Bi-fold door sizes explained: 2 to 6 panels
How many panels should your bi-fold doors have? It depends on the width of your opening, how you’ll use the doors and how you want them to look when they’re closed. This guide explains how bi-fold sizes work and gives worked examples for 2 to 6 panels.
The basic rule: panel width
A bi-fold door is a row of hinged panels (also called leaves or sashes) inside one outer frame. On our bespoke aluminium bi-folds, each panel must be between 500 mm and 1,000 mm wide. To find the panel width, divide the overall frame width by the number of panels. The result is approximate, because the outer frame and the joints between panels take up part of the width.
Overall frame widths can be from 1,200 mm to 7,000 mm, and heights from 1,800 mm to 2,400 mm. For most widths there are two or more panel counts that work, and the choice comes down to looks and practicality.
Worked examples
| Panels | Typical width range* | Example |
|---|---|---|
| 2 panels | 1,200–2,000 mm | 1,800 mm wide: about 900 mm each |
| 3 panels | 1,500–3,000 mm | 2,700 mm wide: about 900 mm each |
| 4 panels | 2,000–4,000 mm | 3,600 mm wide: about 900 mm each |
| 5 panels | 2,500–5,000 mm | 4,500 mm wide: about 900 mm each |
| 6 panels | 3,000–6,000 mm | 5,400 mm wide: about 900 mm each |
*Ranges follow from the 500–1,000 mm panel limit. The configurator checks your exact size.
Fewer, wider panels or more, narrower panels?
Fewer panels mean fewer vertical frame lines across the view when the doors are closed, which many people prefer. Wider panels are heavier, though, and the stack of folded panels sticks out further from the wall when open. More, narrower panels make a slimmer stack and lighter individual leaves, at the cost of more frame lines. For a 3,000 mm opening, 3 panels of about 1,000 mm give the cleanest look. 4 panels of about 750 mm give a neater stack.
Odd or even panel numbers
The number of panels affects how the doors can be arranged. With an odd number of panels (3 or 5), all the panels can stack to one side, and one end panel can work as an everyday access door. With an even number (2, 4 or 6), the panels can stack to one side or be split so half fold each way. Our configurator lets you choose left, right or split stacking for bespoke bi-folds. Our bi-folds can include a traffic door: a single panel that opens on its own for everyday use, without folding back the whole set. If the configurator doesn’t capture the arrangement you want, add your preferred traffic door position in the order notes.
Height
Bespoke bi-folds can be 1,800–2,400 mm high, entered as the overall frame height. Measure from the finished floor level to the underside of the lintel and deduct your installer’s fitting tolerance. Stock bi-folds are 2,090 mm high.
Stock sizes
Our stock-size bi-folds come in 2.0 m (2 panels), 2.4 m (3 panels), 3.0 m (3 panels) and 3.6 m (4 panels), all 2,090 mm high. They’re often available in 5–10 working days once paid, subject to availability, and are a good choice when you’re building a new opening and can size it to suit.
What about 7 panels?
Bespoke bi-folds go up to 7 panels and 7,000 mm wide. For very wide openings, check the structural support above with your builder or engineer. Long spans need a suitable lintel or beam, and that’s outside what we can advise on as a supplier.
Choosing your size
- Measure the structural opening carefully. See how to measure for bi-fold doors.
- Deduct the fitting tolerance your installer wants, to get the frame size.
- Try different panel counts in the configurator and see how each looks in the preview.
- Pick the stacking side and opening direction that suit your space.
Still deciding between door types? Read bi-fold vs sliding vs French doors.
How panel count affects the price
On our bespoke bi-folds, the listed price is built up per panel, so for the same width, fewer, wider panels usually cost less than more, narrower ones. Enter your width in the configurator and switch between the panel counts that fit, and you’ll see the price update straight away. Colour, glass and threshold upgrades are added on top and confirmed on your invoice.
Colours and glass for any size
Every bespoke size is available in Anthracite grey (RAL 7016), White (RAL 9016) or Black (RAL 9005), with dual colour and bespoke RAL options. Glass is double glazed clear (Low-E, argon) as standard, with self-cleaning, solar control, triple glazed and obscure options. Larger panes on wider panels show off the glass more, so solar control can be worth considering on a sunny elevation.
Frequently asked questions
What is the minimum width for a bi-fold door?
Our bespoke bi-folds start at 1,200 mm wide, as 2 panels.
What is the maximum panel width?
Each panel can be up to 1,000 mm wide, and at least 500 mm.
How tall can bi-fold doors be?
Bespoke bi-folds can be 1,800–2,400 mm high. Stock sizes are 2,090 mm high.
Can bi-folds have a traffic door?
Yes. A traffic door is available for everyday access. If the configurator doesn’t capture your preferred arrangement, note it with your order.