That really depends on several different variables including the square footage of the roof itself and กระเบื้องหลังคา the size / type of the tiles being used.
Most of the time when buying roofing tiles / shingles it will state on the packaging how many square’s it will cover. It should also state the “square footage” covered as well.
So once you have your square footage you can then figure out how many tiles / shingles it will take to cover your roof.
Don’t forget to add 10 to 15% for กระเบื้องหลังคา waste in your calculations.