When somebody requests an A4 tri-fold brochure, the printer needs one clarification: is A4 the open size or the folded size? The answer changes the sheet dimensions, panel order and fold calculations.
Bi-fold and tri-fold brochure sizes should not be specified by a product name alone. State the final folded size, the open size and the type of fold.
Important distinction: a bi-fold has two panels and a tri-fold has three. The dimensions of the flat sheet and the folded brochure are not the same.
What are bi-fold and tri-fold brochures?
A bi-fold is divided into two panels and usually provides four printed faces when printed on both sides. A tri-fold has three panels and up to six printed faces. The fold determines their reading order.
Common brochure sizes
| Example | Approximate open size | Approximate folded size |
|---|---|---|
| A4 open bi-fold | 297 × 210 mm | 148.5 × 210 mm before adjustments |
| A3 open bi-fold | 420 × 297 mm | 210 × 297 mm before adjustments |
| A4 open tri-fold | 297 × 210 mm | Nominally 99 × 210 mm |
| A3 open tri-fold | 420 × 297 mm | Nominally 140 × 297 mm |
These are mathematical divisions. A roll fold may need a narrower inner panel so that it closes correctly; the printer’s production template takes priority.
Accordion fold or roll fold?
An accordion fold alternates direction. In a roll fold, one panel folds inside another and may need to be narrower. Do not create three identical panels before confirming the fold.
How to organise the content panels
- Use a paper mock-up to identify the front and back covers.
- Arrange content in the order in which the brochure opens.
- Keep small text away from crease lines.
- Confirm which panels will be partly hidden.
- Leave safe margins near folds and trim lines.
- Check the reading order with a folded proof.
Bleed and PDF dimensions
The trim size is different from the outer bleed area. Many brochures use 3 mm on each side, but the printer should confirm the requirement. Bleed normally surrounds the complete flat artwork; it is not added separately around every internal panel.
Paper weight and folding
Heavier paper may need creasing to prevent cracking. Grain direction, coating and construction also affect how the brochure opens and closes. Our brochure printing service can confirm suitable sizes, papers and fold allowances.
Frequently asked questions
How large is an A4 tri-fold?
It depends on whether A4 describes the open sheet or the folded product. Always specify both dimensions.
How wide is each panel of an open A4 tri-fold?
Nominally about 99 mm, although the chosen fold may require adjustments.
Is a special cutting die required?
That depends on the shape, format and production method. Standard rectangular brochures normally do not need one.
Preparing folded artwork? Tell us the dimensions, quantity, paper and intended use so that we can check the production options.
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