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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.

Network201.148.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
201.148.0.0
Broadcast address
201.151.255.255
First usable
201.148.0.1
Last usable
201.151.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
C (default /24)
As numbers
Hex C9940000 · Integer 3381919744 to 3382181887
Reverse DNS zones
148.201.in-addr.arpa
149.201.in-addr.arpa
150.201.in-addr.arpa
151.201.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001001.10010100.00000000.00000000201.148.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11001001.10010100.00000000.00000000201.148.0.0
Broadcast11001001.10010111.11111111.11111111201.151.255.255
Split into smaller subnets/21
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

201.148.0.0/14 makes 128 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1201.148.0.0/21201.148.0.1 to 201.148.7.254201.148.7.2552,046
2201.148.8.0/21201.148.8.1 to 201.148.15.254201.148.15.2552,046
3201.148.16.0/21201.148.16.1 to 201.148.23.254201.148.23.2552,046
4201.148.24.0/21201.148.24.1 to 201.148.31.254201.148.31.2552,046
5201.148.32.0/21201.148.32.1 to 201.148.39.254201.148.39.2552,046
6201.148.40.0/21201.148.40.1 to 201.148.47.254201.148.47.2552,046
7201.148.48.0/21201.148.48.1 to 201.148.55.254201.148.55.2552,046
8201.148.56.0/21201.148.56.1 to 201.148.63.254201.148.63.2552,046
9201.148.64.0/21201.148.64.1 to 201.148.71.254201.148.71.2552,046
10201.148.72.0/21201.148.72.1 to 201.148.79.254201.148.79.2552,046
11201.148.80.0/21201.148.80.1 to 201.148.87.254201.148.87.2552,046
12201.148.88.0/21201.148.88.1 to 201.148.95.254201.148.95.2552,046
13201.148.96.0/21201.148.96.1 to 201.148.103.254201.148.103.2552,046
14201.148.104.0/21201.148.104.1 to 201.148.111.254201.148.111.2552,046
15201.148.112.0/21201.148.112.1 to 201.148.119.254201.148.119.2552,046
16201.148.120.0/21201.148.120.1 to 201.148.127.254201.148.127.2552,046
17201.148.128.0/21201.148.128.1 to 201.148.135.254201.148.135.2552,046
18201.148.136.0/21201.148.136.1 to 201.148.143.254201.148.143.2552,046
19201.148.144.0/21201.148.144.1 to 201.148.151.254201.148.151.2552,046
20201.148.152.0/21201.148.152.1 to 201.148.159.254201.148.159.2552,046
21201.148.160.0/21201.148.160.1 to 201.148.167.254201.148.167.2552,046
22201.148.168.0/21201.148.168.1 to 201.148.175.254201.148.175.2552,046
23201.148.176.0/21201.148.176.1 to 201.148.183.254201.148.183.2552,046
24201.148.184.0/21201.148.184.1 to 201.148.191.254201.148.191.2552,046
25201.148.192.0/21201.148.192.1 to 201.148.199.254201.148.199.2552,046
26201.148.200.0/21201.148.200.1 to 201.148.207.254201.148.207.2552,046
27201.148.208.0/21201.148.208.1 to 201.148.215.254201.148.215.2552,046
28201.148.216.0/21201.148.216.1 to 201.148.223.254201.148.223.2552,046
29201.148.224.0/21201.148.224.1 to 201.148.231.254201.148.231.2552,046
30201.148.232.0/21201.148.232.1 to 201.148.239.254201.148.239.2552,046
31201.148.240.0/21201.148.240.1 to 201.148.247.254201.148.247.2552,046
32201.148.248.0/21201.148.248.1 to 201.148.255.254201.148.255.2552,046
33201.149.0.0/21201.149.0.1 to 201.149.7.254201.149.7.2552,046
34201.149.8.0/21201.149.8.1 to 201.149.15.254201.149.15.2552,046
35201.149.16.0/21201.149.16.1 to 201.149.23.254201.149.23.2552,046
36201.149.24.0/21201.149.24.1 to 201.149.31.254201.149.31.2552,046
37201.149.32.0/21201.149.32.1 to 201.149.39.254201.149.39.2552,046
38201.149.40.0/21201.149.40.1 to 201.149.47.254201.149.47.2552,046
39201.149.48.0/21201.149.48.1 to 201.149.55.254201.149.55.2552,046
40201.149.56.0/21201.149.56.1 to 201.149.63.254201.149.63.2552,046
41201.149.64.0/21201.149.64.1 to 201.149.71.254201.149.71.2552,046
42201.149.72.0/21201.149.72.1 to 201.149.79.254201.149.79.2552,046
43201.149.80.0/21201.149.80.1 to 201.149.87.254201.149.87.2552,046
44201.149.88.0/21201.149.88.1 to 201.149.95.254201.149.95.2552,046
45201.149.96.0/21201.149.96.1 to 201.149.103.254201.149.103.2552,046
46201.149.104.0/21201.149.104.1 to 201.149.111.254201.149.111.2552,046
47201.149.112.0/21201.149.112.1 to 201.149.119.254201.149.119.2552,046
48201.149.120.0/21201.149.120.1 to 201.149.127.254201.149.127.2552,046
49201.149.128.0/21201.149.128.1 to 201.149.135.254201.149.135.2552,046
50201.149.136.0/21201.149.136.1 to 201.149.143.254201.149.143.2552,046
51201.149.144.0/21201.149.144.1 to 201.149.151.254201.149.151.2552,046
52201.149.152.0/21201.149.152.1 to 201.149.159.254201.149.159.2552,046
53201.149.160.0/21201.149.160.1 to 201.149.167.254201.149.167.2552,046
54201.149.168.0/21201.149.168.1 to 201.149.175.254201.149.175.2552,046
55201.149.176.0/21201.149.176.1 to 201.149.183.254201.149.183.2552,046
56201.149.184.0/21201.149.184.1 to 201.149.191.254201.149.191.2552,046
57201.149.192.0/21201.149.192.1 to 201.149.199.254201.149.199.2552,046
58201.149.200.0/21201.149.200.1 to 201.149.207.254201.149.207.2552,046
59201.149.208.0/21201.149.208.1 to 201.149.215.254201.149.215.2552,046
60201.149.216.0/21201.149.216.1 to 201.149.223.254201.149.223.2552,046
61201.149.224.0/21201.149.224.1 to 201.149.231.254201.149.231.2552,046
62201.149.232.0/21201.149.232.1 to 201.149.239.254201.149.239.2552,046
63201.149.240.0/21201.149.240.1 to 201.149.247.254201.149.247.2552,046
64201.149.248.0/21201.149.248.1 to 201.149.255.254201.149.255.2552,046
65201.150.0.0/21201.150.0.1 to 201.150.7.254201.150.7.2552,046
66201.150.8.0/21201.150.8.1 to 201.150.15.254201.150.15.2552,046
67201.150.16.0/21201.150.16.1 to 201.150.23.254201.150.23.2552,046
68201.150.24.0/21201.150.24.1 to 201.150.31.254201.150.31.2552,046
69201.150.32.0/21201.150.32.1 to 201.150.39.254201.150.39.2552,046
70201.150.40.0/21201.150.40.1 to 201.150.47.254201.150.47.2552,046
71201.150.48.0/21201.150.48.1 to 201.150.55.254201.150.55.2552,046
72201.150.56.0/21201.150.56.1 to 201.150.63.254201.150.63.2552,046
73201.150.64.0/21201.150.64.1 to 201.150.71.254201.150.71.2552,046
74201.150.72.0/21201.150.72.1 to 201.150.79.254201.150.79.2552,046
75201.150.80.0/21201.150.80.1 to 201.150.87.254201.150.87.2552,046
76201.150.88.0/21201.150.88.1 to 201.150.95.254201.150.95.2552,046
77201.150.96.0/21201.150.96.1 to 201.150.103.254201.150.103.2552,046
78201.150.104.0/21201.150.104.1 to 201.150.111.254201.150.111.2552,046
79201.150.112.0/21201.150.112.1 to 201.150.119.254201.150.119.2552,046
80201.150.120.0/21201.150.120.1 to 201.150.127.254201.150.127.2552,046
81201.150.128.0/21201.150.128.1 to 201.150.135.254201.150.135.2552,046
82201.150.136.0/21201.150.136.1 to 201.150.143.254201.150.143.2552,046
83201.150.144.0/21201.150.144.1 to 201.150.151.254201.150.151.2552,046
84201.150.152.0/21201.150.152.1 to 201.150.159.254201.150.159.2552,046
85201.150.160.0/21201.150.160.1 to 201.150.167.254201.150.167.2552,046
86201.150.168.0/21201.150.168.1 to 201.150.175.254201.150.175.2552,046
87201.150.176.0/21201.150.176.1 to 201.150.183.254201.150.183.2552,046
88201.150.184.0/21201.150.184.1 to 201.150.191.254201.150.191.2552,046
89201.150.192.0/21201.150.192.1 to 201.150.199.254201.150.199.2552,046
90201.150.200.0/21201.150.200.1 to 201.150.207.254201.150.207.2552,046
91201.150.208.0/21201.150.208.1 to 201.150.215.254201.150.215.2552,046
92201.150.216.0/21201.150.216.1 to 201.150.223.254201.150.223.2552,046
93201.150.224.0/21201.150.224.1 to 201.150.231.254201.150.231.2552,046
94201.150.232.0/21201.150.232.1 to 201.150.239.254201.150.239.2552,046
95201.150.240.0/21201.150.240.1 to 201.150.247.254201.150.247.2552,046
96201.150.248.0/21201.150.248.1 to 201.150.255.254201.150.255.2552,046
97201.151.0.0/21201.151.0.1 to 201.151.7.254201.151.7.2552,046
98201.151.8.0/21201.151.8.1 to 201.151.15.254201.151.15.2552,046
99201.151.16.0/21201.151.16.1 to 201.151.23.254201.151.23.2552,046
100201.151.24.0/21201.151.24.1 to 201.151.31.254201.151.31.2552,046
101201.151.32.0/21201.151.32.1 to 201.151.39.254201.151.39.2552,046
102201.151.40.0/21201.151.40.1 to 201.151.47.254201.151.47.2552,046
103201.151.48.0/21201.151.48.1 to 201.151.55.254201.151.55.2552,046
104201.151.56.0/21201.151.56.1 to 201.151.63.254201.151.63.2552,046
105201.151.64.0/21201.151.64.1 to 201.151.71.254201.151.71.2552,046
106201.151.72.0/21201.151.72.1 to 201.151.79.254201.151.79.2552,046
107201.151.80.0/21201.151.80.1 to 201.151.87.254201.151.87.2552,046
108201.151.88.0/21201.151.88.1 to 201.151.95.254201.151.95.2552,046
109201.151.96.0/21201.151.96.1 to 201.151.103.254201.151.103.2552,046
110201.151.104.0/21201.151.104.1 to 201.151.111.254201.151.111.2552,046
111201.151.112.0/21201.151.112.1 to 201.151.119.254201.151.119.2552,046
112201.151.120.0/21201.151.120.1 to 201.151.127.254201.151.127.2552,046
113201.151.128.0/21201.151.128.1 to 201.151.135.254201.151.135.2552,046
114201.151.136.0/21201.151.136.1 to 201.151.143.254201.151.143.2552,046
115201.151.144.0/21201.151.144.1 to 201.151.151.254201.151.151.2552,046
116201.151.152.0/21201.151.152.1 to 201.151.159.254201.151.159.2552,046
117201.151.160.0/21201.151.160.1 to 201.151.167.254201.151.167.2552,046
118201.151.168.0/21201.151.168.1 to 201.151.175.254201.151.175.2552,046
119201.151.176.0/21201.151.176.1 to 201.151.183.254201.151.183.2552,046
120201.151.184.0/21201.151.184.1 to 201.151.191.254201.151.191.2552,046
121201.151.192.0/21201.151.192.1 to 201.151.199.254201.151.199.2552,046
122201.151.200.0/21201.151.200.1 to 201.151.207.254201.151.207.2552,046
123201.151.208.0/21201.151.208.1 to 201.151.215.254201.151.215.2552,046
124201.151.216.0/21201.151.216.1 to 201.151.223.254201.151.223.2552,046
125201.151.224.0/21201.151.224.1 to 201.151.231.254201.151.231.2552,046
126201.151.232.0/21201.151.232.1 to 201.151.239.254201.151.239.2552,046
127201.151.240.0/21201.151.240.1 to 201.151.247.254201.151.247.2552,046
128201.151.248.0/21201.151.248.1 to 201.151.255.254201.151.255.2552,046

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.