A standard garage door size does not really exist. For example a new 7’ x 7’ garage door may not fit into the sub-frame of an older 7’ x 7’ garage door due to metrification and more modern operating gear size requirements. Standard garage door sizes usually mean stock door sizes, signifying a garage door that can be obtained quickly from stock for a new build project.
See our page on garage door sizes and measuring for a better idea:
The enormous range of fixing frame options and gear options that affect the overall size of the door mean that although there may be some standard sizes that are stocked the real concern should be with the overall package including the sub fixing frame and the operating gear and not just the ordering size of the door. Some sizes are considered totally standard and heavily competed for with prices nut generally these are only basic single width size steel doors in standard colours.