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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.

Network154.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
154.0.0.0
Broadcast address
154.127.255.255
First usable
154.0.0.1
Last usable
154.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
B (default /16)
As numbers
Hex 9A000000 · Integer 2583691264 to 2592079871
Reverse DNS zones
0.154.in-addr.arpa
1.154.in-addr.arpa
2.154.in-addr.arpa
3.154.in-addr.arpa
4.154.in-addr.arpa
5.154.in-addr.arpa
6.154.in-addr.arpa
7.154.in-addr.arpa
8.154.in-addr.arpa
9.154.in-addr.arpa
10.154.in-addr.arpa
11.154.in-addr.arpa
12.154.in-addr.arpa
13.154.in-addr.arpa
14.154.in-addr.arpa
15.154.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011010.00000000.00000000.00000000154.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network10011010.00000000.00000000.00000000154.0.0.0
Broadcast10011010.01111111.11111111.11111111154.127.255.255
Split into smaller subnets/16
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

154.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1154.0.0.0/16154.0.0.1 to 154.0.255.254154.0.255.25565,534
2154.1.0.0/16154.1.0.1 to 154.1.255.254154.1.255.25565,534
3154.2.0.0/16154.2.0.1 to 154.2.255.254154.2.255.25565,534
4154.3.0.0/16154.3.0.1 to 154.3.255.254154.3.255.25565,534
5154.4.0.0/16154.4.0.1 to 154.4.255.254154.4.255.25565,534
6154.5.0.0/16154.5.0.1 to 154.5.255.254154.5.255.25565,534
7154.6.0.0/16154.6.0.1 to 154.6.255.254154.6.255.25565,534
8154.7.0.0/16154.7.0.1 to 154.7.255.254154.7.255.25565,534
9154.8.0.0/16154.8.0.1 to 154.8.255.254154.8.255.25565,534
10154.9.0.0/16154.9.0.1 to 154.9.255.254154.9.255.25565,534
11154.10.0.0/16154.10.0.1 to 154.10.255.254154.10.255.25565,534
12154.11.0.0/16154.11.0.1 to 154.11.255.254154.11.255.25565,534
13154.12.0.0/16154.12.0.1 to 154.12.255.254154.12.255.25565,534
14154.13.0.0/16154.13.0.1 to 154.13.255.254154.13.255.25565,534
15154.14.0.0/16154.14.0.1 to 154.14.255.254154.14.255.25565,534
16154.15.0.0/16154.15.0.1 to 154.15.255.254154.15.255.25565,534
17154.16.0.0/16154.16.0.1 to 154.16.255.254154.16.255.25565,534
18154.17.0.0/16154.17.0.1 to 154.17.255.254154.17.255.25565,534
19154.18.0.0/16154.18.0.1 to 154.18.255.254154.18.255.25565,534
20154.19.0.0/16154.19.0.1 to 154.19.255.254154.19.255.25565,534
21154.20.0.0/16154.20.0.1 to 154.20.255.254154.20.255.25565,534
22154.21.0.0/16154.21.0.1 to 154.21.255.254154.21.255.25565,534
23154.22.0.0/16154.22.0.1 to 154.22.255.254154.22.255.25565,534
24154.23.0.0/16154.23.0.1 to 154.23.255.254154.23.255.25565,534
25154.24.0.0/16154.24.0.1 to 154.24.255.254154.24.255.25565,534
26154.25.0.0/16154.25.0.1 to 154.25.255.254154.25.255.25565,534
27154.26.0.0/16154.26.0.1 to 154.26.255.254154.26.255.25565,534
28154.27.0.0/16154.27.0.1 to 154.27.255.254154.27.255.25565,534
29154.28.0.0/16154.28.0.1 to 154.28.255.254154.28.255.25565,534
30154.29.0.0/16154.29.0.1 to 154.29.255.254154.29.255.25565,534
31154.30.0.0/16154.30.0.1 to 154.30.255.254154.30.255.25565,534
32154.31.0.0/16154.31.0.1 to 154.31.255.254154.31.255.25565,534
33154.32.0.0/16154.32.0.1 to 154.32.255.254154.32.255.25565,534
34154.33.0.0/16154.33.0.1 to 154.33.255.254154.33.255.25565,534
35154.34.0.0/16154.34.0.1 to 154.34.255.254154.34.255.25565,534
36154.35.0.0/16154.35.0.1 to 154.35.255.254154.35.255.25565,534
37154.36.0.0/16154.36.0.1 to 154.36.255.254154.36.255.25565,534
38154.37.0.0/16154.37.0.1 to 154.37.255.254154.37.255.25565,534
39154.38.0.0/16154.38.0.1 to 154.38.255.254154.38.255.25565,534
40154.39.0.0/16154.39.0.1 to 154.39.255.254154.39.255.25565,534
41154.40.0.0/16154.40.0.1 to 154.40.255.254154.40.255.25565,534
42154.41.0.0/16154.41.0.1 to 154.41.255.254154.41.255.25565,534
43154.42.0.0/16154.42.0.1 to 154.42.255.254154.42.255.25565,534
44154.43.0.0/16154.43.0.1 to 154.43.255.254154.43.255.25565,534
45154.44.0.0/16154.44.0.1 to 154.44.255.254154.44.255.25565,534
46154.45.0.0/16154.45.0.1 to 154.45.255.254154.45.255.25565,534
47154.46.0.0/16154.46.0.1 to 154.46.255.254154.46.255.25565,534
48154.47.0.0/16154.47.0.1 to 154.47.255.254154.47.255.25565,534
49154.48.0.0/16154.48.0.1 to 154.48.255.254154.48.255.25565,534
50154.49.0.0/16154.49.0.1 to 154.49.255.254154.49.255.25565,534
51154.50.0.0/16154.50.0.1 to 154.50.255.254154.50.255.25565,534
52154.51.0.0/16154.51.0.1 to 154.51.255.254154.51.255.25565,534
53154.52.0.0/16154.52.0.1 to 154.52.255.254154.52.255.25565,534
54154.53.0.0/16154.53.0.1 to 154.53.255.254154.53.255.25565,534
55154.54.0.0/16154.54.0.1 to 154.54.255.254154.54.255.25565,534
56154.55.0.0/16154.55.0.1 to 154.55.255.254154.55.255.25565,534
57154.56.0.0/16154.56.0.1 to 154.56.255.254154.56.255.25565,534
58154.57.0.0/16154.57.0.1 to 154.57.255.254154.57.255.25565,534
59154.58.0.0/16154.58.0.1 to 154.58.255.254154.58.255.25565,534
60154.59.0.0/16154.59.0.1 to 154.59.255.254154.59.255.25565,534
61154.60.0.0/16154.60.0.1 to 154.60.255.254154.60.255.25565,534
62154.61.0.0/16154.61.0.1 to 154.61.255.254154.61.255.25565,534
63154.62.0.0/16154.62.0.1 to 154.62.255.254154.62.255.25565,534
64154.63.0.0/16154.63.0.1 to 154.63.255.254154.63.255.25565,534
65154.64.0.0/16154.64.0.1 to 154.64.255.254154.64.255.25565,534
66154.65.0.0/16154.65.0.1 to 154.65.255.254154.65.255.25565,534
67154.66.0.0/16154.66.0.1 to 154.66.255.254154.66.255.25565,534
68154.67.0.0/16154.67.0.1 to 154.67.255.254154.67.255.25565,534
69154.68.0.0/16154.68.0.1 to 154.68.255.254154.68.255.25565,534
70154.69.0.0/16154.69.0.1 to 154.69.255.254154.69.255.25565,534
71154.70.0.0/16154.70.0.1 to 154.70.255.254154.70.255.25565,534
72154.71.0.0/16154.71.0.1 to 154.71.255.254154.71.255.25565,534
73154.72.0.0/16154.72.0.1 to 154.72.255.254154.72.255.25565,534
74154.73.0.0/16154.73.0.1 to 154.73.255.254154.73.255.25565,534
75154.74.0.0/16154.74.0.1 to 154.74.255.254154.74.255.25565,534
76154.75.0.0/16154.75.0.1 to 154.75.255.254154.75.255.25565,534
77154.76.0.0/16154.76.0.1 to 154.76.255.254154.76.255.25565,534
78154.77.0.0/16154.77.0.1 to 154.77.255.254154.77.255.25565,534
79154.78.0.0/16154.78.0.1 to 154.78.255.254154.78.255.25565,534
80154.79.0.0/16154.79.0.1 to 154.79.255.254154.79.255.25565,534
81154.80.0.0/16154.80.0.1 to 154.80.255.254154.80.255.25565,534
82154.81.0.0/16154.81.0.1 to 154.81.255.254154.81.255.25565,534
83154.82.0.0/16154.82.0.1 to 154.82.255.254154.82.255.25565,534
84154.83.0.0/16154.83.0.1 to 154.83.255.254154.83.255.25565,534
85154.84.0.0/16154.84.0.1 to 154.84.255.254154.84.255.25565,534
86154.85.0.0/16154.85.0.1 to 154.85.255.254154.85.255.25565,534
87154.86.0.0/16154.86.0.1 to 154.86.255.254154.86.255.25565,534
88154.87.0.0/16154.87.0.1 to 154.87.255.254154.87.255.25565,534
89154.88.0.0/16154.88.0.1 to 154.88.255.254154.88.255.25565,534
90154.89.0.0/16154.89.0.1 to 154.89.255.254154.89.255.25565,534
91154.90.0.0/16154.90.0.1 to 154.90.255.254154.90.255.25565,534
92154.91.0.0/16154.91.0.1 to 154.91.255.254154.91.255.25565,534
93154.92.0.0/16154.92.0.1 to 154.92.255.254154.92.255.25565,534
94154.93.0.0/16154.93.0.1 to 154.93.255.254154.93.255.25565,534
95154.94.0.0/16154.94.0.1 to 154.94.255.254154.94.255.25565,534
96154.95.0.0/16154.95.0.1 to 154.95.255.254154.95.255.25565,534
97154.96.0.0/16154.96.0.1 to 154.96.255.254154.96.255.25565,534
98154.97.0.0/16154.97.0.1 to 154.97.255.254154.97.255.25565,534
99154.98.0.0/16154.98.0.1 to 154.98.255.254154.98.255.25565,534
100154.99.0.0/16154.99.0.1 to 154.99.255.254154.99.255.25565,534
101154.100.0.0/16154.100.0.1 to 154.100.255.254154.100.255.25565,534
102154.101.0.0/16154.101.0.1 to 154.101.255.254154.101.255.25565,534
103154.102.0.0/16154.102.0.1 to 154.102.255.254154.102.255.25565,534
104154.103.0.0/16154.103.0.1 to 154.103.255.254154.103.255.25565,534
105154.104.0.0/16154.104.0.1 to 154.104.255.254154.104.255.25565,534
106154.105.0.0/16154.105.0.1 to 154.105.255.254154.105.255.25565,534
107154.106.0.0/16154.106.0.1 to 154.106.255.254154.106.255.25565,534
108154.107.0.0/16154.107.0.1 to 154.107.255.254154.107.255.25565,534
109154.108.0.0/16154.108.0.1 to 154.108.255.254154.108.255.25565,534
110154.109.0.0/16154.109.0.1 to 154.109.255.254154.109.255.25565,534
111154.110.0.0/16154.110.0.1 to 154.110.255.254154.110.255.25565,534
112154.111.0.0/16154.111.0.1 to 154.111.255.254154.111.255.25565,534
113154.112.0.0/16154.112.0.1 to 154.112.255.254154.112.255.25565,534
114154.113.0.0/16154.113.0.1 to 154.113.255.254154.113.255.25565,534
115154.114.0.0/16154.114.0.1 to 154.114.255.254154.114.255.25565,534
116154.115.0.0/16154.115.0.1 to 154.115.255.254154.115.255.25565,534
117154.116.0.0/16154.116.0.1 to 154.116.255.254154.116.255.25565,534
118154.117.0.0/16154.117.0.1 to 154.117.255.254154.117.255.25565,534
119154.118.0.0/16154.118.0.1 to 154.118.255.254154.118.255.25565,534
120154.119.0.0/16154.119.0.1 to 154.119.255.254154.119.255.25565,534
121154.120.0.0/16154.120.0.1 to 154.120.255.254154.120.255.25565,534
122154.121.0.0/16154.121.0.1 to 154.121.255.254154.121.255.25565,534
123154.122.0.0/16154.122.0.1 to 154.122.255.254154.122.255.25565,534
124154.123.0.0/16154.123.0.1 to 154.123.255.254154.123.255.25565,534
125154.124.0.0/16154.124.0.1 to 154.124.255.254154.124.255.25565,534
126154.125.0.0/16154.125.0.1 to 154.125.255.254154.125.255.25565,534
127154.126.0.0/16154.126.0.1 to 154.126.255.254154.126.255.25565,534
128154.127.0.0/16154.127.0.1 to 154.127.255.254154.127.255.25565,534

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.