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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.

Network6.167.232.0/23
Usable hosts510
Subnet mask255.255.254.0
Addresses512
Network address
6.167.232.0
Broadcast address
6.167.233.255
First usable
6.167.232.1
Last usable
6.167.233.254
Usable hosts
510 (512 less the network and broadcast addresses)
Subnet mask
255.255.254.0
Wildcard mask
0.0.1.255 (Cisco ACLs, OSPF)
Prefix length
/23
Type
Public public
Old class
A (default /8)
As numbers
Hex 06A7E800 · Integer 111667200 to 111667711
Reverse DNS zones
232.167.6.in-addr.arpa
233.167.6.in-addr.arpa
/23 is not on a 8-bit boundary, so it takes 2 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000110.10100111.11101000.000000006.167.232.0
Subnet mask11111111.11111111.11111110.00000000255.255.254.0
Network00000110.10100111.11101000.000000006.167.232.0
Broadcast00000110.10100111.11101001.111111116.167.233.255
Split into smaller subnets/30
/24 (2)/25 (4)/26 (8)/27 (16)/28 (32)/29 (64)/30 (128)/31 (256)/32 (512)

6.167.232.0/23 makes 128 subnets of /30.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.167.232.0/306.167.232.1 to 6.167.232.26.167.232.32
26.167.232.4/306.167.232.5 to 6.167.232.66.167.232.72
36.167.232.8/306.167.232.9 to 6.167.232.106.167.232.112
46.167.232.12/306.167.232.13 to 6.167.232.146.167.232.152
56.167.232.16/306.167.232.17 to 6.167.232.186.167.232.192
66.167.232.20/306.167.232.21 to 6.167.232.226.167.232.232
76.167.232.24/306.167.232.25 to 6.167.232.266.167.232.272
86.167.232.28/306.167.232.29 to 6.167.232.306.167.232.312
96.167.232.32/306.167.232.33 to 6.167.232.346.167.232.352
106.167.232.36/306.167.232.37 to 6.167.232.386.167.232.392
116.167.232.40/306.167.232.41 to 6.167.232.426.167.232.432
126.167.232.44/306.167.232.45 to 6.167.232.466.167.232.472
136.167.232.48/306.167.232.49 to 6.167.232.506.167.232.512
146.167.232.52/306.167.232.53 to 6.167.232.546.167.232.552
156.167.232.56/306.167.232.57 to 6.167.232.586.167.232.592
166.167.232.60/306.167.232.61 to 6.167.232.626.167.232.632
176.167.232.64/306.167.232.65 to 6.167.232.666.167.232.672
186.167.232.68/306.167.232.69 to 6.167.232.706.167.232.712
196.167.232.72/306.167.232.73 to 6.167.232.746.167.232.752
206.167.232.76/306.167.232.77 to 6.167.232.786.167.232.792
216.167.232.80/306.167.232.81 to 6.167.232.826.167.232.832
226.167.232.84/306.167.232.85 to 6.167.232.866.167.232.872
236.167.232.88/306.167.232.89 to 6.167.232.906.167.232.912
246.167.232.92/306.167.232.93 to 6.167.232.946.167.232.952
256.167.232.96/306.167.232.97 to 6.167.232.986.167.232.992
266.167.232.100/306.167.232.101 to 6.167.232.1026.167.232.1032
276.167.232.104/306.167.232.105 to 6.167.232.1066.167.232.1072
286.167.232.108/306.167.232.109 to 6.167.232.1106.167.232.1112
296.167.232.112/306.167.232.113 to 6.167.232.1146.167.232.1152
306.167.232.116/306.167.232.117 to 6.167.232.1186.167.232.1192
316.167.232.120/306.167.232.121 to 6.167.232.1226.167.232.1232
326.167.232.124/306.167.232.125 to 6.167.232.1266.167.232.1272
336.167.232.128/306.167.232.129 to 6.167.232.1306.167.232.1312
346.167.232.132/306.167.232.133 to 6.167.232.1346.167.232.1352
356.167.232.136/306.167.232.137 to 6.167.232.1386.167.232.1392
366.167.232.140/306.167.232.141 to 6.167.232.1426.167.232.1432
376.167.232.144/306.167.232.145 to 6.167.232.1466.167.232.1472
386.167.232.148/306.167.232.149 to 6.167.232.1506.167.232.1512
396.167.232.152/306.167.232.153 to 6.167.232.1546.167.232.1552
406.167.232.156/306.167.232.157 to 6.167.232.1586.167.232.1592
416.167.232.160/306.167.232.161 to 6.167.232.1626.167.232.1632
426.167.232.164/306.167.232.165 to 6.167.232.1666.167.232.1672
436.167.232.168/306.167.232.169 to 6.167.232.1706.167.232.1712
446.167.232.172/306.167.232.173 to 6.167.232.1746.167.232.1752
456.167.232.176/306.167.232.177 to 6.167.232.1786.167.232.1792
466.167.232.180/306.167.232.181 to 6.167.232.1826.167.232.1832
476.167.232.184/306.167.232.185 to 6.167.232.1866.167.232.1872
486.167.232.188/306.167.232.189 to 6.167.232.1906.167.232.1912
496.167.232.192/306.167.232.193 to 6.167.232.1946.167.232.1952
506.167.232.196/306.167.232.197 to 6.167.232.1986.167.232.1992
516.167.232.200/306.167.232.201 to 6.167.232.2026.167.232.2032
526.167.232.204/306.167.232.205 to 6.167.232.2066.167.232.2072
536.167.232.208/306.167.232.209 to 6.167.232.2106.167.232.2112
546.167.232.212/306.167.232.213 to 6.167.232.2146.167.232.2152
556.167.232.216/306.167.232.217 to 6.167.232.2186.167.232.2192
566.167.232.220/306.167.232.221 to 6.167.232.2226.167.232.2232
576.167.232.224/306.167.232.225 to 6.167.232.2266.167.232.2272
586.167.232.228/306.167.232.229 to 6.167.232.2306.167.232.2312
596.167.232.232/306.167.232.233 to 6.167.232.2346.167.232.2352
606.167.232.236/306.167.232.237 to 6.167.232.2386.167.232.2392
616.167.232.240/306.167.232.241 to 6.167.232.2426.167.232.2432
626.167.232.244/306.167.232.245 to 6.167.232.2466.167.232.2472
636.167.232.248/306.167.232.249 to 6.167.232.2506.167.232.2512
646.167.232.252/306.167.232.253 to 6.167.232.2546.167.232.2552
656.167.233.0/306.167.233.1 to 6.167.233.26.167.233.32
666.167.233.4/306.167.233.5 to 6.167.233.66.167.233.72
676.167.233.8/306.167.233.9 to 6.167.233.106.167.233.112
686.167.233.12/306.167.233.13 to 6.167.233.146.167.233.152
696.167.233.16/306.167.233.17 to 6.167.233.186.167.233.192
706.167.233.20/306.167.233.21 to 6.167.233.226.167.233.232
716.167.233.24/306.167.233.25 to 6.167.233.266.167.233.272
726.167.233.28/306.167.233.29 to 6.167.233.306.167.233.312
736.167.233.32/306.167.233.33 to 6.167.233.346.167.233.352
746.167.233.36/306.167.233.37 to 6.167.233.386.167.233.392
756.167.233.40/306.167.233.41 to 6.167.233.426.167.233.432
766.167.233.44/306.167.233.45 to 6.167.233.466.167.233.472
776.167.233.48/306.167.233.49 to 6.167.233.506.167.233.512
786.167.233.52/306.167.233.53 to 6.167.233.546.167.233.552
796.167.233.56/306.167.233.57 to 6.167.233.586.167.233.592
806.167.233.60/306.167.233.61 to 6.167.233.626.167.233.632
816.167.233.64/306.167.233.65 to 6.167.233.666.167.233.672
826.167.233.68/306.167.233.69 to 6.167.233.706.167.233.712
836.167.233.72/306.167.233.73 to 6.167.233.746.167.233.752
846.167.233.76/306.167.233.77 to 6.167.233.786.167.233.792
856.167.233.80/306.167.233.81 to 6.167.233.826.167.233.832
866.167.233.84/306.167.233.85 to 6.167.233.866.167.233.872
876.167.233.88/306.167.233.89 to 6.167.233.906.167.233.912
886.167.233.92/306.167.233.93 to 6.167.233.946.167.233.952
896.167.233.96/306.167.233.97 to 6.167.233.986.167.233.992
906.167.233.100/306.167.233.101 to 6.167.233.1026.167.233.1032
916.167.233.104/306.167.233.105 to 6.167.233.1066.167.233.1072
926.167.233.108/306.167.233.109 to 6.167.233.1106.167.233.1112
936.167.233.112/306.167.233.113 to 6.167.233.1146.167.233.1152
946.167.233.116/306.167.233.117 to 6.167.233.1186.167.233.1192
956.167.233.120/306.167.233.121 to 6.167.233.1226.167.233.1232
966.167.233.124/306.167.233.125 to 6.167.233.1266.167.233.1272
976.167.233.128/306.167.233.129 to 6.167.233.1306.167.233.1312
986.167.233.132/306.167.233.133 to 6.167.233.1346.167.233.1352
996.167.233.136/306.167.233.137 to 6.167.233.1386.167.233.1392
1006.167.233.140/306.167.233.141 to 6.167.233.1426.167.233.1432
1016.167.233.144/306.167.233.145 to 6.167.233.1466.167.233.1472
1026.167.233.148/306.167.233.149 to 6.167.233.1506.167.233.1512
1036.167.233.152/306.167.233.153 to 6.167.233.1546.167.233.1552
1046.167.233.156/306.167.233.157 to 6.167.233.1586.167.233.1592
1056.167.233.160/306.167.233.161 to 6.167.233.1626.167.233.1632
1066.167.233.164/306.167.233.165 to 6.167.233.1666.167.233.1672
1076.167.233.168/306.167.233.169 to 6.167.233.1706.167.233.1712
1086.167.233.172/306.167.233.173 to 6.167.233.1746.167.233.1752
1096.167.233.176/306.167.233.177 to 6.167.233.1786.167.233.1792
1106.167.233.180/306.167.233.181 to 6.167.233.1826.167.233.1832
1116.167.233.184/306.167.233.185 to 6.167.233.1866.167.233.1872
1126.167.233.188/306.167.233.189 to 6.167.233.1906.167.233.1912
1136.167.233.192/306.167.233.193 to 6.167.233.1946.167.233.1952
1146.167.233.196/306.167.233.197 to 6.167.233.1986.167.233.1992
1156.167.233.200/306.167.233.201 to 6.167.233.2026.167.233.2032
1166.167.233.204/306.167.233.205 to 6.167.233.2066.167.233.2072
1176.167.233.208/306.167.233.209 to 6.167.233.2106.167.233.2112
1186.167.233.212/306.167.233.213 to 6.167.233.2146.167.233.2152
1196.167.233.216/306.167.233.217 to 6.167.233.2186.167.233.2192
1206.167.233.220/306.167.233.221 to 6.167.233.2226.167.233.2232
1216.167.233.224/306.167.233.225 to 6.167.233.2266.167.233.2272
1226.167.233.228/306.167.233.229 to 6.167.233.2306.167.233.2312
1236.167.233.232/306.167.233.233 to 6.167.233.2346.167.233.2352
1246.167.233.236/306.167.233.237 to 6.167.233.2386.167.233.2392
1256.167.233.240/306.167.233.241 to 6.167.233.2426.167.233.2432
1266.167.233.244/306.167.233.245 to 6.167.233.2466.167.233.2472
1276.167.233.248/306.167.233.249 to 6.167.233.2506.167.233.2512
1286.167.233.252/306.167.233.253 to 6.167.233.2546.167.233.2552

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.