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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.

Network91.167.80.128/25
Usable hosts126
Subnet mask255.255.255.128
Addresses128
Network address
91.167.80.128
Broadcast address
91.167.80.255
First usable
91.167.80.129
Last usable
91.167.80.254
Usable hosts
126 (128 less the network and broadcast addresses)
Subnet mask
255.255.255.128
Wildcard mask
0.0.0.127 (Cisco ACLs, OSPF)
Prefix length
/25
Type
Public public
Old class
A (default /8)
As numbers
Hex 5BA75080 · Integer 1537691776 to 1537691903
Reverse DNS zone
80.167.91.in-addr.arpa
Smaller than a /24: the provider delegates it inside the /24 zone (RFC 2317), or sets each PTR record for you.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011011.10100111.01010000.1000000091.167.80.128
Subnet mask11111111.11111111.11111111.10000000255.255.255.128
Network01011011.10100111.01010000.1000000091.167.80.128
Broadcast01011011.10100111.01010000.1111111191.167.80.255
Split into smaller subnets/32
/26 (2)/27 (4)/28 (8)/29 (16)/30 (32)/31 (64)/32 (128)

91.167.80.128/25 makes 128 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
191.167.80.128/3291.167.80.128 to 91.167.80.128—1
291.167.80.129/3291.167.80.129 to 91.167.80.129—1
391.167.80.130/3291.167.80.130 to 91.167.80.130—1
491.167.80.131/3291.167.80.131 to 91.167.80.131—1
591.167.80.132/3291.167.80.132 to 91.167.80.132—1
691.167.80.133/3291.167.80.133 to 91.167.80.133—1
791.167.80.134/3291.167.80.134 to 91.167.80.134—1
891.167.80.135/3291.167.80.135 to 91.167.80.135—1
991.167.80.136/3291.167.80.136 to 91.167.80.136—1
1091.167.80.137/3291.167.80.137 to 91.167.80.137—1
1191.167.80.138/3291.167.80.138 to 91.167.80.138—1
1291.167.80.139/3291.167.80.139 to 91.167.80.139—1
1391.167.80.140/3291.167.80.140 to 91.167.80.140—1
1491.167.80.141/3291.167.80.141 to 91.167.80.141—1
1591.167.80.142/3291.167.80.142 to 91.167.80.142—1
1691.167.80.143/3291.167.80.143 to 91.167.80.143—1
1791.167.80.144/3291.167.80.144 to 91.167.80.144—1
1891.167.80.145/3291.167.80.145 to 91.167.80.145—1
1991.167.80.146/3291.167.80.146 to 91.167.80.146—1
2091.167.80.147/3291.167.80.147 to 91.167.80.147—1
2191.167.80.148/3291.167.80.148 to 91.167.80.148—1
2291.167.80.149/3291.167.80.149 to 91.167.80.149—1
2391.167.80.150/3291.167.80.150 to 91.167.80.150—1
2491.167.80.151/3291.167.80.151 to 91.167.80.151—1
2591.167.80.152/3291.167.80.152 to 91.167.80.152—1
2691.167.80.153/3291.167.80.153 to 91.167.80.153—1
2791.167.80.154/3291.167.80.154 to 91.167.80.154—1
2891.167.80.155/3291.167.80.155 to 91.167.80.155—1
2991.167.80.156/3291.167.80.156 to 91.167.80.156—1
3091.167.80.157/3291.167.80.157 to 91.167.80.157—1
3191.167.80.158/3291.167.80.158 to 91.167.80.158—1
3291.167.80.159/3291.167.80.159 to 91.167.80.159—1
3391.167.80.160/3291.167.80.160 to 91.167.80.160—1
3491.167.80.161/3291.167.80.161 to 91.167.80.161—1
3591.167.80.162/3291.167.80.162 to 91.167.80.162—1
3691.167.80.163/3291.167.80.163 to 91.167.80.163—1
3791.167.80.164/3291.167.80.164 to 91.167.80.164—1
3891.167.80.165/3291.167.80.165 to 91.167.80.165—1
3991.167.80.166/3291.167.80.166 to 91.167.80.166—1
4091.167.80.167/3291.167.80.167 to 91.167.80.167—1
4191.167.80.168/3291.167.80.168 to 91.167.80.168—1
4291.167.80.169/3291.167.80.169 to 91.167.80.169—1
4391.167.80.170/3291.167.80.170 to 91.167.80.170—1
4491.167.80.171/3291.167.80.171 to 91.167.80.171—1
4591.167.80.172/3291.167.80.172 to 91.167.80.172—1
4691.167.80.173/3291.167.80.173 to 91.167.80.173—1
4791.167.80.174/3291.167.80.174 to 91.167.80.174—1
4891.167.80.175/3291.167.80.175 to 91.167.80.175—1
4991.167.80.176/3291.167.80.176 to 91.167.80.176—1
5091.167.80.177/3291.167.80.177 to 91.167.80.177—1
5191.167.80.178/3291.167.80.178 to 91.167.80.178—1
5291.167.80.179/3291.167.80.179 to 91.167.80.179—1
5391.167.80.180/3291.167.80.180 to 91.167.80.180—1
5491.167.80.181/3291.167.80.181 to 91.167.80.181—1
5591.167.80.182/3291.167.80.182 to 91.167.80.182—1
5691.167.80.183/3291.167.80.183 to 91.167.80.183—1
5791.167.80.184/3291.167.80.184 to 91.167.80.184—1
5891.167.80.185/3291.167.80.185 to 91.167.80.185—1
5991.167.80.186/3291.167.80.186 to 91.167.80.186—1
6091.167.80.187/3291.167.80.187 to 91.167.80.187—1
6191.167.80.188/3291.167.80.188 to 91.167.80.188—1
6291.167.80.189/3291.167.80.189 to 91.167.80.189—1
6391.167.80.190/3291.167.80.190 to 91.167.80.190—1
6491.167.80.191/3291.167.80.191 to 91.167.80.191—1
6591.167.80.192/3291.167.80.192 to 91.167.80.192—1
6691.167.80.193/3291.167.80.193 to 91.167.80.193—1
6791.167.80.194/3291.167.80.194 to 91.167.80.194—1
6891.167.80.195/3291.167.80.195 to 91.167.80.195—1
6991.167.80.196/3291.167.80.196 to 91.167.80.196—1
7091.167.80.197/3291.167.80.197 to 91.167.80.197—1
7191.167.80.198/3291.167.80.198 to 91.167.80.198—1
7291.167.80.199/3291.167.80.199 to 91.167.80.199—1
7391.167.80.200/3291.167.80.200 to 91.167.80.200—1
7491.167.80.201/3291.167.80.201 to 91.167.80.201—1
7591.167.80.202/3291.167.80.202 to 91.167.80.202—1
7691.167.80.203/3291.167.80.203 to 91.167.80.203—1
7791.167.80.204/3291.167.80.204 to 91.167.80.204—1
7891.167.80.205/3291.167.80.205 to 91.167.80.205—1
7991.167.80.206/3291.167.80.206 to 91.167.80.206—1
8091.167.80.207/3291.167.80.207 to 91.167.80.207—1
8191.167.80.208/3291.167.80.208 to 91.167.80.208—1
8291.167.80.209/3291.167.80.209 to 91.167.80.209—1
8391.167.80.210/3291.167.80.210 to 91.167.80.210—1
8491.167.80.211/3291.167.80.211 to 91.167.80.211—1
8591.167.80.212/3291.167.80.212 to 91.167.80.212—1
8691.167.80.213/3291.167.80.213 to 91.167.80.213—1
8791.167.80.214/3291.167.80.214 to 91.167.80.214—1
8891.167.80.215/3291.167.80.215 to 91.167.80.215—1
8991.167.80.216/3291.167.80.216 to 91.167.80.216—1
9091.167.80.217/3291.167.80.217 to 91.167.80.217—1
9191.167.80.218/3291.167.80.218 to 91.167.80.218—1
9291.167.80.219/3291.167.80.219 to 91.167.80.219—1
9391.167.80.220/3291.167.80.220 to 91.167.80.220—1
9491.167.80.221/3291.167.80.221 to 91.167.80.221—1
9591.167.80.222/3291.167.80.222 to 91.167.80.222—1
9691.167.80.223/3291.167.80.223 to 91.167.80.223—1
9791.167.80.224/3291.167.80.224 to 91.167.80.224—1
9891.167.80.225/3291.167.80.225 to 91.167.80.225—1
9991.167.80.226/3291.167.80.226 to 91.167.80.226—1
10091.167.80.227/3291.167.80.227 to 91.167.80.227—1
10191.167.80.228/3291.167.80.228 to 91.167.80.228—1
10291.167.80.229/3291.167.80.229 to 91.167.80.229—1
10391.167.80.230/3291.167.80.230 to 91.167.80.230—1
10491.167.80.231/3291.167.80.231 to 91.167.80.231—1
10591.167.80.232/3291.167.80.232 to 91.167.80.232—1
10691.167.80.233/3291.167.80.233 to 91.167.80.233—1
10791.167.80.234/3291.167.80.234 to 91.167.80.234—1
10891.167.80.235/3291.167.80.235 to 91.167.80.235—1
10991.167.80.236/3291.167.80.236 to 91.167.80.236—1
11091.167.80.237/3291.167.80.237 to 91.167.80.237—1
11191.167.80.238/3291.167.80.238 to 91.167.80.238—1
11291.167.80.239/3291.167.80.239 to 91.167.80.239—1
11391.167.80.240/3291.167.80.240 to 91.167.80.240—1
11491.167.80.241/3291.167.80.241 to 91.167.80.241—1
11591.167.80.242/3291.167.80.242 to 91.167.80.242—1
11691.167.80.243/3291.167.80.243 to 91.167.80.243—1
11791.167.80.244/3291.167.80.244 to 91.167.80.244—1
11891.167.80.245/3291.167.80.245 to 91.167.80.245—1
11991.167.80.246/3291.167.80.246 to 91.167.80.246—1
12091.167.80.247/3291.167.80.247 to 91.167.80.247—1
12191.167.80.248/3291.167.80.248 to 91.167.80.248—1
12291.167.80.249/3291.167.80.249 to 91.167.80.249—1
12391.167.80.250/3291.167.80.250 to 91.167.80.250—1
12491.167.80.251/3291.167.80.251 to 91.167.80.251—1
12591.167.80.252/3291.167.80.252 to 91.167.80.252—1
12691.167.80.253/3291.167.80.253 to 91.167.80.253—1
12791.167.80.254/3291.167.80.254 to 91.167.80.254—1
12891.167.80.255/3291.167.80.255 to 91.167.80.255—1

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.