How many gallons will my sink hold? (typical examples)

Kitchen Sink Graphic

In this article we're going to answer the question: “What will my kitchen sink hold?” If this question makes you groan a little bit as you remember sitting in a high school classroom somewhere, or you just share my lack of natural ability with numbers, let me give you a refresher on your tenth grade math to find the answer to this question.

Why does sink weight matter?

You may be wondering what the point is to calculating the gallon capacity of your kitchen sink. Admittedly, you are not likely to need this little piece of information every day, but there may actually be a time when you would like to know how much fluid your sink can hold. 

Diluting cleaning detergents to mop floors, soaking stained clothing, or even brining a Thanksgiving Turkey may require you to know your sink’s capacity or at least have a pretty good idea. 

For a Typical Rectangular Sink

Assuming you have a rectangular shape, like a typical farmhouse sink, you will need to multiply length (L) by width (W) by depth (D) and divide that answer by 231 which is the number of cubic inches of volume in a gallon

See, not so bad.

Keep in mind that you will probably not fill your sink to the very brim so your depth measurement should stop a few inches shy of the top of your sink. 

Kohler Apron Sink

To get the gallon capacity for a typical rectangular sink, multiple length x width x height, and divide that total by 231.

For a Round Sink

If you have a round sink, your formula is similar but includes the radius and 3.14 because the area of a circle = 3.14x radius squared. So you will need to multiply the depth (D) by the radius (half of the diameter) squared. 

The formula looks like this: Radius squared x D x 3.14 then divide that answer by 231. Easy! 

Now that you have sailed through the first two types of sink volume formulas as you travel back to high school math, you are ready for the last and trickiest sink shape to calculate.

The Frustum 

You can think of this shape as a cone with the bottom point lopped off. So now we have two radii to deal with. You will need to multiply the 2 radii and also square each one. To calculate the answer you multiply the depth (D) by 3.14 and divide that number by 3. Now multiply the top radius by itself (which we will call T) and the bottom radius by the top radius. Multiply these two numbers. Now add that number to the bottom radius squared and divide by 231. So, in math terms [(3.14xD)-\3]x(TxT)x(TxB)+(BxB)/231. Phew! 

End of Class

In the event that you would like to know the volume capacity of your kitchen sink in gallons now you have the formulas to find out. I hope that these make sense and that the math part will be worth the turkey brining recipe or whatever you decide to use your sink for. At the end of the day our kitchens are the workhorses of our homes and the sink plays a crucial role in that.

Knowing as much as possible about what your sink is capable of can help you utilize it to the fullest. 

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