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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.

Network152.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
152.0.0.0
Broadcast address
159.255.255.255
First usable
152.0.0.1
Last usable
159.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
B (default /16)
As numbers
Hex 98000000 · Integer 2550136832 to 2684354559
Reverse DNS zones
152.in-addr.arpa
153.in-addr.arpa
154.in-addr.arpa
155.in-addr.arpa
156.in-addr.arpa
157.in-addr.arpa
158.in-addr.arpa
159.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011000.00000000.00000000.00000000152.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network10011000.00000000.00000000.00000000152.0.0.0
Broadcast10011111.11111111.11111111.11111111159.255.255.255
Split into smaller subnets/12
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

152.0.0.0/5 makes 128 subnets of /12.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1152.0.0.0/12152.0.0.1 to 152.15.255.254152.15.255.2551,048,574
2152.16.0.0/12152.16.0.1 to 152.31.255.254152.31.255.2551,048,574
3152.32.0.0/12152.32.0.1 to 152.47.255.254152.47.255.2551,048,574
4152.48.0.0/12152.48.0.1 to 152.63.255.254152.63.255.2551,048,574
5152.64.0.0/12152.64.0.1 to 152.79.255.254152.79.255.2551,048,574
6152.80.0.0/12152.80.0.1 to 152.95.255.254152.95.255.2551,048,574
7152.96.0.0/12152.96.0.1 to 152.111.255.254152.111.255.2551,048,574
8152.112.0.0/12152.112.0.1 to 152.127.255.254152.127.255.2551,048,574
9152.128.0.0/12152.128.0.1 to 152.143.255.254152.143.255.2551,048,574
10152.144.0.0/12152.144.0.1 to 152.159.255.254152.159.255.2551,048,574
11152.160.0.0/12152.160.0.1 to 152.175.255.254152.175.255.2551,048,574
12152.176.0.0/12152.176.0.1 to 152.191.255.254152.191.255.2551,048,574
13152.192.0.0/12152.192.0.1 to 152.207.255.254152.207.255.2551,048,574
14152.208.0.0/12152.208.0.1 to 152.223.255.254152.223.255.2551,048,574
15152.224.0.0/12152.224.0.1 to 152.239.255.254152.239.255.2551,048,574
16152.240.0.0/12152.240.0.1 to 152.255.255.254152.255.255.2551,048,574
17153.0.0.0/12153.0.0.1 to 153.15.255.254153.15.255.2551,048,574
18153.16.0.0/12153.16.0.1 to 153.31.255.254153.31.255.2551,048,574
19153.32.0.0/12153.32.0.1 to 153.47.255.254153.47.255.2551,048,574
20153.48.0.0/12153.48.0.1 to 153.63.255.254153.63.255.2551,048,574
21153.64.0.0/12153.64.0.1 to 153.79.255.254153.79.255.2551,048,574
22153.80.0.0/12153.80.0.1 to 153.95.255.254153.95.255.2551,048,574
23153.96.0.0/12153.96.0.1 to 153.111.255.254153.111.255.2551,048,574
24153.112.0.0/12153.112.0.1 to 153.127.255.254153.127.255.2551,048,574
25153.128.0.0/12153.128.0.1 to 153.143.255.254153.143.255.2551,048,574
26153.144.0.0/12153.144.0.1 to 153.159.255.254153.159.255.2551,048,574
27153.160.0.0/12153.160.0.1 to 153.175.255.254153.175.255.2551,048,574
28153.176.0.0/12153.176.0.1 to 153.191.255.254153.191.255.2551,048,574
29153.192.0.0/12153.192.0.1 to 153.207.255.254153.207.255.2551,048,574
30153.208.0.0/12153.208.0.1 to 153.223.255.254153.223.255.2551,048,574
31153.224.0.0/12153.224.0.1 to 153.239.255.254153.239.255.2551,048,574
32153.240.0.0/12153.240.0.1 to 153.255.255.254153.255.255.2551,048,574
33154.0.0.0/12154.0.0.1 to 154.15.255.254154.15.255.2551,048,574
34154.16.0.0/12154.16.0.1 to 154.31.255.254154.31.255.2551,048,574
35154.32.0.0/12154.32.0.1 to 154.47.255.254154.47.255.2551,048,574
36154.48.0.0/12154.48.0.1 to 154.63.255.254154.63.255.2551,048,574
37154.64.0.0/12154.64.0.1 to 154.79.255.254154.79.255.2551,048,574
38154.80.0.0/12154.80.0.1 to 154.95.255.254154.95.255.2551,048,574
39154.96.0.0/12154.96.0.1 to 154.111.255.254154.111.255.2551,048,574
40154.112.0.0/12154.112.0.1 to 154.127.255.254154.127.255.2551,048,574
41154.128.0.0/12154.128.0.1 to 154.143.255.254154.143.255.2551,048,574
42154.144.0.0/12154.144.0.1 to 154.159.255.254154.159.255.2551,048,574
43154.160.0.0/12154.160.0.1 to 154.175.255.254154.175.255.2551,048,574
44154.176.0.0/12154.176.0.1 to 154.191.255.254154.191.255.2551,048,574
45154.192.0.0/12154.192.0.1 to 154.207.255.254154.207.255.2551,048,574
46154.208.0.0/12154.208.0.1 to 154.223.255.254154.223.255.2551,048,574
47154.224.0.0/12154.224.0.1 to 154.239.255.254154.239.255.2551,048,574
48154.240.0.0/12154.240.0.1 to 154.255.255.254154.255.255.2551,048,574
49155.0.0.0/12155.0.0.1 to 155.15.255.254155.15.255.2551,048,574
50155.16.0.0/12155.16.0.1 to 155.31.255.254155.31.255.2551,048,574
51155.32.0.0/12155.32.0.1 to 155.47.255.254155.47.255.2551,048,574
52155.48.0.0/12155.48.0.1 to 155.63.255.254155.63.255.2551,048,574
53155.64.0.0/12155.64.0.1 to 155.79.255.254155.79.255.2551,048,574
54155.80.0.0/12155.80.0.1 to 155.95.255.254155.95.255.2551,048,574
55155.96.0.0/12155.96.0.1 to 155.111.255.254155.111.255.2551,048,574
56155.112.0.0/12155.112.0.1 to 155.127.255.254155.127.255.2551,048,574
57155.128.0.0/12155.128.0.1 to 155.143.255.254155.143.255.2551,048,574
58155.144.0.0/12155.144.0.1 to 155.159.255.254155.159.255.2551,048,574
59155.160.0.0/12155.160.0.1 to 155.175.255.254155.175.255.2551,048,574
60155.176.0.0/12155.176.0.1 to 155.191.255.254155.191.255.2551,048,574
61155.192.0.0/12155.192.0.1 to 155.207.255.254155.207.255.2551,048,574
62155.208.0.0/12155.208.0.1 to 155.223.255.254155.223.255.2551,048,574
63155.224.0.0/12155.224.0.1 to 155.239.255.254155.239.255.2551,048,574
64155.240.0.0/12155.240.0.1 to 155.255.255.254155.255.255.2551,048,574
65156.0.0.0/12156.0.0.1 to 156.15.255.254156.15.255.2551,048,574
66156.16.0.0/12156.16.0.1 to 156.31.255.254156.31.255.2551,048,574
67156.32.0.0/12156.32.0.1 to 156.47.255.254156.47.255.2551,048,574
68156.48.0.0/12156.48.0.1 to 156.63.255.254156.63.255.2551,048,574
69156.64.0.0/12156.64.0.1 to 156.79.255.254156.79.255.2551,048,574
70156.80.0.0/12156.80.0.1 to 156.95.255.254156.95.255.2551,048,574
71156.96.0.0/12156.96.0.1 to 156.111.255.254156.111.255.2551,048,574
72156.112.0.0/12156.112.0.1 to 156.127.255.254156.127.255.2551,048,574
73156.128.0.0/12156.128.0.1 to 156.143.255.254156.143.255.2551,048,574
74156.144.0.0/12156.144.0.1 to 156.159.255.254156.159.255.2551,048,574
75156.160.0.0/12156.160.0.1 to 156.175.255.254156.175.255.2551,048,574
76156.176.0.0/12156.176.0.1 to 156.191.255.254156.191.255.2551,048,574
77156.192.0.0/12156.192.0.1 to 156.207.255.254156.207.255.2551,048,574
78156.208.0.0/12156.208.0.1 to 156.223.255.254156.223.255.2551,048,574
79156.224.0.0/12156.224.0.1 to 156.239.255.254156.239.255.2551,048,574
80156.240.0.0/12156.240.0.1 to 156.255.255.254156.255.255.2551,048,574
81157.0.0.0/12157.0.0.1 to 157.15.255.254157.15.255.2551,048,574
82157.16.0.0/12157.16.0.1 to 157.31.255.254157.31.255.2551,048,574
83157.32.0.0/12157.32.0.1 to 157.47.255.254157.47.255.2551,048,574
84157.48.0.0/12157.48.0.1 to 157.63.255.254157.63.255.2551,048,574
85157.64.0.0/12157.64.0.1 to 157.79.255.254157.79.255.2551,048,574
86157.80.0.0/12157.80.0.1 to 157.95.255.254157.95.255.2551,048,574
87157.96.0.0/12157.96.0.1 to 157.111.255.254157.111.255.2551,048,574
88157.112.0.0/12157.112.0.1 to 157.127.255.254157.127.255.2551,048,574
89157.128.0.0/12157.128.0.1 to 157.143.255.254157.143.255.2551,048,574
90157.144.0.0/12157.144.0.1 to 157.159.255.254157.159.255.2551,048,574
91157.160.0.0/12157.160.0.1 to 157.175.255.254157.175.255.2551,048,574
92157.176.0.0/12157.176.0.1 to 157.191.255.254157.191.255.2551,048,574
93157.192.0.0/12157.192.0.1 to 157.207.255.254157.207.255.2551,048,574
94157.208.0.0/12157.208.0.1 to 157.223.255.254157.223.255.2551,048,574
95157.224.0.0/12157.224.0.1 to 157.239.255.254157.239.255.2551,048,574
96157.240.0.0/12157.240.0.1 to 157.255.255.254157.255.255.2551,048,574
97158.0.0.0/12158.0.0.1 to 158.15.255.254158.15.255.2551,048,574
98158.16.0.0/12158.16.0.1 to 158.31.255.254158.31.255.2551,048,574
99158.32.0.0/12158.32.0.1 to 158.47.255.254158.47.255.2551,048,574
100158.48.0.0/12158.48.0.1 to 158.63.255.254158.63.255.2551,048,574
101158.64.0.0/12158.64.0.1 to 158.79.255.254158.79.255.2551,048,574
102158.80.0.0/12158.80.0.1 to 158.95.255.254158.95.255.2551,048,574
103158.96.0.0/12158.96.0.1 to 158.111.255.254158.111.255.2551,048,574
104158.112.0.0/12158.112.0.1 to 158.127.255.254158.127.255.2551,048,574
105158.128.0.0/12158.128.0.1 to 158.143.255.254158.143.255.2551,048,574
106158.144.0.0/12158.144.0.1 to 158.159.255.254158.159.255.2551,048,574
107158.160.0.0/12158.160.0.1 to 158.175.255.254158.175.255.2551,048,574
108158.176.0.0/12158.176.0.1 to 158.191.255.254158.191.255.2551,048,574
109158.192.0.0/12158.192.0.1 to 158.207.255.254158.207.255.2551,048,574
110158.208.0.0/12158.208.0.1 to 158.223.255.254158.223.255.2551,048,574
111158.224.0.0/12158.224.0.1 to 158.239.255.254158.239.255.2551,048,574
112158.240.0.0/12158.240.0.1 to 158.255.255.254158.255.255.2551,048,574
113159.0.0.0/12159.0.0.1 to 159.15.255.254159.15.255.2551,048,574
114159.16.0.0/12159.16.0.1 to 159.31.255.254159.31.255.2551,048,574
115159.32.0.0/12159.32.0.1 to 159.47.255.254159.47.255.2551,048,574
116159.48.0.0/12159.48.0.1 to 159.63.255.254159.63.255.2551,048,574
117159.64.0.0/12159.64.0.1 to 159.79.255.254159.79.255.2551,048,574
118159.80.0.0/12159.80.0.1 to 159.95.255.254159.95.255.2551,048,574
119159.96.0.0/12159.96.0.1 to 159.111.255.254159.111.255.2551,048,574
120159.112.0.0/12159.112.0.1 to 159.127.255.254159.127.255.2551,048,574
121159.128.0.0/12159.128.0.1 to 159.143.255.254159.143.255.2551,048,574
122159.144.0.0/12159.144.0.1 to 159.159.255.254159.159.255.2551,048,574
123159.160.0.0/12159.160.0.1 to 159.175.255.254159.175.255.2551,048,574
124159.176.0.0/12159.176.0.1 to 159.191.255.254159.191.255.2551,048,574
125159.192.0.0/12159.192.0.1 to 159.207.255.254159.207.255.2551,048,574
126159.208.0.0/12159.208.0.1 to 159.223.255.254159.223.255.2551,048,574
127159.224.0.0/12159.224.0.1 to 159.239.255.254159.239.255.2551,048,574
128159.240.0.0/12159.240.0.1 to 159.255.255.254159.255.255.2551,048,574

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.