breakitdown

What does /22 mean?

Answer

A /22 leaves 10 host bits: 1,024 addresses, 1,022 usable hosts, with netmask 255.255.252.0. It covers four consecutive /24 networks, such as 10.0.0.0 to 10.0.3.255.

Worked example: 10.0.0.0/22. Type any block to compare.

Try

10.0.0.0/22 is 1,024 addresses: 10.0.0.0 to 10.0.3.255. 1,022 usable for hosts (the first is the network address, the last is broadcast).

1000001010000000000000000000000000000
22 network bits 10 host bits
Network
10.0.0.0
First usable
10.0.0.1
Last usable
10.0.3.254
Broadcast
10.0.3.255
Addresses
1,024
Usable hosts
1,022
Netmask
255.255.252.0
Wildcard (ACL) mask
0.0.3.255
Historic class
A
Range type
Private network · not routed on the internet

Special-purpose range

Private network 10.0.0.0/8 RFC 1918
The largest of the three private IPv4 ranges: 16.7 million addresses for use inside homes and organisations. Not routed on the public internet.

Split it into subnets

or

4 subnets.

SubnetUsable rangeHostsBroadcast
10.0.0.0/2410.0.0.1 – 10.0.0.25425410.0.0.255
10.0.1.0/2410.0.1.1 – 10.0.1.25425410.0.1.255
10.0.2.0/2410.0.2.1 – 10.0.2.25425410.0.2.255
10.0.3.0/2410.0.3.1 – 10.0.3.25425410.0.3.255

Is this IP in the range?

Range to CIDR blocks

What to know

A /22 is the usual next step when a single /24 runs out of addresses: a busy guest Wi-Fi network, a campus floor, or a DHCP pool for many devices. In a cloud VPC it is a mid-sized subnet; AWS's 5 reserved addresses leave 1,019 usable.

Because it spans four /24s, addresses like 10.0.1.255 and 10.0.2.0 are ordinary host addresses inside a /22, not broadcast or network addresses. Only 10.0.0.0 and 10.0.3.255 are special.

Gotchas

Related explainers

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