Pressure Washers: What's the Difference Between PSI and GPM?

When shopping for a pressure washer, you may encounter the terms "PSI" and "GPM." Pressure washers, of course, are devices that use high-pressure water to clean objects. They feature a nozzle. When turned on, pressure washers will release a stream of high-pressure water out of the nozzle. By understanding PSI and GPM, you can choose the right pressure washer for your needs.

What Is PSI?

Pounds per square inch (PSI) is a measurement of a pressure washer's force. As the name suggests, it represents how many pounds per square inch of force the pressure washer is releasing. A higher PSI rating means that the pressure washer produces more force to clean surfaces, which is particularly useful for tough cleaning tasks such as removing oil stains from a driveway or grime from a brick wall.

What Is GPM?

Gallons per minute (GPM) is a measurement of a pressure washer's volume. Pressure washers work by releasing water. The water is pressurized so that it removes dirt and debris. The amount of water released by a pressure washer is measured in GPM. More specifically, GPM is the rate at which a pressure washer releases water.

A higher GPM rating means the pressure washer is releasing more water, which can help clean a larger area in a shorter amount of time.

Differences Between PSI and GPM

PSI and GPM aren't the same. While they are both used in pressure washer specifications, they are different metrics. PSI is a measurement of pressure, whereas GPM is a measurement of water volume or rate. You should consider both of these metrics when shopping for a pressure washer.

Generally speaking, pressure washers with a high PSI and a high GPM are better than those with a low PSI and a low GPM. They are more powerful, and they release more water.

A high PSI, however, isn't always enough for a pressure washer to do its job. If a pressure washer has a high PSI and a low GPM, it will produce a strong and forceful stream of water. But a low GPM means it won't release much water. The pressure washer will produce a small and narrow stream of water, which can make it difficult to clean larger surface areas.

The bottom line is that you shouldn't focus exclusively on PSI when choosing a pressure washer. It needs to have a balance of both PSI and GPM to effectively clean surfaces. The ideal PSI and GPM ratings depend on the specific cleaning task at hand, but you should consider both of these metrics before making a purchase.