/29 subnet mask (255.255.255.248)

A /29 network has 3 host bits, 8 addresses and 6 usable hosts. It is 1/32 of a /24.

/29 at a glance

Netmask: 255.255.255.248
Wildcard mask: 0.0.0.7
Hex mask: 0xFFFFFFF8
Binary mask: 11111111.11111111.11111111.11111000
Host bits: 3
Total addresses: 8
Usable hosts: 6 (minus network and broadcast)
Compared with a /24: 1/32 of a /24

Calculate a /29 in the subnet calculator

Typical uses of a /29

A /29 has 6 usable hosts, or 5 once your ISP router takes one. It is the classic "block of 8" static IP allocation for small businesses, and the smallest subnet Azure and Google Cloud accept (leaving 3 usable in Azure, 4 in GCP).

Well-known /29 blocks

192.0.0.0/29: IPv4 Service Continuity Prefix, used by DS-Lite (RFC 7335)

Example /29 ranges

Network	Network address	First usable	Last usable	Broadcast	Next /29
10.0.0.0/29	10.0.0.0	10.0.0.1	10.0.0.6	10.0.0.7	10.0.0.8/29	calculate
172.16.0.0/29	172.16.0.0	172.16.0.1	172.16.0.6	172.16.0.7	172.16.0.8/29	calculate
192.168.1.0/29	192.168.1.0	192.168.1.1	192.168.1.6	192.168.1.7	192.168.1.8/29	calculate
203.0.113.0/29	203.0.113.0	203.0.113.1	203.0.113.6	203.0.113.7	203.0.113.8/29	calculate

The /29 boundary falls in the fourth octet, so /29 networks start every 8 in that octet (32 per /24): 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120, ....

How many /29s fit

In a	Number of /29 subnets
/8	2,097,152
/16	8,192
/20	512
/24	32
/28	2

What a /29 contains

Smaller block	How many
/30	2
/32	8

Splitting a /29

Into	Subnets	Usable hosts each
/30	2	2
/31	4	2
/32	8	1

/29 in AWS, Azure and Google Cloud

Platform	Allowed subnet sizes	/29 allowed?	Usable after reservation
AWS VPC	/16 to /28	No	-
Azure VNet	/2 to /29	Yes	3 (5 reserved)
Google Cloud VPC	/4 to /29	Yes	4 (4 reserved)

Cloud providers reserve addresses in every subnet (first four and the last address (network, VPC router, DNS, future use, broadcast) on AWS), so the usable count there differs from the classic 2^n - 2.