Whether you're designing a new gazebo or renovating an existing one, it's important to calculate the number of shingles needed to complete the job. This information will help you budget accurately and choose the appropriate materials.
Things You'll Need
 Paper
 Pencil
 Measuring tape
 Ladder
 Calculator
Know Your Gazebo

Determine the number of sides on your gazebo. While many are made up of six equal sides, octagonal gazebos are popular, too.

Understand the shape of each roofing panel. Some gazebos feature triangular roofing panels which meet at the top. But others feature a series of isosceles trapezoids (see image) in which the diagonal lengths are identical. So the distance from the top right to lower left corners is equal to that of the top left to lower right corners.

Determine whether you have a one, two or three tier gazebo. Two roofing levels (see image) are most popular in more ornate models featuring isosceles trapezoids.

In gazebos with more than one tier, determine how many sides are triangular or isosceles trapezoids.
Calculating Square Footage for Triangular Roofing Sections

Measure the base of the roofing panel.

Measure the height of the roofing panel by recording the distance between the apex of the triangle and a point halfway along the triangle's base.

Multiply the base length by height to determine the area in square inches.

Count up how many sides are identical to this triangular panel and multiply this number by the sum determined in Step 3. Divide this sum by 12 to convert into square feet.
Calculate Square Footage of Isosceles Trapezoids

Measure and record the distance in inches between the two bottom corners. Label this "base length."

Measure and record the distance in inches between the top two corners. Label this "top length."

Measure and record the distance between the two pencil points. This measurement should be labelled "height."

Add your base and top lengths together and divide this sum by two to determine the average length. Multiply average length by height to find the area in square inches for each roofing panel.

Determine the number of sides which are identical to this panel and multiply this figure by the sum determined in Step 4. Divide this sum by 12 to convert into square feet.
Determining the Number of Shingles Needed

If necessary, add the sums from Step 4 in Section 2 and Step 5 in Section 3 to determine your total square footage.

Shingles are bundled into squares. Divide the sum from Step 1 by 100 to determine how many squares of shingles are needed.

Shingles are sold in bundles of three squares. Multiply the figure from Step 2 by three to determine how many bundles of shingles are needed to complete the job.
Tips & Warnings
 If you have blueprints or designs for your gazebo, refer to them for the measurements needed.
 Working at heights on a ladder can result in a fall. Always enlist help when measuring your gazebo.
References
 Photo Credit gazebo image by Bryan Crisp from Fotolia.com park gazebo image by Pix by Marti from Fotolia.com gazebo under the trees image by Jake Hellbach from Fotolia.com measuring tape image by Horticulture from Fotolia.com Wooden ladder image by Tasha from Fotolia.com calculator image by gajatz from Fotolia.com measure image by Stanisa Martinovic from Fotolia.com pencil image by AGphotographer from Fotolia.com Pencil image by Alla Chichkina from Fotolia.com measure tape #4 image by Adam Borkowski from Fotolia.com okcheck image by Brett Bouwer from Fotolia.com calculator image by Albo from Fotolia.com Gazebo and flowers image by Rexford Jordan from Fotolia.com wood shingles image by Michel Essiambre from Fotolia.com gazebo image by Trevor Allen from Fotolia.com