PAPER ATLAS

International Envelopes

Global envelope standards outside US commercial numbering.

4 sizes indexedBack to Index

Count

4 Sizes

Largest

B4 Envelope

250 x 353 mm

Smallest

You 4

105 x 235 mm

B4 Envelope

UseInternational envelope for larger documents.
MM250 x 353
IN9.84 x 13.90
CM25.00 x 35.30

Kaku 2

UseJapanese envelope for A4 documents.
MM240 x 332
IN9.45 x 13.07
CM24.00 x 33.20

B5 Envelope

UseEnvelope for medium sheets and forms.
MM176 x 250
IN6.93 x 9.84
CM17.60 x 25.00

You 4

UseJapanese long envelope format.
MM105 x 235
IN4.13 x 9.25
CM10.50 x 23.50

International Envelopes Size Diagram

Visual Scale
W: 9.84 inH: 13.90 in
B4 Envelope
W: 9.45 inH: 13.07 in
Kaku 2
W: 6.93 inH: 9.84 in
B5 Envelope
W: 4.13 inH: 9.25 in
You 4
B4 Envelope9.84 in x 13.90 in
Kaku 29.45 in x 13.07 in
B5 Envelope6.93 in x 9.84 in
You 44.13 in x 9.25 in

International Envelopes Reference Table

All Sizes
NameWidth (mm)Height (mm)Width (cm)Height (cm)Width (in)Height (in)
B4 Envelope25035325.0035.309.8413.90
Kaku 224033224.0033.209.4513.07
B5 Envelope17625017.6025.006.939.84
You 410523510.5023.504.139.25

The Story ofInternational Envelopes

History + Culture

International envelope formats reflect regional mailing habits while still prioritizing predictable fit and handling. Alongside C sizes, regional systems like Japanese envelope standards serve specific office and publishing customs.

For global teams, this category matters because envelope choice affects everything from fold strategy to insertion automation and postage compliance.

Learn More External visual guide · opens in a new tabExplore Japanese envelope stylesA printer's photo guide shows Kaku and You envelopes and how documents fit.