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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.

Network148.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
148.0.0.0
Broadcast address
151.255.255.255
First usable
148.0.0.1
Last usable
151.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex 94000000 · Integer 2483027968 to 2550136831
Reverse DNS zones
148.in-addr.arpa
149.in-addr.arpa
150.in-addr.arpa
151.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010100.00000000.00000000.00000000148.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10010100.00000000.00000000.00000000148.0.0.0
Broadcast10010111.11111111.11111111.11111111151.255.255.255
Split into smaller subnets/13
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

148.0.0.0/6 makes 128 subnets of /13.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1148.0.0.0/13148.0.0.1 to 148.7.255.254148.7.255.255524,286
2148.8.0.0/13148.8.0.1 to 148.15.255.254148.15.255.255524,286
3148.16.0.0/13148.16.0.1 to 148.23.255.254148.23.255.255524,286
4148.24.0.0/13148.24.0.1 to 148.31.255.254148.31.255.255524,286
5148.32.0.0/13148.32.0.1 to 148.39.255.254148.39.255.255524,286
6148.40.0.0/13148.40.0.1 to 148.47.255.254148.47.255.255524,286
7148.48.0.0/13148.48.0.1 to 148.55.255.254148.55.255.255524,286
8148.56.0.0/13148.56.0.1 to 148.63.255.254148.63.255.255524,286
9148.64.0.0/13148.64.0.1 to 148.71.255.254148.71.255.255524,286
10148.72.0.0/13148.72.0.1 to 148.79.255.254148.79.255.255524,286
11148.80.0.0/13148.80.0.1 to 148.87.255.254148.87.255.255524,286
12148.88.0.0/13148.88.0.1 to 148.95.255.254148.95.255.255524,286
13148.96.0.0/13148.96.0.1 to 148.103.255.254148.103.255.255524,286
14148.104.0.0/13148.104.0.1 to 148.111.255.254148.111.255.255524,286
15148.112.0.0/13148.112.0.1 to 148.119.255.254148.119.255.255524,286
16148.120.0.0/13148.120.0.1 to 148.127.255.254148.127.255.255524,286
17148.128.0.0/13148.128.0.1 to 148.135.255.254148.135.255.255524,286
18148.136.0.0/13148.136.0.1 to 148.143.255.254148.143.255.255524,286
19148.144.0.0/13148.144.0.1 to 148.151.255.254148.151.255.255524,286
20148.152.0.0/13148.152.0.1 to 148.159.255.254148.159.255.255524,286
21148.160.0.0/13148.160.0.1 to 148.167.255.254148.167.255.255524,286
22148.168.0.0/13148.168.0.1 to 148.175.255.254148.175.255.255524,286
23148.176.0.0/13148.176.0.1 to 148.183.255.254148.183.255.255524,286
24148.184.0.0/13148.184.0.1 to 148.191.255.254148.191.255.255524,286
25148.192.0.0/13148.192.0.1 to 148.199.255.254148.199.255.255524,286
26148.200.0.0/13148.200.0.1 to 148.207.255.254148.207.255.255524,286
27148.208.0.0/13148.208.0.1 to 148.215.255.254148.215.255.255524,286
28148.216.0.0/13148.216.0.1 to 148.223.255.254148.223.255.255524,286
29148.224.0.0/13148.224.0.1 to 148.231.255.254148.231.255.255524,286
30148.232.0.0/13148.232.0.1 to 148.239.255.254148.239.255.255524,286
31148.240.0.0/13148.240.0.1 to 148.247.255.254148.247.255.255524,286
32148.248.0.0/13148.248.0.1 to 148.255.255.254148.255.255.255524,286
33149.0.0.0/13149.0.0.1 to 149.7.255.254149.7.255.255524,286
34149.8.0.0/13149.8.0.1 to 149.15.255.254149.15.255.255524,286
35149.16.0.0/13149.16.0.1 to 149.23.255.254149.23.255.255524,286
36149.24.0.0/13149.24.0.1 to 149.31.255.254149.31.255.255524,286
37149.32.0.0/13149.32.0.1 to 149.39.255.254149.39.255.255524,286
38149.40.0.0/13149.40.0.1 to 149.47.255.254149.47.255.255524,286
39149.48.0.0/13149.48.0.1 to 149.55.255.254149.55.255.255524,286
40149.56.0.0/13149.56.0.1 to 149.63.255.254149.63.255.255524,286
41149.64.0.0/13149.64.0.1 to 149.71.255.254149.71.255.255524,286
42149.72.0.0/13149.72.0.1 to 149.79.255.254149.79.255.255524,286
43149.80.0.0/13149.80.0.1 to 149.87.255.254149.87.255.255524,286
44149.88.0.0/13149.88.0.1 to 149.95.255.254149.95.255.255524,286
45149.96.0.0/13149.96.0.1 to 149.103.255.254149.103.255.255524,286
46149.104.0.0/13149.104.0.1 to 149.111.255.254149.111.255.255524,286
47149.112.0.0/13149.112.0.1 to 149.119.255.254149.119.255.255524,286
48149.120.0.0/13149.120.0.1 to 149.127.255.254149.127.255.255524,286
49149.128.0.0/13149.128.0.1 to 149.135.255.254149.135.255.255524,286
50149.136.0.0/13149.136.0.1 to 149.143.255.254149.143.255.255524,286
51149.144.0.0/13149.144.0.1 to 149.151.255.254149.151.255.255524,286
52149.152.0.0/13149.152.0.1 to 149.159.255.254149.159.255.255524,286
53149.160.0.0/13149.160.0.1 to 149.167.255.254149.167.255.255524,286
54149.168.0.0/13149.168.0.1 to 149.175.255.254149.175.255.255524,286
55149.176.0.0/13149.176.0.1 to 149.183.255.254149.183.255.255524,286
56149.184.0.0/13149.184.0.1 to 149.191.255.254149.191.255.255524,286
57149.192.0.0/13149.192.0.1 to 149.199.255.254149.199.255.255524,286
58149.200.0.0/13149.200.0.1 to 149.207.255.254149.207.255.255524,286
59149.208.0.0/13149.208.0.1 to 149.215.255.254149.215.255.255524,286
60149.216.0.0/13149.216.0.1 to 149.223.255.254149.223.255.255524,286
61149.224.0.0/13149.224.0.1 to 149.231.255.254149.231.255.255524,286
62149.232.0.0/13149.232.0.1 to 149.239.255.254149.239.255.255524,286
63149.240.0.0/13149.240.0.1 to 149.247.255.254149.247.255.255524,286
64149.248.0.0/13149.248.0.1 to 149.255.255.254149.255.255.255524,286
65150.0.0.0/13150.0.0.1 to 150.7.255.254150.7.255.255524,286
66150.8.0.0/13150.8.0.1 to 150.15.255.254150.15.255.255524,286
67150.16.0.0/13150.16.0.1 to 150.23.255.254150.23.255.255524,286
68150.24.0.0/13150.24.0.1 to 150.31.255.254150.31.255.255524,286
69150.32.0.0/13150.32.0.1 to 150.39.255.254150.39.255.255524,286
70150.40.0.0/13150.40.0.1 to 150.47.255.254150.47.255.255524,286
71150.48.0.0/13150.48.0.1 to 150.55.255.254150.55.255.255524,286
72150.56.0.0/13150.56.0.1 to 150.63.255.254150.63.255.255524,286
73150.64.0.0/13150.64.0.1 to 150.71.255.254150.71.255.255524,286
74150.72.0.0/13150.72.0.1 to 150.79.255.254150.79.255.255524,286
75150.80.0.0/13150.80.0.1 to 150.87.255.254150.87.255.255524,286
76150.88.0.0/13150.88.0.1 to 150.95.255.254150.95.255.255524,286
77150.96.0.0/13150.96.0.1 to 150.103.255.254150.103.255.255524,286
78150.104.0.0/13150.104.0.1 to 150.111.255.254150.111.255.255524,286
79150.112.0.0/13150.112.0.1 to 150.119.255.254150.119.255.255524,286
80150.120.0.0/13150.120.0.1 to 150.127.255.254150.127.255.255524,286
81150.128.0.0/13150.128.0.1 to 150.135.255.254150.135.255.255524,286
82150.136.0.0/13150.136.0.1 to 150.143.255.254150.143.255.255524,286
83150.144.0.0/13150.144.0.1 to 150.151.255.254150.151.255.255524,286
84150.152.0.0/13150.152.0.1 to 150.159.255.254150.159.255.255524,286
85150.160.0.0/13150.160.0.1 to 150.167.255.254150.167.255.255524,286
86150.168.0.0/13150.168.0.1 to 150.175.255.254150.175.255.255524,286
87150.176.0.0/13150.176.0.1 to 150.183.255.254150.183.255.255524,286
88150.184.0.0/13150.184.0.1 to 150.191.255.254150.191.255.255524,286
89150.192.0.0/13150.192.0.1 to 150.199.255.254150.199.255.255524,286
90150.200.0.0/13150.200.0.1 to 150.207.255.254150.207.255.255524,286
91150.208.0.0/13150.208.0.1 to 150.215.255.254150.215.255.255524,286
92150.216.0.0/13150.216.0.1 to 150.223.255.254150.223.255.255524,286
93150.224.0.0/13150.224.0.1 to 150.231.255.254150.231.255.255524,286
94150.232.0.0/13150.232.0.1 to 150.239.255.254150.239.255.255524,286
95150.240.0.0/13150.240.0.1 to 150.247.255.254150.247.255.255524,286
96150.248.0.0/13150.248.0.1 to 150.255.255.254150.255.255.255524,286
97151.0.0.0/13151.0.0.1 to 151.7.255.254151.7.255.255524,286
98151.8.0.0/13151.8.0.1 to 151.15.255.254151.15.255.255524,286
99151.16.0.0/13151.16.0.1 to 151.23.255.254151.23.255.255524,286
100151.24.0.0/13151.24.0.1 to 151.31.255.254151.31.255.255524,286
101151.32.0.0/13151.32.0.1 to 151.39.255.254151.39.255.255524,286
102151.40.0.0/13151.40.0.1 to 151.47.255.254151.47.255.255524,286
103151.48.0.0/13151.48.0.1 to 151.55.255.254151.55.255.255524,286
104151.56.0.0/13151.56.0.1 to 151.63.255.254151.63.255.255524,286
105151.64.0.0/13151.64.0.1 to 151.71.255.254151.71.255.255524,286
106151.72.0.0/13151.72.0.1 to 151.79.255.254151.79.255.255524,286
107151.80.0.0/13151.80.0.1 to 151.87.255.254151.87.255.255524,286
108151.88.0.0/13151.88.0.1 to 151.95.255.254151.95.255.255524,286
109151.96.0.0/13151.96.0.1 to 151.103.255.254151.103.255.255524,286
110151.104.0.0/13151.104.0.1 to 151.111.255.254151.111.255.255524,286
111151.112.0.0/13151.112.0.1 to 151.119.255.254151.119.255.255524,286
112151.120.0.0/13151.120.0.1 to 151.127.255.254151.127.255.255524,286
113151.128.0.0/13151.128.0.1 to 151.135.255.254151.135.255.255524,286
114151.136.0.0/13151.136.0.1 to 151.143.255.254151.143.255.255524,286
115151.144.0.0/13151.144.0.1 to 151.151.255.254151.151.255.255524,286
116151.152.0.0/13151.152.0.1 to 151.159.255.254151.159.255.255524,286
117151.160.0.0/13151.160.0.1 to 151.167.255.254151.167.255.255524,286
118151.168.0.0/13151.168.0.1 to 151.175.255.254151.175.255.255524,286
119151.176.0.0/13151.176.0.1 to 151.183.255.254151.183.255.255524,286
120151.184.0.0/13151.184.0.1 to 151.191.255.254151.191.255.255524,286
121151.192.0.0/13151.192.0.1 to 151.199.255.254151.199.255.255524,286
122151.200.0.0/13151.200.0.1 to 151.207.255.254151.207.255.255524,286
123151.208.0.0/13151.208.0.1 to 151.215.255.254151.215.255.255524,286
124151.216.0.0/13151.216.0.1 to 151.223.255.254151.223.255.255524,286
125151.224.0.0/13151.224.0.1 to 151.231.255.254151.231.255.255524,286
126151.232.0.0/13151.232.0.1 to 151.239.255.254151.239.255.255524,286
127151.240.0.0/13151.240.0.1 to 151.247.255.254151.247.255.255524,286
128151.248.0.0/13151.248.0.1 to 151.255.255.254151.255.255.255524,286

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.