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How to Calculate Surface Area of Swimming Pool

How to calculate the surface area of your pool to help you determine what size heat pump you will need to adequately heat your pool.  If you need assistance, use our Pool Surface Area Calculator.

1. Select Pool Shape 

While most pools are rectangular, numerous different shapes exist. Figuring out what shape your pool is will determine what equation is required to figure its area.

Swimming Pool Shapes

2. Determine Measurements

Determine the measurements your pool will require. The equation for figuring a pools area requires specific estimations relying on the shape. For example, assuming that your pool is round, you need the diameter only:  Measure the distance from the center of the pool to the edge.  For rectangular or square shaped pools, measure length and width.  Find your pool shape below and note the different measurements your pool will require.

How to measure pool shape

3. Measure the Pool

Measure the size of your pool in feet.  Use a measuring tape and lay it down one side of the pool and measure the length, ensuring that it is parallel to the edge of the pool.  To measure width, begin at a corner of the pool and measure from that corner to the closest corner.  Write down both measurements.

4. Calculate Surface Area

For rectangular pools, multiply the first measurement by the second to get the pool area.  For round pools, multiply the diameter by the depth and then multiply by 3.14.

5. Measure Pool Depth

In order to estimate the amount of gallons in a pool, you will need to measure the pools depth in feet.  Put the tape measure into the water to the bottom of the pool and note the measurement on the tape at the level of the top of the pool wall.  If the depth of the pool varies, measure both at the shallowest point and the deepest point.  Find the average depth by adding the two measurements together and dividing by two.