Roof Shingles Calculator — m, m², bundles, cost
How to use this calculator
Choose an input method: enter roof area directly in m², enter footprint length and width with a pitch multiplier, or add multiple roof sections. Select the shingle type and adjust waste. Toggle optional sections for underlayment, starter strip, ridge cap, drip edge, nails, and cost. Results update instantly.
Pitch — select the roof angle in degrees (0° to 45°). Higher pitch = more actual roof area.
Shingle types — 3-Tab (3 bundles/square), Architectural (3-4), Premium (4-5). 1 square = 9.29 m².
Cost — enter price per bundle, per underlayment roll, per ridge bundle, and per drip edge piece. Select your currency below.
Saved Calculations
| Time | Method | Area m² | Squares | Bundles | Cost |
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How to Calculate Roof Shingles (Metric)
This calculator estimates shingle bundles, underlayment rolls, ridge cap bundles, starter strip, drip edge pieces, and roofing nails for asphalt shingle roofs in metric units. Enter the roof area directly in m², use footprint dimensions with a pitch multiplier, or add multiple roof sections for complex roofs. Adjust waste from 5% to 25% depending on roof complexity.
Shingle Coverage
One roofing square covers 9.29 m² (100 ft²) of roof area. 3-Tab shingles come 3 bundles per square, architectural/laminate shingles also 3 bundles per square, and premium/designer shingles 4 bundles per square. Always round bundles up and add waste for cuts, starter courses, and hip/valley trimming.
Pitch Factor
Roof pitch affects the actual surface area. An 18° pitch increases area by 5.4% (factor 1.054), while a 45° pitch increases it by 41.4% (factor 1.414). The pitch factor is 1 / cos(angle). When entering area directly, the area should already be slope-adjusted.
Formulas Used
Adjusted area = footprint area x pitch factor. Squares = adjusted area / 9.29 m². Bundles = squares x bundles_per_square x (1 + waste%). Underlayment rolls = adjusted area x (1 + overlap%) / coverage per roll. Ridge bundles = ridge m / 6 m per bundle. Drip edge pieces = perimeter m / 3 m per piece. Nails = ~80 per bundle.
