Fresh basil

For whole fresh leaves, laid in the cup and pressed down slightly, one US cup of fresh basil weighs between 11.8 and 24 grams (0.42 to 0.85 ounces), depending on how the cup is filled and which source measured it. Use 18.7 grams (0.66 ounces) for whole leaves laid in the cup and pressed down slightly, as America's Test Kitchen's 26 cooks averaged. Every figure behind it is below, with the method each source used.

Chopped, spooned and leveled: 42.4 g (1.5 oz) per cup.

Fresh herbs and aromatics compared: cup weights side by side, the source behind each, and why they differ.

A cup of fresh basil leaves weighs about 12 to 24 g (0.4 to 0.8 oz) depending on how firmly it is filled; laid in the cup and pressed down slightly, as America's Test Kitchen recommends, about 18.7 g. Chopped basil is more than twice as heavy by volume: USDA weighs two tablespoons at 5.3 g, 42.4 g a cup.

Basil is the leaf of Ocimum basilicum, most often the large-leaved sweet or Genovese kind sold in bunches, clamshells and pots. It is measured by the cup for pesto, salads and sauces, and chopped, torn or cut into ribbons by the spoon for garnishes, pizza and pasta.

America's Test Kitchen ran the clearest test of any fresh herb: 26 of its staff each measured a cup of basil leaves and weighed them. Those who filled the cup gingerly got 10 g, those who packed it got 29 g, and the average was 18.7 g. Its pesto recipe is in the same place: 4 cups of leaves, after stemming, weigh 3 oz, 21.3 g a cup. USDA's record weighs a quarter cup of whole leaves at 6 g, 24 g a cup, and Norway's food table, from leaves weighed by its health directorate, 5 g a decilitre, 11.8 g a US cup. The sources span a factor of two, far over the 10% this site allows, because a cup of whole leaves has no natural level, so this entry publishes the range and recommends ATK's average.

For chopped basil there is one measurement, USDA's: two tablespoons weigh 5.3 g, 42.4 g a cup, and this site publishes it. The Culinary Institute of America's conversion chart gives 3 g for a tablespoon of any minced fresh herb, 48 g a cup, and America's Test Kitchen's row for six leafy herbs together gives half an ounce as 3 tablespoons finely minced, 75.6 g a cup; neither is basil's own measurement, so both are listed without a figure.

The physical check: basil leaves are broad, soft and slightly cupped, and whole leaves stack loosely with large air pockets between them. At 18.7 g a cup the leaves take up only about 8% of the cup, which is why a light or a heavy hand changes the weight by a factor of three. Chopping removes most of that air: the pieces are small and limp and settle into each other, and a cup of chopped basil weighs more than twice a cup of whole leaves.

Practical guidance: for whole leaves, lay them in the cup and press down slightly to remove the large air pockets, and count about 19 g a cup. For chopped or torn basil by the spoon, use 2.7 g a tablespoon. For pesto, where basil is the main ingredient, weigh it: a recipe written as 2 cups of leaves can mean anything from 20 to 58 g depending on who filled the cups, as ATK's test shows, and the difference decides how green and how strong the pesto is. Basil bruises and darkens when it is crushed, so press gently and chop it just before use.