Folds and layers
What may fit after a named fold
A4 folded into thirds produces a rectangle of roughly 99 × 210 mm. Real hand folds vary, so measure the finished set when alignment or several sheets matter.
- A4 letter fold / tri-fold
International · Common in the UK and Europe
DL envelope size
110 × 220 mm · converted: 4.331 × 8.661 in
DL is a long envelope format common in the UK and Europe for business correspondence. It is distinct from a DL print-format label and from the US #10 envelope.
- Native dimensions
- 110 × 220 mm
- Converted display
- 4.331 × 8.661 in
- Opening
- open side
- Aliases
- DL envelope, DIN Long
What commonly fits flat
Start with the finished insert
DL is not a natural flat match for A4. Its long narrow face is intended for a finished insert such as an A4 letter fold, not an unfolded 210 × 297 mm sheet.
- A4 paper folded into thirds
Nominal exterior size ≠ usable interior space
Seams, lining, stock thickness, contents and manufacturing tolerance can reduce practical room. Confirm the manufactured envelope and sample before bulk use.
Decision
When to choose DL
Choose DL for an A4-based letter-fold workflow. Choose #10 for a US Letter workflow, or C5 when a single A4 half-fold is preferred.
Nearest useful alternative
DL compared with #10
#10 is narrower but longer. The two serve similar roles in different paper systems without being interchangeable.
The overlay is proportional to the canonical nominal dimensions. It compares the face rectangles only; it does not claim equal construction, internal capacity or postal treatment.
Clearance and tolerance
Why a positive number can still be too tight
Matcher clearance is applied per edge. Its “remaining” value is the total unused width and height after that allowance. A technically passing result with less than 2 mm remaining on either final dimension is labelled borderline and is never ranked as an ordinary recommendation.
Standards and rights note
Common current market convention. ISO 269:1985, the former correspondence-envelope standard, was withdrawn on 27 April 2009.
Minimum factual dimensions independently recorded. No standard or manufacturer wording, table, diagram, photograph, logo or dieline is reproduced.