What Is the Capacity of a Sink?

A kitchen sink's capacity in gallons is important to know when searching for the ideal style and size of the sink to put in your home. Capacity affects your ability to perform certain washing and cooking tasks, and it determines how effective your sink is in the long run.

Capacity is the amount a certain vessel will hold. Capacity relates to individual units; for instance, the capacity of a theater is measured in persons, or it is a volume measurement, like when a container capacity is measured in liters. Either way it tells you how much something holds or contains. Not all items have a capacity measurement, but that does not mean there is no way to measure it.

Sink capacity is not measured by the manufacturer and it is not listed as one of the measurements on the sink's specifications.

However, there is a way to determine the precise capacity of a kitchen sink. Measuring capacity is the same as measuring volume in most cases where the vessel or container holds water or another liquid. Since sinks hold water, measuring the volume gives you an ideal capacity measurement. Use this measurement to compare the capacity of different sinks.

When purchasing sinks you see three main measurements. This includes the length and width of the sink along with the bowl depth. Remember that the length and width of the rimmed sink is not the same as the bowl dimensions. To find the sink capacity, always use the sink bowl measurements, not the overall sink dimensions.

Simply multiply bowl depth by bowl width, and multiply that by the sink's length to obtain the volume or capacity. When comparing kitchen sink capacities, keep in mind that you are unlikely to fill your sink to the very edge. Consider subtracting a couple of inches from your kitchen sink height measurement to get a realistic measurement.

To get a better idea of how much liquid the sink can hold, you can translate this volume measurement into gallons. You should divide your volume measurement by 231 to convert the units from cubic volume by inches to gallons. In double-bowl sinks, there are two separate bowls, and each is a different size. So find the capacity for both separately and add them together.

For example, consider a kitchen sink that measures 22 by 33 inches and has a maximum depth of 8 inches. Subtract at least 2 inches from the depth to give you room for dishes without risking overflow. Now the calculation is 22 x 33 x 6 = 4,356. Divide this by 231, and you'll discover this large sink can hold at least 18 gallons of water.

There are advantages to large versus small kitchen sink dimensions. A larger capacity sink holds more dishes, fruit and water for cleaning, for one. However, large capacity sinks require more countertop space; therefore, you have less room to prepare food.

Large capacity sinks also weigh more when full, so they will pull down on the countertop and put more weight and pressure on your cabinetry. This places stress on your cabinets and countertop. This is especially true in undermount sinks that mount under the countertop. These require a strong, solid countertop surface like granite or marble to perform properly.

You can compromise by purchasing a kitchen sink that is deep but not wide. This allows you to still fill the sink with plenty of water for handwashing dishes and produce without sacrificing counter space.