免费涂料加仑数计算器
计算所需涂料加仑数，自动扣除门窗面积，输入房间尺寸即可获得准确估算。
所需加仑数
2
Gallons Needed vs Coverage Rate
公式
## How to Calculate Paint Gallons with Deductions ### Formula **Net Area = (Perimeter × Height) - (Doors × 21 sq ft) - (Windows × 15 sq ft)** **Gallons = (Net Area × Coats) / Coverage Rate** A standard door opening is about 3 ft × 7 ft = 21 sq ft. A standard window is about 3 ft × 5 ft = 15 sq ft. One gallon of paint covers approximately 350 sq ft.
计算示例
A 14×14 ft room (56 ft perimeter), 8 ft ceiling, 2 doors, 4 windows, 2 coats.
- 01Gross wall area = 56 × 8 = 448 sq ft
- 02Door deductions = 2 × 21 = 42 sq ft
- 03Window deductions = 4 × 15 = 60 sq ft
- 04Net paintable area = 448 - 42 - 60 = 346 sq ft
- 05Gallons = 346 × 2 / 350 = 1.98 → 2 gallons
常见问题
What size do you assume for doors and windows?
This calculator uses industry-standard estimates: 21 sq ft per door (3 ft × 7 ft) and 15 sq ft per window (3 ft × 5 ft). For non-standard sizes, adjust the count accordingly.
Should I buy extra paint?
Yes. It is wise to keep a small amount of extra paint for touch-ups. The ceiling function in the calculation already rounds up to the next whole gallon.
Does primer count as a coat?
No. If you need primer (e.g., for new drywall or drastic color changes), apply it first, then add your finish coats on top.
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