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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.

Network26.2.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
26.2.0.0
Broadcast address
26.2.31.255
First usable
26.2.0.1
Last usable
26.2.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A020000 · Integer 436338688 to 436346879
Reverse DNS zones
0.2.26.in-addr.arpa
1.2.26.in-addr.arpa
2.2.26.in-addr.arpa
3.2.26.in-addr.arpa
4.2.26.in-addr.arpa
5.2.26.in-addr.arpa
6.2.26.in-addr.arpa
7.2.26.in-addr.arpa
8.2.26.in-addr.arpa
9.2.26.in-addr.arpa
10.2.26.in-addr.arpa
11.2.26.in-addr.arpa
12.2.26.in-addr.arpa
13.2.26.in-addr.arpa
14.2.26.in-addr.arpa
15.2.26.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.00000010.00000000.0000000026.2.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00011010.00000010.00000000.0000000026.2.0.0
Broadcast00011010.00000010.00011111.1111111126.2.31.255
Split into smaller subnets/26
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

26.2.0.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.2.0.0/2626.2.0.1 to 26.2.0.6226.2.0.6362
226.2.0.64/2626.2.0.65 to 26.2.0.12626.2.0.12762
326.2.0.128/2626.2.0.129 to 26.2.0.19026.2.0.19162
426.2.0.192/2626.2.0.193 to 26.2.0.25426.2.0.25562
526.2.1.0/2626.2.1.1 to 26.2.1.6226.2.1.6362
626.2.1.64/2626.2.1.65 to 26.2.1.12626.2.1.12762
726.2.1.128/2626.2.1.129 to 26.2.1.19026.2.1.19162
826.2.1.192/2626.2.1.193 to 26.2.1.25426.2.1.25562
926.2.2.0/2626.2.2.1 to 26.2.2.6226.2.2.6362
1026.2.2.64/2626.2.2.65 to 26.2.2.12626.2.2.12762
1126.2.2.128/2626.2.2.129 to 26.2.2.19026.2.2.19162
1226.2.2.192/2626.2.2.193 to 26.2.2.25426.2.2.25562
1326.2.3.0/2626.2.3.1 to 26.2.3.6226.2.3.6362
1426.2.3.64/2626.2.3.65 to 26.2.3.12626.2.3.12762
1526.2.3.128/2626.2.3.129 to 26.2.3.19026.2.3.19162
1626.2.3.192/2626.2.3.193 to 26.2.3.25426.2.3.25562
1726.2.4.0/2626.2.4.1 to 26.2.4.6226.2.4.6362
1826.2.4.64/2626.2.4.65 to 26.2.4.12626.2.4.12762
1926.2.4.128/2626.2.4.129 to 26.2.4.19026.2.4.19162
2026.2.4.192/2626.2.4.193 to 26.2.4.25426.2.4.25562
2126.2.5.0/2626.2.5.1 to 26.2.5.6226.2.5.6362
2226.2.5.64/2626.2.5.65 to 26.2.5.12626.2.5.12762
2326.2.5.128/2626.2.5.129 to 26.2.5.19026.2.5.19162
2426.2.5.192/2626.2.5.193 to 26.2.5.25426.2.5.25562
2526.2.6.0/2626.2.6.1 to 26.2.6.6226.2.6.6362
2626.2.6.64/2626.2.6.65 to 26.2.6.12626.2.6.12762
2726.2.6.128/2626.2.6.129 to 26.2.6.19026.2.6.19162
2826.2.6.192/2626.2.6.193 to 26.2.6.25426.2.6.25562
2926.2.7.0/2626.2.7.1 to 26.2.7.6226.2.7.6362
3026.2.7.64/2626.2.7.65 to 26.2.7.12626.2.7.12762
3126.2.7.128/2626.2.7.129 to 26.2.7.19026.2.7.19162
3226.2.7.192/2626.2.7.193 to 26.2.7.25426.2.7.25562
3326.2.8.0/2626.2.8.1 to 26.2.8.6226.2.8.6362
3426.2.8.64/2626.2.8.65 to 26.2.8.12626.2.8.12762
3526.2.8.128/2626.2.8.129 to 26.2.8.19026.2.8.19162
3626.2.8.192/2626.2.8.193 to 26.2.8.25426.2.8.25562
3726.2.9.0/2626.2.9.1 to 26.2.9.6226.2.9.6362
3826.2.9.64/2626.2.9.65 to 26.2.9.12626.2.9.12762
3926.2.9.128/2626.2.9.129 to 26.2.9.19026.2.9.19162
4026.2.9.192/2626.2.9.193 to 26.2.9.25426.2.9.25562
4126.2.10.0/2626.2.10.1 to 26.2.10.6226.2.10.6362
4226.2.10.64/2626.2.10.65 to 26.2.10.12626.2.10.12762
4326.2.10.128/2626.2.10.129 to 26.2.10.19026.2.10.19162
4426.2.10.192/2626.2.10.193 to 26.2.10.25426.2.10.25562
4526.2.11.0/2626.2.11.1 to 26.2.11.6226.2.11.6362
4626.2.11.64/2626.2.11.65 to 26.2.11.12626.2.11.12762
4726.2.11.128/2626.2.11.129 to 26.2.11.19026.2.11.19162
4826.2.11.192/2626.2.11.193 to 26.2.11.25426.2.11.25562
4926.2.12.0/2626.2.12.1 to 26.2.12.6226.2.12.6362
5026.2.12.64/2626.2.12.65 to 26.2.12.12626.2.12.12762
5126.2.12.128/2626.2.12.129 to 26.2.12.19026.2.12.19162
5226.2.12.192/2626.2.12.193 to 26.2.12.25426.2.12.25562
5326.2.13.0/2626.2.13.1 to 26.2.13.6226.2.13.6362
5426.2.13.64/2626.2.13.65 to 26.2.13.12626.2.13.12762
5526.2.13.128/2626.2.13.129 to 26.2.13.19026.2.13.19162
5626.2.13.192/2626.2.13.193 to 26.2.13.25426.2.13.25562
5726.2.14.0/2626.2.14.1 to 26.2.14.6226.2.14.6362
5826.2.14.64/2626.2.14.65 to 26.2.14.12626.2.14.12762
5926.2.14.128/2626.2.14.129 to 26.2.14.19026.2.14.19162
6026.2.14.192/2626.2.14.193 to 26.2.14.25426.2.14.25562
6126.2.15.0/2626.2.15.1 to 26.2.15.6226.2.15.6362
6226.2.15.64/2626.2.15.65 to 26.2.15.12626.2.15.12762
6326.2.15.128/2626.2.15.129 to 26.2.15.19026.2.15.19162
6426.2.15.192/2626.2.15.193 to 26.2.15.25426.2.15.25562
6526.2.16.0/2626.2.16.1 to 26.2.16.6226.2.16.6362
6626.2.16.64/2626.2.16.65 to 26.2.16.12626.2.16.12762
6726.2.16.128/2626.2.16.129 to 26.2.16.19026.2.16.19162
6826.2.16.192/2626.2.16.193 to 26.2.16.25426.2.16.25562
6926.2.17.0/2626.2.17.1 to 26.2.17.6226.2.17.6362
7026.2.17.64/2626.2.17.65 to 26.2.17.12626.2.17.12762
7126.2.17.128/2626.2.17.129 to 26.2.17.19026.2.17.19162
7226.2.17.192/2626.2.17.193 to 26.2.17.25426.2.17.25562
7326.2.18.0/2626.2.18.1 to 26.2.18.6226.2.18.6362
7426.2.18.64/2626.2.18.65 to 26.2.18.12626.2.18.12762
7526.2.18.128/2626.2.18.129 to 26.2.18.19026.2.18.19162
7626.2.18.192/2626.2.18.193 to 26.2.18.25426.2.18.25562
7726.2.19.0/2626.2.19.1 to 26.2.19.6226.2.19.6362
7826.2.19.64/2626.2.19.65 to 26.2.19.12626.2.19.12762
7926.2.19.128/2626.2.19.129 to 26.2.19.19026.2.19.19162
8026.2.19.192/2626.2.19.193 to 26.2.19.25426.2.19.25562
8126.2.20.0/2626.2.20.1 to 26.2.20.6226.2.20.6362
8226.2.20.64/2626.2.20.65 to 26.2.20.12626.2.20.12762
8326.2.20.128/2626.2.20.129 to 26.2.20.19026.2.20.19162
8426.2.20.192/2626.2.20.193 to 26.2.20.25426.2.20.25562
8526.2.21.0/2626.2.21.1 to 26.2.21.6226.2.21.6362
8626.2.21.64/2626.2.21.65 to 26.2.21.12626.2.21.12762
8726.2.21.128/2626.2.21.129 to 26.2.21.19026.2.21.19162
8826.2.21.192/2626.2.21.193 to 26.2.21.25426.2.21.25562
8926.2.22.0/2626.2.22.1 to 26.2.22.6226.2.22.6362
9026.2.22.64/2626.2.22.65 to 26.2.22.12626.2.22.12762
9126.2.22.128/2626.2.22.129 to 26.2.22.19026.2.22.19162
9226.2.22.192/2626.2.22.193 to 26.2.22.25426.2.22.25562
9326.2.23.0/2626.2.23.1 to 26.2.23.6226.2.23.6362
9426.2.23.64/2626.2.23.65 to 26.2.23.12626.2.23.12762
9526.2.23.128/2626.2.23.129 to 26.2.23.19026.2.23.19162
9626.2.23.192/2626.2.23.193 to 26.2.23.25426.2.23.25562
9726.2.24.0/2626.2.24.1 to 26.2.24.6226.2.24.6362
9826.2.24.64/2626.2.24.65 to 26.2.24.12626.2.24.12762
9926.2.24.128/2626.2.24.129 to 26.2.24.19026.2.24.19162
10026.2.24.192/2626.2.24.193 to 26.2.24.25426.2.24.25562
10126.2.25.0/2626.2.25.1 to 26.2.25.6226.2.25.6362
10226.2.25.64/2626.2.25.65 to 26.2.25.12626.2.25.12762
10326.2.25.128/2626.2.25.129 to 26.2.25.19026.2.25.19162
10426.2.25.192/2626.2.25.193 to 26.2.25.25426.2.25.25562
10526.2.26.0/2626.2.26.1 to 26.2.26.6226.2.26.6362
10626.2.26.64/2626.2.26.65 to 26.2.26.12626.2.26.12762
10726.2.26.128/2626.2.26.129 to 26.2.26.19026.2.26.19162
10826.2.26.192/2626.2.26.193 to 26.2.26.25426.2.26.25562
10926.2.27.0/2626.2.27.1 to 26.2.27.6226.2.27.6362
11026.2.27.64/2626.2.27.65 to 26.2.27.12626.2.27.12762
11126.2.27.128/2626.2.27.129 to 26.2.27.19026.2.27.19162
11226.2.27.192/2626.2.27.193 to 26.2.27.25426.2.27.25562
11326.2.28.0/2626.2.28.1 to 26.2.28.6226.2.28.6362
11426.2.28.64/2626.2.28.65 to 26.2.28.12626.2.28.12762
11526.2.28.128/2626.2.28.129 to 26.2.28.19026.2.28.19162
11626.2.28.192/2626.2.28.193 to 26.2.28.25426.2.28.25562
11726.2.29.0/2626.2.29.1 to 26.2.29.6226.2.29.6362
11826.2.29.64/2626.2.29.65 to 26.2.29.12626.2.29.12762
11926.2.29.128/2626.2.29.129 to 26.2.29.19026.2.29.19162
12026.2.29.192/2626.2.29.193 to 26.2.29.25426.2.29.25562
12126.2.30.0/2626.2.30.1 to 26.2.30.6226.2.30.6362
12226.2.30.64/2626.2.30.65 to 26.2.30.12626.2.30.12762
12326.2.30.128/2626.2.30.129 to 26.2.30.19026.2.30.19162
12426.2.30.192/2626.2.30.193 to 26.2.30.25426.2.30.25562
12526.2.31.0/2626.2.31.1 to 26.2.31.6226.2.31.6362
12626.2.31.64/2626.2.31.65 to 26.2.31.12626.2.31.12762
12726.2.31.128/2626.2.31.129 to 26.2.31.19026.2.31.19162
12826.2.31.192/2626.2.31.193 to 26.2.31.25426.2.31.25562

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.