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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.

Network20.32.232.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
20.32.232.0
Broadcast address
20.32.235.255
First usable
20.32.232.1
Last usable
20.32.235.254
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 1420E800 · Integer 337700864 to 337701887
Reverse DNS zones
232.32.20.in-addr.arpa
233.32.20.in-addr.arpa
234.32.20.in-addr.arpa
235.32.20.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
Address00010100.00100000.11101000.0000000020.32.232.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00010100.00100000.11101000.0000000020.32.232.0
Broadcast00010100.00100000.11101011.1111111120.32.235.255
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)

20.32.232.0/22 makes 128 subnets of /29.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
120.32.232.0/2920.32.232.1 to 20.32.232.620.32.232.76
220.32.232.8/2920.32.232.9 to 20.32.232.1420.32.232.156
320.32.232.16/2920.32.232.17 to 20.32.232.2220.32.232.236
420.32.232.24/2920.32.232.25 to 20.32.232.3020.32.232.316
520.32.232.32/2920.32.232.33 to 20.32.232.3820.32.232.396
620.32.232.40/2920.32.232.41 to 20.32.232.4620.32.232.476
720.32.232.48/2920.32.232.49 to 20.32.232.5420.32.232.556
820.32.232.56/2920.32.232.57 to 20.32.232.6220.32.232.636
920.32.232.64/2920.32.232.65 to 20.32.232.7020.32.232.716
1020.32.232.72/2920.32.232.73 to 20.32.232.7820.32.232.796
1120.32.232.80/2920.32.232.81 to 20.32.232.8620.32.232.876
1220.32.232.88/2920.32.232.89 to 20.32.232.9420.32.232.956
1320.32.232.96/2920.32.232.97 to 20.32.232.10220.32.232.1036
1420.32.232.104/2920.32.232.105 to 20.32.232.11020.32.232.1116
1520.32.232.112/2920.32.232.113 to 20.32.232.11820.32.232.1196
1620.32.232.120/2920.32.232.121 to 20.32.232.12620.32.232.1276
1720.32.232.128/2920.32.232.129 to 20.32.232.13420.32.232.1356
1820.32.232.136/2920.32.232.137 to 20.32.232.14220.32.232.1436
1920.32.232.144/2920.32.232.145 to 20.32.232.15020.32.232.1516
2020.32.232.152/2920.32.232.153 to 20.32.232.15820.32.232.1596
2120.32.232.160/2920.32.232.161 to 20.32.232.16620.32.232.1676
2220.32.232.168/2920.32.232.169 to 20.32.232.17420.32.232.1756
2320.32.232.176/2920.32.232.177 to 20.32.232.18220.32.232.1836
2420.32.232.184/2920.32.232.185 to 20.32.232.19020.32.232.1916
2520.32.232.192/2920.32.232.193 to 20.32.232.19820.32.232.1996
2620.32.232.200/2920.32.232.201 to 20.32.232.20620.32.232.2076
2720.32.232.208/2920.32.232.209 to 20.32.232.21420.32.232.2156
2820.32.232.216/2920.32.232.217 to 20.32.232.22220.32.232.2236
2920.32.232.224/2920.32.232.225 to 20.32.232.23020.32.232.2316
3020.32.232.232/2920.32.232.233 to 20.32.232.23820.32.232.2396
3120.32.232.240/2920.32.232.241 to 20.32.232.24620.32.232.2476
3220.32.232.248/2920.32.232.249 to 20.32.232.25420.32.232.2556
3320.32.233.0/2920.32.233.1 to 20.32.233.620.32.233.76
3420.32.233.8/2920.32.233.9 to 20.32.233.1420.32.233.156
3520.32.233.16/2920.32.233.17 to 20.32.233.2220.32.233.236
3620.32.233.24/2920.32.233.25 to 20.32.233.3020.32.233.316
3720.32.233.32/2920.32.233.33 to 20.32.233.3820.32.233.396
3820.32.233.40/2920.32.233.41 to 20.32.233.4620.32.233.476
3920.32.233.48/2920.32.233.49 to 20.32.233.5420.32.233.556
4020.32.233.56/2920.32.233.57 to 20.32.233.6220.32.233.636
4120.32.233.64/2920.32.233.65 to 20.32.233.7020.32.233.716
4220.32.233.72/2920.32.233.73 to 20.32.233.7820.32.233.796
4320.32.233.80/2920.32.233.81 to 20.32.233.8620.32.233.876
4420.32.233.88/2920.32.233.89 to 20.32.233.9420.32.233.956
4520.32.233.96/2920.32.233.97 to 20.32.233.10220.32.233.1036
4620.32.233.104/2920.32.233.105 to 20.32.233.11020.32.233.1116
4720.32.233.112/2920.32.233.113 to 20.32.233.11820.32.233.1196
4820.32.233.120/2920.32.233.121 to 20.32.233.12620.32.233.1276
4920.32.233.128/2920.32.233.129 to 20.32.233.13420.32.233.1356
5020.32.233.136/2920.32.233.137 to 20.32.233.14220.32.233.1436
5120.32.233.144/2920.32.233.145 to 20.32.233.15020.32.233.1516
5220.32.233.152/2920.32.233.153 to 20.32.233.15820.32.233.1596
5320.32.233.160/2920.32.233.161 to 20.32.233.16620.32.233.1676
5420.32.233.168/2920.32.233.169 to 20.32.233.17420.32.233.1756
5520.32.233.176/2920.32.233.177 to 20.32.233.18220.32.233.1836
5620.32.233.184/2920.32.233.185 to 20.32.233.19020.32.233.1916
5720.32.233.192/2920.32.233.193 to 20.32.233.19820.32.233.1996
5820.32.233.200/2920.32.233.201 to 20.32.233.20620.32.233.2076
5920.32.233.208/2920.32.233.209 to 20.32.233.21420.32.233.2156
6020.32.233.216/2920.32.233.217 to 20.32.233.22220.32.233.2236
6120.32.233.224/2920.32.233.225 to 20.32.233.23020.32.233.2316
6220.32.233.232/2920.32.233.233 to 20.32.233.23820.32.233.2396
6320.32.233.240/2920.32.233.241 to 20.32.233.24620.32.233.2476
6420.32.233.248/2920.32.233.249 to 20.32.233.25420.32.233.2556
6520.32.234.0/2920.32.234.1 to 20.32.234.620.32.234.76
6620.32.234.8/2920.32.234.9 to 20.32.234.1420.32.234.156
6720.32.234.16/2920.32.234.17 to 20.32.234.2220.32.234.236
6820.32.234.24/2920.32.234.25 to 20.32.234.3020.32.234.316
6920.32.234.32/2920.32.234.33 to 20.32.234.3820.32.234.396
7020.32.234.40/2920.32.234.41 to 20.32.234.4620.32.234.476
7120.32.234.48/2920.32.234.49 to 20.32.234.5420.32.234.556
7220.32.234.56/2920.32.234.57 to 20.32.234.6220.32.234.636
7320.32.234.64/2920.32.234.65 to 20.32.234.7020.32.234.716
7420.32.234.72/2920.32.234.73 to 20.32.234.7820.32.234.796
7520.32.234.80/2920.32.234.81 to 20.32.234.8620.32.234.876
7620.32.234.88/2920.32.234.89 to 20.32.234.9420.32.234.956
7720.32.234.96/2920.32.234.97 to 20.32.234.10220.32.234.1036
7820.32.234.104/2920.32.234.105 to 20.32.234.11020.32.234.1116
7920.32.234.112/2920.32.234.113 to 20.32.234.11820.32.234.1196
8020.32.234.120/2920.32.234.121 to 20.32.234.12620.32.234.1276
8120.32.234.128/2920.32.234.129 to 20.32.234.13420.32.234.1356
8220.32.234.136/2920.32.234.137 to 20.32.234.14220.32.234.1436
8320.32.234.144/2920.32.234.145 to 20.32.234.15020.32.234.1516
8420.32.234.152/2920.32.234.153 to 20.32.234.15820.32.234.1596
8520.32.234.160/2920.32.234.161 to 20.32.234.16620.32.234.1676
8620.32.234.168/2920.32.234.169 to 20.32.234.17420.32.234.1756
8720.32.234.176/2920.32.234.177 to 20.32.234.18220.32.234.1836
8820.32.234.184/2920.32.234.185 to 20.32.234.19020.32.234.1916
8920.32.234.192/2920.32.234.193 to 20.32.234.19820.32.234.1996
9020.32.234.200/2920.32.234.201 to 20.32.234.20620.32.234.2076
9120.32.234.208/2920.32.234.209 to 20.32.234.21420.32.234.2156
9220.32.234.216/2920.32.234.217 to 20.32.234.22220.32.234.2236
9320.32.234.224/2920.32.234.225 to 20.32.234.23020.32.234.2316
9420.32.234.232/2920.32.234.233 to 20.32.234.23820.32.234.2396
9520.32.234.240/2920.32.234.241 to 20.32.234.24620.32.234.2476
9620.32.234.248/2920.32.234.249 to 20.32.234.25420.32.234.2556
9720.32.235.0/2920.32.235.1 to 20.32.235.620.32.235.76
9820.32.235.8/2920.32.235.9 to 20.32.235.1420.32.235.156
9920.32.235.16/2920.32.235.17 to 20.32.235.2220.32.235.236
10020.32.235.24/2920.32.235.25 to 20.32.235.3020.32.235.316
10120.32.235.32/2920.32.235.33 to 20.32.235.3820.32.235.396
10220.32.235.40/2920.32.235.41 to 20.32.235.4620.32.235.476
10320.32.235.48/2920.32.235.49 to 20.32.235.5420.32.235.556
10420.32.235.56/2920.32.235.57 to 20.32.235.6220.32.235.636
10520.32.235.64/2920.32.235.65 to 20.32.235.7020.32.235.716
10620.32.235.72/2920.32.235.73 to 20.32.235.7820.32.235.796
10720.32.235.80/2920.32.235.81 to 20.32.235.8620.32.235.876
10820.32.235.88/2920.32.235.89 to 20.32.235.9420.32.235.956
10920.32.235.96/2920.32.235.97 to 20.32.235.10220.32.235.1036
11020.32.235.104/2920.32.235.105 to 20.32.235.11020.32.235.1116
11120.32.235.112/2920.32.235.113 to 20.32.235.11820.32.235.1196
11220.32.235.120/2920.32.235.121 to 20.32.235.12620.32.235.1276
11320.32.235.128/2920.32.235.129 to 20.32.235.13420.32.235.1356
11420.32.235.136/2920.32.235.137 to 20.32.235.14220.32.235.1436
11520.32.235.144/2920.32.235.145 to 20.32.235.15020.32.235.1516
11620.32.235.152/2920.32.235.153 to 20.32.235.15820.32.235.1596
11720.32.235.160/2920.32.235.161 to 20.32.235.16620.32.235.1676
11820.32.235.168/2920.32.235.169 to 20.32.235.17420.32.235.1756
11920.32.235.176/2920.32.235.177 to 20.32.235.18220.32.235.1836
12020.32.235.184/2920.32.235.185 to 20.32.235.19020.32.235.1916
12120.32.235.192/2920.32.235.193 to 20.32.235.19820.32.235.1996
12220.32.235.200/2920.32.235.201 to 20.32.235.20620.32.235.2076
12320.32.235.208/2920.32.235.209 to 20.32.235.21420.32.235.2156
12420.32.235.216/2920.32.235.217 to 20.32.235.22220.32.235.2236
12520.32.235.224/2920.32.235.225 to 20.32.235.23020.32.235.2316
12620.32.235.232/2920.32.235.233 to 20.32.235.23820.32.235.2396
12720.32.235.240/2920.32.235.241 to 20.32.235.24620.32.235.2476
12820.32.235.248/2920.32.235.249 to 20.32.235.25420.32.235.2556

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.