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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.

Network90.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
90.0.0.0
Broadcast address
90.127.255.255
First usable
90.0.0.1
Last usable
90.127.255.254
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 5A000000 · Integer 1509949440 to 1518338047
Reverse DNS zones
0.90.in-addr.arpa
1.90.in-addr.arpa
2.90.in-addr.arpa
3.90.in-addr.arpa
4.90.in-addr.arpa
5.90.in-addr.arpa
6.90.in-addr.arpa
7.90.in-addr.arpa
8.90.in-addr.arpa
9.90.in-addr.arpa
10.90.in-addr.arpa
11.90.in-addr.arpa
12.90.in-addr.arpa
13.90.in-addr.arpa
14.90.in-addr.arpa
15.90.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
Address01011010.00000000.00000000.0000000090.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01011010.00000000.00000000.0000000090.0.0.0
Broadcast01011010.01111111.11111111.1111111190.127.255.255
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)

90.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
190.0.0.0/1690.0.0.1 to 90.0.255.25490.0.255.25565,534
290.1.0.0/1690.1.0.1 to 90.1.255.25490.1.255.25565,534
390.2.0.0/1690.2.0.1 to 90.2.255.25490.2.255.25565,534
490.3.0.0/1690.3.0.1 to 90.3.255.25490.3.255.25565,534
590.4.0.0/1690.4.0.1 to 90.4.255.25490.4.255.25565,534
690.5.0.0/1690.5.0.1 to 90.5.255.25490.5.255.25565,534
790.6.0.0/1690.6.0.1 to 90.6.255.25490.6.255.25565,534
890.7.0.0/1690.7.0.1 to 90.7.255.25490.7.255.25565,534
990.8.0.0/1690.8.0.1 to 90.8.255.25490.8.255.25565,534
1090.9.0.0/1690.9.0.1 to 90.9.255.25490.9.255.25565,534
1190.10.0.0/1690.10.0.1 to 90.10.255.25490.10.255.25565,534
1290.11.0.0/1690.11.0.1 to 90.11.255.25490.11.255.25565,534
1390.12.0.0/1690.12.0.1 to 90.12.255.25490.12.255.25565,534
1490.13.0.0/1690.13.0.1 to 90.13.255.25490.13.255.25565,534
1590.14.0.0/1690.14.0.1 to 90.14.255.25490.14.255.25565,534
1690.15.0.0/1690.15.0.1 to 90.15.255.25490.15.255.25565,534
1790.16.0.0/1690.16.0.1 to 90.16.255.25490.16.255.25565,534
1890.17.0.0/1690.17.0.1 to 90.17.255.25490.17.255.25565,534
1990.18.0.0/1690.18.0.1 to 90.18.255.25490.18.255.25565,534
2090.19.0.0/1690.19.0.1 to 90.19.255.25490.19.255.25565,534
2190.20.0.0/1690.20.0.1 to 90.20.255.25490.20.255.25565,534
2290.21.0.0/1690.21.0.1 to 90.21.255.25490.21.255.25565,534
2390.22.0.0/1690.22.0.1 to 90.22.255.25490.22.255.25565,534
2490.23.0.0/1690.23.0.1 to 90.23.255.25490.23.255.25565,534
2590.24.0.0/1690.24.0.1 to 90.24.255.25490.24.255.25565,534
2690.25.0.0/1690.25.0.1 to 90.25.255.25490.25.255.25565,534
2790.26.0.0/1690.26.0.1 to 90.26.255.25490.26.255.25565,534
2890.27.0.0/1690.27.0.1 to 90.27.255.25490.27.255.25565,534
2990.28.0.0/1690.28.0.1 to 90.28.255.25490.28.255.25565,534
3090.29.0.0/1690.29.0.1 to 90.29.255.25490.29.255.25565,534
3190.30.0.0/1690.30.0.1 to 90.30.255.25490.30.255.25565,534
3290.31.0.0/1690.31.0.1 to 90.31.255.25490.31.255.25565,534
3390.32.0.0/1690.32.0.1 to 90.32.255.25490.32.255.25565,534
3490.33.0.0/1690.33.0.1 to 90.33.255.25490.33.255.25565,534
3590.34.0.0/1690.34.0.1 to 90.34.255.25490.34.255.25565,534
3690.35.0.0/1690.35.0.1 to 90.35.255.25490.35.255.25565,534
3790.36.0.0/1690.36.0.1 to 90.36.255.25490.36.255.25565,534
3890.37.0.0/1690.37.0.1 to 90.37.255.25490.37.255.25565,534
3990.38.0.0/1690.38.0.1 to 90.38.255.25490.38.255.25565,534
4090.39.0.0/1690.39.0.1 to 90.39.255.25490.39.255.25565,534
4190.40.0.0/1690.40.0.1 to 90.40.255.25490.40.255.25565,534
4290.41.0.0/1690.41.0.1 to 90.41.255.25490.41.255.25565,534
4390.42.0.0/1690.42.0.1 to 90.42.255.25490.42.255.25565,534
4490.43.0.0/1690.43.0.1 to 90.43.255.25490.43.255.25565,534
4590.44.0.0/1690.44.0.1 to 90.44.255.25490.44.255.25565,534
4690.45.0.0/1690.45.0.1 to 90.45.255.25490.45.255.25565,534
4790.46.0.0/1690.46.0.1 to 90.46.255.25490.46.255.25565,534
4890.47.0.0/1690.47.0.1 to 90.47.255.25490.47.255.25565,534
4990.48.0.0/1690.48.0.1 to 90.48.255.25490.48.255.25565,534
5090.49.0.0/1690.49.0.1 to 90.49.255.25490.49.255.25565,534
5190.50.0.0/1690.50.0.1 to 90.50.255.25490.50.255.25565,534
5290.51.0.0/1690.51.0.1 to 90.51.255.25490.51.255.25565,534
5390.52.0.0/1690.52.0.1 to 90.52.255.25490.52.255.25565,534
5490.53.0.0/1690.53.0.1 to 90.53.255.25490.53.255.25565,534
5590.54.0.0/1690.54.0.1 to 90.54.255.25490.54.255.25565,534
5690.55.0.0/1690.55.0.1 to 90.55.255.25490.55.255.25565,534
5790.56.0.0/1690.56.0.1 to 90.56.255.25490.56.255.25565,534
5890.57.0.0/1690.57.0.1 to 90.57.255.25490.57.255.25565,534
5990.58.0.0/1690.58.0.1 to 90.58.255.25490.58.255.25565,534
6090.59.0.0/1690.59.0.1 to 90.59.255.25490.59.255.25565,534
6190.60.0.0/1690.60.0.1 to 90.60.255.25490.60.255.25565,534
6290.61.0.0/1690.61.0.1 to 90.61.255.25490.61.255.25565,534
6390.62.0.0/1690.62.0.1 to 90.62.255.25490.62.255.25565,534
6490.63.0.0/1690.63.0.1 to 90.63.255.25490.63.255.25565,534
6590.64.0.0/1690.64.0.1 to 90.64.255.25490.64.255.25565,534
6690.65.0.0/1690.65.0.1 to 90.65.255.25490.65.255.25565,534
6790.66.0.0/1690.66.0.1 to 90.66.255.25490.66.255.25565,534
6890.67.0.0/1690.67.0.1 to 90.67.255.25490.67.255.25565,534
6990.68.0.0/1690.68.0.1 to 90.68.255.25490.68.255.25565,534
7090.69.0.0/1690.69.0.1 to 90.69.255.25490.69.255.25565,534
7190.70.0.0/1690.70.0.1 to 90.70.255.25490.70.255.25565,534
7290.71.0.0/1690.71.0.1 to 90.71.255.25490.71.255.25565,534
7390.72.0.0/1690.72.0.1 to 90.72.255.25490.72.255.25565,534
7490.73.0.0/1690.73.0.1 to 90.73.255.25490.73.255.25565,534
7590.74.0.0/1690.74.0.1 to 90.74.255.25490.74.255.25565,534
7690.75.0.0/1690.75.0.1 to 90.75.255.25490.75.255.25565,534
7790.76.0.0/1690.76.0.1 to 90.76.255.25490.76.255.25565,534
7890.77.0.0/1690.77.0.1 to 90.77.255.25490.77.255.25565,534
7990.78.0.0/1690.78.0.1 to 90.78.255.25490.78.255.25565,534
8090.79.0.0/1690.79.0.1 to 90.79.255.25490.79.255.25565,534
8190.80.0.0/1690.80.0.1 to 90.80.255.25490.80.255.25565,534
8290.81.0.0/1690.81.0.1 to 90.81.255.25490.81.255.25565,534
8390.82.0.0/1690.82.0.1 to 90.82.255.25490.82.255.25565,534
8490.83.0.0/1690.83.0.1 to 90.83.255.25490.83.255.25565,534
8590.84.0.0/1690.84.0.1 to 90.84.255.25490.84.255.25565,534
8690.85.0.0/1690.85.0.1 to 90.85.255.25490.85.255.25565,534
8790.86.0.0/1690.86.0.1 to 90.86.255.25490.86.255.25565,534
8890.87.0.0/1690.87.0.1 to 90.87.255.25490.87.255.25565,534
8990.88.0.0/1690.88.0.1 to 90.88.255.25490.88.255.25565,534
9090.89.0.0/1690.89.0.1 to 90.89.255.25490.89.255.25565,534
9190.90.0.0/1690.90.0.1 to 90.90.255.25490.90.255.25565,534
9290.91.0.0/1690.91.0.1 to 90.91.255.25490.91.255.25565,534
9390.92.0.0/1690.92.0.1 to 90.92.255.25490.92.255.25565,534
9490.93.0.0/1690.93.0.1 to 90.93.255.25490.93.255.25565,534
9590.94.0.0/1690.94.0.1 to 90.94.255.25490.94.255.25565,534
9690.95.0.0/1690.95.0.1 to 90.95.255.25490.95.255.25565,534
9790.96.0.0/1690.96.0.1 to 90.96.255.25490.96.255.25565,534
9890.97.0.0/1690.97.0.1 to 90.97.255.25490.97.255.25565,534
9990.98.0.0/1690.98.0.1 to 90.98.255.25490.98.255.25565,534
10090.99.0.0/1690.99.0.1 to 90.99.255.25490.99.255.25565,534
10190.100.0.0/1690.100.0.1 to 90.100.255.25490.100.255.25565,534
10290.101.0.0/1690.101.0.1 to 90.101.255.25490.101.255.25565,534
10390.102.0.0/1690.102.0.1 to 90.102.255.25490.102.255.25565,534
10490.103.0.0/1690.103.0.1 to 90.103.255.25490.103.255.25565,534
10590.104.0.0/1690.104.0.1 to 90.104.255.25490.104.255.25565,534
10690.105.0.0/1690.105.0.1 to 90.105.255.25490.105.255.25565,534
10790.106.0.0/1690.106.0.1 to 90.106.255.25490.106.255.25565,534
10890.107.0.0/1690.107.0.1 to 90.107.255.25490.107.255.25565,534
10990.108.0.0/1690.108.0.1 to 90.108.255.25490.108.255.25565,534
11090.109.0.0/1690.109.0.1 to 90.109.255.25490.109.255.25565,534
11190.110.0.0/1690.110.0.1 to 90.110.255.25490.110.255.25565,534
11290.111.0.0/1690.111.0.1 to 90.111.255.25490.111.255.25565,534
11390.112.0.0/1690.112.0.1 to 90.112.255.25490.112.255.25565,534
11490.113.0.0/1690.113.0.1 to 90.113.255.25490.113.255.25565,534
11590.114.0.0/1690.114.0.1 to 90.114.255.25490.114.255.25565,534
11690.115.0.0/1690.115.0.1 to 90.115.255.25490.115.255.25565,534
11790.116.0.0/1690.116.0.1 to 90.116.255.25490.116.255.25565,534
11890.117.0.0/1690.117.0.1 to 90.117.255.25490.117.255.25565,534
11990.118.0.0/1690.118.0.1 to 90.118.255.25490.118.255.25565,534
12090.119.0.0/1690.119.0.1 to 90.119.255.25490.119.255.25565,534
12190.120.0.0/1690.120.0.1 to 90.120.255.25490.120.255.25565,534
12290.121.0.0/1690.121.0.1 to 90.121.255.25490.121.255.25565,534
12390.122.0.0/1690.122.0.1 to 90.122.255.25490.122.255.25565,534
12490.123.0.0/1690.123.0.1 to 90.123.255.25490.123.255.25565,534
12590.124.0.0/1690.124.0.1 to 90.124.255.25490.124.255.25565,534
12690.125.0.0/1690.125.0.1 to 90.125.255.25490.125.255.25565,534
12790.126.0.0/1690.126.0.1 to 90.126.255.25490.126.255.25565,534
12890.127.0.0/1690.127.0.1 to 90.127.255.25490.127.255.25565,534

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.