design tool
Trifold panel size calculator
On a roll fold trifold the panel that tucks inside is a little narrower than the other two: on A4 that is 100, 100 and 97 millimetres, and on US Letter 3.688, 3.688 and 3.624 inches. Pick the sheet and the fold to get all three widths, where each fold falls on both faces, and a drawing of which panel is which.
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- Runs on your device, nothing is uploaded
- Free, no sign in
- No watermark, no file limit
How it works
- 1
Pick the sheet
Choose A4, US Letter, US Legal, A3, US Tabloid, or Custom size and type the width and height in millimetres.
- 2
Pick the fold
Roll fold is the familiar trifold with one panel tucked inside. Z fold zigzags open with three equal panels.
- 3
Check the offset
For a roll fold, the tucked panel starts 3 mm narrower on A sizes and 1/16 inch on US sheets. Change it to your printer's figure.
- 4
Set your guides
Read the fold positions for the outside and inside faces, or press Copy the measurements to paste them into a print brief.
Why one panel is narrower
A roll fold, also called a letter fold, wraps one end panel inside the other. If all three panels were exactly a third of the sheet, the inner one would butt against the fold of the outer one, buckle, and stop the brochure lying flat. So printers shave a little off the panel that tucks in and share it between the other two. Printivity's figures for a US Letter brochure are 3.688 inches for two panels and 3.624 for the tucked one, a difference of about 1.6 millimetres; on A4 the usual set up is 100, 100 and 97. The calculator works it out for any sheet: each full panel is the sheet width plus the offset, divided by three, and the tucked panel is that minus the offset.
Which panel is which
The flat file is the part people get wrong. Seen from the outside, with the sheet laid landscape, the right hand panel is the front cover, the middle panel is the back cover, and the narrow left panel is the flap a reader sees first on opening the cover. Turn the sheet over left to right and the inside face reads as three panels, with the narrow tucked panel now on the right. The drawing labels every panel on both faces and shades the covers, so you can match it against your layout before anything is printed.
Z folds are simpler
A Z fold folds in alternate directions, like a concertina, so no panel tucks inside another and all three can be exactly equal: 99 millimetres on A4 and 3.667 inches on US Letter. The cover can be either end panel, depending on which way the first fold goes, so the drawing assumes the left panel of the outside face and says so. Z folds suit content with an order, such as a schedule or a set of steps, because each panel is revealed in turn as the sheet opens.
Fold positions and setting guides
Fold positions are given from the left edge of each face, because that is how layout apps place guides. For an A4 roll fold the outside face folds at 97 and 197 millimetres and the inside face at 100 and 200. Keep text and important images a few millimetres away from every fold line, since folding machines drift slightly and paper cracks along the crease on heavier stock. The flyer builder's two trifold designs are separate designs, one for each face, and the flyer export has no bleed or crop marks, so ask the printer how they want those added.
Limits worth knowing
The offset is a convention, not a standard: thicker paper needs more and thin paper less, and only the printer knows their machine. The calculator covers roll and Z folds on a landscape sheet and does not draw bleed. Every figure is worked out in this tab; nothing is uploaded and nothing is stored, ever.
Limits
- The roll fold offset is 2 to 3 mm by convention on A sizes, and 1/16 of an inch on US sheets. The printer's own figure always wins, because it depends on the paper's thickness.
- The offset can be set from 0 to 6 mm. Zero on a roll fold gets a warning that the tucked panel will catch on the fold.
- A custom sheet whose width is shorter than its height gets a plain message to swap the numbers, since a trifold folds across the long edge.
What it does not do
- It does not add bleed or crop marks; add the bleed your printer asks for outside the sheet.
- It does not draw gate folds, double parallel folds or four panel layouts.
- It does not produce a template file; it gives the numbers to set guides in your own layout app.
Questions people ask
What size is a folded A4 trifold?
About 100 by 210 millimetres for a roll fold, and 99 by 210 for a Z fold. That fits a DL envelope, which is 110 by 220, with room to spare, and it sits in most brochure racks. A folded US Letter trifold is about 3.69 by 8.5 inches, which slips into a standard number 10 envelope.
How much bigger should the front panels be?
Only slightly. On A4 the two full panels are usually 100 millimetres and the tucked panel 97, so the full panels are 1 millimetre over a third and the tucked one 2 under. On US Letter the gap is about 1/16 of an inch. Heavier card needs a larger difference, which is why the printer's template should always be checked.
Do I design both sides as one file?
Usually yes: one landscape page for the outside face and one for the inside face, each the full sheet size plus bleed. Printers print one, turn the sheet over, print the other, then fold. The drawing here shows both faces as they appear in that file, so the panel order on screen matches what the printer will receive.
Can I use this for an 11 by 17 brochure?
Yes. Pick US Tabloid, 17 by 11 inches, and the panels come out at about 5.69, 5.69 and 5.62 inches for a roll fold with the default 1/16 inch offset. Larger sheets on heavier paper often need a slightly bigger offset, so confirm the figure with the print shop before you set the guides.
Should text cross a fold?
No. Keep every line of text inside one panel, at least 3 to 4 millimetres from each fold, because a fold rarely lands exactly on the line and the crease can crack ink on coated stock. An image can run across a fold on purpose, but put the subject's face and any small detail away from the crease.
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Background reading: the question page on this.
Written and checked by the OneCraft team. Last checked .