PaperSizes.guide exists because the answer to “what size is A4?” should take one glance, not a scroll past three adverts and a wall of copied text.
Our mission
To make every paper size answerable at a glance: exact to its standard, drawn to scale, explained in plain words, and free to use and reuse.
What this site is
A reference for every paper, envelope, photo and card size in real use: 324 sizes across 23 standards, each with dimensions in millimetres, centimetres, inches, points and pixels, drawn to scale, with notes on what it is for and how to print on it.
Around the reference sit ten tools that do the maths people actually need: identifying a mystery sheet, scaling between sizes, working out pixels for a print, picking an envelope, tiling a poster, imposing a booklet.
Who makes it
He maintains the dataset behind this site, along with its free API and the npm and PyPI packages built from it.
Find Usman on Itechtics, X, GitHub and WordPress.org.
How we keep it accurate
ISO and ANSI dimensions are generated from the published formulas rather than typed in, so a rounding slip cannot creep in. Regional and historical sizes are cross-checked against at least two independent references, and every page states the standard it comes from. The methodology page spells out the sources.
Found a mistake? Tell us. Corrections are published with a note on the page.
Open data
The full dataset is free to download and reuse under a Creative Commons Attribution licence. See the data page.
Advertising and affiliate links
The site is free to use and may carry advertising and, in future, links to paper and print suppliers that pay a commission. Those never affect which sizes are listed or what the pages say about them.