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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.

Network148.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
148.0.0.0
Broadcast address
148.255.255.255
First usable
148.0.0.1
Last usable
148.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 94000000 · Integer 2483027968 to 2499805183
Reverse DNS zone
148.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010100..00000000.00000000.00000000148.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10010100..00000000.00000000.00000000148.0.0.0
Broadcast10010100..11111111.11111111.11111111148.255.255.255
Split into smaller subnets/15
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

148.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1148.0.0.0/15148.0.0.1 to 148.1.255.254148.1.255.255131,070
2148.2.0.0/15148.2.0.1 to 148.3.255.254148.3.255.255131,070
3148.4.0.0/15148.4.0.1 to 148.5.255.254148.5.255.255131,070
4148.6.0.0/15148.6.0.1 to 148.7.255.254148.7.255.255131,070
5148.8.0.0/15148.8.0.1 to 148.9.255.254148.9.255.255131,070
6148.10.0.0/15148.10.0.1 to 148.11.255.254148.11.255.255131,070
7148.12.0.0/15148.12.0.1 to 148.13.255.254148.13.255.255131,070
8148.14.0.0/15148.14.0.1 to 148.15.255.254148.15.255.255131,070
9148.16.0.0/15148.16.0.1 to 148.17.255.254148.17.255.255131,070
10148.18.0.0/15148.18.0.1 to 148.19.255.254148.19.255.255131,070
11148.20.0.0/15148.20.0.1 to 148.21.255.254148.21.255.255131,070
12148.22.0.0/15148.22.0.1 to 148.23.255.254148.23.255.255131,070
13148.24.0.0/15148.24.0.1 to 148.25.255.254148.25.255.255131,070
14148.26.0.0/15148.26.0.1 to 148.27.255.254148.27.255.255131,070
15148.28.0.0/15148.28.0.1 to 148.29.255.254148.29.255.255131,070
16148.30.0.0/15148.30.0.1 to 148.31.255.254148.31.255.255131,070
17148.32.0.0/15148.32.0.1 to 148.33.255.254148.33.255.255131,070
18148.34.0.0/15148.34.0.1 to 148.35.255.254148.35.255.255131,070
19148.36.0.0/15148.36.0.1 to 148.37.255.254148.37.255.255131,070
20148.38.0.0/15148.38.0.1 to 148.39.255.254148.39.255.255131,070
21148.40.0.0/15148.40.0.1 to 148.41.255.254148.41.255.255131,070
22148.42.0.0/15148.42.0.1 to 148.43.255.254148.43.255.255131,070
23148.44.0.0/15148.44.0.1 to 148.45.255.254148.45.255.255131,070
24148.46.0.0/15148.46.0.1 to 148.47.255.254148.47.255.255131,070
25148.48.0.0/15148.48.0.1 to 148.49.255.254148.49.255.255131,070
26148.50.0.0/15148.50.0.1 to 148.51.255.254148.51.255.255131,070
27148.52.0.0/15148.52.0.1 to 148.53.255.254148.53.255.255131,070
28148.54.0.0/15148.54.0.1 to 148.55.255.254148.55.255.255131,070
29148.56.0.0/15148.56.0.1 to 148.57.255.254148.57.255.255131,070
30148.58.0.0/15148.58.0.1 to 148.59.255.254148.59.255.255131,070
31148.60.0.0/15148.60.0.1 to 148.61.255.254148.61.255.255131,070
32148.62.0.0/15148.62.0.1 to 148.63.255.254148.63.255.255131,070
33148.64.0.0/15148.64.0.1 to 148.65.255.254148.65.255.255131,070
34148.66.0.0/15148.66.0.1 to 148.67.255.254148.67.255.255131,070
35148.68.0.0/15148.68.0.1 to 148.69.255.254148.69.255.255131,070
36148.70.0.0/15148.70.0.1 to 148.71.255.254148.71.255.255131,070
37148.72.0.0/15148.72.0.1 to 148.73.255.254148.73.255.255131,070
38148.74.0.0/15148.74.0.1 to 148.75.255.254148.75.255.255131,070
39148.76.0.0/15148.76.0.1 to 148.77.255.254148.77.255.255131,070
40148.78.0.0/15148.78.0.1 to 148.79.255.254148.79.255.255131,070
41148.80.0.0/15148.80.0.1 to 148.81.255.254148.81.255.255131,070
42148.82.0.0/15148.82.0.1 to 148.83.255.254148.83.255.255131,070
43148.84.0.0/15148.84.0.1 to 148.85.255.254148.85.255.255131,070
44148.86.0.0/15148.86.0.1 to 148.87.255.254148.87.255.255131,070
45148.88.0.0/15148.88.0.1 to 148.89.255.254148.89.255.255131,070
46148.90.0.0/15148.90.0.1 to 148.91.255.254148.91.255.255131,070
47148.92.0.0/15148.92.0.1 to 148.93.255.254148.93.255.255131,070
48148.94.0.0/15148.94.0.1 to 148.95.255.254148.95.255.255131,070
49148.96.0.0/15148.96.0.1 to 148.97.255.254148.97.255.255131,070
50148.98.0.0/15148.98.0.1 to 148.99.255.254148.99.255.255131,070
51148.100.0.0/15148.100.0.1 to 148.101.255.254148.101.255.255131,070
52148.102.0.0/15148.102.0.1 to 148.103.255.254148.103.255.255131,070
53148.104.0.0/15148.104.0.1 to 148.105.255.254148.105.255.255131,070
54148.106.0.0/15148.106.0.1 to 148.107.255.254148.107.255.255131,070
55148.108.0.0/15148.108.0.1 to 148.109.255.254148.109.255.255131,070
56148.110.0.0/15148.110.0.1 to 148.111.255.254148.111.255.255131,070
57148.112.0.0/15148.112.0.1 to 148.113.255.254148.113.255.255131,070
58148.114.0.0/15148.114.0.1 to 148.115.255.254148.115.255.255131,070
59148.116.0.0/15148.116.0.1 to 148.117.255.254148.117.255.255131,070
60148.118.0.0/15148.118.0.1 to 148.119.255.254148.119.255.255131,070
61148.120.0.0/15148.120.0.1 to 148.121.255.254148.121.255.255131,070
62148.122.0.0/15148.122.0.1 to 148.123.255.254148.123.255.255131,070
63148.124.0.0/15148.124.0.1 to 148.125.255.254148.125.255.255131,070
64148.126.0.0/15148.126.0.1 to 148.127.255.254148.127.255.255131,070
65148.128.0.0/15148.128.0.1 to 148.129.255.254148.129.255.255131,070
66148.130.0.0/15148.130.0.1 to 148.131.255.254148.131.255.255131,070
67148.132.0.0/15148.132.0.1 to 148.133.255.254148.133.255.255131,070
68148.134.0.0/15148.134.0.1 to 148.135.255.254148.135.255.255131,070
69148.136.0.0/15148.136.0.1 to 148.137.255.254148.137.255.255131,070
70148.138.0.0/15148.138.0.1 to 148.139.255.254148.139.255.255131,070
71148.140.0.0/15148.140.0.1 to 148.141.255.254148.141.255.255131,070
72148.142.0.0/15148.142.0.1 to 148.143.255.254148.143.255.255131,070
73148.144.0.0/15148.144.0.1 to 148.145.255.254148.145.255.255131,070
74148.146.0.0/15148.146.0.1 to 148.147.255.254148.147.255.255131,070
75148.148.0.0/15148.148.0.1 to 148.149.255.254148.149.255.255131,070
76148.150.0.0/15148.150.0.1 to 148.151.255.254148.151.255.255131,070
77148.152.0.0/15148.152.0.1 to 148.153.255.254148.153.255.255131,070
78148.154.0.0/15148.154.0.1 to 148.155.255.254148.155.255.255131,070
79148.156.0.0/15148.156.0.1 to 148.157.255.254148.157.255.255131,070
80148.158.0.0/15148.158.0.1 to 148.159.255.254148.159.255.255131,070
81148.160.0.0/15148.160.0.1 to 148.161.255.254148.161.255.255131,070
82148.162.0.0/15148.162.0.1 to 148.163.255.254148.163.255.255131,070
83148.164.0.0/15148.164.0.1 to 148.165.255.254148.165.255.255131,070
84148.166.0.0/15148.166.0.1 to 148.167.255.254148.167.255.255131,070
85148.168.0.0/15148.168.0.1 to 148.169.255.254148.169.255.255131,070
86148.170.0.0/15148.170.0.1 to 148.171.255.254148.171.255.255131,070
87148.172.0.0/15148.172.0.1 to 148.173.255.254148.173.255.255131,070
88148.174.0.0/15148.174.0.1 to 148.175.255.254148.175.255.255131,070
89148.176.0.0/15148.176.0.1 to 148.177.255.254148.177.255.255131,070
90148.178.0.0/15148.178.0.1 to 148.179.255.254148.179.255.255131,070
91148.180.0.0/15148.180.0.1 to 148.181.255.254148.181.255.255131,070
92148.182.0.0/15148.182.0.1 to 148.183.255.254148.183.255.255131,070
93148.184.0.0/15148.184.0.1 to 148.185.255.254148.185.255.255131,070
94148.186.0.0/15148.186.0.1 to 148.187.255.254148.187.255.255131,070
95148.188.0.0/15148.188.0.1 to 148.189.255.254148.189.255.255131,070
96148.190.0.0/15148.190.0.1 to 148.191.255.254148.191.255.255131,070
97148.192.0.0/15148.192.0.1 to 148.193.255.254148.193.255.255131,070
98148.194.0.0/15148.194.0.1 to 148.195.255.254148.195.255.255131,070
99148.196.0.0/15148.196.0.1 to 148.197.255.254148.197.255.255131,070
100148.198.0.0/15148.198.0.1 to 148.199.255.254148.199.255.255131,070
101148.200.0.0/15148.200.0.1 to 148.201.255.254148.201.255.255131,070
102148.202.0.0/15148.202.0.1 to 148.203.255.254148.203.255.255131,070
103148.204.0.0/15148.204.0.1 to 148.205.255.254148.205.255.255131,070
104148.206.0.0/15148.206.0.1 to 148.207.255.254148.207.255.255131,070
105148.208.0.0/15148.208.0.1 to 148.209.255.254148.209.255.255131,070
106148.210.0.0/15148.210.0.1 to 148.211.255.254148.211.255.255131,070
107148.212.0.0/15148.212.0.1 to 148.213.255.254148.213.255.255131,070
108148.214.0.0/15148.214.0.1 to 148.215.255.254148.215.255.255131,070
109148.216.0.0/15148.216.0.1 to 148.217.255.254148.217.255.255131,070
110148.218.0.0/15148.218.0.1 to 148.219.255.254148.219.255.255131,070
111148.220.0.0/15148.220.0.1 to 148.221.255.254148.221.255.255131,070
112148.222.0.0/15148.222.0.1 to 148.223.255.254148.223.255.255131,070
113148.224.0.0/15148.224.0.1 to 148.225.255.254148.225.255.255131,070
114148.226.0.0/15148.226.0.1 to 148.227.255.254148.227.255.255131,070
115148.228.0.0/15148.228.0.1 to 148.229.255.254148.229.255.255131,070
116148.230.0.0/15148.230.0.1 to 148.231.255.254148.231.255.255131,070
117148.232.0.0/15148.232.0.1 to 148.233.255.254148.233.255.255131,070
118148.234.0.0/15148.234.0.1 to 148.235.255.254148.235.255.255131,070
119148.236.0.0/15148.236.0.1 to 148.237.255.254148.237.255.255131,070
120148.238.0.0/15148.238.0.1 to 148.239.255.254148.239.255.255131,070
121148.240.0.0/15148.240.0.1 to 148.241.255.254148.241.255.255131,070
122148.242.0.0/15148.242.0.1 to 148.243.255.254148.243.255.255131,070
123148.244.0.0/15148.244.0.1 to 148.245.255.254148.245.255.255131,070
124148.246.0.0/15148.246.0.1 to 148.247.255.254148.247.255.255131,070
125148.248.0.0/15148.248.0.1 to 148.249.255.254148.249.255.255131,070
126148.250.0.0/15148.250.0.1 to 148.251.255.254148.251.255.255131,070
127148.252.0.0/15148.252.0.1 to 148.253.255.254148.253.255.255131,070
128148.254.0.0/15148.254.0.1 to 148.255.255.254148.255.255.255131,070

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.