One of the first decisions when buying bifold doors is how many panels you need. It is not just about width — the panel count determines how the doors fold, whether you get a single "traffic door" for everyday use, and how much the set costs. Here is a plain-English guide to 2, 3, 4 and 5-panel aluminium bifold doors and which suits your opening.
A quick rule of thumb on width
Each bifold panel is typically between 500mm and 1200mm wide, with most homeowners landing around 800–900mm per panel for the best balance of strength, glass area and smooth operation. As a rough guide: a 2-panel set suits openings up to about 1.8m, 3 panels up to 2.4m, 4 panels up to 3.2m, and 5 panels up to 4.0m.
Fold patterns and the traffic door
A "traffic door" is a single panel you can open on its own, like a normal door, without folding the whole set back — ideal for popping in and out without unlocking everything. Configurations are described by how panels fold left and right. For example, a 3-panel set is often "2+1" (two fold one way, one the other, giving a traffic door), while a 4-panel set can be "3+1" or a symmetrical "2+2".
- 2 panels: simple and cost-effective for narrower openings; folds to one side. Great for utility rooms, snugs and smaller extensions
- 3 panels: the most popular residential choice; a 2+1 split gives a handy traffic door and opens up most of the wall
- 4 panels: ideal for wider rear extensions; choose 3+1 for a traffic door or 2+2 to fold away cleanly to both sides
- 5 panels: for large openings where you want a dramatic, near-full-width opening; usually 4+1 or 3+2
Does more panels mean more cost?
Yes — more panels mean more aluminium, glass and hardware, so price rises with panel count and overall width. A larger set also needs a properly sized structural opening and a level, well-supported threshold. Our bifold door cost guide breaks down typical prices for each configuration so you can budget before you buy.
Tell us your opening width and we will recommend the ideal panel configuration and fold pattern, then send a free quote for your aluminium bifold doors.
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