Oatmeal Serving Weights & Milk Calculator

In this article, I’ve put together everything you need to know about oatmeal (or porridge) weights, servings for various serving sizes of oatmeal made with milk or water.

As well as all this, you can find all the facts and figures in our easy-to-use tables, and you can also calculate how much milk or water you need per serving of oatmeal using our calculator.

Also in this Article

If you’re in a hurry and looking for specific information, use the links below to skip to the section you need:

How Much Oatmeal for a Serving?

I’ve researched and tested various portions of oatmeal (or porridge) to see how much oatmeal and milk or water you need to make various portion sizes.

I looked at various brands, including the top brand Quaker to find their serving recommendations, and the average recommended serving is 40g (1.4oz) of oats per person.

40g (1.4oz) of oats makes a medium-sized portion that is a good-sized serving for an average eater when cooked with milk or water. If you prefer a smaller or larger serving, use the table below to see how many oats you’ll need per serving:

Oatmeal (Porridge) Serving SizeOat Weight (in Grams)Oat Weight (in Ounces)
Small25g0.9oz
Medium40g1.4oz
Large55g1.9oz
Extra Large75g2.6oz
The table shows how much oatmeal (porridge) you need for each serving size.

How Much Milk or water to use for Oatmeal?

The recommended amount of milk or water to use for an average medium-sized 40g (1.4oz) portion of oatmeal is 275ml per serving.

The recommended serving of milk produces oatmeal with a smooth, fairly loose consistency. I prefer my oatmeal a little thicker, and f you do too, I’d recommend using 250ml of milk or water per 40g (1.4oz) of oats.

The table below will help you determine how much milk or water you’ll need for each serving size (see above), depending on how thick you like your oatmeal.

Please note this is based on traditional or rolled oats such as Quaker oats and will work for any milk, including nut, soya, and oat milk.

Oatmeal (Porridge) Serving SizeMilk/Water Amount
(for average consistency)
Milk/Water Amount
(for thicker oatmeal)
Small (25g/0.9oz)172ml156ml
Medium (40g/1.4oz)275ml250ml
Large (55g/1.9oz)378ml344ml
Extra Large (75g/2.6oz)516ml469ml
Table to show how much milk or water you need per serving size of oatmeal (porridge).

Oatmeal to Milk/Water Ratio

If you know an oat to milk or water ratio, you can quickly work out how much milk or water you need for any amount of rolled or traditional oats.

To get the figures for the ratio, I calculated the amount of milk or water per gram of oats by dividing the recommended liquid amount of 275ml by the recommended oats (40g) to get a figure which can be multiplied by each gram of oats.

So I completed the calculation above and also worked out a figure for thicker oatmeal (or porridge), and here are the results:

To work out how much milk or water you need for standard thickness oatmeal, you need to multiply the number of dry oats in your serving by 6.88.

For example, if you want to use 50g of oats, do the following calculation; 50 x 6.88 = 344ml (milk or water).

For a thicker oatmeal consistency, you will need to multiply the oat amount in grams by 6.25 to get the amount of milk or water that you’ll need for your serving.

Oatmeal Milk/Water Calculator

The calculator below will help you work out how much milk or water you will need for any serving of oatmeal (based on the ratios above).

Select your preferred oatmeal thickness and enter the weight of your serving of oats (in grams) to get the information you need.

Oatmeal Serving Calculator

If you’re looking to make oatmeal (or porridge) for your family, friends, or a large group, this section will help you work out how much oats and water or milk you will need to make enough to feed everyone.

The calculator is based on the serving sizes and milk to oats ratio calculation above and will produce oatmeal (or porridge) of standard consistency. It will also work for traditional or rolled oats such as Quaker and for various types of milk, including nut, soya, and oat milk.

Enter how many people you’re looking to feed along with the portion size per person to begin:

More Oatmeal Serving FAQ’s

Below are some of the most frequently asked questions about oatmeal, weights, and servings, in case there’s anything else you need to know:

How many people do 100g of oats serve for oatmeal?

100g of oats will be enough to make two medium-sized servings of oatmeal.

How much milk or water do you need for 100g of oats?

When making oatmeal with 100g of traditional or rolled oats, you will need 688ml of water or milk to make oatmeal of standard consistency.

I hope this article has helped you to find the information you were looking for; you might also find the following articles helpful too:

Oatmeal Calories With & Without Milk

Weetabix Servings, Calories & Weights (in Charts)

Shredded Wheat Servings, Calories & Weights (in Charts)