How to replace butter with olive oil: a conversion table for cakes and recipes

To replace butter with olive oil, use about 80% of the weight as a base: 100 g of butter becomes about 80 g of oil. The conversion works well in cakes and muffins; shortcrust pastry, puff pastry and creams need adjustments because butter contains water and is solid at room temperature.

The formula solves the calculation, not the whole recipe. Oil makes batters soft and stays liquid; butter incorporates air, gives structure and contains a share of water. By choosing flavour and technique you avoid a greasy or unsupported cake.

Formula and table

Grams or millilitres

For precision, weigh the oil in grams. If the recipe works in millilitres, bear in mind that density and measuring jug change the number: don't automatically treat 80 g as 80 ml. In home cooking a small difference is tolerable for a cake, less so for shortcrust and fine pastry.

Which oil to choose

A delicate extra virgin olive oil goes with citrus, cocoa, nuts and breakfast cakes; an intense one can come through too strongly in vanilla or creams. Taste it first. Neutral oils reduce the aromatic impact, but the choice depends on the result and doesn't make the cake automatically “light”: oil is still high in calories.

Adapting different doughs

Mistakes to avoid

Replacing 1:1 often makes the batter too greasy. Don't add oil all at once to a mixture that is already badly emulsified. Don't expect the same whipping as butter with sugar. If the batter looks too dry, correct with small quantities of the liquid in the recipe, not with more oil.

Practical method

Calculate 80%, weigh the oil, choose a compatible one and note the result. For an important recipe try half a dose. The next time, change by 5% at a time: flour, eggs and method count as much as the conversion.

Why 80% works

Traditional butter contains about 80% fat and a share of water and solids; oil is almost entirely fat. Using 80% brings the quantity of lipids close, but doesn't recreate water, crystalline structure or the ability to whip. It is a chemical starting point, not a perfect identity.

Rebalancing the liquids

In a cake the missing water can be made up by the recipe itself, especially with eggs, yoghurt or milk. If the batter is visibly thicker, add the liquid provided by the recipe a teaspoon at a time. Avoid correcting before you have mixed: different flours absorb differently.

Olive oil shortcrust

Mix oil, eggs and sugar, then fold in the flour without overworking. Resting helps hydration, but the dough won't become as pliable as a cold-butter shortcrust. Roll out between two sheets and chill if needed. Use a recipe designed for oil when the result must be flawless.

Testing in the kitchen

Divide a simple recipe into two half doses: original and conversion. Weigh the batter, measure the diameter of the tin and bake together. Compare height, moistness, aroma and keeping the next day. Noting one change at a time turns the generic rule into a reliable conversion for your recipe.

In-depth guide to replacing butter with olive oil

Why the conversion starts at 80%

Traditional butter contains about 80% fat and a share of water and milk solids, while oil is almost entirely fat. That is why replacing 100 g of butter with about 80 g of oil is a more sensible starting point than a one-to-one ratio. The rule brings the quantity of fat close, but doesn't recreate water, crystalline structure, pliability or the ability to incorporate air. The result can therefore change even when the lipid balance is similar.

Use a scale: converting grams to millilitres without considering density adds another approximation. For small quantities the difference may be tolerable, but in cakes and shortcrust it affects structure. Note the conversion and change one variable at a time. If the recipe is based on whipped or cold laminated butter, oil often requires a different technique and not a simple numerical substitution. When the result must be flawless, prefer a recipe originally designed for oil.

Create a conversion table for the quantities you use most often: 50, 80, 100, 125 and 150 g of butter. Calculate 80% in grams of oil and keep the sheet near your recipes. Don't round too much in small batters and use the scale. Next to each row leave a space for the result. Over time you can adjust the percentage for a specific recipe without confusing the general rule with the formula already tested in your oven.

Cakes, muffins and soft batters

In batters where the butter is melted, substitution is generally simpler. Mix the oil with the liquid ingredients and emulsify well before adding flour. Watch the final consistency: flours, eggs, cocoa and fruit absorb differently. If the batter looks too thick, consider small additions of the liquid already in the recipe, not random water. If it is too runny, don't automatically correct with lots of flour, because you might get a dry, heavy cake.

Oil tends to keep softness even at room temperature, while the milky flavour of butter is missing. Choose a delicate profile for vanilla, citrus and neutral batters; a fruitier extra virgin olive oil can enhance chocolate, nuts and rustic cakes. Bake in the same tin and check a few minutes before the usual time, without opening the oven too early. Let it cool completely before judging texture: a warm cake can seem moister than it will be the next day.

For the first test choose a simple batter with melted butter, not puff pastry. Divide the ingredients into two half doses and use identical tins. Photograph the consistency before baking and weigh the finished product. Taste warm and cold. If the oil version is moister, don't reduce the fat straight away: look at baking and liquids. A controlled comparison shows the direction of the correction and reduces the risk of blaming every difference on the oil chosen.

Shortcrust, biscuits and crumbly doughs

In shortcrust, cold butter contributes to pliability and crumbliness. Oil doesn't solidify in the same way and can produce a softer, more fragile dough that is harder to roll out. Mix oil, eggs and sugar, fold in the flour without overworking and let it rest. Rolling out between two sheets reduces the need to add flour. If necessary chill the dough, knowing it won't become identical to a butter shortcrust.

For shaped biscuits, test a small tray: watch how much they spread, whether the edges hold and how the crispness changes after cooling. Adjust flour or liquid gradually and note the grams. Don't compensate with very hard doughs before resting. Flavours such as citrus, cocoa, almonds and spices can harmonise with the profile of the oil. If you want flakiness or a very precise shape, a specific oil recipe will give more reliable results than an improvised conversion.

In shortcrust, note the room temperature and resting time, because they affect workability. Roll out between sheets of the same thickness and bake a small test. If the biscuits spread, adjust the dough gradually or use a dedicated recipe. Don't add large quantities of flour on the worktop: it changes proportions and makes it hard to replicate. The oil result can be excellent while having a different crumbliness. Judge it for what it is, not only as an imitation of butter.

Creams, sauces and savoury preparations

In savoury preparations the substitution depends on the function. For sauteing vegetables or dressing, oil can easily take the place of butter, adjusting quantity and intensity. In a béchamel or an emulsified sauce, flavour and structure change and the technique of the recipe must be respected. Oil doesn't contribute milk solids and doesn't brown in the same way. An intense extra virgin olive oil can dominate delicate dishes, while a balanced profile widens the uses.

In mashes and velvety soups add the oil gradually at the end of preparation to assess consistency and aroma. In risottos it can replace part of the butter, but the mantecatura (final creaming) requires the right emulsion and liquid; pouring it on the surface is not enough. For bread and focaccia use recipes formulated with oil, in which hydration and dough are already balanced. The question is not only how many grams to use, but what job the butter did: cooking fat, aroma, structure, lamination or emulsion.

For savoury preparations, write next to the butter its function. If it is for sauteing, the substitution is direct; if it emulsifies or creams, add the oil at the right moment and with the right liquid; if it creates solid layers, a simple conversion is not enough. This question prevents many failures. Taste also needs calibrating: try half a dose of an intense extra virgin olive oil and finish after tasting. The oil must blend into the recipe, not be chosen only for theoretical reasons.

Choosing the oil according to the recipe

Taste the oil on its own before using it in a cake. A delicate, clean fruitiness is versatile; grassy and pungent notes can become the stars in batters with cocoa, citrus, honey or nuts. Avoid a rancid product thinking baking will hide the defect: the unpleasant aroma can remain. The colour of the oil can slightly change the batter, but it is not a quality criterion. Freshness and balance matter more than the shade.

To compare two oils, divide a simple recipe into identical half doses and change only the oil. Use the same tin, weight and time. Taste on the baking day and the next, assessing aroma, moistness and persistence. This test shows how much the character remains perceptible. Store the oil away from light and heat and choose a size consistent with how often you bake. A delicate oil opened many months ago is not necessarily better than a more intense one that is fresh and well dosed.

Organise a tasting of the oils intended for cakes on plain bread, then with a small piece of the main ingredient, such as chocolate or orange. A profile that seems strong on its own can harmonise in the batter. Always check freshness and absence of rancidity. If the cake is for children or guests, consider preferences without promising that a delicate oil is lower in calories. The difference is sensory. Use small bottles if you bake rarely, so the product stays intact.

Testing and correction method

Start from the 80% conversion, weigh all the ingredients and photograph the consistency of the batter. If possible, divide the recipe in two: original version and oil version. Bake together in identical containers and record height, time, colour, moistness and how it holds when cut. The next day assess softness and aroma. Change just one element in the next test, for example five grams of oil or a small quantity of the liquid in the recipe. Without a method, you won't know which correction worked.

Create a personal sheet for recurring recipes with original butter, oil used, conversion, liquids and result. After two or three tests you will have a reliable formula for that flour, that tin and your oven. Don't turn the general rule into a universal promise: croissants, puff pastry and whipped creams require structures that oil doesn't directly replicate. The conversion works best when you understand the function of the fat and accept a result that is different but intentional, not an imperfect copy.

After each test give notes for structure, flavour, moistness, ease and keeping the next day. Change just one item and repeat. When you find the formula, rewrite the complete oil recipe instead of leaving calculations in the margin. Give grams, not just spoonfuls, and specify the profile used. This step turns a successful experiment into a repeatable recipe. The substitution becomes reliable when the new batter has its own clear procedure and doesn't depend on remembering the original version.

In summary

To replace butter with olive oil, use about 80% of the weight as a base: 100 g of butter becomes about 80 g of oil. The conversion works well in cakes and muffins; shortcrust pastry, puff pastry and creams need adjustments because butter contains water and is solid at room temperature.

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FAQ

How much oil for 100 g of butter?

About 80 g as a starting point.

Can I use extra virgin olive oil in cakes?

Yes, choosing a profile suited to the flavours of the recipe.

Will the cake have fewer calories?

Not necessarily; it depends on quantity and the overall recipe.

Does the conversion work for puff pastry?

No: the structure requires a recipe designed specifically for oil.

How much oil do I need instead of 150 g of butter?

Using the practical 80% rule, you need about 120 g of oil. The recipe may need a small adjustment of the liquids.

How much oil do I need instead of 200 g of butter?

The basic conversion gives about 160 g of oil. Check the consistency of the batter, because butter and oil contain different amounts of water.

In the conversion, is it better to use grams or millilitres?

Grams are more precise because oil and water have different densities. If you use millilitres, rely on a specific table and a measuring jug.

Which extra virgin olive oil should I choose for cakes?

An oil with a delicate or medium fruitiness blends in more easily. Intense profiles work when you want an obvious aroma, for example with cocoa or citrus.

Can butter be replaced with oil in biscuits?

Yes, but the texture will be different and the dough may need resting or less liquid. Start from 80% and do a small test.

Does replacing butter always make a cake vegan?

No. The recipe may contain eggs, milk, honey or other animal ingredients. Check the whole list, not only the fat used.