Comment Comment by gilleain Also, when it comes to envelopes:"This means that C4 is slightly larger than A4, and slightly smaller than B4. The practical usage of this is that a letter written on A4 paper fits inside a C4 envelope, and both A4 paper and C4 envelope fits inside a B4 envelope."https://en.wikipedia.org/wiki/Paper_size#C_series parent gilleain 4 years ago
"This means that C4 is slightly larger than A4, and slightly smaller than B4. The practical usage of this is that a letter written on A4 paper fits inside a C4 envelope, and both A4 paper and C4 envelope fits inside a B4 envelope."
https://en.wikipedia.org/wiki/Paper_size#C_series