Paper and Envelope Size Calculator
Look up nominal A and B paper sizes, C envelope sizes, and common US sheet sizes.
Formula and sources updated · Data sources · 3View algorithm, constants and default inputs (JSON)
About this calculator
A and B formats are paper sizes; C formats are envelope sizes designed around compatible sheets. Dimensions are nominal millimetres rounded to whole values, with inch conversions. Paper and envelope manufacturing tolerances apply.
Worked example
calculated with the default values below
Paper size A4 Result 210 × 297 mm · Width 210 mm · Height 297 mm · Area 623.70 cm² · Width 8.27 in · Height 11.69 in
Data sources
Disclaimer
These calculators give general conversion results. Rounding and the precision of the value you enter both affect the output, so treat displayed decimals as indicative rather than exact.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
(w, h) = lookup(size); A = w × h ÷ 100; w_in = w ÷ 25.4; h_in = h ÷ 25.4
- size
- Paper format (A0-A10, B0-B5, C4, Letter...)
- w
- Width (mm)
- h
- Height (mm)
- A
- Area (cm2)
A/B are nominal trimmed paper sizes; C sizes are nominal envelope sizes. Dimensions are in millimetres; real manufacturing tolerances may vary.
Frequently asked questions
Are C-series sizes paper sizes?
No. A and B series here are paper formats; C series lists nominal envelope sizes designed around common paper formats. The dimensions are nominal millimetres, and actual products may vary within manufacturing tolerances.