You may measure your pool using the conventional method for recording your dimensions or for a more accurate method use the A-B My Pool application on your phone or tablet device.  Both methods work and are described below.  Advantages to using the A-B My Pool application are:

clearer capture of dimensions as handwritten numbers or information can be unclear. 
the ability to see the finished drawing of your pool perimeter based on your measurements. 
the ability to easily attach pictures to your measurements for a clearer representation of your pool to the product designer.

The A-B My Pool app may be downloaded by using the links in the left column.   

Tools needed-

  • Tape measure long enough to capture the diagonal measurement of your pool plus 10 feet.  A 150 foot reel type tape measure is the preferred tool of professionals.
  • Chalk - sidewalk chalk works well as it is often easier to see on concrete and brick.  It also easily washes off the pool deck.  Do not use any type of crayon or permanent marker.  In lieu of chalk you may use bright blue, green, or pink masking tape.  Point numbers can be written on the tape and it is easily removed.
  • Measuring Form - provides an organized record of your measurements.  A large notepad or plain paper may also be used.  A measuring form may be dowloaded from the link in the left column of this page. (A form or paper is not needed when using A-B My Pool but may prove helpful.)
  • Pen or Pencil - for recording your measurements.
  • Clipboard - for more easily holding the measuring form or notepad and providing a firm writing surface.
  • Camera - for taking pictures of your pool and any obstacles.  This will be of tremendous benefit to the product designer.  (Easily use your phone or tablet with A-B My Pool for this step.)
  • An assistant - someone to hold the opposite end of the tape measure and/or clearly record the measurements.

Establishing an A-B point-

The A-B measurement format is simply two points on your pool deck or adjacent area with one point labeled A and the second labeled B.  Some important considerations are:

  • When facing your pool the A point should be on your left and the B point should be on your right.  Should you inadvertently reverse these points please note this on your measurements as the pool profile will generate a mirror or reversed image of your pool.
  • The A and B point should be a minimum of 3 feet from the edge of the pool or any obstruction to be measured.
  • The distance between the A and B point should be a minimum of 15 feet.  As the distance between the points grows shorter, the capture of the measurements in design software becomes more difficult.
  • The distance between the A and B point should be no more than 2/3 the length of the pool.
  • The line that intersects the A and B point if extended past either point cannot intersect any portion of the pool or objects on the deck that may need measuring.

Perimeter and Obstacle points-

Once you have established your A-B line the next step is clearly identifying the points around the perimeter of your pool and any obstacles that may need identification.  To do this:

  • Beginning directly across from the A point mark the edge of the pool with chalk and number the point as 1. 
  • Continuing in a clockwise manner move approximately 3 feet to your left and make a second mark numbered as 2.  Continue this marking around the entire perimeter of your pool.
  • At any corner or radius along the perimeter of the pool, place the numbered chalk marks at 1 foot intervals.  This will allow the software to more accurately capture radiuses along the perimeter.
  • If you are measuring for a safety cover, you can identify any points for deck obstacles when numbering your pool perimeter.  Obstacles are any non-removable features on the pool deck that may intersect the safety cover.  These include handrails, slide legs, diving stands, fill spouts, water features, rock outcroppings, or raised walls.  To do so mark them consecutive with your pool perimeter and mark a numbered point at the front corners, any mid-points if they extend closer to the pool than the corners, and any back corners if they are within 36 inches of the pool perimeter. 


  • Beginning with your A point, measure from A to Point 1 and record your measurement in feet and inches as A1. (Easily record on your phone or tablet using the A-B My Pool application.)
  • Maintaining one end of your tape measure on your A point, measure from A to Point 2 and record your measurement as A2. 
  • Continue this process around the entire perimeter of your pool to Point 3, 4, etc. and to any obstacle points.  Clearly record each point as you measure. (the A-B My Pool app takes the guesswork out of handwritten information.)
  • Repeat the measuring process using your B point as the reference point and continue around the pool perimeter to the same numbered points used from your A point.     
  • Selecting opposite points along the pool perimeter that represent the pool's greatest length,  measure between the two perimeter points  and record them as Point #(?) to Point #(?) and that dimension. When measuring for a safety cover use the inside of the pool coping or edge for your inside dimensions.  When measuring for a vinyl liner use the pool wall for your inside dimensions.    
  • Repeat the above process for the pools greatest width and record the dimension.
  • If the pool has multiple widths (kidney or freeform shapes) or lengths, or if you are unsure you have captured the greatest length or width add an additional cross measurement to your dimensions.
  • If the pool is a variation of a rectangle, record diagonal measurements from opposing corner points.  These dimensions will help the designer validate if the pool is " in square".

The Third Dimension for a vinyl liner measurment-

When measuring for an inground vinyl liner we must take into account the varying depths, slopes, and features inside the pool.  To do this place points around the pool perimeter at each change in depth or the beginning and end of each slope, step or bench.  Helpful hints for measuring these features may be found in the links in the left column of this page.

Anchor Measurements for a  replacement safety cover-

If you are replacing your existing safety cover and wish the new cover straps to match your existing anchor locations, you will need to provide a second set of A-B measurements separate from your perimeter measurements.  Do not mark cover anchors when marking perimeter points.  They must be in a separate sequence from the perimeter measurement points.
Using the same method as for measuring the perimeter, mark each anchor point with a point number.  If using A-B My Pool, begin the anchor numbering by skipping the next sequential point in your perimeter measure and beginning with the next point number.  Measure from A to each anchor point and then from B to each anchor point.


pocket magic!

Proper measurement of a pool allows the manufacturer to create a vinyl liner or safety cover that will fit properly and provide years of service.  Using the A-B measurement format provides the most reliable method for ensuring that all features of the pool are properly represented and accounted for when the dimensions are presented to the manufacturer.

How to Measure