What is the CDB file format?
.cdb is a database format associated with the Symbian operating system, used by older Nokia mobile phones - most commonly the Series 60 (S60) smartphones of the early-to-mid 2000s. The file is almost always named contacts.cdb and stored in the phone's internal memory. It holds contact records including names, phone numbers, postal addresses, and e-mail addresses. Contact data residing on a SIM card is not stored as .cdb files.
The format is a binary Symbian DBMS store with no publicly documented magic bytes or specification. Worth noting: the .cdb extension is also claimed by several unrelated programs (Pocket Access / Windows CE databases, ClipBook files, and others), so a .cdb not originating from a Nokia handset is likely a different format entirely.
Contact data can be synchronised between devices using dedicated software. Nokia PC Suite was the primary tool for this purpose, but it has been discontinued following Symbian's retirement around 2013; third-party conversion utilities are now the practical route. Contacts in .cdb files can be exported to .vcf files used by the vCard standard, allowing import into Google Contacts, Outlook, or any modern smartphone. Contacts could also be shared between compatible handsets directly or via MMS.
Security & safety
RISK: LOWA Nokia contacts .cdb is a passive database file, not executable, so opening or copying it is safe. The real concern is privacy: it holds personal contact details (names, numbers, addresses), so don't upload it to untrusted online "CDB viewers" - many are adware/PUP portals and there is no standard web viewer for this Symbian format. Use a reputable offline tool and delete working copies once you've exported the contacts to vCard.
Format details
in a nutshell- Pocket Access / Windows CE database (CDB) - Windows Mobile/Pocket PC used .cdb as a Pocket Access (Windows CE) database - the name the db originally recorded; a different format.
- Microsoft Card File / ClipBook (CDB) - Older Microsoft tools used .cdb for Card File and ClipBook databases - unrelated to phone contacts.
- Various app/game databases (CDB) - Many programs (e.g. TurboTax, some games, address-book apps) reuse .cdb for their own internal databases.
Programs that open CDB files
Windows2 apps
Nokisoft Noki
Paid Load the Nokia phone/backup and export contacts to vCard (.vcf); the tool reads contacts.cdb. Verify the vendor is still live before relying on it. 
vCard (.vcf) target via export
Free Once exported to .vcf, import the contacts into Google Contacts / Outlook (Import > vCard). This is the practical endpoint, not opening the .cdb directly. Technical details
deep spec| Container format | Symbian DBMS binary store (on-device relational database engine) |
| Encoding | Binary, little-endian byte order |
| Typical filename | contacts.cdb |
| Stored fields | Contact names, phone numbers, postal addresses, e-mail addresses, and additional contact metadata |
| MIME type | application/octet-stream (no dedicated MIME type registered for this format) |
| Associated platforms | Symbian OS (Series 60 / Nokia smartphones); Windows via Nokia PC Suite or third-party tools |
| File signature | No public magic bytes - not identifiable by signature alone; shares .cdb extension with unrelated formats |
| Typical file size | Tens of KB to a few MB, scaling with the number of stored contacts |
| Compression | Stored uncompressed |
| Access control | No file-level encryption; device-level access restriction only |
| Primary sync tool | Nokia PC Suite (now discontinued); third-party utilities required for current use |
| Export target | .vcf (vCard) for import into Google Contacts, Outlook, or modern smartphones |
| Superseded by | Cloud-based contact storage (Google Contacts, iCloud, Exchange ActiveSync) on modern platforms |
| Extension conflict | .cdb also claimed by Pocket Access / Windows CE databases, ClipBook files, and various game or app databases - unrelated formats |
| Lifecycle status | Legacy format; effectively frozen since Symbian's discontinuation around 2013 |
| Released | Symbian OS / Series 60 era (early-mid 2000s Nokia smartphones) |
| Latest version | N/A (tied to Symbian; effectively frozen since Symbian's discontinuation ~2013) |
CDB conversions
Community Q&A
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