How Many Gallons In A Hot Tub

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Table of Contents

How Do I Calculate How Many Gallons of Water Are In a Hot Tub?

If you want to determine the exact number of gallons in your hot tub and you don't have the manual or spec sheet to tell you, there are a few different ways to see how much water your hot tub can hold.

Dimension Calculation Method

All you'll need is a tape measure.

For square or rectangular hot tubs, start by measuring the length, width, and depth in inches. Multiply the length by the width by the depth. Take that result and divide it by 1,728.
For completely round hot tubs, start by measuring the depth and the width across the center of the hot tub. Multiply the depth diameter by the width diameter, and divide the result by 1,728.
For hot tubs with seats, multiply your result by 2.4. For hot tubs without seats multiply your result by 4.8.

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Timed Fill Method

A tape measure is not required for this method.

Start by turning on your hose to fill your hot tub up to a set point.

Set a timer when you start filling your tub and let it run until the hot tub is full. You will then have to take the time it took to fill your hot tub and convert it to seconds.

Start by multiplying the hours by 60, and take the total additional minutes and multiply those by 60. Any additional seconds can be added on last.

So, for example, let's say that it took one hour and 30 minutes to fill up your hot tub.

The calculation would look something like this:

1 hour = 60 minutes

60 minutes + 30 minutes = 90 minutes

90 minutes x 60 = 5,400 seconds.

Now, take a one-gallon jug and set your hose to the same pressure. Making sure you're using the same hose setting is crucial, so you don't get any variation.

When you start filling the jug, set your timer. As soon as the jug is full, stop your timer.

If it takes more than a minute to fill your jug, convert the time into seconds. This number, we'll give you the single-gallon flow rate in seconds.

Next, divide the total number of seconds it took to fill your hot tub by the total number of seconds it took to fill your one-gallon jug to get the approximate number of gallons.

You can get the same rough estimate with a five-gallon bucket if you divide by five gallons instead. This calculation method can tell you how much water your hot tub holds, whether it is square, triangular, or perfectly round.

Hot Tub Capacity

How Many Gallons in a 2-Person Hot Tub?

If you're looking for the smallest and most space-friendly hot tub size, you might consider a two-person hot tub. Two-person hot tubs will likely hold anywhere between 150 and 220 gallons.

How Many Gallons in a 3-Person Hot Tub?

If a two-person hot tub is a bit too tight of a squeeze for you and you want to enjoy the benefits of additional space, you might consider going with a three-person hot tub. Three-person hot tubs often hold anywhere between 200 and 300 gallons.

How Many Gallons in a 4-Person Hot Tub?

Four-person hot tubs are pretty standard, as they are small enough to fit in compact outdoor spaces yet have enough room to enjoy with friends and family. You can often expect anywhere between 275 - 350 gallons of water in four-person hot tubs.

How Many Gallons in a 5-Person Hot Tub?

Five-person hot tubs are pretty similar in size to four-person hot tubs, though they often come with additional features, such as loungers or bench seating. You can expect around 300 - 375 gallons of water in most five-person hot tubs.

How Many Gallons in a 6-Person Hot Tub?

Six-person hot tubs offer more than enough room to entertain large groups of friends or family. Your average six-person hot tub will hold anywhere between 320 and 475 gallons of water.

How Many Gallons in a 7-Person Hot Tub?

Getting up into the larger realm of hot tubs, we have seven-person models. These large hot tubs, which offer plenty of space and seating options for large groups, often hold anywhere between 400 and 500 gallons of water.

How Many Gallons in an 8-Person Hot Tub?

An eight-person hot tub is pretty much as big as it gets before you start moving into swim spa territory. You can expect one of these large hot tub models to hold anywhere between 550 and 625 gallons of water.

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About The Author

Bobby Gifford // Staff Writer

Bobby Gifford has over 17 years of experience with hot tubs and swimming pools. He has owned one pool and several hot tub brands over the years and has a wide scope of knowledge including buying information, maintenance and industry trends.