Mayonnaise: How Many Grams in a Cup?

1 US cup of mayonnaise (mayo) weighs about 225 grams — roughly 220–230 g for regular mayo. As a quick guide, 1/2 cup of mayonnaise is about 112 g, 1/4 cup about 56 g and 2 cups about 450 g. Light and fat-free mayo hold more water, so they weigh more per cup (about 250–256 g).

Why mayonnaise cup weights vary

Mayonnaise looks consistent, but the grams in one cup shift with a few real factors. That is why published values for “1 cup of mayo in grams” range from roughly 220 g to 256 g:

• Density. Regular mayonnaise is mostly oil, which is lighter than water (density ≈ 0.95 g/mL). One US cup (236.6 mL) therefore works out to about 225 g rather than the 237 g a cup of water would weigh.
• Regular vs light vs fat-free. Light and fat-free mayo replace oil with water and thickeners, so they are actually heavier by the cup. USDA FNDDS lists regular mayonnaise at 220 g per cup, light mayo at 250 g and fat-free at 256 g.
• Brand differences. Recipes vary between brands (Hellmann’s, Duke’s, Kewpie, store labels), so the same cup can drift a few grams either way.
• Air pockets and method. Spooning mayo into a cup traps air and reads light; pressing it down packs more in. Leveling with a knife — or simply weighing on a scale — gives the most repeatable result.
• US cup vs metric cup. A US cup is 236.6 mL (≈ 225 g of mayo), while a metric cup is 250 mL (≈ 238 g). Check which cup your recipe assumes.

Common mayo conversions

These are the mayonnaise amounts people search for most. All values use regular mayo at about 0.95 g/mL, the same figure the converter and chart above use:

• 1 cup of mayo in grams: about 225 g (USDA lists 220 g for regular).
• 3/4 cup of mayonnaise: about 169 g.
• 2/3 cup of mayo: about 150 g.
• 1/2 cup (half cup) of mayonnaise: about 112 g.
• 1/3 cup of mayo: about 75 g.
• 1/4 cup of mayonnaise: about 56 g.
• 2 cups of mayo in grams: about 450 g.

Mayonnaise conversion FAQ

How many grams is 1 cup of mayonnaise?

One US cup of regular mayonnaise weighs about 225 grams (USDA FNDDS lists 220 g for regular mayo). Light mayonnaise is heavier at around 250 g per cup, and fat-free reaches about 256 g.

How many grams is 1/2 cup of mayonnaise?

Half a US cup of mayonnaise weighs about 112 grams. For reference, 1/4 cup is roughly 56 grams, 1/3 cup about 75 grams and 3/4 cup about 169 grams.

Is mayo the same as mayonnaise for conversion?

Yes. 'Mayo' is just the everyday name for mayonnaise, so the same cup-to-gram values apply. Only the type — regular, light or fat-free — changes the weight.

Why do different sources give different gram values for mayonnaise?

Brand, fat content and how you fill the cup all matter. Regular mayo is about 220–225 g per cup, while light and fat-free versions hold more water and reach 250–256 g. Spooning traps air and reads light, so weighing on a scale is the most accurate.