A-B Measuring System for Kidney Pool Covers

A kidney pool has two rounded lobes joined by one inward curve. The A-B measuring system records both lobes and the inside curve to within about an inch so the finished cover follows the pool accurately.

Submit A-B Measurements → Print Measuring Form Review Measuring Tips

Questions before you begin? Call 800-982-6966 and we will help you prepare the layout.

Kidney-shaped pool with two rounded lobes and one inward curve

Kidney Pool Measuring

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Prepare Before You Measure

Print a worksheet, review the measuring tips, and watch the A-B video before marking points around the pool.

How Kidney Covers Are Priced

Find the pool size. Rotate the measured box until one side touches two points without crossing the perimeter, then set the other sides at the pool's furthest extents.
Set the priced box. Add 2 feet on every side, increasing both dimensions by 4 feet.

Diagram showing a rotated pool bounded at its maximum extents by a yellow 16-by-32-foot measurement box inside an orange 20-by-36-foot pricing box

Measure Your Kidney Pool in Five Steps

Work clockwise, keep the tape straight and tight, and record each measurement as you go.

The illustrations use a more irregular pool as the example. Follow the same A-B process around both kidney lobes and place closer points through the inward curve.

A-B reference line positioned beside an irregular example for a kidney-shaped pool

Step 1: Establish the A-B Line

Run a straight A-B line parallel to the pool, at least 4 feet from the water's edge and at least two-thirds the length of the pool. Point A must be to the left of point B. Measure the full A-B line and record it on your A-B measuring sheet. The example line is 20 feet long. Draw your A-B line along the bottom of the pool sketch.

Measurement points marked around an irregular example for a kidney-shaped pool

Step 2: Mark the Pool Perimeter

Use chalk to mark points at the water’s edge. Place marks about 2 to 3 feet apart around the rounded lobes and about 1 foot apart through the single inward curve. Add points wherever the outline changes direction so the kidney shape is recorded accurately.

Perimeter measurement points numbered clockwise around an irregular example for a kidney-shaped pool

Step 3: Number Every Point Clockwise

Start near the center of the A-B line and number every chalk mark in a clockwise direction. Continue until every point around the pool has a unique number.

Tape measurements taken from point A to each numbered pool perimeter point

Step 4a: Measure from Point A

Have an assistant hold the end of the tape at point A. Working clockwise, measure from A to every numbered perimeter point and record each distance on the A-B measuring sheet.

Tape measurements taken from point B to each numbered pool perimeter point

Step 4b: Measure from Point B

Move the tape to point B. Working clockwise again, measure from B to every numbered perimeter point and record each distance beside the matching A measurement.

Diagonal cross-check measurements drawn across an irregular example for a kidney-shaped pool

Step 5: Add Cross-Check Dimensions

Add 2 or 3 diagonal measurements between numbered points and record them on the A-B measuring sheet. Also mark stairs, rocks, walls, or other deck features within 2 feet of the water's edge so we can account for possible cover interference.

Ready to Send Your Kidney Layout?

Enter your A-B measurements and comments online so our team can review the layout for your custom pool cover.

Submit A-B Measurements → Download A-B Measuring Sheet

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A-B Measuring for Kidney Pool Covers