C series and DL envelope sizes
Helps you pick the right envelope for A paper, such as C4 for an unfolded A4 sheet and DL for a sheet folded in thirds.
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How to use it
- Enter envelope.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Sizes come from the ISO 269 table in mm, and inches = mm ÷ 25.4. A Cn envelope is designed to hold an An sheet flat.
Example
Inputs: Envelope = C4. Result: Envelope size: 229 × 324 mm; Width: 22.9 cm; Length: 32.4 cm.
Limits and caveats
- Sizes are outer envelope dimensions; allow some room for thick paper or inserts.
Questions about this tool
Which envelope fits an unfolded A4 sheet?
A C4 envelope, 229 × 324 mm.
What size is a DL envelope?
It is 110 × 220 mm and holds an A4 sheet folded in thirds.
Which envelope fits A4 folded in half?
A4 folded in half is A5 size, so a C5 envelope (162 × 229 mm) fits it.