
You also have to factor in the amount of waste. Waste has to do with trimming at ceiling and floor, trimming around windows and doors and vanities and etc. And with matching the pattern.
This pattern has a 30” pattern repeat. That means, depending on the height of your wall, you can lose nearly 3’ just to match one strip to the next. In this photo, you can see 2’ length being cut off. All that gets tossed into the trash.

Here’s a look at the scrap pile.
Multiply that by 20 strips needed to get around the room. !

So, please, before purchasing your wallpaper, please let the installer measure and calculate how much you need. I prefer to / insist on measuring in person, but some of my colleagues will calculate from your measurements, drawings and photos.
The pattern is called Frutto Proibito and is by Cole & Son .