Inputs to result
Material length = measured ridge and hip length × (1 + allowance% ÷ 100); bundles = ceil(material length ÷ installed coverage per bundle).
Roofing
Ridge Cap Calculator
Estimate hip and ridge cap shingle bundles from combined linear ridge and hip footage, cutting waste, and product coverage per bundle.
Enter combined ridge and hip lengths, a cutting allowance and the product's installed linear coverage per bundle.
Calculation and worked example reviewed 2026-11-12. See our calculation methodology.
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Roofing
US UNITSEnter your measurements
YOUR ESTIMATE
4 cap bundles66 linear ft incl. allowance20 linear ft effective coverage per bundle.
Verify the chosen cap product and hip details.
Formula and example
How this calculation works
This estimator converts your entered jobsite inputs (combined ridge and hip length, cutting allowance, installed coverage per bundle) into consistent US trade units, computes the exact geometric baseline first, and then applies any selected waste or order allowance so you can verify both numbers before purchasing materials.
How does the ridge cap calculator formula work?
Material length = measured ridge and hip length × (1 + allowance% ÷ 100); bundles = ceil(material length ÷ installed coverage per bundle).
(Ridge Cap Calculator)where:
- Combined ridge and hip length – Entered in ft (default reference: 60 ft);
- Cutting allowance – Entered in % (default reference: 10 %);
- Installed coverage per bundle – Entered in ft (default reference: 20 ft);
Check the math
A 60 ft ridge with 10% allowance needs 66 linear ft of cap. At 20 linear ft per bundle, plan 4 bundles.
Quick lookup chart
Hip & Ridge Cap Bundle Reference by Linear Footage
Compares standard profile ridge cap (20–25 linear ft/bundle) vs. high-profile architectural cap (20 linear ft/bundle).
| Ridge + Hip Length | Length w/ 10% Waste | Bundles @ 20 lin ft | Bundles @ 30 lin ft |
|---|---|---|---|
| 40 linear ft | 44.0 ft | 3 bundles | 2 bundles |
| 60 linear ft | 66.0 ft | 4 bundles | 3 bundles |
| 90 linear ft | 99.0 ft | 5 bundles | 4 bundles |
| 120 linear ft | 132.0 ft | 7 bundles | 5 bundles |
Before you use this result
Use the actual cap product coverage after exposure and overlap. Starter/termination pieces, ventilation and special hip details require separate planning.
- Measure both horizontal ridge lines and diagonal hip rafters—hip lengths are longer than plan view by the hip slope factor.
- Verify the exact exposed linear footage per bundle on the manufacturer data sheet (commonly 20, 25, or 30 linear feet).
- Check nail length requirements: ridge caps over ridge vents require longer roofing nails to penetrate the roof deck by at least 3/4 in.
Questions answered
Calculator FAQ
Do I add hips and ridges together?+
Yes, when the same cap product and coverage apply to all the measured runs.
Can I use field shingles as ridge caps?+
Follow the selected roofing system's product instructions; this calculator only estimates a stated cap coverage.