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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.

Network66.167.220.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
66.167.220.0
Broadcast address
66.167.223.255
First usable
66.167.220.1
Last usable
66.167.223.254
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 42A7DC00 · Integer 1118297088 to 1118298111
Reverse DNS zones
220.167.66.in-addr.arpa
221.167.66.in-addr.arpa
222.167.66.in-addr.arpa
223.167.66.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
Address01000010.10100111.11011100.0000000066.167.220.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network01000010.10100111.11011100.0000000066.167.220.0
Broadcast01000010.10100111.11011111.1111111166.167.223.255
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)

66.167.220.0/22 makes 128 subnets of /29.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
166.167.220.0/2966.167.220.1 to 66.167.220.666.167.220.76
266.167.220.8/2966.167.220.9 to 66.167.220.1466.167.220.156
366.167.220.16/2966.167.220.17 to 66.167.220.2266.167.220.236
466.167.220.24/2966.167.220.25 to 66.167.220.3066.167.220.316
566.167.220.32/2966.167.220.33 to 66.167.220.3866.167.220.396
666.167.220.40/2966.167.220.41 to 66.167.220.4666.167.220.476
766.167.220.48/2966.167.220.49 to 66.167.220.5466.167.220.556
866.167.220.56/2966.167.220.57 to 66.167.220.6266.167.220.636
966.167.220.64/2966.167.220.65 to 66.167.220.7066.167.220.716
1066.167.220.72/2966.167.220.73 to 66.167.220.7866.167.220.796
1166.167.220.80/2966.167.220.81 to 66.167.220.8666.167.220.876
1266.167.220.88/2966.167.220.89 to 66.167.220.9466.167.220.956
1366.167.220.96/2966.167.220.97 to 66.167.220.10266.167.220.1036
1466.167.220.104/2966.167.220.105 to 66.167.220.11066.167.220.1116
1566.167.220.112/2966.167.220.113 to 66.167.220.11866.167.220.1196
1666.167.220.120/2966.167.220.121 to 66.167.220.12666.167.220.1276
1766.167.220.128/2966.167.220.129 to 66.167.220.13466.167.220.1356
1866.167.220.136/2966.167.220.137 to 66.167.220.14266.167.220.1436
1966.167.220.144/2966.167.220.145 to 66.167.220.15066.167.220.1516
2066.167.220.152/2966.167.220.153 to 66.167.220.15866.167.220.1596
2166.167.220.160/2966.167.220.161 to 66.167.220.16666.167.220.1676
2266.167.220.168/2966.167.220.169 to 66.167.220.17466.167.220.1756
2366.167.220.176/2966.167.220.177 to 66.167.220.18266.167.220.1836
2466.167.220.184/2966.167.220.185 to 66.167.220.19066.167.220.1916
2566.167.220.192/2966.167.220.193 to 66.167.220.19866.167.220.1996
2666.167.220.200/2966.167.220.201 to 66.167.220.20666.167.220.2076
2766.167.220.208/2966.167.220.209 to 66.167.220.21466.167.220.2156
2866.167.220.216/2966.167.220.217 to 66.167.220.22266.167.220.2236
2966.167.220.224/2966.167.220.225 to 66.167.220.23066.167.220.2316
3066.167.220.232/2966.167.220.233 to 66.167.220.23866.167.220.2396
3166.167.220.240/2966.167.220.241 to 66.167.220.24666.167.220.2476
3266.167.220.248/2966.167.220.249 to 66.167.220.25466.167.220.2556
3366.167.221.0/2966.167.221.1 to 66.167.221.666.167.221.76
3466.167.221.8/2966.167.221.9 to 66.167.221.1466.167.221.156
3566.167.221.16/2966.167.221.17 to 66.167.221.2266.167.221.236
3666.167.221.24/2966.167.221.25 to 66.167.221.3066.167.221.316
3766.167.221.32/2966.167.221.33 to 66.167.221.3866.167.221.396
3866.167.221.40/2966.167.221.41 to 66.167.221.4666.167.221.476
3966.167.221.48/2966.167.221.49 to 66.167.221.5466.167.221.556
4066.167.221.56/2966.167.221.57 to 66.167.221.6266.167.221.636
4166.167.221.64/2966.167.221.65 to 66.167.221.7066.167.221.716
4266.167.221.72/2966.167.221.73 to 66.167.221.7866.167.221.796
4366.167.221.80/2966.167.221.81 to 66.167.221.8666.167.221.876
4466.167.221.88/2966.167.221.89 to 66.167.221.9466.167.221.956
4566.167.221.96/2966.167.221.97 to 66.167.221.10266.167.221.1036
4666.167.221.104/2966.167.221.105 to 66.167.221.11066.167.221.1116
4766.167.221.112/2966.167.221.113 to 66.167.221.11866.167.221.1196
4866.167.221.120/2966.167.221.121 to 66.167.221.12666.167.221.1276
4966.167.221.128/2966.167.221.129 to 66.167.221.13466.167.221.1356
5066.167.221.136/2966.167.221.137 to 66.167.221.14266.167.221.1436
5166.167.221.144/2966.167.221.145 to 66.167.221.15066.167.221.1516
5266.167.221.152/2966.167.221.153 to 66.167.221.15866.167.221.1596
5366.167.221.160/2966.167.221.161 to 66.167.221.16666.167.221.1676
5466.167.221.168/2966.167.221.169 to 66.167.221.17466.167.221.1756
5566.167.221.176/2966.167.221.177 to 66.167.221.18266.167.221.1836
5666.167.221.184/2966.167.221.185 to 66.167.221.19066.167.221.1916
5766.167.221.192/2966.167.221.193 to 66.167.221.19866.167.221.1996
5866.167.221.200/2966.167.221.201 to 66.167.221.20666.167.221.2076
5966.167.221.208/2966.167.221.209 to 66.167.221.21466.167.221.2156
6066.167.221.216/2966.167.221.217 to 66.167.221.22266.167.221.2236
6166.167.221.224/2966.167.221.225 to 66.167.221.23066.167.221.2316
6266.167.221.232/2966.167.221.233 to 66.167.221.23866.167.221.2396
6366.167.221.240/2966.167.221.241 to 66.167.221.24666.167.221.2476
6466.167.221.248/2966.167.221.249 to 66.167.221.25466.167.221.2556
6566.167.222.0/2966.167.222.1 to 66.167.222.666.167.222.76
6666.167.222.8/2966.167.222.9 to 66.167.222.1466.167.222.156
6766.167.222.16/2966.167.222.17 to 66.167.222.2266.167.222.236
6866.167.222.24/2966.167.222.25 to 66.167.222.3066.167.222.316
6966.167.222.32/2966.167.222.33 to 66.167.222.3866.167.222.396
7066.167.222.40/2966.167.222.41 to 66.167.222.4666.167.222.476
7166.167.222.48/2966.167.222.49 to 66.167.222.5466.167.222.556
7266.167.222.56/2966.167.222.57 to 66.167.222.6266.167.222.636
7366.167.222.64/2966.167.222.65 to 66.167.222.7066.167.222.716
7466.167.222.72/2966.167.222.73 to 66.167.222.7866.167.222.796
7566.167.222.80/2966.167.222.81 to 66.167.222.8666.167.222.876
7666.167.222.88/2966.167.222.89 to 66.167.222.9466.167.222.956
7766.167.222.96/2966.167.222.97 to 66.167.222.10266.167.222.1036
7866.167.222.104/2966.167.222.105 to 66.167.222.11066.167.222.1116
7966.167.222.112/2966.167.222.113 to 66.167.222.11866.167.222.1196
8066.167.222.120/2966.167.222.121 to 66.167.222.12666.167.222.1276
8166.167.222.128/2966.167.222.129 to 66.167.222.13466.167.222.1356
8266.167.222.136/2966.167.222.137 to 66.167.222.14266.167.222.1436
8366.167.222.144/2966.167.222.145 to 66.167.222.15066.167.222.1516
8466.167.222.152/2966.167.222.153 to 66.167.222.15866.167.222.1596
8566.167.222.160/2966.167.222.161 to 66.167.222.16666.167.222.1676
8666.167.222.168/2966.167.222.169 to 66.167.222.17466.167.222.1756
8766.167.222.176/2966.167.222.177 to 66.167.222.18266.167.222.1836
8866.167.222.184/2966.167.222.185 to 66.167.222.19066.167.222.1916
8966.167.222.192/2966.167.222.193 to 66.167.222.19866.167.222.1996
9066.167.222.200/2966.167.222.201 to 66.167.222.20666.167.222.2076
9166.167.222.208/2966.167.222.209 to 66.167.222.21466.167.222.2156
9266.167.222.216/2966.167.222.217 to 66.167.222.22266.167.222.2236
9366.167.222.224/2966.167.222.225 to 66.167.222.23066.167.222.2316
9466.167.222.232/2966.167.222.233 to 66.167.222.23866.167.222.2396
9566.167.222.240/2966.167.222.241 to 66.167.222.24666.167.222.2476
9666.167.222.248/2966.167.222.249 to 66.167.222.25466.167.222.2556
9766.167.223.0/2966.167.223.1 to 66.167.223.666.167.223.76
9866.167.223.8/2966.167.223.9 to 66.167.223.1466.167.223.156
9966.167.223.16/2966.167.223.17 to 66.167.223.2266.167.223.236
10066.167.223.24/2966.167.223.25 to 66.167.223.3066.167.223.316
10166.167.223.32/2966.167.223.33 to 66.167.223.3866.167.223.396
10266.167.223.40/2966.167.223.41 to 66.167.223.4666.167.223.476
10366.167.223.48/2966.167.223.49 to 66.167.223.5466.167.223.556
10466.167.223.56/2966.167.223.57 to 66.167.223.6266.167.223.636
10566.167.223.64/2966.167.223.65 to 66.167.223.7066.167.223.716
10666.167.223.72/2966.167.223.73 to 66.167.223.7866.167.223.796
10766.167.223.80/2966.167.223.81 to 66.167.223.8666.167.223.876
10866.167.223.88/2966.167.223.89 to 66.167.223.9466.167.223.956
10966.167.223.96/2966.167.223.97 to 66.167.223.10266.167.223.1036
11066.167.223.104/2966.167.223.105 to 66.167.223.11066.167.223.1116
11166.167.223.112/2966.167.223.113 to 66.167.223.11866.167.223.1196
11266.167.223.120/2966.167.223.121 to 66.167.223.12666.167.223.1276
11366.167.223.128/2966.167.223.129 to 66.167.223.13466.167.223.1356
11466.167.223.136/2966.167.223.137 to 66.167.223.14266.167.223.1436
11566.167.223.144/2966.167.223.145 to 66.167.223.15066.167.223.1516
11666.167.223.152/2966.167.223.153 to 66.167.223.15866.167.223.1596
11766.167.223.160/2966.167.223.161 to 66.167.223.16666.167.223.1676
11866.167.223.168/2966.167.223.169 to 66.167.223.17466.167.223.1756
11966.167.223.176/2966.167.223.177 to 66.167.223.18266.167.223.1836
12066.167.223.184/2966.167.223.185 to 66.167.223.19066.167.223.1916
12166.167.223.192/2966.167.223.193 to 66.167.223.19866.167.223.1996
12266.167.223.200/2966.167.223.201 to 66.167.223.20666.167.223.2076
12366.167.223.208/2966.167.223.209 to 66.167.223.21466.167.223.2156
12466.167.223.216/2966.167.223.217 to 66.167.223.22266.167.223.2236
12566.167.223.224/2966.167.223.225 to 66.167.223.23066.167.223.2316
12666.167.223.232/2966.167.223.233 to 66.167.223.23866.167.223.2396
12766.167.223.240/2966.167.223.241 to 66.167.223.24666.167.223.2476
12866.167.223.248/2966.167.223.249 to 66.167.223.25466.167.223.2556

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.