List of Western Digital model number codes

This is a list of the trailing letter codes in Western Digital main model number codes (for exampe, the "EZRZ" in WD30EZRZ), and their meanings. Main model numbers prior to 2005 only use what is defined as the third and fourth letters in this article (for example, the "JS" in WD2500JS), but otherwise follow the same format, though Scorpio drives use different RPM and interface letters to distinguish them from their Caviar counterparts.

Numbers: Capacity

The first two, three or four numbers contain the capacity, encoded as capacity divided by 10. There exist exceptions to this rule, especially where Black, Gold and Red Pro drives are concerned. Interpreting this capacity requires the first letter defined below.

First letter: Capacity and form factor

The first letter defines the unit of measurement for the capacity preceding it, as well as the form factor. The capacity is equal to the number in the model divided by 10 (rounded down in cases where the final digit of the capacity contains additional information, as is often the case in Black and other drives). For example, in the WD5000BEVT, $5000÷10=500$, and the capacity letter, B, signifies GB, therefore the capacity is 500 GB. For the WDC WD101EDAZ-xxTA3Ax, $101÷10=10.1$ TB, but since the trailing 1 carries revision information (about this drive being air-filled), the capacity must be rounded down to 10 TB.

Code	Unit	Form factor
A	GB	3.5"
B	GB	2.5" 9.5 mm
C	TB	2.5" 12.5 mm (VelociRaptor only)
D	TB	2.5" 12.5 mm (VelociRaptor with IcePak only)
E	TB; capacity is rounded to nearest integer on 10 TB air models.	3.5"
F	TB; uses four digit numbers equalling capacity divided by 1000.	3.5" (Nearline/Red Pro/Black)
G	GB	2.5" 12.5 mm (VelociRaptor with backplane-incompatible IcePak only)
H	GB	2.5" 12.5 mm (VelociRaptor with IcePak only)
J	TB	2.5" 9.5 mm
K	GB (prior to 2015)	2.5" 12.5 mm (prior to 2015)
	TB (since 2015)	3.5" (Nearline/Red Pro/Black, >= 10 TB, since 2015)
L	GB	2.5" 7 mm
M	GB	2.5" 5 mm
N	TB	2.5" 15 mm
P	TB; capacity is rounded to nearest integer.	3.5" (Purple)
S	TB	2.5" 7 mm
T	TB	2.5" 12.5 mm
X	TB	2.5" 9.5 mm (SSHDs)

Second letter: Business unit

The second letter denotes the business unit of Western Digital that the drive is designed for. It also indicates whether the drive supports Advanced Format.

Code	Business unit	Advanced Format?
A	Desktop PC (Caviar/Blue/Green/Black)	No (most models) 512e (many 512e Western Digital Green drives, WDC WD80EAZZ-xxBKLBx)
B	Nearline (Re/Se)	No
C	Video (AV, soldered USB interface drives only)	512e
D	Raptor (prior to 2008)	No (prior to 2008)
	Self-encrypting drive (since 2008)	512e (since 2008)
E	Mobile PC (Scorpio/Blue/Green/Black)	No
F	NAS (Red)	512e
G	Mobile surveillance (Purple)	Unknown
H	Raptor X (window special edition)	No
	VelociRaptor	512e
J	Mobile PC (Scorpio Black) with free-fall sensor	No
	Surveillance (Purple), China only	512e
K	Xe	No
L	VelociRaptor	No
M	Internal Use/WD Branded	No (prior to Firebird family) Yes (since Firebird family)
P	Mobile PC (Blue/Green/Black)	512e
Q	Mobile PC (Blue/Black), extended availability	512e
R	Nearline (Re/Se/Gold)	512e
T	Mobile PC (Blue/Green/Black) with free-fall sensor	512e
U	Video/Surveillance (AV/Purple)	512e
V	Video (AV)	No
X	Nearline	4Kn
Y	Nearline (<= 4 platters only)	No or 512e (varies with model)
Z	Desktop PC (Caviar/Blue/Green/Black)	512e

Third letter: Spindle speed and cache

The third letter indicates how fast a drive spins, as well as how much cache it has. Note that IntelliPower is understood to be equivalent to 5,400 RPM.

Code	Speed (RPM)	Cache	Notes
A	5,400	2 MB	Prior to 2017.
		256 MB	Since 2017.
B	7,200	2 MB	Prior to 2017.
		256 MB	Since 2017.
C	5,400	16 MB
D	5,400	32 MB
E	5,400	768 KB (early models) 2 MB (later models)	Protégé models only.
	7,200	64 MB	Only used on 3.5" models <= 2 TB.
F	10,000	16 MB	Prior to 2018.
	5,400	512 MB	Since 2018. Most models with this letter under-reported their RPM.
G	10,000	8 MB	Prior to 2018.
	7,200	512 MB	Since 2018.
H	10,000	8 MB	Prior to 2018.
J	7,200	8 MB
K	7,200	16 MB
L	7,200	32 MB
P	5,400	EM
R	5,400	64 MB	Purple drives (except WDC WD80PUZX-xxNEAYx) always report this letter, regardless of their actual spindle speed and/or cache. Instead, the last digit of the capacity carries revision information.
S	7,200	8 MB	Used on Western Digital Caviar RE drives prior to the introduction of the first and second digits.
		64 MB	Used on 3.5" drives > 2 TB, or 2.5" drives.
T	10,000	EM
U	5,400	2 MB	Used only on Scorpio models prior to the introduction of the first and second digits.
V	5,400	8 MB
W	7,200	128 MB
Y	7,200	EM
Z	5,400	128 MB

Fourth letter: Interface

The fourth letter defines the interface the drive uses.

Code	Standard	Version/Speed (MB/s)
A	PATA	UDMA 66
B	PATA	UDMA 100 (Desktop)
C	PATA (ZIF)	UDMA 100?
D	SATA	SATA-I/150
E	PATA	UDMA 100 (Mobile)
F	SAS	3/300
G	SAS	6/600
K	SATA (SFF-8784)	SATA-III/600
M	USB-C	USB 3.0/625
P	SATA (Purple Pro)	SATA-III/600
S	SATA	SATA-II/300 (Desktop) SATA-I/150 (Mobile)
T	SATA	SATA-II/300
U	USB mini-B (prior to 2021) SATA (Purple) (since 2021)	USB 2.0/- (prior to 2021) SATA-III/600 (since 2021)
V	USB micro-B	USB 2.0/-
W	USB micro-B	USB 3.0/625
X	SATA	SATA-III/600
Z	SATA	SATA-III/600

See also

• List of Western Digital customer codes