/13 subnet mask (255.248.0.0)

A /13 network has 19 host bits, 524,288 addresses and 524,286 usable hosts. It is 2,048 /24 networks.

/13 at a glance

Netmask: 255.248.0.0
Wildcard mask: 0.7.255.255
Hex mask: 0xFFF80000
Binary mask: 11111111.11111000.00000000.00000000
Host bits: 19
Total addresses: 524,288
Usable hosts: 524,286 (minus network and broadcast)
Compared with a /24: 2,048 /24 networks

Calculate a /13 in the subnet calculator

Typical uses of a /13

A /13 is eight /16s. Cloud planners use it as the per-region or per-account block when every VPC is a /16: one /13 gives eight full-size AWS VPCs.

Example /13 ranges

Network	Network address	First usable	Last usable	Broadcast	Next /13
10.0.0.0/13	10.0.0.0	10.0.0.1	10.7.255.254	10.7.255.255	10.8.0.0/13	calculate
172.16.0.0/13	172.16.0.0	172.16.0.1	172.23.255.254	172.23.255.255	172.24.0.0/13	calculate

The /13 boundary falls in the second octet, so /13 networks start every 8 in that octet (32 per /8): 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120, ....

How many /13s fit

In a	Number of /13 subnets
/8	32

What a /13 contains

Smaller block	How many
/16	8
/24	2,048
/26	8,192
/28	32,768
/29	65,536
/30	131,072
/32	524,288

Splitting a /13

Into	Subnets	Usable hosts each
/14	2	262,142
/15	4	131,070
/16	8	65,534
/17	16	32,766

/13 in AWS, Azure and Google Cloud

Platform	Allowed subnet sizes	/13 allowed?	Usable after reservation
AWS VPC	/16 to /28	No	-
Azure VNet	/2 to /29	Yes	524,283 (5 reserved)
Google Cloud VPC	/4 to /29	Yes	524,284 (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.