Mushroom Weights and Calories (Various Types In Charts)

In this article, I’ve put together an ultimate guide with charts so you can quickly work out the exact weights and calories of various portions and types of edible mushrooms.

I’ve also done research into how much mushrooms shrink during the cooking process and I’ve recorded my findings below.

Button (Closed Cup) Mushroom Weights

The most common variety of mushrooms which we eat is the button or closed cup mushroom and these are widely available in stores and supermarkets.

Button mushrooms are the smaller version of an open cup flat mushroom which have not been allowed to grow open and flat. They are also sold as ‘baby’ mushrooms and these simply button mushrooms which are picked early when they’re very small.

I did some research and weighed a large selection of raw baby button mushrooms along with mixed-sized standard button mushrooms to get some average weights and found the following.

A baby button mushroom weighs around 5-10g/0.18-0.35oz, a medium-sized button mushroom weighs around 20-25g/0.7-0.88oz and a large button mushroom weighs around 50-60g/1.76-2.12oz.

Use the chart below to find the weight conversions for various sizes of button (closed cup) mushrooms:

Small (baby) button
mushroom weight
Medium button
mushroom weight
Large button
mushroom weight
5-10g20-25g50-60g
0.18-0.35oz0.7-0.88oz1.76-2.12oz
0.005-0.01kg0.02-0.025kg0.05-0.06kg
0.01-0.02lb0.04-0.06lb0.1-0.13lb

Flat Mushroom (Open Cup) Weights

A large flat mushroom is the same as a button mushroom, but it’s been allowed to grow to a bigger size and has opened out, which is something mushrooms do before they spore.

Large flat mushrooms are the most common type of large mushroom and are becoming increasingly popular in vegan and vegetarian dishes.

I weighed a number of raw flat mushrooms that were bought from a supermarket to get an average weight and the results were as follows:

An average medium-sized flat (open cup) white mushroom weighs around 60-70g/2.12-2.5oz, smaller flat mushrooms weigh around 50-60g/1.76-2.12oz and large flat mushrooms weigh 70g/2.5oz plus.

Use the chart below to find the weight conversions for various sizes of flat white (open cup) mushrooms:

Small flat white
mushroom weight
Medium flat white
mushroom weight
Large flat white
mushroom weight
50-60g60-70g70g plus
1.76-2.12oz2.12-2.5oz2.5oz plus
0.05-0.06kg0.06-0.07kg0.07kg plus
0.01-0.13lb0.13-0.15lb0.15lb plus
image to show what a large flat open cup mushroom looks like

Flat Portobello Mushroom Weights

Like flat white mushrooms, Portobello mushrooms are open cup mushrooms that have been allowed to grow to a bigger size and open out.

Portobello mushrooms are also known as brown mushrooms and can be cooked in the same way as a large flat white mushroom.

An average medium-sized flat (open cup) Portobello (or brown) mushroom weighs around 60-70g/2.12-2.5oz, smaller flat mushrooms weigh around 50-60g/1.76-2.12oz and large flat mushrooms weigh 70g/2.5oz plus.

Use the chart below to find the weight conversions for various sizes of flat Portobello/brown (open cup) mushrooms:

Small flat Portobello/brown
mushroom weight
Medium flat Portobello/brown
mushroom weight
Large flat Portobello/brown
mushroom weight
50-60g60-70g70g plus
1.76-2.12oz2.12-2.5oz2.5oz plus
0.05-0.06kg0.06-0.07kg0.07kg plus
0.01-0.13lb0.13-0.15lb0.15lb plus
image to show what a large flat Portobello mushroom looks like

Chestnut (Brown) Mushroom Weights

Chestnut or brown mushrooms are similar to button mushrooms, but they have a nutter flavor and a brown outer skin.

Chestnut mushrooms are closed cup and have not grown enough that they’ve started to open out to become a ‘flat mushroom’.

I did some research and weighed a large selection of mixed-sized closed cup chestnut (or brown) mushrooms to get some average weights and found the following:

A small chestnut mushroom weighs around 5-10g/0.18-0.35oz, a medium-sized chestnut mushroom weighs around 10-20g/0.35-0.71oz and a large button mushroom weighs around 20-40g/0.71-0.09oz.

Use the chart below to find the weight conversions for various sizes of chestnut (or brown) mushrooms:

Small (baby) button
mushroom weight
Medium button
mushroom weight
Large button
mushroom weight
5-10g10-20g20-40g
0.18-0.35oz0.35-0.71oz0.71-0.09oz
0.005-0.01kg0.01-0.02kg0.02-0.04kg
0.01-0.02lb0.02-0.04lb0.04-0.01lb
image to show what a chestnut or brown closed cup mushroom looks like

Oyster Mushroom Weights

Oyster mushrooms come in various sizes and are generally sold in a cluster because they grow on one main stalk.

The average weight of a cluster of oyster mushrooms when they’re sold in a cluster is 150g/5.29oz.

Image to show what a cluster of oyster mushrooms look like

How Much Do Mushrooms Shrink When Cooked?

If you’ve ever cooked any variety of mushrooms, you’ll know that they shrink in size quite considerably during the cooking process.

It’s useful to know how mush foods shrink while cooking if you’re trying to work out portion sizes for recipe planning or for calorie counting.

I did research and cooked ordinary white button mushrooms in only their ow juices to see how much they weighed after cooking and here are the results:

I cooked 200g of sliced button mushrooms in a pan and gently sweated them down in their own juices until they’d shrunk down and once drained the mushrooms weighed 150g. This was a reduction of 25% of the original raw mushroom weight.

To work out how much your portion of mushroom will shrink during cooking, use this simple equation:

Raw mushroom weight minus 25% = cooked mushroom weight

How Many Mushrooms are in a Serving?

A serving of mushrooms is equal to one cup or 70g/2.5oz of raw chopped mushroom of any type.

A serving of this size contains 15 calories (in kcal) and will reduce in weight to around 53g/1.87oz when cooked and drained.

Mushroom Weight and Calorie Chart

Use the chart below to find more mushroom serving weights and calories, these figures are based on generic raw mushroom types and should work for all varieties.

Button mushroom weights use an assumption of an average medium mushroom weighing 20g/0.7oz each and for flat mushrooms, I’ve used an averaged medium-sized mushroom weight of 60g/2.12oz.

Mushroom Serving SizeAverage Raw WeightCalories (in kcal)
1 average button mushroom20g/0.71oz4
2 average button mushrooms40g/1.41oz9
3 average button mushrooms60g/2.12oz13
4 average button mushrooms80g/2.82oz18
5 average button mushrooms100g/3.53oz22
6 average button mushrooms120g/4.23oz26
7 average button mushrooms140g/4.94oz31
8 average button mushrooms160g/5.64oz35
9 average button mushrooms180g/6.35oz39
10 average button mushrooms200g/0.71oz44
1 average flat mushroom60g/2.12oz13
2 average flat mushrooms 120g/4.23oz26
3 average flat mushrooms180g/6.35oz39
4 average flat mushrooms240g/8.47oz53
5 average flat mushrooms300g/10.58oz66
6 average flat mushrooms360g/12.7oz79
7 average flat mushrooms420g/14.82oz92
8 average flat mushrooms480g/16.93oz105
9 average flat mushrooms540g/19.05oz118
10 average flat mushrooms600g/21.16oz131
25g of mushroom25g/0.88oz5
50g of mushroom50g/1.76oz11
75g of mushroom75g/2.65oz16
100g of mushroom100g/3.53oz22
1oz of mushroom28g/1oz6
2oz of mushroom57g/2oz12
3oz of mushroom85g/3oz19
4oz of mushroom113g/4oz25

More Mushroom Weight FAQs

How many mushrooms are in 100g?

Based on an average medium-sized button mushroom weighing around 20g/0.71oz, there are around 5 average-sized button (or closed cup) mushrooms in 100g.

How many mushrooms are in a pound?

Based on an average medium-sized button mushroom weighing around 20g/0.71oz, there are around 23 average-sized button (or closed cup) mushrooms in a pound.

How many mushrooms are in a kilogram?

Based on an average medium-sized button mushroom weighing around 20g/0.71oz, there are around 50 average-sized button (or closed cup) mushrooms in a kilogram.

Related Articles

I hope this post helped you to find the information you were looking for, you might also like the following related articles:

Spinach Weights, Calories & Servings (with calculator & Charts)

Cauliflower Weights & Calories (In Charts & Images)