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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.

Network48.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
48.0.0.0
Broadcast address
48.127.255.255
First usable
48.0.0.1
Last usable
48.127.255.254
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 30000000 · Integer 805306368 to 813694975
Reverse DNS zones
0.48.in-addr.arpa
1.48.in-addr.arpa
2.48.in-addr.arpa
3.48.in-addr.arpa
4.48.in-addr.arpa
5.48.in-addr.arpa
6.48.in-addr.arpa
7.48.in-addr.arpa
8.48.in-addr.arpa
9.48.in-addr.arpa
10.48.in-addr.arpa
11.48.in-addr.arpa
12.48.in-addr.arpa
13.48.in-addr.arpa
14.48.in-addr.arpa
15.48.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
Address00110000.00000000.00000000.0000000048.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00110000.00000000.00000000.0000000048.0.0.0
Broadcast00110000.01111111.11111111.1111111148.127.255.255
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)

48.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
148.0.0.0/1648.0.0.1 to 48.0.255.25448.0.255.25565,534
248.1.0.0/1648.1.0.1 to 48.1.255.25448.1.255.25565,534
348.2.0.0/1648.2.0.1 to 48.2.255.25448.2.255.25565,534
448.3.0.0/1648.3.0.1 to 48.3.255.25448.3.255.25565,534
548.4.0.0/1648.4.0.1 to 48.4.255.25448.4.255.25565,534
648.5.0.0/1648.5.0.1 to 48.5.255.25448.5.255.25565,534
748.6.0.0/1648.6.0.1 to 48.6.255.25448.6.255.25565,534
848.7.0.0/1648.7.0.1 to 48.7.255.25448.7.255.25565,534
948.8.0.0/1648.8.0.1 to 48.8.255.25448.8.255.25565,534
1048.9.0.0/1648.9.0.1 to 48.9.255.25448.9.255.25565,534
1148.10.0.0/1648.10.0.1 to 48.10.255.25448.10.255.25565,534
1248.11.0.0/1648.11.0.1 to 48.11.255.25448.11.255.25565,534
1348.12.0.0/1648.12.0.1 to 48.12.255.25448.12.255.25565,534
1448.13.0.0/1648.13.0.1 to 48.13.255.25448.13.255.25565,534
1548.14.0.0/1648.14.0.1 to 48.14.255.25448.14.255.25565,534
1648.15.0.0/1648.15.0.1 to 48.15.255.25448.15.255.25565,534
1748.16.0.0/1648.16.0.1 to 48.16.255.25448.16.255.25565,534
1848.17.0.0/1648.17.0.1 to 48.17.255.25448.17.255.25565,534
1948.18.0.0/1648.18.0.1 to 48.18.255.25448.18.255.25565,534
2048.19.0.0/1648.19.0.1 to 48.19.255.25448.19.255.25565,534
2148.20.0.0/1648.20.0.1 to 48.20.255.25448.20.255.25565,534
2248.21.0.0/1648.21.0.1 to 48.21.255.25448.21.255.25565,534
2348.22.0.0/1648.22.0.1 to 48.22.255.25448.22.255.25565,534
2448.23.0.0/1648.23.0.1 to 48.23.255.25448.23.255.25565,534
2548.24.0.0/1648.24.0.1 to 48.24.255.25448.24.255.25565,534
2648.25.0.0/1648.25.0.1 to 48.25.255.25448.25.255.25565,534
2748.26.0.0/1648.26.0.1 to 48.26.255.25448.26.255.25565,534
2848.27.0.0/1648.27.0.1 to 48.27.255.25448.27.255.25565,534
2948.28.0.0/1648.28.0.1 to 48.28.255.25448.28.255.25565,534
3048.29.0.0/1648.29.0.1 to 48.29.255.25448.29.255.25565,534
3148.30.0.0/1648.30.0.1 to 48.30.255.25448.30.255.25565,534
3248.31.0.0/1648.31.0.1 to 48.31.255.25448.31.255.25565,534
3348.32.0.0/1648.32.0.1 to 48.32.255.25448.32.255.25565,534
3448.33.0.0/1648.33.0.1 to 48.33.255.25448.33.255.25565,534
3548.34.0.0/1648.34.0.1 to 48.34.255.25448.34.255.25565,534
3648.35.0.0/1648.35.0.1 to 48.35.255.25448.35.255.25565,534
3748.36.0.0/1648.36.0.1 to 48.36.255.25448.36.255.25565,534
3848.37.0.0/1648.37.0.1 to 48.37.255.25448.37.255.25565,534
3948.38.0.0/1648.38.0.1 to 48.38.255.25448.38.255.25565,534
4048.39.0.0/1648.39.0.1 to 48.39.255.25448.39.255.25565,534
4148.40.0.0/1648.40.0.1 to 48.40.255.25448.40.255.25565,534
4248.41.0.0/1648.41.0.1 to 48.41.255.25448.41.255.25565,534
4348.42.0.0/1648.42.0.1 to 48.42.255.25448.42.255.25565,534
4448.43.0.0/1648.43.0.1 to 48.43.255.25448.43.255.25565,534
4548.44.0.0/1648.44.0.1 to 48.44.255.25448.44.255.25565,534
4648.45.0.0/1648.45.0.1 to 48.45.255.25448.45.255.25565,534
4748.46.0.0/1648.46.0.1 to 48.46.255.25448.46.255.25565,534
4848.47.0.0/1648.47.0.1 to 48.47.255.25448.47.255.25565,534
4948.48.0.0/1648.48.0.1 to 48.48.255.25448.48.255.25565,534
5048.49.0.0/1648.49.0.1 to 48.49.255.25448.49.255.25565,534
5148.50.0.0/1648.50.0.1 to 48.50.255.25448.50.255.25565,534
5248.51.0.0/1648.51.0.1 to 48.51.255.25448.51.255.25565,534
5348.52.0.0/1648.52.0.1 to 48.52.255.25448.52.255.25565,534
5448.53.0.0/1648.53.0.1 to 48.53.255.25448.53.255.25565,534
5548.54.0.0/1648.54.0.1 to 48.54.255.25448.54.255.25565,534
5648.55.0.0/1648.55.0.1 to 48.55.255.25448.55.255.25565,534
5748.56.0.0/1648.56.0.1 to 48.56.255.25448.56.255.25565,534
5848.57.0.0/1648.57.0.1 to 48.57.255.25448.57.255.25565,534
5948.58.0.0/1648.58.0.1 to 48.58.255.25448.58.255.25565,534
6048.59.0.0/1648.59.0.1 to 48.59.255.25448.59.255.25565,534
6148.60.0.0/1648.60.0.1 to 48.60.255.25448.60.255.25565,534
6248.61.0.0/1648.61.0.1 to 48.61.255.25448.61.255.25565,534
6348.62.0.0/1648.62.0.1 to 48.62.255.25448.62.255.25565,534
6448.63.0.0/1648.63.0.1 to 48.63.255.25448.63.255.25565,534
6548.64.0.0/1648.64.0.1 to 48.64.255.25448.64.255.25565,534
6648.65.0.0/1648.65.0.1 to 48.65.255.25448.65.255.25565,534
6748.66.0.0/1648.66.0.1 to 48.66.255.25448.66.255.25565,534
6848.67.0.0/1648.67.0.1 to 48.67.255.25448.67.255.25565,534
6948.68.0.0/1648.68.0.1 to 48.68.255.25448.68.255.25565,534
7048.69.0.0/1648.69.0.1 to 48.69.255.25448.69.255.25565,534
7148.70.0.0/1648.70.0.1 to 48.70.255.25448.70.255.25565,534
7248.71.0.0/1648.71.0.1 to 48.71.255.25448.71.255.25565,534
7348.72.0.0/1648.72.0.1 to 48.72.255.25448.72.255.25565,534
7448.73.0.0/1648.73.0.1 to 48.73.255.25448.73.255.25565,534
7548.74.0.0/1648.74.0.1 to 48.74.255.25448.74.255.25565,534
7648.75.0.0/1648.75.0.1 to 48.75.255.25448.75.255.25565,534
7748.76.0.0/1648.76.0.1 to 48.76.255.25448.76.255.25565,534
7848.77.0.0/1648.77.0.1 to 48.77.255.25448.77.255.25565,534
7948.78.0.0/1648.78.0.1 to 48.78.255.25448.78.255.25565,534
8048.79.0.0/1648.79.0.1 to 48.79.255.25448.79.255.25565,534
8148.80.0.0/1648.80.0.1 to 48.80.255.25448.80.255.25565,534
8248.81.0.0/1648.81.0.1 to 48.81.255.25448.81.255.25565,534
8348.82.0.0/1648.82.0.1 to 48.82.255.25448.82.255.25565,534
8448.83.0.0/1648.83.0.1 to 48.83.255.25448.83.255.25565,534
8548.84.0.0/1648.84.0.1 to 48.84.255.25448.84.255.25565,534
8648.85.0.0/1648.85.0.1 to 48.85.255.25448.85.255.25565,534
8748.86.0.0/1648.86.0.1 to 48.86.255.25448.86.255.25565,534
8848.87.0.0/1648.87.0.1 to 48.87.255.25448.87.255.25565,534
8948.88.0.0/1648.88.0.1 to 48.88.255.25448.88.255.25565,534
9048.89.0.0/1648.89.0.1 to 48.89.255.25448.89.255.25565,534
9148.90.0.0/1648.90.0.1 to 48.90.255.25448.90.255.25565,534
9248.91.0.0/1648.91.0.1 to 48.91.255.25448.91.255.25565,534
9348.92.0.0/1648.92.0.1 to 48.92.255.25448.92.255.25565,534
9448.93.0.0/1648.93.0.1 to 48.93.255.25448.93.255.25565,534
9548.94.0.0/1648.94.0.1 to 48.94.255.25448.94.255.25565,534
9648.95.0.0/1648.95.0.1 to 48.95.255.25448.95.255.25565,534
9748.96.0.0/1648.96.0.1 to 48.96.255.25448.96.255.25565,534
9848.97.0.0/1648.97.0.1 to 48.97.255.25448.97.255.25565,534
9948.98.0.0/1648.98.0.1 to 48.98.255.25448.98.255.25565,534
10048.99.0.0/1648.99.0.1 to 48.99.255.25448.99.255.25565,534
10148.100.0.0/1648.100.0.1 to 48.100.255.25448.100.255.25565,534
10248.101.0.0/1648.101.0.1 to 48.101.255.25448.101.255.25565,534
10348.102.0.0/1648.102.0.1 to 48.102.255.25448.102.255.25565,534
10448.103.0.0/1648.103.0.1 to 48.103.255.25448.103.255.25565,534
10548.104.0.0/1648.104.0.1 to 48.104.255.25448.104.255.25565,534
10648.105.0.0/1648.105.0.1 to 48.105.255.25448.105.255.25565,534
10748.106.0.0/1648.106.0.1 to 48.106.255.25448.106.255.25565,534
10848.107.0.0/1648.107.0.1 to 48.107.255.25448.107.255.25565,534
10948.108.0.0/1648.108.0.1 to 48.108.255.25448.108.255.25565,534
11048.109.0.0/1648.109.0.1 to 48.109.255.25448.109.255.25565,534
11148.110.0.0/1648.110.0.1 to 48.110.255.25448.110.255.25565,534
11248.111.0.0/1648.111.0.1 to 48.111.255.25448.111.255.25565,534
11348.112.0.0/1648.112.0.1 to 48.112.255.25448.112.255.25565,534
11448.113.0.0/1648.113.0.1 to 48.113.255.25448.113.255.25565,534
11548.114.0.0/1648.114.0.1 to 48.114.255.25448.114.255.25565,534
11648.115.0.0/1648.115.0.1 to 48.115.255.25448.115.255.25565,534
11748.116.0.0/1648.116.0.1 to 48.116.255.25448.116.255.25565,534
11848.117.0.0/1648.117.0.1 to 48.117.255.25448.117.255.25565,534
11948.118.0.0/1648.118.0.1 to 48.118.255.25448.118.255.25565,534
12048.119.0.0/1648.119.0.1 to 48.119.255.25448.119.255.25565,534
12148.120.0.0/1648.120.0.1 to 48.120.255.25448.120.255.25565,534
12248.121.0.0/1648.121.0.1 to 48.121.255.25448.121.255.25565,534
12348.122.0.0/1648.122.0.1 to 48.122.255.25448.122.255.25565,534
12448.123.0.0/1648.123.0.1 to 48.123.255.25448.123.255.25565,534
12548.124.0.0/1648.124.0.1 to 48.124.255.25448.124.255.25565,534
12648.125.0.0/1648.125.0.1 to 48.125.255.25448.125.255.25565,534
12748.126.0.0/1648.126.0.1 to 48.126.255.25448.126.255.25565,534
12848.127.0.0/1648.127.0.1 to 48.127.255.25448.127.255.25565,534

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.