From there, you

And the last important question is how many rolls you need to buy? Standard width of the roll — meter or one and a half, long — 10 or 18 meters. Multiplying these indicators, you can find out that one roll can cover so much. Having calculated the area of ​​the room, having previously read out the area of ​​windows and door from there, you can count how much you need a roll. Do not be afraid to round the most, it is better to buy wallpaper with a margin, in case something suddenly fails the first time.