Method of measurement In order to calculate the required length of the architrave on the window cut 45 degree angle:

First thing you need to do is multiply the inside of the window reveal (h) by 2 and add the width (a), then multiply the width (b) by 4.

(2 x h + a) + 4 x b In order to calculate the required length of the architrave on the window together with beads:

You need to multiply the inside of the window reveal (h) by 2 and add the width of the window (a).

2 x h + a In order to calculate the required length of cornice above the window:

You need to multiply the width of the architrave (b) by 2 and add the width of the inside of the window reveal (a), than multiply by 4 the depth of the cornice (c) and the result, add to your previously done measurements.

(2 x b + a ) + 4 x c In order to calculate the required length of cornice under the sill window:

You need to multiply by 2 the width of the architrave (b) and add width of the inside of the window reveal (a), then multiply the depth of the cornice (c) by 4 and the result,add to your previously done measurements.

(2 x b + a ) + 4 x c 