C6 envelope size and dimensions
A C6 envelope measures 114 × 162 mm, which is 11.4 × 16.2 cm or 4.5 × 6.4 inches. It fits A6 cards, A5 folded once and A4 folded twice. It goes as a standard Letter with Royal Mail and as a Standardbrief in Germany.
Contents of this page
C6 envelope, landscape
162 × 114mm
- Centimetres
- 16.2 × 11.4 cm
- Inches
- 6.38 × 4.49 in
- Pixels at 300 dpi
- 1913 × 1346 px
- Points (pt)
- 459 × 323 pt
- Area
- 0.0185 m²
- Weight at 80 gsm
- 1.48 g
C6 is the envelope for greeting cards, invitations, thank-you notes and vouchers. Because it fits within the cheapest letter band in both the UK and Germany, it is also the most economical way to post a card in an envelope.
C6 in every unit
| Unit | Width × height |
|---|---|
| Millimetres | 114 × 162 mm |
| Centimetres | 11.4 × 16.2 cm |
| Metres | 0.114 × 0.162 m |
| Inches | 4.49 × 6.38 in |
| DTP points (1/72 in) | 323 × 459 pt |
| Area | 184.7 cm², or 0.0185 m² |
| Diagonal | 198.1 mm |
| Aspect ratio | 1 : 1.421 |
What fits in a C6 envelope
| Contents | Folded to | Note |
|---|---|---|
| A6 card | 105 × 148 mm | the normal case, 4.5 to 7 mm to spare all round |
| A5 folded once | 105 × 148 mm | folded cards and invitations |
| A4 folded twice | 105 × 148.5 mm | cross fold, four layers of paper |
| DL card | 99 × 210 mm | does not fit, use a DL envelope |
Postage and weight
With Royal Mail, a C6 envelope is a Letter up to 100 g and 5 mm thick. In Germany it is a Standardbrief up to 20 g and 5 mm (€0.95 in 2026) and a Kompaktbrief up to 50 g and 10 mm (€1.10). The envelope itself weighs only 3 to 4 g.
With cards, thickness is usually the issue. A folded A5 card on 300 g/m² board weighs about 9 g and stays well under the limit with its envelope. Add a ribbon, a tag or confetti, though, and it soon gets thicker than 5 mm, which moves it into the next band.
C6, C6/5 and DL
| Envelope | Size | For |
|---|---|---|
| C6 | 114 × 162 mm | A6, A5 folded once, A4 folded twice |
| C6/5 | 114 × 229 mm | A4 folded in three, with more room |
| DL | 110 × 220 mm | A4 folded in three, DL cards |
The name C6/5 comes from its short side matching C6 and its long side matching C5.
Frequently asked questions
How big is a C6 envelope?
114 × 162 mm, which is 11.4 × 16.2 cm or about 4.5 × 6.4 inches.
Does an A6 card fit in a C6 envelope?
Yes. A6 measures 105 × 148 mm, leaving a few millimetres to spare all round.
Is a C6 envelope a standard letter?
Yes. Royal Mail treats it as a Letter up to 100 g and 5 mm. In Germany it is a Standardbrief up to 20 g.
How do I fold A4 for a C6 envelope?
Fold it twice: once in half, then once more at right angles. That turns A4 into A6.