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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.

Network26.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
26.64.0.0
Broadcast address
26.127.255.255
First usable
26.64.0.1
Last usable
26.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A400000 · Integer 440401920 to 444596223
Reverse DNS zones
64.26.in-addr.arpa
65.26.in-addr.arpa
66.26.in-addr.arpa
67.26.in-addr.arpa
68.26.in-addr.arpa
69.26.in-addr.arpa
70.26.in-addr.arpa
71.26.in-addr.arpa
72.26.in-addr.arpa
73.26.in-addr.arpa
74.26.in-addr.arpa
75.26.in-addr.arpa
76.26.in-addr.arpa
77.26.in-addr.arpa
78.26.in-addr.arpa
79.26.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.01000000.00000000.0000000026.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00011010.01000000.00000000.0000000026.64.0.0
Broadcast00011010.01111111.11111111.1111111126.127.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

26.64.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.64.0.0/1726.64.0.1 to 26.64.127.25426.64.127.25532,766
226.64.128.0/1726.64.128.1 to 26.64.255.25426.64.255.25532,766
326.65.0.0/1726.65.0.1 to 26.65.127.25426.65.127.25532,766
426.65.128.0/1726.65.128.1 to 26.65.255.25426.65.255.25532,766
526.66.0.0/1726.66.0.1 to 26.66.127.25426.66.127.25532,766
626.66.128.0/1726.66.128.1 to 26.66.255.25426.66.255.25532,766
726.67.0.0/1726.67.0.1 to 26.67.127.25426.67.127.25532,766
826.67.128.0/1726.67.128.1 to 26.67.255.25426.67.255.25532,766
926.68.0.0/1726.68.0.1 to 26.68.127.25426.68.127.25532,766
1026.68.128.0/1726.68.128.1 to 26.68.255.25426.68.255.25532,766
1126.69.0.0/1726.69.0.1 to 26.69.127.25426.69.127.25532,766
1226.69.128.0/1726.69.128.1 to 26.69.255.25426.69.255.25532,766
1326.70.0.0/1726.70.0.1 to 26.70.127.25426.70.127.25532,766
1426.70.128.0/1726.70.128.1 to 26.70.255.25426.70.255.25532,766
1526.71.0.0/1726.71.0.1 to 26.71.127.25426.71.127.25532,766
1626.71.128.0/1726.71.128.1 to 26.71.255.25426.71.255.25532,766
1726.72.0.0/1726.72.0.1 to 26.72.127.25426.72.127.25532,766
1826.72.128.0/1726.72.128.1 to 26.72.255.25426.72.255.25532,766
1926.73.0.0/1726.73.0.1 to 26.73.127.25426.73.127.25532,766
2026.73.128.0/1726.73.128.1 to 26.73.255.25426.73.255.25532,766
2126.74.0.0/1726.74.0.1 to 26.74.127.25426.74.127.25532,766
2226.74.128.0/1726.74.128.1 to 26.74.255.25426.74.255.25532,766
2326.75.0.0/1726.75.0.1 to 26.75.127.25426.75.127.25532,766
2426.75.128.0/1726.75.128.1 to 26.75.255.25426.75.255.25532,766
2526.76.0.0/1726.76.0.1 to 26.76.127.25426.76.127.25532,766
2626.76.128.0/1726.76.128.1 to 26.76.255.25426.76.255.25532,766
2726.77.0.0/1726.77.0.1 to 26.77.127.25426.77.127.25532,766
2826.77.128.0/1726.77.128.1 to 26.77.255.25426.77.255.25532,766
2926.78.0.0/1726.78.0.1 to 26.78.127.25426.78.127.25532,766
3026.78.128.0/1726.78.128.1 to 26.78.255.25426.78.255.25532,766
3126.79.0.0/1726.79.0.1 to 26.79.127.25426.79.127.25532,766
3226.79.128.0/1726.79.128.1 to 26.79.255.25426.79.255.25532,766
3326.80.0.0/1726.80.0.1 to 26.80.127.25426.80.127.25532,766
3426.80.128.0/1726.80.128.1 to 26.80.255.25426.80.255.25532,766
3526.81.0.0/1726.81.0.1 to 26.81.127.25426.81.127.25532,766
3626.81.128.0/1726.81.128.1 to 26.81.255.25426.81.255.25532,766
3726.82.0.0/1726.82.0.1 to 26.82.127.25426.82.127.25532,766
3826.82.128.0/1726.82.128.1 to 26.82.255.25426.82.255.25532,766
3926.83.0.0/1726.83.0.1 to 26.83.127.25426.83.127.25532,766
4026.83.128.0/1726.83.128.1 to 26.83.255.25426.83.255.25532,766
4126.84.0.0/1726.84.0.1 to 26.84.127.25426.84.127.25532,766
4226.84.128.0/1726.84.128.1 to 26.84.255.25426.84.255.25532,766
4326.85.0.0/1726.85.0.1 to 26.85.127.25426.85.127.25532,766
4426.85.128.0/1726.85.128.1 to 26.85.255.25426.85.255.25532,766
4526.86.0.0/1726.86.0.1 to 26.86.127.25426.86.127.25532,766
4626.86.128.0/1726.86.128.1 to 26.86.255.25426.86.255.25532,766
4726.87.0.0/1726.87.0.1 to 26.87.127.25426.87.127.25532,766
4826.87.128.0/1726.87.128.1 to 26.87.255.25426.87.255.25532,766
4926.88.0.0/1726.88.0.1 to 26.88.127.25426.88.127.25532,766
5026.88.128.0/1726.88.128.1 to 26.88.255.25426.88.255.25532,766
5126.89.0.0/1726.89.0.1 to 26.89.127.25426.89.127.25532,766
5226.89.128.0/1726.89.128.1 to 26.89.255.25426.89.255.25532,766
5326.90.0.0/1726.90.0.1 to 26.90.127.25426.90.127.25532,766
5426.90.128.0/1726.90.128.1 to 26.90.255.25426.90.255.25532,766
5526.91.0.0/1726.91.0.1 to 26.91.127.25426.91.127.25532,766
5626.91.128.0/1726.91.128.1 to 26.91.255.25426.91.255.25532,766
5726.92.0.0/1726.92.0.1 to 26.92.127.25426.92.127.25532,766
5826.92.128.0/1726.92.128.1 to 26.92.255.25426.92.255.25532,766
5926.93.0.0/1726.93.0.1 to 26.93.127.25426.93.127.25532,766
6026.93.128.0/1726.93.128.1 to 26.93.255.25426.93.255.25532,766
6126.94.0.0/1726.94.0.1 to 26.94.127.25426.94.127.25532,766
6226.94.128.0/1726.94.128.1 to 26.94.255.25426.94.255.25532,766
6326.95.0.0/1726.95.0.1 to 26.95.127.25426.95.127.25532,766
6426.95.128.0/1726.95.128.1 to 26.95.255.25426.95.255.25532,766
6526.96.0.0/1726.96.0.1 to 26.96.127.25426.96.127.25532,766
6626.96.128.0/1726.96.128.1 to 26.96.255.25426.96.255.25532,766
6726.97.0.0/1726.97.0.1 to 26.97.127.25426.97.127.25532,766
6826.97.128.0/1726.97.128.1 to 26.97.255.25426.97.255.25532,766
6926.98.0.0/1726.98.0.1 to 26.98.127.25426.98.127.25532,766
7026.98.128.0/1726.98.128.1 to 26.98.255.25426.98.255.25532,766
7126.99.0.0/1726.99.0.1 to 26.99.127.25426.99.127.25532,766
7226.99.128.0/1726.99.128.1 to 26.99.255.25426.99.255.25532,766
7326.100.0.0/1726.100.0.1 to 26.100.127.25426.100.127.25532,766
7426.100.128.0/1726.100.128.1 to 26.100.255.25426.100.255.25532,766
7526.101.0.0/1726.101.0.1 to 26.101.127.25426.101.127.25532,766
7626.101.128.0/1726.101.128.1 to 26.101.255.25426.101.255.25532,766
7726.102.0.0/1726.102.0.1 to 26.102.127.25426.102.127.25532,766
7826.102.128.0/1726.102.128.1 to 26.102.255.25426.102.255.25532,766
7926.103.0.0/1726.103.0.1 to 26.103.127.25426.103.127.25532,766
8026.103.128.0/1726.103.128.1 to 26.103.255.25426.103.255.25532,766
8126.104.0.0/1726.104.0.1 to 26.104.127.25426.104.127.25532,766
8226.104.128.0/1726.104.128.1 to 26.104.255.25426.104.255.25532,766
8326.105.0.0/1726.105.0.1 to 26.105.127.25426.105.127.25532,766
8426.105.128.0/1726.105.128.1 to 26.105.255.25426.105.255.25532,766
8526.106.0.0/1726.106.0.1 to 26.106.127.25426.106.127.25532,766
8626.106.128.0/1726.106.128.1 to 26.106.255.25426.106.255.25532,766
8726.107.0.0/1726.107.0.1 to 26.107.127.25426.107.127.25532,766
8826.107.128.0/1726.107.128.1 to 26.107.255.25426.107.255.25532,766
8926.108.0.0/1726.108.0.1 to 26.108.127.25426.108.127.25532,766
9026.108.128.0/1726.108.128.1 to 26.108.255.25426.108.255.25532,766
9126.109.0.0/1726.109.0.1 to 26.109.127.25426.109.127.25532,766
9226.109.128.0/1726.109.128.1 to 26.109.255.25426.109.255.25532,766
9326.110.0.0/1726.110.0.1 to 26.110.127.25426.110.127.25532,766
9426.110.128.0/1726.110.128.1 to 26.110.255.25426.110.255.25532,766
9526.111.0.0/1726.111.0.1 to 26.111.127.25426.111.127.25532,766
9626.111.128.0/1726.111.128.1 to 26.111.255.25426.111.255.25532,766
9726.112.0.0/1726.112.0.1 to 26.112.127.25426.112.127.25532,766
9826.112.128.0/1726.112.128.1 to 26.112.255.25426.112.255.25532,766
9926.113.0.0/1726.113.0.1 to 26.113.127.25426.113.127.25532,766
10026.113.128.0/1726.113.128.1 to 26.113.255.25426.113.255.25532,766
10126.114.0.0/1726.114.0.1 to 26.114.127.25426.114.127.25532,766
10226.114.128.0/1726.114.128.1 to 26.114.255.25426.114.255.25532,766
10326.115.0.0/1726.115.0.1 to 26.115.127.25426.115.127.25532,766
10426.115.128.0/1726.115.128.1 to 26.115.255.25426.115.255.25532,766
10526.116.0.0/1726.116.0.1 to 26.116.127.25426.116.127.25532,766
10626.116.128.0/1726.116.128.1 to 26.116.255.25426.116.255.25532,766
10726.117.0.0/1726.117.0.1 to 26.117.127.25426.117.127.25532,766
10826.117.128.0/1726.117.128.1 to 26.117.255.25426.117.255.25532,766
10926.118.0.0/1726.118.0.1 to 26.118.127.25426.118.127.25532,766
11026.118.128.0/1726.118.128.1 to 26.118.255.25426.118.255.25532,766
11126.119.0.0/1726.119.0.1 to 26.119.127.25426.119.127.25532,766
11226.119.128.0/1726.119.128.1 to 26.119.255.25426.119.255.25532,766
11326.120.0.0/1726.120.0.1 to 26.120.127.25426.120.127.25532,766
11426.120.128.0/1726.120.128.1 to 26.120.255.25426.120.255.25532,766
11526.121.0.0/1726.121.0.1 to 26.121.127.25426.121.127.25532,766
11626.121.128.0/1726.121.128.1 to 26.121.255.25426.121.255.25532,766
11726.122.0.0/1726.122.0.1 to 26.122.127.25426.122.127.25532,766
11826.122.128.0/1726.122.128.1 to 26.122.255.25426.122.255.25532,766
11926.123.0.0/1726.123.0.1 to 26.123.127.25426.123.127.25532,766
12026.123.128.0/1726.123.128.1 to 26.123.255.25426.123.255.25532,766
12126.124.0.0/1726.124.0.1 to 26.124.127.25426.124.127.25532,766
12226.124.128.0/1726.124.128.1 to 26.124.255.25426.124.255.25532,766
12326.125.0.0/1726.125.0.1 to 26.125.127.25426.125.127.25532,766
12426.125.128.0/1726.125.128.1 to 26.125.255.25426.125.255.25532,766
12526.126.0.0/1726.126.0.1 to 26.126.127.25426.126.127.25532,766
12626.126.128.0/1726.126.128.1 to 26.126.255.25426.126.255.25532,766
12726.127.0.0/1726.127.0.1 to 26.127.127.25426.127.127.25532,766
12826.127.128.0/1726.127.128.1 to 26.127.255.25426.127.255.25532,766

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.