Calculate measured roof-section area. For slopes, measure the surface or apply a separate pitch calculation before ordering materials.
仕組み
1
形状の選択
Choose the shape that matches your space.
2
寸法を入力してください
測定値を任意の単位で入力します。数量、廃棄係数、材料価格を追加します。
3
結果を取得する
面積 (ft²、in²、yd²、m²、エーカー) とコスト見積もりをすべて一度に表示します。
よくある質問
How do I calculate the square footage of a roof?
On a simple gable roof, measure base length and width, then multiply by a slope factor: 1.054 for 4/12 pitch, 1.118 for 6/12, 1.202 for 8/12. Or measure the roof surface directly if you can reach it safely.
What is a "roofing square" and how does it relate to square feet?
One roofing square is 100 sq ft. Shingles and underlayment are sold by the square. Divide roof area by 100 for squares needed. Add 10 to 15% for ridges, valleys, and cuts.
How do I measure roof area from the ground?
Measure the building footprint (length × width) and multiply by a pitch factor for your slope. Satellite tools and roof measurement apps help too. Complex roofs with dormers need each section measured separately.
What waste factor should I use for roofing?
Use 10% for simple gable roofs. Use 15% for hip roofs, dormers, or valleys. Use 15 to 20% for complex roofs with skylights and penetrations. Steep roofs waste more because cuts are harder.
How do I calculate ceiling area vs. roof area?
Ceiling area is flat: room length × width below. Roof area includes slope, so it is larger. A vaulted or cathedral ceiling matches roof area for that section. Flat ceilings match floor area.