There is no universal business card size. There are two, they are close enough to look interchangeable, and they are not.
| Region | Size | In the other unit |
|---|---|---|
| Europe and most of the world | 85 × 55 mm | 3.35 × 2.17 in |
| United States and Canada | 3.5 × 2 in | 89 × 51 mm |
| Japan (meishi) | 91 × 55 mm | 3.58 × 2.17 in |
The US card is four millimetres wider and four shorter. That is enough that a US card will not sit in a European cardholder or a wallet slot sized for one, and a European card rattles in a US holder.
The European size is not arbitrary: it is the ID-1 format from ISO/IEC 7810, the same as every bank card. That is why a card in that size fits the slot in a wallet designed for cards.
Why printing at home rarely works
Weight, mostly. A commercially printed business card is 300 to 400 gsm — stiff enough to have a snap when handled. Most domestic printers top out around 160 gsm, and many jam well before that.
The difference is immediately obvious in the hand. A 160 gsm card feels like thick paper, not like a card, and everyone who receives one knows what happened.
For a handful before an event that is entirely fine. For anything representing a business, the home-printed sheet is better used as a proof.
Bleed, and why an A4 sheet cannot do it
If a design has colour running to the edge, the artwork must extend 3 mm beyond the trim line — the bleed — because no cutting process is accurate to the millimetre.
On a commercial press that is standard. On an A4 sheet it is impossible in the way that matters: cards laid edge to edge share cut lines, so extending one card’s colour past the line means covering its neighbour.
The practical answer for a home-printed sheet is a design with a white margin, so a cut a millimetre off does not show.
Crop marks belong outside the corners
Marks printed on the cut line end up as ink on the finished card. The convention is to place them just outside each corner, so the blade can be lined up against them without them appearing on the result.
The grid should also be centred on the page rather than started from a corner. An off-centre grid leaves a different margin on each edge, so a guillotine set up from the paper edge is wrong on one side.
Questions people ask
Which size should I choose? Wherever the cards will be handed out. If it is genuinely international, the European size fits more wallets because it matches bank cards.
How many fit on A4? Ten at the European size, in two columns of five.
Should I print double-sided? If you do, check the alignment on your printer first — domestic duplex is often a millimetre or two out, which shows on a card.
What about rounded corners? They need a die, which is a commercial process. Cutting them by hand never looks right.
The business card maker lays out both sizes with crop marks as a vector PDF, and the certificate maker and signature generator cover the other things that end up printed.