OnScreen Barcode Scanner overview

OnScreen Barcode Scanner lets you scan barcodes directly from your Mac's screen. Ideal for checking your barcodes without having to print them out for use with a cumbersome hand scanner. Simply click the "Scan" button and select the screen area to scan. It's as easy as taking a screen shot. OnScreen Barcode Scanner will display the type and number of any successfully detected barcodes in the selected area. Supported barcodes are: EAN-8 EAN-13 UPC-A UPC-E ISBN.

Some tips and hints:

Barcodes should be the approximately the right way up to scan efficiently.
Large barcodes scan better than small ones. Zoom in if possible.
If there is more than one barcode in your scanned area then you will get details for each unique barcode. Duplicate codes are only shown once.