Ridge Cap Shingles Calculator
Count hip-and-ridge cap shingle bundles and individual caps from total ridge and hip length, exposure and waste.
How it works
Caps = ceil(total ridge+hip length × 12 ÷ exposure × (1 + waste%)) · Bundles = ceil(caps ÷ caps per bundle)
Ridge and hip caps are the folded shingle pieces that seal the peak where two roof planes meet. Each cap is laid with a fixed exposure — commonly about 5⅝ inches to match the shingle course — so the number of caps is the total ridge and hip length divided by that exposure. Dedicated hip-and-ridge products come a set number of caps per bundle; if you cut caps from three-tab shingles, a bundle yields more but the exposure math is the same.
Worked example
A roof with 40 ft of ridge and 20 ft of hip has 60 ft = 720 inches to cover. At 5.625-inch exposure that is 128 caps; adding 5% waste gives about 135 caps, and at 20 caps per bundle you need 7 bundles.
Frequently asked questions
What is the exposure on a ridge cap?
The exposure is the visible length of each cap after the next one overlaps it — typically around 5 to 6 inches for standard hip-and-ridge shingles, set to line up with the field shingle courses. Manufacturers print the exact figure on the bundle.
Can I cut my own caps from field shingles?
Yes, three-tab shingles can be cut into three caps each, but architectural (laminated) shingles are too thick to fold and should not be used as caps. Purpose-made hip-and-ridge caps also carry a matching warranty.
Do I count hips as well as the ridge?
Yes — every hip runs from a corner up to the ridge and needs caps just like the main ridge. Add all hip lengths to the ridge length before dividing by the exposure.
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This calculator is for educational purposes. Double-check important results before acting on them.