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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.

Network26.112.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
26.112.0.0
Broadcast address
26.112.63.255
First usable
26.112.0.1
Last usable
26.112.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A700000 · Integer 443547648 to 443564031
Reverse DNS zones
0.112.26.in-addr.arpa
1.112.26.in-addr.arpa
2.112.26.in-addr.arpa
3.112.26.in-addr.arpa
4.112.26.in-addr.arpa
5.112.26.in-addr.arpa
6.112.26.in-addr.arpa
7.112.26.in-addr.arpa
8.112.26.in-addr.arpa
9.112.26.in-addr.arpa
10.112.26.in-addr.arpa
11.112.26.in-addr.arpa
12.112.26.in-addr.arpa
13.112.26.in-addr.arpa
14.112.26.in-addr.arpa
15.112.26.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.01110000.00000000.0000000026.112.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00011010.01110000.00000000.0000000026.112.0.0
Broadcast00011010.01110000.00111111.1111111126.112.63.255
Split into smaller subnets/25
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

26.112.0.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.112.0.0/2526.112.0.1 to 26.112.0.12626.112.0.127126
226.112.0.128/2526.112.0.129 to 26.112.0.25426.112.0.255126
326.112.1.0/2526.112.1.1 to 26.112.1.12626.112.1.127126
426.112.1.128/2526.112.1.129 to 26.112.1.25426.112.1.255126
526.112.2.0/2526.112.2.1 to 26.112.2.12626.112.2.127126
626.112.2.128/2526.112.2.129 to 26.112.2.25426.112.2.255126
726.112.3.0/2526.112.3.1 to 26.112.3.12626.112.3.127126
826.112.3.128/2526.112.3.129 to 26.112.3.25426.112.3.255126
926.112.4.0/2526.112.4.1 to 26.112.4.12626.112.4.127126
1026.112.4.128/2526.112.4.129 to 26.112.4.25426.112.4.255126
1126.112.5.0/2526.112.5.1 to 26.112.5.12626.112.5.127126
1226.112.5.128/2526.112.5.129 to 26.112.5.25426.112.5.255126
1326.112.6.0/2526.112.6.1 to 26.112.6.12626.112.6.127126
1426.112.6.128/2526.112.6.129 to 26.112.6.25426.112.6.255126
1526.112.7.0/2526.112.7.1 to 26.112.7.12626.112.7.127126
1626.112.7.128/2526.112.7.129 to 26.112.7.25426.112.7.255126
1726.112.8.0/2526.112.8.1 to 26.112.8.12626.112.8.127126
1826.112.8.128/2526.112.8.129 to 26.112.8.25426.112.8.255126
1926.112.9.0/2526.112.9.1 to 26.112.9.12626.112.9.127126
2026.112.9.128/2526.112.9.129 to 26.112.9.25426.112.9.255126
2126.112.10.0/2526.112.10.1 to 26.112.10.12626.112.10.127126
2226.112.10.128/2526.112.10.129 to 26.112.10.25426.112.10.255126
2326.112.11.0/2526.112.11.1 to 26.112.11.12626.112.11.127126
2426.112.11.128/2526.112.11.129 to 26.112.11.25426.112.11.255126
2526.112.12.0/2526.112.12.1 to 26.112.12.12626.112.12.127126
2626.112.12.128/2526.112.12.129 to 26.112.12.25426.112.12.255126
2726.112.13.0/2526.112.13.1 to 26.112.13.12626.112.13.127126
2826.112.13.128/2526.112.13.129 to 26.112.13.25426.112.13.255126
2926.112.14.0/2526.112.14.1 to 26.112.14.12626.112.14.127126
3026.112.14.128/2526.112.14.129 to 26.112.14.25426.112.14.255126
3126.112.15.0/2526.112.15.1 to 26.112.15.12626.112.15.127126
3226.112.15.128/2526.112.15.129 to 26.112.15.25426.112.15.255126
3326.112.16.0/2526.112.16.1 to 26.112.16.12626.112.16.127126
3426.112.16.128/2526.112.16.129 to 26.112.16.25426.112.16.255126
3526.112.17.0/2526.112.17.1 to 26.112.17.12626.112.17.127126
3626.112.17.128/2526.112.17.129 to 26.112.17.25426.112.17.255126
3726.112.18.0/2526.112.18.1 to 26.112.18.12626.112.18.127126
3826.112.18.128/2526.112.18.129 to 26.112.18.25426.112.18.255126
3926.112.19.0/2526.112.19.1 to 26.112.19.12626.112.19.127126
4026.112.19.128/2526.112.19.129 to 26.112.19.25426.112.19.255126
4126.112.20.0/2526.112.20.1 to 26.112.20.12626.112.20.127126
4226.112.20.128/2526.112.20.129 to 26.112.20.25426.112.20.255126
4326.112.21.0/2526.112.21.1 to 26.112.21.12626.112.21.127126
4426.112.21.128/2526.112.21.129 to 26.112.21.25426.112.21.255126
4526.112.22.0/2526.112.22.1 to 26.112.22.12626.112.22.127126
4626.112.22.128/2526.112.22.129 to 26.112.22.25426.112.22.255126
4726.112.23.0/2526.112.23.1 to 26.112.23.12626.112.23.127126
4826.112.23.128/2526.112.23.129 to 26.112.23.25426.112.23.255126
4926.112.24.0/2526.112.24.1 to 26.112.24.12626.112.24.127126
5026.112.24.128/2526.112.24.129 to 26.112.24.25426.112.24.255126
5126.112.25.0/2526.112.25.1 to 26.112.25.12626.112.25.127126
5226.112.25.128/2526.112.25.129 to 26.112.25.25426.112.25.255126
5326.112.26.0/2526.112.26.1 to 26.112.26.12626.112.26.127126
5426.112.26.128/2526.112.26.129 to 26.112.26.25426.112.26.255126
5526.112.27.0/2526.112.27.1 to 26.112.27.12626.112.27.127126
5626.112.27.128/2526.112.27.129 to 26.112.27.25426.112.27.255126
5726.112.28.0/2526.112.28.1 to 26.112.28.12626.112.28.127126
5826.112.28.128/2526.112.28.129 to 26.112.28.25426.112.28.255126
5926.112.29.0/2526.112.29.1 to 26.112.29.12626.112.29.127126
6026.112.29.128/2526.112.29.129 to 26.112.29.25426.112.29.255126
6126.112.30.0/2526.112.30.1 to 26.112.30.12626.112.30.127126
6226.112.30.128/2526.112.30.129 to 26.112.30.25426.112.30.255126
6326.112.31.0/2526.112.31.1 to 26.112.31.12626.112.31.127126
6426.112.31.128/2526.112.31.129 to 26.112.31.25426.112.31.255126
6526.112.32.0/2526.112.32.1 to 26.112.32.12626.112.32.127126
6626.112.32.128/2526.112.32.129 to 26.112.32.25426.112.32.255126
6726.112.33.0/2526.112.33.1 to 26.112.33.12626.112.33.127126
6826.112.33.128/2526.112.33.129 to 26.112.33.25426.112.33.255126
6926.112.34.0/2526.112.34.1 to 26.112.34.12626.112.34.127126
7026.112.34.128/2526.112.34.129 to 26.112.34.25426.112.34.255126
7126.112.35.0/2526.112.35.1 to 26.112.35.12626.112.35.127126
7226.112.35.128/2526.112.35.129 to 26.112.35.25426.112.35.255126
7326.112.36.0/2526.112.36.1 to 26.112.36.12626.112.36.127126
7426.112.36.128/2526.112.36.129 to 26.112.36.25426.112.36.255126
7526.112.37.0/2526.112.37.1 to 26.112.37.12626.112.37.127126
7626.112.37.128/2526.112.37.129 to 26.112.37.25426.112.37.255126
7726.112.38.0/2526.112.38.1 to 26.112.38.12626.112.38.127126
7826.112.38.128/2526.112.38.129 to 26.112.38.25426.112.38.255126
7926.112.39.0/2526.112.39.1 to 26.112.39.12626.112.39.127126
8026.112.39.128/2526.112.39.129 to 26.112.39.25426.112.39.255126
8126.112.40.0/2526.112.40.1 to 26.112.40.12626.112.40.127126
8226.112.40.128/2526.112.40.129 to 26.112.40.25426.112.40.255126
8326.112.41.0/2526.112.41.1 to 26.112.41.12626.112.41.127126
8426.112.41.128/2526.112.41.129 to 26.112.41.25426.112.41.255126
8526.112.42.0/2526.112.42.1 to 26.112.42.12626.112.42.127126
8626.112.42.128/2526.112.42.129 to 26.112.42.25426.112.42.255126
8726.112.43.0/2526.112.43.1 to 26.112.43.12626.112.43.127126
8826.112.43.128/2526.112.43.129 to 26.112.43.25426.112.43.255126
8926.112.44.0/2526.112.44.1 to 26.112.44.12626.112.44.127126
9026.112.44.128/2526.112.44.129 to 26.112.44.25426.112.44.255126
9126.112.45.0/2526.112.45.1 to 26.112.45.12626.112.45.127126
9226.112.45.128/2526.112.45.129 to 26.112.45.25426.112.45.255126
9326.112.46.0/2526.112.46.1 to 26.112.46.12626.112.46.127126
9426.112.46.128/2526.112.46.129 to 26.112.46.25426.112.46.255126
9526.112.47.0/2526.112.47.1 to 26.112.47.12626.112.47.127126
9626.112.47.128/2526.112.47.129 to 26.112.47.25426.112.47.255126
9726.112.48.0/2526.112.48.1 to 26.112.48.12626.112.48.127126
9826.112.48.128/2526.112.48.129 to 26.112.48.25426.112.48.255126
9926.112.49.0/2526.112.49.1 to 26.112.49.12626.112.49.127126
10026.112.49.128/2526.112.49.129 to 26.112.49.25426.112.49.255126
10126.112.50.0/2526.112.50.1 to 26.112.50.12626.112.50.127126
10226.112.50.128/2526.112.50.129 to 26.112.50.25426.112.50.255126
10326.112.51.0/2526.112.51.1 to 26.112.51.12626.112.51.127126
10426.112.51.128/2526.112.51.129 to 26.112.51.25426.112.51.255126
10526.112.52.0/2526.112.52.1 to 26.112.52.12626.112.52.127126
10626.112.52.128/2526.112.52.129 to 26.112.52.25426.112.52.255126
10726.112.53.0/2526.112.53.1 to 26.112.53.12626.112.53.127126
10826.112.53.128/2526.112.53.129 to 26.112.53.25426.112.53.255126
10926.112.54.0/2526.112.54.1 to 26.112.54.12626.112.54.127126
11026.112.54.128/2526.112.54.129 to 26.112.54.25426.112.54.255126
11126.112.55.0/2526.112.55.1 to 26.112.55.12626.112.55.127126
11226.112.55.128/2526.112.55.129 to 26.112.55.25426.112.55.255126
11326.112.56.0/2526.112.56.1 to 26.112.56.12626.112.56.127126
11426.112.56.128/2526.112.56.129 to 26.112.56.25426.112.56.255126
11526.112.57.0/2526.112.57.1 to 26.112.57.12626.112.57.127126
11626.112.57.128/2526.112.57.129 to 26.112.57.25426.112.57.255126
11726.112.58.0/2526.112.58.1 to 26.112.58.12626.112.58.127126
11826.112.58.128/2526.112.58.129 to 26.112.58.25426.112.58.255126
11926.112.59.0/2526.112.59.1 to 26.112.59.12626.112.59.127126
12026.112.59.128/2526.112.59.129 to 26.112.59.25426.112.59.255126
12126.112.60.0/2526.112.60.1 to 26.112.60.12626.112.60.127126
12226.112.60.128/2526.112.60.129 to 26.112.60.25426.112.60.255126
12326.112.61.0/2526.112.61.1 to 26.112.61.12626.112.61.127126
12426.112.61.128/2526.112.61.129 to 26.112.61.25426.112.61.255126
12526.112.62.0/2526.112.62.1 to 26.112.62.12626.112.62.127126
12626.112.62.128/2526.112.62.129 to 26.112.62.25426.112.62.255126
12726.112.63.0/2526.112.63.1 to 26.112.63.12626.112.63.127126
12826.112.63.128/2526.112.63.129 to 26.112.63.25426.112.63.255126

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.