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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.

Network148.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
148.192.0.0
Broadcast address
148.255.255.255
First usable
148.192.0.1
Last usable
148.255.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex 94C00000 · Integer 2495610880 to 2499805183
Reverse DNS zones
192.148.in-addr.arpa
193.148.in-addr.arpa
194.148.in-addr.arpa
195.148.in-addr.arpa
196.148.in-addr.arpa
197.148.in-addr.arpa
198.148.in-addr.arpa
199.148.in-addr.arpa
200.148.in-addr.arpa
201.148.in-addr.arpa
202.148.in-addr.arpa
203.148.in-addr.arpa
204.148.in-addr.arpa
205.148.in-addr.arpa
206.148.in-addr.arpa
207.148.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010100.11000000.00000000.00000000148.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10010100.11000000.00000000.00000000148.192.0.0
Broadcast10010100.11111111.11111111.11111111148.255.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

148.192.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1148.192.0.0/17148.192.0.1 to 148.192.127.254148.192.127.25532,766
2148.192.128.0/17148.192.128.1 to 148.192.255.254148.192.255.25532,766
3148.193.0.0/17148.193.0.1 to 148.193.127.254148.193.127.25532,766
4148.193.128.0/17148.193.128.1 to 148.193.255.254148.193.255.25532,766
5148.194.0.0/17148.194.0.1 to 148.194.127.254148.194.127.25532,766
6148.194.128.0/17148.194.128.1 to 148.194.255.254148.194.255.25532,766
7148.195.0.0/17148.195.0.1 to 148.195.127.254148.195.127.25532,766
8148.195.128.0/17148.195.128.1 to 148.195.255.254148.195.255.25532,766
9148.196.0.0/17148.196.0.1 to 148.196.127.254148.196.127.25532,766
10148.196.128.0/17148.196.128.1 to 148.196.255.254148.196.255.25532,766
11148.197.0.0/17148.197.0.1 to 148.197.127.254148.197.127.25532,766
12148.197.128.0/17148.197.128.1 to 148.197.255.254148.197.255.25532,766
13148.198.0.0/17148.198.0.1 to 148.198.127.254148.198.127.25532,766
14148.198.128.0/17148.198.128.1 to 148.198.255.254148.198.255.25532,766
15148.199.0.0/17148.199.0.1 to 148.199.127.254148.199.127.25532,766
16148.199.128.0/17148.199.128.1 to 148.199.255.254148.199.255.25532,766
17148.200.0.0/17148.200.0.1 to 148.200.127.254148.200.127.25532,766
18148.200.128.0/17148.200.128.1 to 148.200.255.254148.200.255.25532,766
19148.201.0.0/17148.201.0.1 to 148.201.127.254148.201.127.25532,766
20148.201.128.0/17148.201.128.1 to 148.201.255.254148.201.255.25532,766
21148.202.0.0/17148.202.0.1 to 148.202.127.254148.202.127.25532,766
22148.202.128.0/17148.202.128.1 to 148.202.255.254148.202.255.25532,766
23148.203.0.0/17148.203.0.1 to 148.203.127.254148.203.127.25532,766
24148.203.128.0/17148.203.128.1 to 148.203.255.254148.203.255.25532,766
25148.204.0.0/17148.204.0.1 to 148.204.127.254148.204.127.25532,766
26148.204.128.0/17148.204.128.1 to 148.204.255.254148.204.255.25532,766
27148.205.0.0/17148.205.0.1 to 148.205.127.254148.205.127.25532,766
28148.205.128.0/17148.205.128.1 to 148.205.255.254148.205.255.25532,766
29148.206.0.0/17148.206.0.1 to 148.206.127.254148.206.127.25532,766
30148.206.128.0/17148.206.128.1 to 148.206.255.254148.206.255.25532,766
31148.207.0.0/17148.207.0.1 to 148.207.127.254148.207.127.25532,766
32148.207.128.0/17148.207.128.1 to 148.207.255.254148.207.255.25532,766
33148.208.0.0/17148.208.0.1 to 148.208.127.254148.208.127.25532,766
34148.208.128.0/17148.208.128.1 to 148.208.255.254148.208.255.25532,766
35148.209.0.0/17148.209.0.1 to 148.209.127.254148.209.127.25532,766
36148.209.128.0/17148.209.128.1 to 148.209.255.254148.209.255.25532,766
37148.210.0.0/17148.210.0.1 to 148.210.127.254148.210.127.25532,766
38148.210.128.0/17148.210.128.1 to 148.210.255.254148.210.255.25532,766
39148.211.0.0/17148.211.0.1 to 148.211.127.254148.211.127.25532,766
40148.211.128.0/17148.211.128.1 to 148.211.255.254148.211.255.25532,766
41148.212.0.0/17148.212.0.1 to 148.212.127.254148.212.127.25532,766
42148.212.128.0/17148.212.128.1 to 148.212.255.254148.212.255.25532,766
43148.213.0.0/17148.213.0.1 to 148.213.127.254148.213.127.25532,766
44148.213.128.0/17148.213.128.1 to 148.213.255.254148.213.255.25532,766
45148.214.0.0/17148.214.0.1 to 148.214.127.254148.214.127.25532,766
46148.214.128.0/17148.214.128.1 to 148.214.255.254148.214.255.25532,766
47148.215.0.0/17148.215.0.1 to 148.215.127.254148.215.127.25532,766
48148.215.128.0/17148.215.128.1 to 148.215.255.254148.215.255.25532,766
49148.216.0.0/17148.216.0.1 to 148.216.127.254148.216.127.25532,766
50148.216.128.0/17148.216.128.1 to 148.216.255.254148.216.255.25532,766
51148.217.0.0/17148.217.0.1 to 148.217.127.254148.217.127.25532,766
52148.217.128.0/17148.217.128.1 to 148.217.255.254148.217.255.25532,766
53148.218.0.0/17148.218.0.1 to 148.218.127.254148.218.127.25532,766
54148.218.128.0/17148.218.128.1 to 148.218.255.254148.218.255.25532,766
55148.219.0.0/17148.219.0.1 to 148.219.127.254148.219.127.25532,766
56148.219.128.0/17148.219.128.1 to 148.219.255.254148.219.255.25532,766
57148.220.0.0/17148.220.0.1 to 148.220.127.254148.220.127.25532,766
58148.220.128.0/17148.220.128.1 to 148.220.255.254148.220.255.25532,766
59148.221.0.0/17148.221.0.1 to 148.221.127.254148.221.127.25532,766
60148.221.128.0/17148.221.128.1 to 148.221.255.254148.221.255.25532,766
61148.222.0.0/17148.222.0.1 to 148.222.127.254148.222.127.25532,766
62148.222.128.0/17148.222.128.1 to 148.222.255.254148.222.255.25532,766
63148.223.0.0/17148.223.0.1 to 148.223.127.254148.223.127.25532,766
64148.223.128.0/17148.223.128.1 to 148.223.255.254148.223.255.25532,766
65148.224.0.0/17148.224.0.1 to 148.224.127.254148.224.127.25532,766
66148.224.128.0/17148.224.128.1 to 148.224.255.254148.224.255.25532,766
67148.225.0.0/17148.225.0.1 to 148.225.127.254148.225.127.25532,766
68148.225.128.0/17148.225.128.1 to 148.225.255.254148.225.255.25532,766
69148.226.0.0/17148.226.0.1 to 148.226.127.254148.226.127.25532,766
70148.226.128.0/17148.226.128.1 to 148.226.255.254148.226.255.25532,766
71148.227.0.0/17148.227.0.1 to 148.227.127.254148.227.127.25532,766
72148.227.128.0/17148.227.128.1 to 148.227.255.254148.227.255.25532,766
73148.228.0.0/17148.228.0.1 to 148.228.127.254148.228.127.25532,766
74148.228.128.0/17148.228.128.1 to 148.228.255.254148.228.255.25532,766
75148.229.0.0/17148.229.0.1 to 148.229.127.254148.229.127.25532,766
76148.229.128.0/17148.229.128.1 to 148.229.255.254148.229.255.25532,766
77148.230.0.0/17148.230.0.1 to 148.230.127.254148.230.127.25532,766
78148.230.128.0/17148.230.128.1 to 148.230.255.254148.230.255.25532,766
79148.231.0.0/17148.231.0.1 to 148.231.127.254148.231.127.25532,766
80148.231.128.0/17148.231.128.1 to 148.231.255.254148.231.255.25532,766
81148.232.0.0/17148.232.0.1 to 148.232.127.254148.232.127.25532,766
82148.232.128.0/17148.232.128.1 to 148.232.255.254148.232.255.25532,766
83148.233.0.0/17148.233.0.1 to 148.233.127.254148.233.127.25532,766
84148.233.128.0/17148.233.128.1 to 148.233.255.254148.233.255.25532,766
85148.234.0.0/17148.234.0.1 to 148.234.127.254148.234.127.25532,766
86148.234.128.0/17148.234.128.1 to 148.234.255.254148.234.255.25532,766
87148.235.0.0/17148.235.0.1 to 148.235.127.254148.235.127.25532,766
88148.235.128.0/17148.235.128.1 to 148.235.255.254148.235.255.25532,766
89148.236.0.0/17148.236.0.1 to 148.236.127.254148.236.127.25532,766
90148.236.128.0/17148.236.128.1 to 148.236.255.254148.236.255.25532,766
91148.237.0.0/17148.237.0.1 to 148.237.127.254148.237.127.25532,766
92148.237.128.0/17148.237.128.1 to 148.237.255.254148.237.255.25532,766
93148.238.0.0/17148.238.0.1 to 148.238.127.254148.238.127.25532,766
94148.238.128.0/17148.238.128.1 to 148.238.255.254148.238.255.25532,766
95148.239.0.0/17148.239.0.1 to 148.239.127.254148.239.127.25532,766
96148.239.128.0/17148.239.128.1 to 148.239.255.254148.239.255.25532,766
97148.240.0.0/17148.240.0.1 to 148.240.127.254148.240.127.25532,766
98148.240.128.0/17148.240.128.1 to 148.240.255.254148.240.255.25532,766
99148.241.0.0/17148.241.0.1 to 148.241.127.254148.241.127.25532,766
100148.241.128.0/17148.241.128.1 to 148.241.255.254148.241.255.25532,766
101148.242.0.0/17148.242.0.1 to 148.242.127.254148.242.127.25532,766
102148.242.128.0/17148.242.128.1 to 148.242.255.254148.242.255.25532,766
103148.243.0.0/17148.243.0.1 to 148.243.127.254148.243.127.25532,766
104148.243.128.0/17148.243.128.1 to 148.243.255.254148.243.255.25532,766
105148.244.0.0/17148.244.0.1 to 148.244.127.254148.244.127.25532,766
106148.244.128.0/17148.244.128.1 to 148.244.255.254148.244.255.25532,766
107148.245.0.0/17148.245.0.1 to 148.245.127.254148.245.127.25532,766
108148.245.128.0/17148.245.128.1 to 148.245.255.254148.245.255.25532,766
109148.246.0.0/17148.246.0.1 to 148.246.127.254148.246.127.25532,766
110148.246.128.0/17148.246.128.1 to 148.246.255.254148.246.255.25532,766
111148.247.0.0/17148.247.0.1 to 148.247.127.254148.247.127.25532,766
112148.247.128.0/17148.247.128.1 to 148.247.255.254148.247.255.25532,766
113148.248.0.0/17148.248.0.1 to 148.248.127.254148.248.127.25532,766
114148.248.128.0/17148.248.128.1 to 148.248.255.254148.248.255.25532,766
115148.249.0.0/17148.249.0.1 to 148.249.127.254148.249.127.25532,766
116148.249.128.0/17148.249.128.1 to 148.249.255.254148.249.255.25532,766
117148.250.0.0/17148.250.0.1 to 148.250.127.254148.250.127.25532,766
118148.250.128.0/17148.250.128.1 to 148.250.255.254148.250.255.25532,766
119148.251.0.0/17148.251.0.1 to 148.251.127.254148.251.127.25532,766
120148.251.128.0/17148.251.128.1 to 148.251.255.254148.251.255.25532,766
121148.252.0.0/17148.252.0.1 to 148.252.127.254148.252.127.25532,766
122148.252.128.0/17148.252.128.1 to 148.252.255.254148.252.255.25532,766
123148.253.0.0/17148.253.0.1 to 148.253.127.254148.253.127.25532,766
124148.253.128.0/17148.253.128.1 to 148.253.255.254148.253.255.25532,766
125148.254.0.0/17148.254.0.1 to 148.254.127.254148.254.127.25532,766
126148.254.128.0/17148.254.128.1 to 148.254.255.254148.254.255.25532,766
127148.255.0.0/17148.255.0.1 to 148.255.127.254148.255.127.25532,766
128148.255.128.0/17148.255.128.1 to 148.255.255.254148.255.255.25532,766

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.