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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.

Network83.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
83.0.0.0
Broadcast address
83.127.255.255
First usable
83.0.0.1
Last usable
83.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 53000000 · Integer 1392508928 to 1400897535
Reverse DNS zones
0.83.in-addr.arpa
1.83.in-addr.arpa
2.83.in-addr.arpa
3.83.in-addr.arpa
4.83.in-addr.arpa
5.83.in-addr.arpa
6.83.in-addr.arpa
7.83.in-addr.arpa
8.83.in-addr.arpa
9.83.in-addr.arpa
10.83.in-addr.arpa
11.83.in-addr.arpa
12.83.in-addr.arpa
13.83.in-addr.arpa
14.83.in-addr.arpa
15.83.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010011.00000000.00000000.0000000083.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01010011.00000000.00000000.0000000083.0.0.0
Broadcast01010011.01111111.11111111.1111111183.127.255.255
Split into smaller subnets/16
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

83.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
183.0.0.0/1683.0.0.1 to 83.0.255.25483.0.255.25565,534
283.1.0.0/1683.1.0.1 to 83.1.255.25483.1.255.25565,534
383.2.0.0/1683.2.0.1 to 83.2.255.25483.2.255.25565,534
483.3.0.0/1683.3.0.1 to 83.3.255.25483.3.255.25565,534
583.4.0.0/1683.4.0.1 to 83.4.255.25483.4.255.25565,534
683.5.0.0/1683.5.0.1 to 83.5.255.25483.5.255.25565,534
783.6.0.0/1683.6.0.1 to 83.6.255.25483.6.255.25565,534
883.7.0.0/1683.7.0.1 to 83.7.255.25483.7.255.25565,534
983.8.0.0/1683.8.0.1 to 83.8.255.25483.8.255.25565,534
1083.9.0.0/1683.9.0.1 to 83.9.255.25483.9.255.25565,534
1183.10.0.0/1683.10.0.1 to 83.10.255.25483.10.255.25565,534
1283.11.0.0/1683.11.0.1 to 83.11.255.25483.11.255.25565,534
1383.12.0.0/1683.12.0.1 to 83.12.255.25483.12.255.25565,534
1483.13.0.0/1683.13.0.1 to 83.13.255.25483.13.255.25565,534
1583.14.0.0/1683.14.0.1 to 83.14.255.25483.14.255.25565,534
1683.15.0.0/1683.15.0.1 to 83.15.255.25483.15.255.25565,534
1783.16.0.0/1683.16.0.1 to 83.16.255.25483.16.255.25565,534
1883.17.0.0/1683.17.0.1 to 83.17.255.25483.17.255.25565,534
1983.18.0.0/1683.18.0.1 to 83.18.255.25483.18.255.25565,534
2083.19.0.0/1683.19.0.1 to 83.19.255.25483.19.255.25565,534
2183.20.0.0/1683.20.0.1 to 83.20.255.25483.20.255.25565,534
2283.21.0.0/1683.21.0.1 to 83.21.255.25483.21.255.25565,534
2383.22.0.0/1683.22.0.1 to 83.22.255.25483.22.255.25565,534
2483.23.0.0/1683.23.0.1 to 83.23.255.25483.23.255.25565,534
2583.24.0.0/1683.24.0.1 to 83.24.255.25483.24.255.25565,534
2683.25.0.0/1683.25.0.1 to 83.25.255.25483.25.255.25565,534
2783.26.0.0/1683.26.0.1 to 83.26.255.25483.26.255.25565,534
2883.27.0.0/1683.27.0.1 to 83.27.255.25483.27.255.25565,534
2983.28.0.0/1683.28.0.1 to 83.28.255.25483.28.255.25565,534
3083.29.0.0/1683.29.0.1 to 83.29.255.25483.29.255.25565,534
3183.30.0.0/1683.30.0.1 to 83.30.255.25483.30.255.25565,534
3283.31.0.0/1683.31.0.1 to 83.31.255.25483.31.255.25565,534
3383.32.0.0/1683.32.0.1 to 83.32.255.25483.32.255.25565,534
3483.33.0.0/1683.33.0.1 to 83.33.255.25483.33.255.25565,534
3583.34.0.0/1683.34.0.1 to 83.34.255.25483.34.255.25565,534
3683.35.0.0/1683.35.0.1 to 83.35.255.25483.35.255.25565,534
3783.36.0.0/1683.36.0.1 to 83.36.255.25483.36.255.25565,534
3883.37.0.0/1683.37.0.1 to 83.37.255.25483.37.255.25565,534
3983.38.0.0/1683.38.0.1 to 83.38.255.25483.38.255.25565,534
4083.39.0.0/1683.39.0.1 to 83.39.255.25483.39.255.25565,534
4183.40.0.0/1683.40.0.1 to 83.40.255.25483.40.255.25565,534
4283.41.0.0/1683.41.0.1 to 83.41.255.25483.41.255.25565,534
4383.42.0.0/1683.42.0.1 to 83.42.255.25483.42.255.25565,534
4483.43.0.0/1683.43.0.1 to 83.43.255.25483.43.255.25565,534
4583.44.0.0/1683.44.0.1 to 83.44.255.25483.44.255.25565,534
4683.45.0.0/1683.45.0.1 to 83.45.255.25483.45.255.25565,534
4783.46.0.0/1683.46.0.1 to 83.46.255.25483.46.255.25565,534
4883.47.0.0/1683.47.0.1 to 83.47.255.25483.47.255.25565,534
4983.48.0.0/1683.48.0.1 to 83.48.255.25483.48.255.25565,534
5083.49.0.0/1683.49.0.1 to 83.49.255.25483.49.255.25565,534
5183.50.0.0/1683.50.0.1 to 83.50.255.25483.50.255.25565,534
5283.51.0.0/1683.51.0.1 to 83.51.255.25483.51.255.25565,534
5383.52.0.0/1683.52.0.1 to 83.52.255.25483.52.255.25565,534
5483.53.0.0/1683.53.0.1 to 83.53.255.25483.53.255.25565,534
5583.54.0.0/1683.54.0.1 to 83.54.255.25483.54.255.25565,534
5683.55.0.0/1683.55.0.1 to 83.55.255.25483.55.255.25565,534
5783.56.0.0/1683.56.0.1 to 83.56.255.25483.56.255.25565,534
5883.57.0.0/1683.57.0.1 to 83.57.255.25483.57.255.25565,534
5983.58.0.0/1683.58.0.1 to 83.58.255.25483.58.255.25565,534
6083.59.0.0/1683.59.0.1 to 83.59.255.25483.59.255.25565,534
6183.60.0.0/1683.60.0.1 to 83.60.255.25483.60.255.25565,534
6283.61.0.0/1683.61.0.1 to 83.61.255.25483.61.255.25565,534
6383.62.0.0/1683.62.0.1 to 83.62.255.25483.62.255.25565,534
6483.63.0.0/1683.63.0.1 to 83.63.255.25483.63.255.25565,534
6583.64.0.0/1683.64.0.1 to 83.64.255.25483.64.255.25565,534
6683.65.0.0/1683.65.0.1 to 83.65.255.25483.65.255.25565,534
6783.66.0.0/1683.66.0.1 to 83.66.255.25483.66.255.25565,534
6883.67.0.0/1683.67.0.1 to 83.67.255.25483.67.255.25565,534
6983.68.0.0/1683.68.0.1 to 83.68.255.25483.68.255.25565,534
7083.69.0.0/1683.69.0.1 to 83.69.255.25483.69.255.25565,534
7183.70.0.0/1683.70.0.1 to 83.70.255.25483.70.255.25565,534
7283.71.0.0/1683.71.0.1 to 83.71.255.25483.71.255.25565,534
7383.72.0.0/1683.72.0.1 to 83.72.255.25483.72.255.25565,534
7483.73.0.0/1683.73.0.1 to 83.73.255.25483.73.255.25565,534
7583.74.0.0/1683.74.0.1 to 83.74.255.25483.74.255.25565,534
7683.75.0.0/1683.75.0.1 to 83.75.255.25483.75.255.25565,534
7783.76.0.0/1683.76.0.1 to 83.76.255.25483.76.255.25565,534
7883.77.0.0/1683.77.0.1 to 83.77.255.25483.77.255.25565,534
7983.78.0.0/1683.78.0.1 to 83.78.255.25483.78.255.25565,534
8083.79.0.0/1683.79.0.1 to 83.79.255.25483.79.255.25565,534
8183.80.0.0/1683.80.0.1 to 83.80.255.25483.80.255.25565,534
8283.81.0.0/1683.81.0.1 to 83.81.255.25483.81.255.25565,534
8383.82.0.0/1683.82.0.1 to 83.82.255.25483.82.255.25565,534
8483.83.0.0/1683.83.0.1 to 83.83.255.25483.83.255.25565,534
8583.84.0.0/1683.84.0.1 to 83.84.255.25483.84.255.25565,534
8683.85.0.0/1683.85.0.1 to 83.85.255.25483.85.255.25565,534
8783.86.0.0/1683.86.0.1 to 83.86.255.25483.86.255.25565,534
8883.87.0.0/1683.87.0.1 to 83.87.255.25483.87.255.25565,534
8983.88.0.0/1683.88.0.1 to 83.88.255.25483.88.255.25565,534
9083.89.0.0/1683.89.0.1 to 83.89.255.25483.89.255.25565,534
9183.90.0.0/1683.90.0.1 to 83.90.255.25483.90.255.25565,534
9283.91.0.0/1683.91.0.1 to 83.91.255.25483.91.255.25565,534
9383.92.0.0/1683.92.0.1 to 83.92.255.25483.92.255.25565,534
9483.93.0.0/1683.93.0.1 to 83.93.255.25483.93.255.25565,534
9583.94.0.0/1683.94.0.1 to 83.94.255.25483.94.255.25565,534
9683.95.0.0/1683.95.0.1 to 83.95.255.25483.95.255.25565,534
9783.96.0.0/1683.96.0.1 to 83.96.255.25483.96.255.25565,534
9883.97.0.0/1683.97.0.1 to 83.97.255.25483.97.255.25565,534
9983.98.0.0/1683.98.0.1 to 83.98.255.25483.98.255.25565,534
10083.99.0.0/1683.99.0.1 to 83.99.255.25483.99.255.25565,534
10183.100.0.0/1683.100.0.1 to 83.100.255.25483.100.255.25565,534
10283.101.0.0/1683.101.0.1 to 83.101.255.25483.101.255.25565,534
10383.102.0.0/1683.102.0.1 to 83.102.255.25483.102.255.25565,534
10483.103.0.0/1683.103.0.1 to 83.103.255.25483.103.255.25565,534
10583.104.0.0/1683.104.0.1 to 83.104.255.25483.104.255.25565,534
10683.105.0.0/1683.105.0.1 to 83.105.255.25483.105.255.25565,534
10783.106.0.0/1683.106.0.1 to 83.106.255.25483.106.255.25565,534
10883.107.0.0/1683.107.0.1 to 83.107.255.25483.107.255.25565,534
10983.108.0.0/1683.108.0.1 to 83.108.255.25483.108.255.25565,534
11083.109.0.0/1683.109.0.1 to 83.109.255.25483.109.255.25565,534
11183.110.0.0/1683.110.0.1 to 83.110.255.25483.110.255.25565,534
11283.111.0.0/1683.111.0.1 to 83.111.255.25483.111.255.25565,534
11383.112.0.0/1683.112.0.1 to 83.112.255.25483.112.255.25565,534
11483.113.0.0/1683.113.0.1 to 83.113.255.25483.113.255.25565,534
11583.114.0.0/1683.114.0.1 to 83.114.255.25483.114.255.25565,534
11683.115.0.0/1683.115.0.1 to 83.115.255.25483.115.255.25565,534
11783.116.0.0/1683.116.0.1 to 83.116.255.25483.116.255.25565,534
11883.117.0.0/1683.117.0.1 to 83.117.255.25483.117.255.25565,534
11983.118.0.0/1683.118.0.1 to 83.118.255.25483.118.255.25565,534
12083.119.0.0/1683.119.0.1 to 83.119.255.25483.119.255.25565,534
12183.120.0.0/1683.120.0.1 to 83.120.255.25483.120.255.25565,534
12283.121.0.0/1683.121.0.1 to 83.121.255.25483.121.255.25565,534
12383.122.0.0/1683.122.0.1 to 83.122.255.25483.122.255.25565,534
12483.123.0.0/1683.123.0.1 to 83.123.255.25483.123.255.25565,534
12583.124.0.0/1683.124.0.1 to 83.124.255.25483.124.255.25565,534
12683.125.0.0/1683.125.0.1 to 83.125.255.25483.125.255.25565,534
12783.126.0.0/1683.126.0.1 to 83.126.255.25483.126.255.25565,534
12883.127.0.0/1683.127.0.1 to 83.127.255.25483.127.255.25565,534

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.