Why are the outer panels on a tri-fold slightly narrower?

On a parallel (roll/C-fold), the panels fold inside one another. The innermost panel sits at the full width, while the two outer panels must be slightly narrower — typically 1–2 mm each — so they wrap around and nest without creating a buckle or gap. This tool applies a 1.5 mm (or 0.06 in) reduction per outer panel by default.

What is the difference between a z-fold and an accordion fold?

They are the same fold pattern. The panels alternate direction (forward, back, forward…) like a concertina or accordion. Because every panel folds outward rather than nesting inside, all panels are equal width — no offset reduction is needed.

A gate fold has two outer panels that fold inward to meet in the middle, with a larger center panel behind them. Each outer panel is typically half the center panel width, so all three sections can close flush. This calculator sets each outer panel to roughly half the finished width and the center panel to the full finished width.

How much bleed should I add?

Standard commercial printing uses 3 mm (0.125 in) bleed on all outer edges. For each panel, add 3 mm to the left and right edges that touch the trim or cut line. Fold lines do not need bleed.

Does this calculator handle height?

No — height is constant across all panels on a standard fold, so it equals the finished piece height. Use your layout application to set the document height and add 3 mm bleed top and bottom.

Can I use this for a Z-fold with more than three panels?

Yes. Select "Accordion / Z-fold" and choose 4, 6, or 8 panels. All panels are equal width. Odd-count accordion folds (5, 7…) are uncommon in commercial print; even counts work best.

Foldout Panel Calculator

Name: Foldout Panel Calculator
Availability: InStock
Author: Nham Vu

Enter the finished piece width, unit, fold type, and panel count to get exact panel widths and flat sheet size for your folded print job.

Fold Settings

Finished piece width

Width of one closed panel (e.g. 210 mm for DL).

Fold type

Panels nest inside each other; outer panels are trimmed slightly narrower.

Number of panels: 3

2345678

Show bleed recommendations

Set your fold settings and click Calculate.

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Summary

Enter the finished piece width, unit, fold type, and panel count to get exact panel widths and flat sheet size for your folded print job.

How it works

Enter the finished piece width (the width of a single closed panel) in mm or inches.
Select the fold type: parallel (roll/C-fold), accordion (z-fold), or gate fold.
Set the number of panels (2 to 8).
The tool calculates the width of each panel, applying the inner-panel reduction for parallel folds so they nest cleanly.
Review the flat sheet width, individual panel widths, and the suggested bleed amount.
Copy the values directly into your layout application or paste them into your print order.

Use cases

Lay out a standard tri-fold brochure and get accurate panel widths before opening InDesign.
Plan a gate-fold cover for a catalog or invitation without guessing the math.
Calculate a four-panel accordion fold for a take-away menu or event program.
Confirm the flat sheet size a print shop will require for a given finished width.
Quickly convert a client-supplied finished width into all panel dimensions in seconds.
Avoid mis-registered folds caused by equal-width panels on a roll fold.
Get bleed recommendations to include when briefing a designer on a new print piece.
Check panel widths for both mm and inch workflows without switching between tools.

Frequently Asked Questions

Last updated: 2026-07-15 · Reviewed by Nham Vu