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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.

Network160.0.0.0/4
Usable hosts268,435,454
Subnet mask240.0.0.0
Addresses268,435,456
Network address
160.0.0.0
Broadcast address
175.255.255.255
First usable
160.0.0.1
Last usable
175.255.255.254
Usable hosts
268,435,454 (268,435,456 less the network and broadcast addresses)
Subnet mask
240.0.0.0
Wildcard mask
15.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/4
Type
Public public
Old class
B (default /16)
As numbers
Hex A0000000 · Integer 2684354560 to 2952790015
Reverse DNS zones
160.in-addr.arpa
161.in-addr.arpa
162.in-addr.arpa
163.in-addr.arpa
164.in-addr.arpa
165.in-addr.arpa
166.in-addr.arpa
167.in-addr.arpa
168.in-addr.arpa
169.in-addr.arpa
170.in-addr.arpa
171.in-addr.arpa
172.in-addr.arpa
173.in-addr.arpa
174.in-addr.arpa
175.in-addr.arpa
/4 is not on a 8-bit boundary, so it takes 16 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100000.00000000.00000000.00000000160.0.0.0
Subnet mask11110000.00000000.00000000.00000000240.0.0.0
Network10100000.00000000.00000000.00000000160.0.0.0
Broadcast10101111.11111111.11111111.11111111175.255.255.255
Split into smaller subnets/11
/5 (2)/6 (4)/7 (8)/8 (16)/9 (32)/10 (64)/11 (128)/12 (256)/13 (512)/14 (1,024)/15 (2,048)/16 (4,096)

160.0.0.0/4 makes 128 subnets of /11.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1160.0.0.0/11160.0.0.1 to 160.31.255.254160.31.255.2552,097,150
2160.32.0.0/11160.32.0.1 to 160.63.255.254160.63.255.2552,097,150
3160.64.0.0/11160.64.0.1 to 160.95.255.254160.95.255.2552,097,150
4160.96.0.0/11160.96.0.1 to 160.127.255.254160.127.255.2552,097,150
5160.128.0.0/11160.128.0.1 to 160.159.255.254160.159.255.2552,097,150
6160.160.0.0/11160.160.0.1 to 160.191.255.254160.191.255.2552,097,150
7160.192.0.0/11160.192.0.1 to 160.223.255.254160.223.255.2552,097,150
8160.224.0.0/11160.224.0.1 to 160.255.255.254160.255.255.2552,097,150
9161.0.0.0/11161.0.0.1 to 161.31.255.254161.31.255.2552,097,150
10161.32.0.0/11161.32.0.1 to 161.63.255.254161.63.255.2552,097,150
11161.64.0.0/11161.64.0.1 to 161.95.255.254161.95.255.2552,097,150
12161.96.0.0/11161.96.0.1 to 161.127.255.254161.127.255.2552,097,150
13161.128.0.0/11161.128.0.1 to 161.159.255.254161.159.255.2552,097,150
14161.160.0.0/11161.160.0.1 to 161.191.255.254161.191.255.2552,097,150
15161.192.0.0/11161.192.0.1 to 161.223.255.254161.223.255.2552,097,150
16161.224.0.0/11161.224.0.1 to 161.255.255.254161.255.255.2552,097,150
17162.0.0.0/11162.0.0.1 to 162.31.255.254162.31.255.2552,097,150
18162.32.0.0/11162.32.0.1 to 162.63.255.254162.63.255.2552,097,150
19162.64.0.0/11162.64.0.1 to 162.95.255.254162.95.255.2552,097,150
20162.96.0.0/11162.96.0.1 to 162.127.255.254162.127.255.2552,097,150
21162.128.0.0/11162.128.0.1 to 162.159.255.254162.159.255.2552,097,150
22162.160.0.0/11162.160.0.1 to 162.191.255.254162.191.255.2552,097,150
23162.192.0.0/11162.192.0.1 to 162.223.255.254162.223.255.2552,097,150
24162.224.0.0/11162.224.0.1 to 162.255.255.254162.255.255.2552,097,150
25163.0.0.0/11163.0.0.1 to 163.31.255.254163.31.255.2552,097,150
26163.32.0.0/11163.32.0.1 to 163.63.255.254163.63.255.2552,097,150
27163.64.0.0/11163.64.0.1 to 163.95.255.254163.95.255.2552,097,150
28163.96.0.0/11163.96.0.1 to 163.127.255.254163.127.255.2552,097,150
29163.128.0.0/11163.128.0.1 to 163.159.255.254163.159.255.2552,097,150
30163.160.0.0/11163.160.0.1 to 163.191.255.254163.191.255.2552,097,150
31163.192.0.0/11163.192.0.1 to 163.223.255.254163.223.255.2552,097,150
32163.224.0.0/11163.224.0.1 to 163.255.255.254163.255.255.2552,097,150
33164.0.0.0/11164.0.0.1 to 164.31.255.254164.31.255.2552,097,150
34164.32.0.0/11164.32.0.1 to 164.63.255.254164.63.255.2552,097,150
35164.64.0.0/11164.64.0.1 to 164.95.255.254164.95.255.2552,097,150
36164.96.0.0/11164.96.0.1 to 164.127.255.254164.127.255.2552,097,150
37164.128.0.0/11164.128.0.1 to 164.159.255.254164.159.255.2552,097,150
38164.160.0.0/11164.160.0.1 to 164.191.255.254164.191.255.2552,097,150
39164.192.0.0/11164.192.0.1 to 164.223.255.254164.223.255.2552,097,150
40164.224.0.0/11164.224.0.1 to 164.255.255.254164.255.255.2552,097,150
41165.0.0.0/11165.0.0.1 to 165.31.255.254165.31.255.2552,097,150
42165.32.0.0/11165.32.0.1 to 165.63.255.254165.63.255.2552,097,150
43165.64.0.0/11165.64.0.1 to 165.95.255.254165.95.255.2552,097,150
44165.96.0.0/11165.96.0.1 to 165.127.255.254165.127.255.2552,097,150
45165.128.0.0/11165.128.0.1 to 165.159.255.254165.159.255.2552,097,150
46165.160.0.0/11165.160.0.1 to 165.191.255.254165.191.255.2552,097,150
47165.192.0.0/11165.192.0.1 to 165.223.255.254165.223.255.2552,097,150
48165.224.0.0/11165.224.0.1 to 165.255.255.254165.255.255.2552,097,150
49166.0.0.0/11166.0.0.1 to 166.31.255.254166.31.255.2552,097,150
50166.32.0.0/11166.32.0.1 to 166.63.255.254166.63.255.2552,097,150
51166.64.0.0/11166.64.0.1 to 166.95.255.254166.95.255.2552,097,150
52166.96.0.0/11166.96.0.1 to 166.127.255.254166.127.255.2552,097,150
53166.128.0.0/11166.128.0.1 to 166.159.255.254166.159.255.2552,097,150
54166.160.0.0/11166.160.0.1 to 166.191.255.254166.191.255.2552,097,150
55166.192.0.0/11166.192.0.1 to 166.223.255.254166.223.255.2552,097,150
56166.224.0.0/11166.224.0.1 to 166.255.255.254166.255.255.2552,097,150
57167.0.0.0/11167.0.0.1 to 167.31.255.254167.31.255.2552,097,150
58167.32.0.0/11167.32.0.1 to 167.63.255.254167.63.255.2552,097,150
59167.64.0.0/11167.64.0.1 to 167.95.255.254167.95.255.2552,097,150
60167.96.0.0/11167.96.0.1 to 167.127.255.254167.127.255.2552,097,150
61167.128.0.0/11167.128.0.1 to 167.159.255.254167.159.255.2552,097,150
62167.160.0.0/11167.160.0.1 to 167.191.255.254167.191.255.2552,097,150
63167.192.0.0/11167.192.0.1 to 167.223.255.254167.223.255.2552,097,150
64167.224.0.0/11167.224.0.1 to 167.255.255.254167.255.255.2552,097,150
65168.0.0.0/11168.0.0.1 to 168.31.255.254168.31.255.2552,097,150
66168.32.0.0/11168.32.0.1 to 168.63.255.254168.63.255.2552,097,150
67168.64.0.0/11168.64.0.1 to 168.95.255.254168.95.255.2552,097,150
68168.96.0.0/11168.96.0.1 to 168.127.255.254168.127.255.2552,097,150
69168.128.0.0/11168.128.0.1 to 168.159.255.254168.159.255.2552,097,150
70168.160.0.0/11168.160.0.1 to 168.191.255.254168.191.255.2552,097,150
71168.192.0.0/11168.192.0.1 to 168.223.255.254168.223.255.2552,097,150
72168.224.0.0/11168.224.0.1 to 168.255.255.254168.255.255.2552,097,150
73169.0.0.0/11169.0.0.1 to 169.31.255.254169.31.255.2552,097,150
74169.32.0.0/11169.32.0.1 to 169.63.255.254169.63.255.2552,097,150
75169.64.0.0/11169.64.0.1 to 169.95.255.254169.95.255.2552,097,150
76169.96.0.0/11169.96.0.1 to 169.127.255.254169.127.255.2552,097,150
77169.128.0.0/11169.128.0.1 to 169.159.255.254169.159.255.2552,097,150
78169.160.0.0/11169.160.0.1 to 169.191.255.254169.191.255.2552,097,150
79169.192.0.0/11169.192.0.1 to 169.223.255.254169.223.255.2552,097,150
80169.224.0.0/11169.224.0.1 to 169.255.255.254169.255.255.2552,097,150
81170.0.0.0/11170.0.0.1 to 170.31.255.254170.31.255.2552,097,150
82170.32.0.0/11170.32.0.1 to 170.63.255.254170.63.255.2552,097,150
83170.64.0.0/11170.64.0.1 to 170.95.255.254170.95.255.2552,097,150
84170.96.0.0/11170.96.0.1 to 170.127.255.254170.127.255.2552,097,150
85170.128.0.0/11170.128.0.1 to 170.159.255.254170.159.255.2552,097,150
86170.160.0.0/11170.160.0.1 to 170.191.255.254170.191.255.2552,097,150
87170.192.0.0/11170.192.0.1 to 170.223.255.254170.223.255.2552,097,150
88170.224.0.0/11170.224.0.1 to 170.255.255.254170.255.255.2552,097,150
89171.0.0.0/11171.0.0.1 to 171.31.255.254171.31.255.2552,097,150
90171.32.0.0/11171.32.0.1 to 171.63.255.254171.63.255.2552,097,150
91171.64.0.0/11171.64.0.1 to 171.95.255.254171.95.255.2552,097,150
92171.96.0.0/11171.96.0.1 to 171.127.255.254171.127.255.2552,097,150
93171.128.0.0/11171.128.0.1 to 171.159.255.254171.159.255.2552,097,150
94171.160.0.0/11171.160.0.1 to 171.191.255.254171.191.255.2552,097,150
95171.192.0.0/11171.192.0.1 to 171.223.255.254171.223.255.2552,097,150
96171.224.0.0/11171.224.0.1 to 171.255.255.254171.255.255.2552,097,150
97172.0.0.0/11172.0.0.1 to 172.31.255.254172.31.255.2552,097,150
98172.32.0.0/11172.32.0.1 to 172.63.255.254172.63.255.2552,097,150
99172.64.0.0/11172.64.0.1 to 172.95.255.254172.95.255.2552,097,150
100172.96.0.0/11172.96.0.1 to 172.127.255.254172.127.255.2552,097,150
101172.128.0.0/11172.128.0.1 to 172.159.255.254172.159.255.2552,097,150
102172.160.0.0/11172.160.0.1 to 172.191.255.254172.191.255.2552,097,150
103172.192.0.0/11172.192.0.1 to 172.223.255.254172.223.255.2552,097,150
104172.224.0.0/11172.224.0.1 to 172.255.255.254172.255.255.2552,097,150
105173.0.0.0/11173.0.0.1 to 173.31.255.254173.31.255.2552,097,150
106173.32.0.0/11173.32.0.1 to 173.63.255.254173.63.255.2552,097,150
107173.64.0.0/11173.64.0.1 to 173.95.255.254173.95.255.2552,097,150
108173.96.0.0/11173.96.0.1 to 173.127.255.254173.127.255.2552,097,150
109173.128.0.0/11173.128.0.1 to 173.159.255.254173.159.255.2552,097,150
110173.160.0.0/11173.160.0.1 to 173.191.255.254173.191.255.2552,097,150
111173.192.0.0/11173.192.0.1 to 173.223.255.254173.223.255.2552,097,150
112173.224.0.0/11173.224.0.1 to 173.255.255.254173.255.255.2552,097,150
113174.0.0.0/11174.0.0.1 to 174.31.255.254174.31.255.2552,097,150
114174.32.0.0/11174.32.0.1 to 174.63.255.254174.63.255.2552,097,150
115174.64.0.0/11174.64.0.1 to 174.95.255.254174.95.255.2552,097,150
116174.96.0.0/11174.96.0.1 to 174.127.255.254174.127.255.2552,097,150
117174.128.0.0/11174.128.0.1 to 174.159.255.254174.159.255.2552,097,150
118174.160.0.0/11174.160.0.1 to 174.191.255.254174.191.255.2552,097,150
119174.192.0.0/11174.192.0.1 to 174.223.255.254174.223.255.2552,097,150
120174.224.0.0/11174.224.0.1 to 174.255.255.254174.255.255.2552,097,150
121175.0.0.0/11175.0.0.1 to 175.31.255.254175.31.255.2552,097,150
122175.32.0.0/11175.32.0.1 to 175.63.255.254175.63.255.2552,097,150
123175.64.0.0/11175.64.0.1 to 175.95.255.254175.95.255.2552,097,150
124175.96.0.0/11175.96.0.1 to 175.127.255.254175.127.255.2552,097,150
125175.128.0.0/11175.128.0.1 to 175.159.255.254175.159.255.2552,097,150
126175.160.0.0/11175.160.0.1 to 175.191.255.254175.191.255.2552,097,150
127175.192.0.0/11175.192.0.1 to 175.223.255.254175.223.255.2552,097,150
128175.224.0.0/11175.224.0.1 to 175.255.255.254175.255.255.2552,097,150

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.