The pool calculator tells you how much water you will need to fill pools of various sizes and depths. 🏊 This is useful information that will help you to better estimate the cost of the water, as well as the amount of time you need to go from an empty pool to floating around with a cool drink in your hand. If you're wondering how many gallons your pool has, give this tool a try! Please note that the pool volume calculator assumes that the depth of the pool changes evenly and gradually from one end to the other, as is generally the case. If this does not apply to your pool size, figures computed by the pool calculator can still be in the same ballpark.
How does the pool volume calculator work?
The pool water calculator is a tool similar to the volume calculator; it also uses also the formulas from the square footage calculator.
It's a simple matter of getting the surface area of the pool and then multiplying that by the average depth.
 Start by entering the pool size (length and width).
 Then add its depth at two endpoints.
 If there is both a shallow and a deep end, enter the shallow depth in the first field and the deepest point in the second. Otherwise, enter two identical values.
 If the depth of your pool changes drastically instead of gradually, you may want to consider dividing it in half, with a separate pool calculator measurement for each part (as in the image on the right).
You could go one step further and, knowing the density of water (which is approximately 1 kilogram per liter) work out how much water in such pool would weight.
Formulas behind pool calculator
To find out how many gallons is your pool, simply apply one of the formulas:
 Rectangular / square pool
volume = length * width * (depth1 + depth2) / 2
The first two agents is of course the formula for the area of the rectangle.
 Oval / circle pool
volume = (π * length * width / 4) * (depth1 + depth2) / 2
The first part of the equation comes from a standard area of an ellipsis formula: A = π * a * b
, where a, b
are the distances between the center and the ellipse's vertex, lying on the horizontal and vertical axes. In our case, we have the length and width values that are the doubled distances a
and b
, so in the final formula, we need to divide the surface area of an oval by 4.
You are wondering why we average the depths (depth1 + depth2) / 2
? Have a look at the pictures:
 Here you have the standard rectangular pool.
l
stands for the length of the pool,w
for width,d1
is depth on one end of the pool andd2
is the depth on the other end.
 Let's take the right trapezoidal side of the pool. "Cut" the triangle, with one apex in the midpoint of the side, as in the picture.
 Flip and move it to the other side to form a rectangle. The edge of the new shape is the average of two sides, so
(d1 + d2) / 2
.
The area of such rectangle is then length * (depth1 + depth2) / 2
. Multiply it by the third dimension  the width  and you'll get the final formula for rectangular pool volume:
volume = length * width * (depth1 + depth2) / 2
How many gallons is my pool?
Let's calculate it with this pool volume calculator!

Choose the shape of your pool. You can select between two types  rectangular/square pool or oval/circle one. Assume that you have a standard rectangular pool, so leave the default value.

Enter the dimensions of the swimming pool. Let's say that the pool is 12 ft wide and 50 ft long. Depth is gradually changing from 4 to 6 feet.

The pool calculator shows the volume of water needed to fill up the pool. In our case, it's 22,441.57 US gallons.
Our tool is sometimes called the pool size calculator or pool gallon calculator because it works with any units, not just the metric ones. If we didn't autodetect your preferred units, click on meters to change it to gallons.
If your pool doesn't vary in depth, but is some kind of a fancy shape like bow front or cylinder, check out this aquarium calculator  it has some nice 3D shapes options. If the pool of your dreams comes in some custom or eccentric shape, check out the manufacturer's website.
Advanced mode:

If you know what's the price of water in your area, you can calculate the cost of filling up the pool. Click on the
Advanced mode
button, and an additional part will appear. The pool gallon calculator takes the result of the previous section and multiplies it by the applicable rates of your local water supply. All for you, to find out how much the last step towards beating the heat will cost!Let's take the average cost of the water in the US, which is $1.50 per 1000 gallons. For our exemplary pool, the cost of water is $33.66. Not so bad, huh?
This calculator finds the total volume of your pool  in reality, you never fill the pool all the way to the brim. Also, you may want to have a look at our other tool associated with the submerged objects, its volume and weight  the buoyancy calculator.
Olympic swimming pool volume
To calculate the Olympic swimming pool volume, you need to know its dimensions. The length of the pool is 50 m, width 25 m, and the depth varies: 2.0 m is the minimum, but 3.0 m is the depth recommended. If you're not familiar with those metric units, check out this length converter to convert easily the pool size to US or imperial units.
Olympicsize swimming pool contains 2,500,000 L of water, assuming a nominal depth of 2 m. It's around 550,000 imp gal and 660,000 US gal  if you don't believe, you can check it with our volume converter tool, where you'll find other volume units as well. Try to calculate the Olympic swimming pool volume for a recommended depth of 3 meters  or use the pool calculator to get the answer in the blink of an eye.
Have you ever wondered how many tea or tablespoons of water can fit into the Olympic swimming pool? We neither. But now you can check it! Awesome, isn't it?
Pool calculator and other related tools
If you're thinking about construction🔨 your own pool in the backyard, you may want to calculate the amount of paint or tiles needed.
The pool may also bring holidays to your mind  when laying on the beach🌴 or by the pool, don't forget about putting sunscreen on! Make sure you know how long you can safely stay in the sun and which SPF factor to use  have a look at our amazing sunbathing calculator👙 to find the answers.
If the pool word for you is associated mostly with the sports and fitness🏊, you may want to check how many calories you'll burn during swimming  give this calories burned calculator a go! Also, you may found the tools for assessing your speed or pace quite useful.