How many panes do I need for my bifold opening?

There is no single fixed answer; the panel count balances panel width, weight, sightlines and whether you want a traffic door.

Panel count by opening width

The table gives a practical starting point for how many panes suit common UK opening widths, keeping each panel in a comfortable size range. Dividing the opening by a target panel width of roughly 0.75 metres gives a sensible number, which you then round to suit a traffic door or a particular fold pattern.

Treat these as a guide rather than a fixed rule. The surveyor sets the final split after confirming the structural opening, because the chosen system, the glazing weight and your access preferences all nudge the count one way or the other.

Indicative figures for guidance; the surveyor sets the final split.

What affects the right number

Several factors decide the ideal panel count beyond simple division. The aim is panels that are wide enough for a clean view but light enough to fold smoothly and last, while leaving the option of a traffic door if you want one.

• Panel weight: wider panels are heavier, so very wide ones may need to be split into more, narrower leaves to stay within the running gear's limits.
• Sightlines: fewer, wider panels give a cleaner view; more panels add frames across the glazing.
• Traffic door: if you want a hinged access door, an odd number of panels makes it easier to include.
• Fold direction: where you want the panels to stack can favour a particular split.
• Glass size: safety and thermal glazing add weight, nudging towards narrower panels on a given opening.

Balancing view against weight

The choice often comes down to a trade-off between the cleanest possible view and practical weight. Wide panels of close to a metre give the most glass and fewest frames, which suits a contemporary look, but each panel is heavier on the hinges and rollers and can be harder to fold smoothly over time. Narrower panels are lighter and easier to operate but break up the glazed wall with more frames.

For most UK homes, panels around 0.7 to 0.85 metres strike a sensible balance between view and weight. If a traffic door matters for everyday use, choosing an odd panel count such as three or five lets you include one without compromising the fold pattern. Taller doors lean towards narrower panels too, because height adds weight and a tall, wide panel is the most prone to sagging, so the height of your opening feeds into the panel count as well as the width.

From rule of thumb to final specification

The division rule gives a starting count, but the final specification is set by a survey that confirms the structural opening, checks it is square and level, and matches the panel split to the chosen system's limits. The surveyor also factors in the threshold type and the fold direction, so the doors stack where you want them and clear the opening cleanly.

It is worth describing how you will use the doors when you plan the layout: whether you want a traffic door, which side you want the panels to stack, and how important the slimmest sightlines are to you. Those preferences turn the rough panel count into a precise configuration. Because the door is made to measure, getting the split right at the survey stage avoids any compromise later, and a heavier or wider run will also feed into the structural opening and lintel design above it.

A simple way to sanity-check a proposed panel count is to picture the doors both open and closed. Closed, count how many frames cross the view and decide whether that suits the look you want; fewer, wider panels give a cleaner glazed wall, more panels give a more divided one. Open, picture where the folded leaves stack and whether that side has clear space, since a higher panel count needs a little more room to gather the leaves. Then think about daily access: if you will pop in and out often, an odd count with a traffic door earns its place. Walking through those three views, closed appearance, open stacking and everyday access, turns the rule-of-thumb number into a count you will be happy living with. The surveyor can then confirm it against the system's weight limits and the structural opening so the final door both looks right and folds smoothly.

Frequently asked questions

Sources & further reading

• HomeOwners Alliance — bifold doors guide
• Checkatrade — bifold door cost guide
• MyJobQuote — bifold door prices

Figures on this page are typical UK ranges drawn from published sources and depend on your specific opening and material. They are guidance, not a quotation.