Each panel of a brochure may have a different size depending on the folding method – this is so that the brochure folds and closes nicely. Generally the difference is only 1-3mm between panels.
Our Blank Layout Templates have the sizes clearly outlined. Ensure you (or your designer) are using the right template for the folding-option you will be ordering. It also means that brochure designs are not interchangeable between folding types (for example, you cannot use a design for a 3-panel trifold and order a 3-panel accordion-fold). Your design will need to be adjusted to match the folding lines.