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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.

Network26.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
26.0.0.0
Broadcast address
27.255.255.255
First usable
26.0.0.1
Last usable
27.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A000000 · Integer 436207616 to 469762047
Reverse DNS zones
26.in-addr.arpa
27.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.00000000.00000000.0000000026.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00011010.00000000.00000000.0000000026.0.0.0
Broadcast00011011.11111111.11111111.1111111127.255.255.255
Split into smaller subnets/14
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

26.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.0.0.0/1426.0.0.1 to 26.3.255.25426.3.255.255262,142
226.4.0.0/1426.4.0.1 to 26.7.255.25426.7.255.255262,142
326.8.0.0/1426.8.0.1 to 26.11.255.25426.11.255.255262,142
426.12.0.0/1426.12.0.1 to 26.15.255.25426.15.255.255262,142
526.16.0.0/1426.16.0.1 to 26.19.255.25426.19.255.255262,142
626.20.0.0/1426.20.0.1 to 26.23.255.25426.23.255.255262,142
726.24.0.0/1426.24.0.1 to 26.27.255.25426.27.255.255262,142
826.28.0.0/1426.28.0.1 to 26.31.255.25426.31.255.255262,142
926.32.0.0/1426.32.0.1 to 26.35.255.25426.35.255.255262,142
1026.36.0.0/1426.36.0.1 to 26.39.255.25426.39.255.255262,142
1126.40.0.0/1426.40.0.1 to 26.43.255.25426.43.255.255262,142
1226.44.0.0/1426.44.0.1 to 26.47.255.25426.47.255.255262,142
1326.48.0.0/1426.48.0.1 to 26.51.255.25426.51.255.255262,142
1426.52.0.0/1426.52.0.1 to 26.55.255.25426.55.255.255262,142
1526.56.0.0/1426.56.0.1 to 26.59.255.25426.59.255.255262,142
1626.60.0.0/1426.60.0.1 to 26.63.255.25426.63.255.255262,142
1726.64.0.0/1426.64.0.1 to 26.67.255.25426.67.255.255262,142
1826.68.0.0/1426.68.0.1 to 26.71.255.25426.71.255.255262,142
1926.72.0.0/1426.72.0.1 to 26.75.255.25426.75.255.255262,142
2026.76.0.0/1426.76.0.1 to 26.79.255.25426.79.255.255262,142
2126.80.0.0/1426.80.0.1 to 26.83.255.25426.83.255.255262,142
2226.84.0.0/1426.84.0.1 to 26.87.255.25426.87.255.255262,142
2326.88.0.0/1426.88.0.1 to 26.91.255.25426.91.255.255262,142
2426.92.0.0/1426.92.0.1 to 26.95.255.25426.95.255.255262,142
2526.96.0.0/1426.96.0.1 to 26.99.255.25426.99.255.255262,142
2626.100.0.0/1426.100.0.1 to 26.103.255.25426.103.255.255262,142
2726.104.0.0/1426.104.0.1 to 26.107.255.25426.107.255.255262,142
2826.108.0.0/1426.108.0.1 to 26.111.255.25426.111.255.255262,142
2926.112.0.0/1426.112.0.1 to 26.115.255.25426.115.255.255262,142
3026.116.0.0/1426.116.0.1 to 26.119.255.25426.119.255.255262,142
3126.120.0.0/1426.120.0.1 to 26.123.255.25426.123.255.255262,142
3226.124.0.0/1426.124.0.1 to 26.127.255.25426.127.255.255262,142
3326.128.0.0/1426.128.0.1 to 26.131.255.25426.131.255.255262,142
3426.132.0.0/1426.132.0.1 to 26.135.255.25426.135.255.255262,142
3526.136.0.0/1426.136.0.1 to 26.139.255.25426.139.255.255262,142
3626.140.0.0/1426.140.0.1 to 26.143.255.25426.143.255.255262,142
3726.144.0.0/1426.144.0.1 to 26.147.255.25426.147.255.255262,142
3826.148.0.0/1426.148.0.1 to 26.151.255.25426.151.255.255262,142
3926.152.0.0/1426.152.0.1 to 26.155.255.25426.155.255.255262,142
4026.156.0.0/1426.156.0.1 to 26.159.255.25426.159.255.255262,142
4126.160.0.0/1426.160.0.1 to 26.163.255.25426.163.255.255262,142
4226.164.0.0/1426.164.0.1 to 26.167.255.25426.167.255.255262,142
4326.168.0.0/1426.168.0.1 to 26.171.255.25426.171.255.255262,142
4426.172.0.0/1426.172.0.1 to 26.175.255.25426.175.255.255262,142
4526.176.0.0/1426.176.0.1 to 26.179.255.25426.179.255.255262,142
4626.180.0.0/1426.180.0.1 to 26.183.255.25426.183.255.255262,142
4726.184.0.0/1426.184.0.1 to 26.187.255.25426.187.255.255262,142
4826.188.0.0/1426.188.0.1 to 26.191.255.25426.191.255.255262,142
4926.192.0.0/1426.192.0.1 to 26.195.255.25426.195.255.255262,142
5026.196.0.0/1426.196.0.1 to 26.199.255.25426.199.255.255262,142
5126.200.0.0/1426.200.0.1 to 26.203.255.25426.203.255.255262,142
5226.204.0.0/1426.204.0.1 to 26.207.255.25426.207.255.255262,142
5326.208.0.0/1426.208.0.1 to 26.211.255.25426.211.255.255262,142
5426.212.0.0/1426.212.0.1 to 26.215.255.25426.215.255.255262,142
5526.216.0.0/1426.216.0.1 to 26.219.255.25426.219.255.255262,142
5626.220.0.0/1426.220.0.1 to 26.223.255.25426.223.255.255262,142
5726.224.0.0/1426.224.0.1 to 26.227.255.25426.227.255.255262,142
5826.228.0.0/1426.228.0.1 to 26.231.255.25426.231.255.255262,142
5926.232.0.0/1426.232.0.1 to 26.235.255.25426.235.255.255262,142
6026.236.0.0/1426.236.0.1 to 26.239.255.25426.239.255.255262,142
6126.240.0.0/1426.240.0.1 to 26.243.255.25426.243.255.255262,142
6226.244.0.0/1426.244.0.1 to 26.247.255.25426.247.255.255262,142
6326.248.0.0/1426.248.0.1 to 26.251.255.25426.251.255.255262,142
6426.252.0.0/1426.252.0.1 to 26.255.255.25426.255.255.255262,142
6527.0.0.0/1427.0.0.1 to 27.3.255.25427.3.255.255262,142
6627.4.0.0/1427.4.0.1 to 27.7.255.25427.7.255.255262,142
6727.8.0.0/1427.8.0.1 to 27.11.255.25427.11.255.255262,142
6827.12.0.0/1427.12.0.1 to 27.15.255.25427.15.255.255262,142
6927.16.0.0/1427.16.0.1 to 27.19.255.25427.19.255.255262,142
7027.20.0.0/1427.20.0.1 to 27.23.255.25427.23.255.255262,142
7127.24.0.0/1427.24.0.1 to 27.27.255.25427.27.255.255262,142
7227.28.0.0/1427.28.0.1 to 27.31.255.25427.31.255.255262,142
7327.32.0.0/1427.32.0.1 to 27.35.255.25427.35.255.255262,142
7427.36.0.0/1427.36.0.1 to 27.39.255.25427.39.255.255262,142
7527.40.0.0/1427.40.0.1 to 27.43.255.25427.43.255.255262,142
7627.44.0.0/1427.44.0.1 to 27.47.255.25427.47.255.255262,142
7727.48.0.0/1427.48.0.1 to 27.51.255.25427.51.255.255262,142
7827.52.0.0/1427.52.0.1 to 27.55.255.25427.55.255.255262,142
7927.56.0.0/1427.56.0.1 to 27.59.255.25427.59.255.255262,142
8027.60.0.0/1427.60.0.1 to 27.63.255.25427.63.255.255262,142
8127.64.0.0/1427.64.0.1 to 27.67.255.25427.67.255.255262,142
8227.68.0.0/1427.68.0.1 to 27.71.255.25427.71.255.255262,142
8327.72.0.0/1427.72.0.1 to 27.75.255.25427.75.255.255262,142
8427.76.0.0/1427.76.0.1 to 27.79.255.25427.79.255.255262,142
8527.80.0.0/1427.80.0.1 to 27.83.255.25427.83.255.255262,142
8627.84.0.0/1427.84.0.1 to 27.87.255.25427.87.255.255262,142
8727.88.0.0/1427.88.0.1 to 27.91.255.25427.91.255.255262,142
8827.92.0.0/1427.92.0.1 to 27.95.255.25427.95.255.255262,142
8927.96.0.0/1427.96.0.1 to 27.99.255.25427.99.255.255262,142
9027.100.0.0/1427.100.0.1 to 27.103.255.25427.103.255.255262,142
9127.104.0.0/1427.104.0.1 to 27.107.255.25427.107.255.255262,142
9227.108.0.0/1427.108.0.1 to 27.111.255.25427.111.255.255262,142
9327.112.0.0/1427.112.0.1 to 27.115.255.25427.115.255.255262,142
9427.116.0.0/1427.116.0.1 to 27.119.255.25427.119.255.255262,142
9527.120.0.0/1427.120.0.1 to 27.123.255.25427.123.255.255262,142
9627.124.0.0/1427.124.0.1 to 27.127.255.25427.127.255.255262,142
9727.128.0.0/1427.128.0.1 to 27.131.255.25427.131.255.255262,142
9827.132.0.0/1427.132.0.1 to 27.135.255.25427.135.255.255262,142
9927.136.0.0/1427.136.0.1 to 27.139.255.25427.139.255.255262,142
10027.140.0.0/1427.140.0.1 to 27.143.255.25427.143.255.255262,142
10127.144.0.0/1427.144.0.1 to 27.147.255.25427.147.255.255262,142
10227.148.0.0/1427.148.0.1 to 27.151.255.25427.151.255.255262,142
10327.152.0.0/1427.152.0.1 to 27.155.255.25427.155.255.255262,142
10427.156.0.0/1427.156.0.1 to 27.159.255.25427.159.255.255262,142
10527.160.0.0/1427.160.0.1 to 27.163.255.25427.163.255.255262,142
10627.164.0.0/1427.164.0.1 to 27.167.255.25427.167.255.255262,142
10727.168.0.0/1427.168.0.1 to 27.171.255.25427.171.255.255262,142
10827.172.0.0/1427.172.0.1 to 27.175.255.25427.175.255.255262,142
10927.176.0.0/1427.176.0.1 to 27.179.255.25427.179.255.255262,142
11027.180.0.0/1427.180.0.1 to 27.183.255.25427.183.255.255262,142
11127.184.0.0/1427.184.0.1 to 27.187.255.25427.187.255.255262,142
11227.188.0.0/1427.188.0.1 to 27.191.255.25427.191.255.255262,142
11327.192.0.0/1427.192.0.1 to 27.195.255.25427.195.255.255262,142
11427.196.0.0/1427.196.0.1 to 27.199.255.25427.199.255.255262,142
11527.200.0.0/1427.200.0.1 to 27.203.255.25427.203.255.255262,142
11627.204.0.0/1427.204.0.1 to 27.207.255.25427.207.255.255262,142
11727.208.0.0/1427.208.0.1 to 27.211.255.25427.211.255.255262,142
11827.212.0.0/1427.212.0.1 to 27.215.255.25427.215.255.255262,142
11927.216.0.0/1427.216.0.1 to 27.219.255.25427.219.255.255262,142
12027.220.0.0/1427.220.0.1 to 27.223.255.25427.223.255.255262,142
12127.224.0.0/1427.224.0.1 to 27.227.255.25427.227.255.255262,142
12227.228.0.0/1427.228.0.1 to 27.231.255.25427.231.255.255262,142
12327.232.0.0/1427.232.0.1 to 27.235.255.25427.235.255.255262,142
12427.236.0.0/1427.236.0.1 to 27.239.255.25427.239.255.255262,142
12527.240.0.0/1427.240.0.1 to 27.243.255.25427.243.255.255262,142
12627.244.0.0/1427.244.0.1 to 27.247.255.25427.247.255.255262,142
12727.248.0.0/1427.248.0.1 to 27.251.255.25427.251.255.255262,142
12827.252.0.0/1427.252.0.1 to 27.255.255.25427.255.255.255262,142

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.