---
title: "C4 envelope size — 229 × 324 mm"
description: "C4 envelope: 229 × 324 mm — holds A4 unfolded. Full dimensions in millimetres, centimetres and inches, and what the standard actually specifies."
url: https://atoneplace.net/size/c4-envelope/
site: "At One Place"
---

# C4 envelope size

**C4 envelope: 229 × 324 mm**

229 × 324 mm — holds A4 unfolded.

Takes an unfolded A4 sheet. The C series is sized to hold the corresponding A size with a few millimetres to spare, and each C size in turn fits inside the B size of the same number — so A4 fits C4 fits B4.

## The numbers

- **Millimetres:** 229 × 324
- **Centimetres:** 22.9 × 32.4
- **Inches:** 9.02 × 12.76
- **Aspect ratio:** 1.4148 : 1
- **Area:** 0.0742 m²
- **Defined by:** ISO 269

## Envelope sizes

| Size | Millimetres | Inches |
| --- | --- | --- |
| C4 envelope ← | 229 × 324 mm | 9.02 × 12.76 |
| C5 envelope | 162 × 229 mm | 6.38 × 9.02 |
| DL envelope | 220 × 110 mm | 8.66 × 4.33 |

## Common questions

### What size is C4 envelope?

229 × 324 mm — holds A4 unfolded.

### Which standard defines C4 envelope?

ISO 269

## Related pages

- [DL envelope size](https://atoneplace.net/size/dl-envelope/)
- [C5 envelope size](https://atoneplace.net/size/c5-envelope/)

## Sources

- Official vendor product documentation — At One Place (/about/)