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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.

Network26.22.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
26.22.0.0
Broadcast address
26.22.127.255
First usable
26.22.0.1
Last usable
26.22.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A160000 · Integer 437649408 to 437682175
Reverse DNS zones
0.22.26.in-addr.arpa
1.22.26.in-addr.arpa
2.22.26.in-addr.arpa
3.22.26.in-addr.arpa
4.22.26.in-addr.arpa
5.22.26.in-addr.arpa
6.22.26.in-addr.arpa
7.22.26.in-addr.arpa
8.22.26.in-addr.arpa
9.22.26.in-addr.arpa
10.22.26.in-addr.arpa
11.22.26.in-addr.arpa
12.22.26.in-addr.arpa
13.22.26.in-addr.arpa
14.22.26.in-addr.arpa
15.22.26.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.00010110.00000000.0000000026.22.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00011010.00010110.00000000.0000000026.22.0.0
Broadcast00011010.00010110.01111111.1111111126.22.127.255
Split into smaller subnets/24
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

26.22.0.0/17 makes 128 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.22.0.0/2426.22.0.1 to 26.22.0.25426.22.0.255254
226.22.1.0/2426.22.1.1 to 26.22.1.25426.22.1.255254
326.22.2.0/2426.22.2.1 to 26.22.2.25426.22.2.255254
426.22.3.0/2426.22.3.1 to 26.22.3.25426.22.3.255254
526.22.4.0/2426.22.4.1 to 26.22.4.25426.22.4.255254
626.22.5.0/2426.22.5.1 to 26.22.5.25426.22.5.255254
726.22.6.0/2426.22.6.1 to 26.22.6.25426.22.6.255254
826.22.7.0/2426.22.7.1 to 26.22.7.25426.22.7.255254
926.22.8.0/2426.22.8.1 to 26.22.8.25426.22.8.255254
1026.22.9.0/2426.22.9.1 to 26.22.9.25426.22.9.255254
1126.22.10.0/2426.22.10.1 to 26.22.10.25426.22.10.255254
1226.22.11.0/2426.22.11.1 to 26.22.11.25426.22.11.255254
1326.22.12.0/2426.22.12.1 to 26.22.12.25426.22.12.255254
1426.22.13.0/2426.22.13.1 to 26.22.13.25426.22.13.255254
1526.22.14.0/2426.22.14.1 to 26.22.14.25426.22.14.255254
1626.22.15.0/2426.22.15.1 to 26.22.15.25426.22.15.255254
1726.22.16.0/2426.22.16.1 to 26.22.16.25426.22.16.255254
1826.22.17.0/2426.22.17.1 to 26.22.17.25426.22.17.255254
1926.22.18.0/2426.22.18.1 to 26.22.18.25426.22.18.255254
2026.22.19.0/2426.22.19.1 to 26.22.19.25426.22.19.255254
2126.22.20.0/2426.22.20.1 to 26.22.20.25426.22.20.255254
2226.22.21.0/2426.22.21.1 to 26.22.21.25426.22.21.255254
2326.22.22.0/2426.22.22.1 to 26.22.22.25426.22.22.255254
2426.22.23.0/2426.22.23.1 to 26.22.23.25426.22.23.255254
2526.22.24.0/2426.22.24.1 to 26.22.24.25426.22.24.255254
2626.22.25.0/2426.22.25.1 to 26.22.25.25426.22.25.255254
2726.22.26.0/2426.22.26.1 to 26.22.26.25426.22.26.255254
2826.22.27.0/2426.22.27.1 to 26.22.27.25426.22.27.255254
2926.22.28.0/2426.22.28.1 to 26.22.28.25426.22.28.255254
3026.22.29.0/2426.22.29.1 to 26.22.29.25426.22.29.255254
3126.22.30.0/2426.22.30.1 to 26.22.30.25426.22.30.255254
3226.22.31.0/2426.22.31.1 to 26.22.31.25426.22.31.255254
3326.22.32.0/2426.22.32.1 to 26.22.32.25426.22.32.255254
3426.22.33.0/2426.22.33.1 to 26.22.33.25426.22.33.255254
3526.22.34.0/2426.22.34.1 to 26.22.34.25426.22.34.255254
3626.22.35.0/2426.22.35.1 to 26.22.35.25426.22.35.255254
3726.22.36.0/2426.22.36.1 to 26.22.36.25426.22.36.255254
3826.22.37.0/2426.22.37.1 to 26.22.37.25426.22.37.255254
3926.22.38.0/2426.22.38.1 to 26.22.38.25426.22.38.255254
4026.22.39.0/2426.22.39.1 to 26.22.39.25426.22.39.255254
4126.22.40.0/2426.22.40.1 to 26.22.40.25426.22.40.255254
4226.22.41.0/2426.22.41.1 to 26.22.41.25426.22.41.255254
4326.22.42.0/2426.22.42.1 to 26.22.42.25426.22.42.255254
4426.22.43.0/2426.22.43.1 to 26.22.43.25426.22.43.255254
4526.22.44.0/2426.22.44.1 to 26.22.44.25426.22.44.255254
4626.22.45.0/2426.22.45.1 to 26.22.45.25426.22.45.255254
4726.22.46.0/2426.22.46.1 to 26.22.46.25426.22.46.255254
4826.22.47.0/2426.22.47.1 to 26.22.47.25426.22.47.255254
4926.22.48.0/2426.22.48.1 to 26.22.48.25426.22.48.255254
5026.22.49.0/2426.22.49.1 to 26.22.49.25426.22.49.255254
5126.22.50.0/2426.22.50.1 to 26.22.50.25426.22.50.255254
5226.22.51.0/2426.22.51.1 to 26.22.51.25426.22.51.255254
5326.22.52.0/2426.22.52.1 to 26.22.52.25426.22.52.255254
5426.22.53.0/2426.22.53.1 to 26.22.53.25426.22.53.255254
5526.22.54.0/2426.22.54.1 to 26.22.54.25426.22.54.255254
5626.22.55.0/2426.22.55.1 to 26.22.55.25426.22.55.255254
5726.22.56.0/2426.22.56.1 to 26.22.56.25426.22.56.255254
5826.22.57.0/2426.22.57.1 to 26.22.57.25426.22.57.255254
5926.22.58.0/2426.22.58.1 to 26.22.58.25426.22.58.255254
6026.22.59.0/2426.22.59.1 to 26.22.59.25426.22.59.255254
6126.22.60.0/2426.22.60.1 to 26.22.60.25426.22.60.255254
6226.22.61.0/2426.22.61.1 to 26.22.61.25426.22.61.255254
6326.22.62.0/2426.22.62.1 to 26.22.62.25426.22.62.255254
6426.22.63.0/2426.22.63.1 to 26.22.63.25426.22.63.255254
6526.22.64.0/2426.22.64.1 to 26.22.64.25426.22.64.255254
6626.22.65.0/2426.22.65.1 to 26.22.65.25426.22.65.255254
6726.22.66.0/2426.22.66.1 to 26.22.66.25426.22.66.255254
6826.22.67.0/2426.22.67.1 to 26.22.67.25426.22.67.255254
6926.22.68.0/2426.22.68.1 to 26.22.68.25426.22.68.255254
7026.22.69.0/2426.22.69.1 to 26.22.69.25426.22.69.255254
7126.22.70.0/2426.22.70.1 to 26.22.70.25426.22.70.255254
7226.22.71.0/2426.22.71.1 to 26.22.71.25426.22.71.255254
7326.22.72.0/2426.22.72.1 to 26.22.72.25426.22.72.255254
7426.22.73.0/2426.22.73.1 to 26.22.73.25426.22.73.255254
7526.22.74.0/2426.22.74.1 to 26.22.74.25426.22.74.255254
7626.22.75.0/2426.22.75.1 to 26.22.75.25426.22.75.255254
7726.22.76.0/2426.22.76.1 to 26.22.76.25426.22.76.255254
7826.22.77.0/2426.22.77.1 to 26.22.77.25426.22.77.255254
7926.22.78.0/2426.22.78.1 to 26.22.78.25426.22.78.255254
8026.22.79.0/2426.22.79.1 to 26.22.79.25426.22.79.255254
8126.22.80.0/2426.22.80.1 to 26.22.80.25426.22.80.255254
8226.22.81.0/2426.22.81.1 to 26.22.81.25426.22.81.255254
8326.22.82.0/2426.22.82.1 to 26.22.82.25426.22.82.255254
8426.22.83.0/2426.22.83.1 to 26.22.83.25426.22.83.255254
8526.22.84.0/2426.22.84.1 to 26.22.84.25426.22.84.255254
8626.22.85.0/2426.22.85.1 to 26.22.85.25426.22.85.255254
8726.22.86.0/2426.22.86.1 to 26.22.86.25426.22.86.255254
8826.22.87.0/2426.22.87.1 to 26.22.87.25426.22.87.255254
8926.22.88.0/2426.22.88.1 to 26.22.88.25426.22.88.255254
9026.22.89.0/2426.22.89.1 to 26.22.89.25426.22.89.255254
9126.22.90.0/2426.22.90.1 to 26.22.90.25426.22.90.255254
9226.22.91.0/2426.22.91.1 to 26.22.91.25426.22.91.255254
9326.22.92.0/2426.22.92.1 to 26.22.92.25426.22.92.255254
9426.22.93.0/2426.22.93.1 to 26.22.93.25426.22.93.255254
9526.22.94.0/2426.22.94.1 to 26.22.94.25426.22.94.255254
9626.22.95.0/2426.22.95.1 to 26.22.95.25426.22.95.255254
9726.22.96.0/2426.22.96.1 to 26.22.96.25426.22.96.255254
9826.22.97.0/2426.22.97.1 to 26.22.97.25426.22.97.255254
9926.22.98.0/2426.22.98.1 to 26.22.98.25426.22.98.255254
10026.22.99.0/2426.22.99.1 to 26.22.99.25426.22.99.255254
10126.22.100.0/2426.22.100.1 to 26.22.100.25426.22.100.255254
10226.22.101.0/2426.22.101.1 to 26.22.101.25426.22.101.255254
10326.22.102.0/2426.22.102.1 to 26.22.102.25426.22.102.255254
10426.22.103.0/2426.22.103.1 to 26.22.103.25426.22.103.255254
10526.22.104.0/2426.22.104.1 to 26.22.104.25426.22.104.255254
10626.22.105.0/2426.22.105.1 to 26.22.105.25426.22.105.255254
10726.22.106.0/2426.22.106.1 to 26.22.106.25426.22.106.255254
10826.22.107.0/2426.22.107.1 to 26.22.107.25426.22.107.255254
10926.22.108.0/2426.22.108.1 to 26.22.108.25426.22.108.255254
11026.22.109.0/2426.22.109.1 to 26.22.109.25426.22.109.255254
11126.22.110.0/2426.22.110.1 to 26.22.110.25426.22.110.255254
11226.22.111.0/2426.22.111.1 to 26.22.111.25426.22.111.255254
11326.22.112.0/2426.22.112.1 to 26.22.112.25426.22.112.255254
11426.22.113.0/2426.22.113.1 to 26.22.113.25426.22.113.255254
11526.22.114.0/2426.22.114.1 to 26.22.114.25426.22.114.255254
11626.22.115.0/2426.22.115.1 to 26.22.115.25426.22.115.255254
11726.22.116.0/2426.22.116.1 to 26.22.116.25426.22.116.255254
11826.22.117.0/2426.22.117.1 to 26.22.117.25426.22.117.255254
11926.22.118.0/2426.22.118.1 to 26.22.118.25426.22.118.255254
12026.22.119.0/2426.22.119.1 to 26.22.119.25426.22.119.255254
12126.22.120.0/2426.22.120.1 to 26.22.120.25426.22.120.255254
12226.22.121.0/2426.22.121.1 to 26.22.121.25426.22.121.255254
12326.22.122.0/2426.22.122.1 to 26.22.122.25426.22.122.255254
12426.22.123.0/2426.22.123.1 to 26.22.123.25426.22.123.255254
12526.22.124.0/2426.22.124.1 to 26.22.124.25426.22.124.255254
12626.22.125.0/2426.22.125.1 to 26.22.125.25426.22.125.255254
12726.22.126.0/2426.22.126.1 to 26.22.126.25426.22.126.255254
12826.22.127.0/2426.22.127.1 to 26.22.127.25426.22.127.255254

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.