Bleed and trim are essential in printing, it ensures that your book will look exactly as you intended, without any white borders or unfinished edges.
Bleed refers to the area of the design that extends beyond the final trim size. This extra area is crucial because it allows for minor variations in the printing and trimming process. When a book is printed, it is printed on a larger sheet than the final trim size. Bleed ensures that the image goes to the edge of the sheet of paper, even if the final trim size is slightly off. If there is no bleed, a slight shift during the printing or trimming of your book may result in a thin white border around the final product, such as an image or coloured background.
Trim refers to the final size of the printed piece after it has been cut down from the larger printed sheet. The trim marks indicate where the paper should be cut to ensure it is the correct final size.
Unfortunately, Microsoft Word is not designed for professional print design, and it doesn't have built-in tools for setting up bleed and trim. However, there is a workaround you can use to achieve similar results. You can create a custom page size in Word that is slightly larger than the final size of your document.
The calculator below assumes that you have used mirror margins or the gutter option in the word document. Please see the previous article on setting up books margins before you proceed. BOOK MARGINS