent oil; Oil to Butter does the reverse.

Oil TypeChoose the oil you are using — affects flavour and, via density, the tablespoon figure (coconut sets solid when cool, the closest texture to butter).

Butter Weight

How We Calculate This

The conversion between butter and oil is based on their fat content. UK butter is a minimum 80% milkfat (with ~20% water and milk solids), while cooking oils are nearly 100% fat, so you match the fat by weight.

Conversion Formulas

Butter to oil: Oil weight = Butter weight × 0.80
Oil to butter: Butter weight = Oil weight × 1.25

A common kitchen rule of thumb is ¾ — use about ¾ cup of oil per cup of butter (× 0.75, reverse × 1.33). That is close to the fat-matching figure above; either is fine for most cakes and bakes.

Tablespoon figures use the oil's density: all cooking oils are roughly 0.91–0.93 g/ml, so a 15 ml UK tablespoon of oil weighs about 13.5–14 g. Choosing an oil type adjusts this slightly (olive is marginally lighter, melted coconut marginally heavier).

Best Uses

Oil works best in: muffins, quick breads, carrot cake, chocolate cake
Butter is preferred for: shortbread, scones, pastry, buttercream

Frequently Asked Questions

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.