Wallpaper Calculator. Determine roll amount(s) for your room. Unit of Measurement: Metric (Metres and Centimetres) Imperial (Feet and Inches) Length of 1st wall: m cm Length of 2nd wall: m cm Length of 3rd wall: m cm Length of 4th wall: m cm Height of walls: m cm Roll width: cm Pattern repeat: cm Approximaterolls of 10m (33ft) paper needed. Step 1Tab 2Step 1 In-put values of the measurements you are working with. If you do not know this, measure up your walls you are decorating with. Tab 2 After inputting values, pressing the estimate button will calculate a rough amount of rolls to use for your decorating. Notice Important! Although this is a calculator with many algorithms, occasionally glitches may appear. If any problems do occur contact one of our team immediately.