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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network22.64.28.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
22.64.28.0
Broadcast address
22.64.31.255
First usable
22.64.28.1
Last usable
22.64.31.254
Usable hosts
1,022 (1,024 less the network and broadcast addresses)
Subnet mask
255.255.252.0
Wildcard mask
0.0.3.255 (Cisco ACLs, OSPF)
Prefix length
/22
Type
Public public
Old class
A (default /8)
As numbers
Hex 16401C00 · Integer 373300224 to 373301247
Reverse DNS zones
28.64.22.in-addr.arpa
29.64.22.in-addr.arpa
30.64.22.in-addr.arpa
31.64.22.in-addr.arpa
/22 is not on a 8-bit boundary, so it takes 4 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010110.01000000.00011100.0000000022.64.28.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00010110.01000000.00011100.0000000022.64.28.0
Broadcast00010110.01000000.00011111.1111111122.64.31.255
Split into smaller subnets/29
/23 (2)/24 (4)/25 (8)/26 (16)/27 (32)/28 (64)/29 (128)/30 (256)/31 (512)/32 (1,024)

22.64.28.0/22 makes 128 subnets of /29.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
122.64.28.0/2922.64.28.1 to 22.64.28.622.64.28.76
222.64.28.8/2922.64.28.9 to 22.64.28.1422.64.28.156
322.64.28.16/2922.64.28.17 to 22.64.28.2222.64.28.236
422.64.28.24/2922.64.28.25 to 22.64.28.3022.64.28.316
522.64.28.32/2922.64.28.33 to 22.64.28.3822.64.28.396
622.64.28.40/2922.64.28.41 to 22.64.28.4622.64.28.476
722.64.28.48/2922.64.28.49 to 22.64.28.5422.64.28.556
822.64.28.56/2922.64.28.57 to 22.64.28.6222.64.28.636
922.64.28.64/2922.64.28.65 to 22.64.28.7022.64.28.716
1022.64.28.72/2922.64.28.73 to 22.64.28.7822.64.28.796
1122.64.28.80/2922.64.28.81 to 22.64.28.8622.64.28.876
1222.64.28.88/2922.64.28.89 to 22.64.28.9422.64.28.956
1322.64.28.96/2922.64.28.97 to 22.64.28.10222.64.28.1036
1422.64.28.104/2922.64.28.105 to 22.64.28.11022.64.28.1116
1522.64.28.112/2922.64.28.113 to 22.64.28.11822.64.28.1196
1622.64.28.120/2922.64.28.121 to 22.64.28.12622.64.28.1276
1722.64.28.128/2922.64.28.129 to 22.64.28.13422.64.28.1356
1822.64.28.136/2922.64.28.137 to 22.64.28.14222.64.28.1436
1922.64.28.144/2922.64.28.145 to 22.64.28.15022.64.28.1516
2022.64.28.152/2922.64.28.153 to 22.64.28.15822.64.28.1596
2122.64.28.160/2922.64.28.161 to 22.64.28.16622.64.28.1676
2222.64.28.168/2922.64.28.169 to 22.64.28.17422.64.28.1756
2322.64.28.176/2922.64.28.177 to 22.64.28.18222.64.28.1836
2422.64.28.184/2922.64.28.185 to 22.64.28.19022.64.28.1916
2522.64.28.192/2922.64.28.193 to 22.64.28.19822.64.28.1996
2622.64.28.200/2922.64.28.201 to 22.64.28.20622.64.28.2076
2722.64.28.208/2922.64.28.209 to 22.64.28.21422.64.28.2156
2822.64.28.216/2922.64.28.217 to 22.64.28.22222.64.28.2236
2922.64.28.224/2922.64.28.225 to 22.64.28.23022.64.28.2316
3022.64.28.232/2922.64.28.233 to 22.64.28.23822.64.28.2396
3122.64.28.240/2922.64.28.241 to 22.64.28.24622.64.28.2476
3222.64.28.248/2922.64.28.249 to 22.64.28.25422.64.28.2556
3322.64.29.0/2922.64.29.1 to 22.64.29.622.64.29.76
3422.64.29.8/2922.64.29.9 to 22.64.29.1422.64.29.156
3522.64.29.16/2922.64.29.17 to 22.64.29.2222.64.29.236
3622.64.29.24/2922.64.29.25 to 22.64.29.3022.64.29.316
3722.64.29.32/2922.64.29.33 to 22.64.29.3822.64.29.396
3822.64.29.40/2922.64.29.41 to 22.64.29.4622.64.29.476
3922.64.29.48/2922.64.29.49 to 22.64.29.5422.64.29.556
4022.64.29.56/2922.64.29.57 to 22.64.29.6222.64.29.636
4122.64.29.64/2922.64.29.65 to 22.64.29.7022.64.29.716
4222.64.29.72/2922.64.29.73 to 22.64.29.7822.64.29.796
4322.64.29.80/2922.64.29.81 to 22.64.29.8622.64.29.876
4422.64.29.88/2922.64.29.89 to 22.64.29.9422.64.29.956
4522.64.29.96/2922.64.29.97 to 22.64.29.10222.64.29.1036
4622.64.29.104/2922.64.29.105 to 22.64.29.11022.64.29.1116
4722.64.29.112/2922.64.29.113 to 22.64.29.11822.64.29.1196
4822.64.29.120/2922.64.29.121 to 22.64.29.12622.64.29.1276
4922.64.29.128/2922.64.29.129 to 22.64.29.13422.64.29.1356
5022.64.29.136/2922.64.29.137 to 22.64.29.14222.64.29.1436
5122.64.29.144/2922.64.29.145 to 22.64.29.15022.64.29.1516
5222.64.29.152/2922.64.29.153 to 22.64.29.15822.64.29.1596
5322.64.29.160/2922.64.29.161 to 22.64.29.16622.64.29.1676
5422.64.29.168/2922.64.29.169 to 22.64.29.17422.64.29.1756
5522.64.29.176/2922.64.29.177 to 22.64.29.18222.64.29.1836
5622.64.29.184/2922.64.29.185 to 22.64.29.19022.64.29.1916
5722.64.29.192/2922.64.29.193 to 22.64.29.19822.64.29.1996
5822.64.29.200/2922.64.29.201 to 22.64.29.20622.64.29.2076
5922.64.29.208/2922.64.29.209 to 22.64.29.21422.64.29.2156
6022.64.29.216/2922.64.29.217 to 22.64.29.22222.64.29.2236
6122.64.29.224/2922.64.29.225 to 22.64.29.23022.64.29.2316
6222.64.29.232/2922.64.29.233 to 22.64.29.23822.64.29.2396
6322.64.29.240/2922.64.29.241 to 22.64.29.24622.64.29.2476
6422.64.29.248/2922.64.29.249 to 22.64.29.25422.64.29.2556
6522.64.30.0/2922.64.30.1 to 22.64.30.622.64.30.76
6622.64.30.8/2922.64.30.9 to 22.64.30.1422.64.30.156
6722.64.30.16/2922.64.30.17 to 22.64.30.2222.64.30.236
6822.64.30.24/2922.64.30.25 to 22.64.30.3022.64.30.316
6922.64.30.32/2922.64.30.33 to 22.64.30.3822.64.30.396
7022.64.30.40/2922.64.30.41 to 22.64.30.4622.64.30.476
7122.64.30.48/2922.64.30.49 to 22.64.30.5422.64.30.556
7222.64.30.56/2922.64.30.57 to 22.64.30.6222.64.30.636
7322.64.30.64/2922.64.30.65 to 22.64.30.7022.64.30.716
7422.64.30.72/2922.64.30.73 to 22.64.30.7822.64.30.796
7522.64.30.80/2922.64.30.81 to 22.64.30.8622.64.30.876
7622.64.30.88/2922.64.30.89 to 22.64.30.9422.64.30.956
7722.64.30.96/2922.64.30.97 to 22.64.30.10222.64.30.1036
7822.64.30.104/2922.64.30.105 to 22.64.30.11022.64.30.1116
7922.64.30.112/2922.64.30.113 to 22.64.30.11822.64.30.1196
8022.64.30.120/2922.64.30.121 to 22.64.30.12622.64.30.1276
8122.64.30.128/2922.64.30.129 to 22.64.30.13422.64.30.1356
8222.64.30.136/2922.64.30.137 to 22.64.30.14222.64.30.1436
8322.64.30.144/2922.64.30.145 to 22.64.30.15022.64.30.1516
8422.64.30.152/2922.64.30.153 to 22.64.30.15822.64.30.1596
8522.64.30.160/2922.64.30.161 to 22.64.30.16622.64.30.1676
8622.64.30.168/2922.64.30.169 to 22.64.30.17422.64.30.1756
8722.64.30.176/2922.64.30.177 to 22.64.30.18222.64.30.1836
8822.64.30.184/2922.64.30.185 to 22.64.30.19022.64.30.1916
8922.64.30.192/2922.64.30.193 to 22.64.30.19822.64.30.1996
9022.64.30.200/2922.64.30.201 to 22.64.30.20622.64.30.2076
9122.64.30.208/2922.64.30.209 to 22.64.30.21422.64.30.2156
9222.64.30.216/2922.64.30.217 to 22.64.30.22222.64.30.2236
9322.64.30.224/2922.64.30.225 to 22.64.30.23022.64.30.2316
9422.64.30.232/2922.64.30.233 to 22.64.30.23822.64.30.2396
9522.64.30.240/2922.64.30.241 to 22.64.30.24622.64.30.2476
9622.64.30.248/2922.64.30.249 to 22.64.30.25422.64.30.2556
9722.64.31.0/2922.64.31.1 to 22.64.31.622.64.31.76
9822.64.31.8/2922.64.31.9 to 22.64.31.1422.64.31.156
9922.64.31.16/2922.64.31.17 to 22.64.31.2222.64.31.236
10022.64.31.24/2922.64.31.25 to 22.64.31.3022.64.31.316
10122.64.31.32/2922.64.31.33 to 22.64.31.3822.64.31.396
10222.64.31.40/2922.64.31.41 to 22.64.31.4622.64.31.476
10322.64.31.48/2922.64.31.49 to 22.64.31.5422.64.31.556
10422.64.31.56/2922.64.31.57 to 22.64.31.6222.64.31.636
10522.64.31.64/2922.64.31.65 to 22.64.31.7022.64.31.716
10622.64.31.72/2922.64.31.73 to 22.64.31.7822.64.31.796
10722.64.31.80/2922.64.31.81 to 22.64.31.8622.64.31.876
10822.64.31.88/2922.64.31.89 to 22.64.31.9422.64.31.956
10922.64.31.96/2922.64.31.97 to 22.64.31.10222.64.31.1036
11022.64.31.104/2922.64.31.105 to 22.64.31.11022.64.31.1116
11122.64.31.112/2922.64.31.113 to 22.64.31.11822.64.31.1196
11222.64.31.120/2922.64.31.121 to 22.64.31.12622.64.31.1276
11322.64.31.128/2922.64.31.129 to 22.64.31.13422.64.31.1356
11422.64.31.136/2922.64.31.137 to 22.64.31.14222.64.31.1436
11522.64.31.144/2922.64.31.145 to 22.64.31.15022.64.31.1516
11622.64.31.152/2922.64.31.153 to 22.64.31.15822.64.31.1596
11722.64.31.160/2922.64.31.161 to 22.64.31.16622.64.31.1676
11822.64.31.168/2922.64.31.169 to 22.64.31.17422.64.31.1756
11922.64.31.176/2922.64.31.177 to 22.64.31.18222.64.31.1836
12022.64.31.184/2922.64.31.185 to 22.64.31.19022.64.31.1916
12122.64.31.192/2922.64.31.193 to 22.64.31.19822.64.31.1996
12222.64.31.200/2922.64.31.201 to 22.64.31.20622.64.31.2076
12322.64.31.208/2922.64.31.209 to 22.64.31.21422.64.31.2156
12422.64.31.216/2922.64.31.217 to 22.64.31.22222.64.31.2236
12522.64.31.224/2922.64.31.225 to 22.64.31.23022.64.31.2316
12622.64.31.232/2922.64.31.233 to 22.64.31.23822.64.31.2396
12722.64.31.240/2922.64.31.241 to 22.64.31.24622.64.31.2476
12822.64.31.248/2922.64.31.249 to 22.64.31.25422.64.31.2556

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.