/10 subnet mask (255.192.0.0)

A /10 network has 22 host bits, 4,194,304 addresses and 4,194,302 usable hosts. It is 16,384 /24 networks.

/10 at a glance

Netmask: 255.192.0.0
Wildcard mask: 0.63.255.255
Hex mask: 0xFFC00000
Binary mask: 11111111.11000000.00000000.00000000
Host bits: 22
Total addresses: 4,194,304
Usable hosts: 4,194,302 (minus network and broadcast)
Compared with a /24: 16,384 /24 networks

Calculate a /10 in the subnet calculator

Typical uses of a /10

A /10 is the size of 100.64.0.0/10, the shared address space ISPs use behind carrier-grade NAT (RFC 6598). Tailscale assigns node addresses from it. Avoid it for your own LANs if you might run CGNAT or Tailscale, because routes will collide.

Well-known /10 blocks

100.64.0.0/10: Shared address space for carrier-grade NAT (RFC 6598); also used by Tailscale for node addresses

Example /10 ranges

Network	Network address	First usable	Last usable	Broadcast	Next /10
10.0.0.0/10	10.0.0.0	10.0.0.1	10.63.255.254	10.63.255.255	10.64.0.0/10	calculate

The /10 boundary falls in the second octet, so /10 networks start every 64 in that octet (4 per /8): 0, 64, 128, 192.

How many /10s fit

In a	Number of /10 subnets
/8	4

What a /10 contains

Smaller block	How many
/16	64
/24	16,384
/26	65,536
/28	262,144
/29	524,288
/30	1,048,576
/32	4,194,304

Splitting a /10

Into	Subnets	Usable hosts each
/11	2	2,097,150
/12	4	1,048,574
/13	8	524,286
/14	16	262,142

/10 in AWS, Azure and Google Cloud

Platform	Allowed subnet sizes	/10 allowed?	Usable after reservation
AWS VPC	/16 to /28	No	-
Azure VNet	/2 to /29	Yes	4,194,299 (5 reserved)
Google Cloud VPC	/4 to /29	Yes	4,194,300 (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.