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Barcodehammer
English

Twenty kinds of code

What each kind is, where you come across it, which characters are allowed in it and how long the content has to be. All twenty are in the free version.

In short

Barcodehammer creates twenty kinds of code. Thirteen of them come back under their own name when you scan. ISBN, ITF-14 and GS1-128 can be read back as well, but then under the name of the code they technically are. EAN-2, EAN-5, Telepen and RM4SCC can be created but not scanned back, and the app says so before you make one.

Two-dimensional codes

Square or block shaped, with a lot of text in them. Readable from any angle.

The four two-dimensional codes and their properties
Type What for Content Scanning back
QR The familiar black and white squares. They hold a lot: a web address, a piece of text, the details of a wifi network. Every phone camera reads them, even at an angle or upside down. Any text, including accents and emoji. Up to 2953 characters. ✓
Data Matrix Looks like a QR, but fits in far less space. You find it on small parts and on boxes of medicine, where a QR would not fit. Any text. Up to 2335 characters. ✓
Aztec Recognisable by the small block in the middle. Widely used for train tickets and boarding passes, because it reads well off a phone screen. Any text. Up to 3067 characters. ✓
PDF417 A wide block of short bars, stacked in rows. Found on driving licences, boarding passes and parcel labels; a whole line of data fits in it. Any text. Up to 1850 characters. ✓

Barcodes

Bars side by side, as on packaging in a shop. Usually just a number.

The sixteen barcodes and their properties
Type What for Content Scanning back
EAN-13 The barcode on nearly every product in a shop: thirteen digits. The first digits say in which country the number was issued, not where the product comes from. 12 digits, the check digit is added. ✓
EAN-8 The short form of EAN-13, eight digits. For small packages the long code will not fit on, such as a packet of chewing gum. 7 digits, the check digit is added. ✓
UPC-A The American form of EAN-13, twelve digits. Tills in Europe usually read it just fine as well. 11 digits, the check digit is added. ✓
UPC-E A shortened UPC-A for small packages: the zeros have been left out. The till turns it back into the long code by itself. 7 digits, the check digit is added. ✓
ISBN The number of a book. 12 digits, the check digit is added. Yes, but the app then calls it EAN-13
Code 128 For letters, digits and punctuation mixed together, with no fixed length. Widely used in warehouses and on shipping labels. Letters, digits and punctuation; no accents or emoji. ✓
GS1-128 Code 128 with fixed fields inside it: best-before date, batch number, quantity. The brackets in the content say which field follows. Letters, digits and punctuation. Yes, but the app then calls it Code 128
Code 39 An old, simple code with capitals and digits. Still in full use in industry and government, because almost every scanner knows it. Uppercase, digits and - . $ / + % and space. ✓
Code 93 A more compact successor to Code 39, with the same sort of content. It takes less room, but not every old scanner reads it. Letters, digits and punctuation. ✓
ITF Digits only, always an even number of them. Printed on corrugated cardboard, where fine bars would blur. Digits only. ✓
ITF-14 The code on a box full of identical articles: fourteen digits, with the article number worked into it. 13 digits, the check digit is added. Yes, but the app then calls it ITF
Codabar An old code for libraries, blood banks and couriers. Simple in structure, and indestructible for exactly that reason. Letters, digits and punctuation. ✓
EAN-2 Two digits as an addition next to an EAN, for example the issue number of a magazine. Not meant to be used on its own. Exactly 2 digits. ✗
EAN-5 Five digits next to an EAN-13, usually the price of a book. This one too belongs beside another code. Exactly 5 digits. ✗
Telepen A British code for libraries; it handles all ordinary letters and characters. Outside that world you rarely meet it. Letters, digits and punctuation. ✗
RM4SCC The bars with ascenders and descenders that Royal Mail prints on post, for the postcode. Sorting machines read them; phones do not. Uppercase and digits. ✗

Why can the app not read everything it makes?

Because the reading is done by the barcode recognition of the operating system, and that list is fixed. An app cannot add anything to it, however much it would like to.

Barcodehammer deals with that by saying so instead of keeping quiet about it: if you pick a type that cannot be scanned back, it says so under the choice before you type anything. That way you do not find out at the moment you need the code.

What is a check digit?

The last digit of a code, worked out from all the digits before it. The till works it out again; if it does not match, something has been misread or made up.

For EAN-13, EAN-8, UPC-A, UPC-E, ISBN and ITF-14 Barcodehammer works that digit out itself if you leave it off, and says which digit was added. If you do type it, the app checks whether it is right.

If a type has a fixed length, the app counts along under the input field, for example 9 of the 12 digits. That way you can see how far you are without needing an error message for it.

Only for what you type yourself

For a scanned code the app says nothing about validity. The recognition of the operating system only hands over codes with a correct check digit, so a "valid" tick would be false reassurance. And a code being right still says nothing about whether the product or the ticket is genuine.

Which characters may I use?

That differs per type, and the app checks it before anything is drawn. Four groups:

  • Any text, including accents and emoji: QR, Data Matrix, Aztec and PDF417.
  • Letters, digits and punctuation, without accents or emoji: Code 128, GS1-128, Code 93, Codabar and Telepen.
  • Uppercase, digits and - . $ / + % and space: Code 39 and RM4SCC.
  • Digits only: EAN-13, EAN-8, UPC-A, UPC-E, ISBN, ITF, ITF-14, EAN-2 and EAN-5.

In the app this sits behind the i beside each type in the list as well.

Further reading

Creating codes

How the make screen works, with a logo in a QR and export to SVG or PDF.

Read on

Manual

Step by step through the app, in the same order as the help in the app itself.

Read on