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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.

Network190.167.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
190.167.0.0
Broadcast address
190.167.63.255
First usable
190.167.0.1
Last usable
190.167.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
B (default /16)
As numbers
Hex BEA70000 · Integer 3198615552 to 3198631935
Reverse DNS zones
0.167.190.in-addr.arpa
1.167.190.in-addr.arpa
2.167.190.in-addr.arpa
3.167.190.in-addr.arpa
4.167.190.in-addr.arpa
5.167.190.in-addr.arpa
6.167.190.in-addr.arpa
7.167.190.in-addr.arpa
8.167.190.in-addr.arpa
9.167.190.in-addr.arpa
10.167.190.in-addr.arpa
11.167.190.in-addr.arpa
12.167.190.in-addr.arpa
13.167.190.in-addr.arpa
14.167.190.in-addr.arpa
15.167.190.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111110.10100111.00000000.00000000190.167.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network10111110.10100111.00000000.00000000190.167.0.0
Broadcast10111110.10100111.00111111.11111111190.167.63.255
Split into smaller subnets/25
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

190.167.0.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1190.167.0.0/25190.167.0.1 to 190.167.0.126190.167.0.127126
2190.167.0.128/25190.167.0.129 to 190.167.0.254190.167.0.255126
3190.167.1.0/25190.167.1.1 to 190.167.1.126190.167.1.127126
4190.167.1.128/25190.167.1.129 to 190.167.1.254190.167.1.255126
5190.167.2.0/25190.167.2.1 to 190.167.2.126190.167.2.127126
6190.167.2.128/25190.167.2.129 to 190.167.2.254190.167.2.255126
7190.167.3.0/25190.167.3.1 to 190.167.3.126190.167.3.127126
8190.167.3.128/25190.167.3.129 to 190.167.3.254190.167.3.255126
9190.167.4.0/25190.167.4.1 to 190.167.4.126190.167.4.127126
10190.167.4.128/25190.167.4.129 to 190.167.4.254190.167.4.255126
11190.167.5.0/25190.167.5.1 to 190.167.5.126190.167.5.127126
12190.167.5.128/25190.167.5.129 to 190.167.5.254190.167.5.255126
13190.167.6.0/25190.167.6.1 to 190.167.6.126190.167.6.127126
14190.167.6.128/25190.167.6.129 to 190.167.6.254190.167.6.255126
15190.167.7.0/25190.167.7.1 to 190.167.7.126190.167.7.127126
16190.167.7.128/25190.167.7.129 to 190.167.7.254190.167.7.255126
17190.167.8.0/25190.167.8.1 to 190.167.8.126190.167.8.127126
18190.167.8.128/25190.167.8.129 to 190.167.8.254190.167.8.255126
19190.167.9.0/25190.167.9.1 to 190.167.9.126190.167.9.127126
20190.167.9.128/25190.167.9.129 to 190.167.9.254190.167.9.255126
21190.167.10.0/25190.167.10.1 to 190.167.10.126190.167.10.127126
22190.167.10.128/25190.167.10.129 to 190.167.10.254190.167.10.255126
23190.167.11.0/25190.167.11.1 to 190.167.11.126190.167.11.127126
24190.167.11.128/25190.167.11.129 to 190.167.11.254190.167.11.255126
25190.167.12.0/25190.167.12.1 to 190.167.12.126190.167.12.127126
26190.167.12.128/25190.167.12.129 to 190.167.12.254190.167.12.255126
27190.167.13.0/25190.167.13.1 to 190.167.13.126190.167.13.127126
28190.167.13.128/25190.167.13.129 to 190.167.13.254190.167.13.255126
29190.167.14.0/25190.167.14.1 to 190.167.14.126190.167.14.127126
30190.167.14.128/25190.167.14.129 to 190.167.14.254190.167.14.255126
31190.167.15.0/25190.167.15.1 to 190.167.15.126190.167.15.127126
32190.167.15.128/25190.167.15.129 to 190.167.15.254190.167.15.255126
33190.167.16.0/25190.167.16.1 to 190.167.16.126190.167.16.127126
34190.167.16.128/25190.167.16.129 to 190.167.16.254190.167.16.255126
35190.167.17.0/25190.167.17.1 to 190.167.17.126190.167.17.127126
36190.167.17.128/25190.167.17.129 to 190.167.17.254190.167.17.255126
37190.167.18.0/25190.167.18.1 to 190.167.18.126190.167.18.127126
38190.167.18.128/25190.167.18.129 to 190.167.18.254190.167.18.255126
39190.167.19.0/25190.167.19.1 to 190.167.19.126190.167.19.127126
40190.167.19.128/25190.167.19.129 to 190.167.19.254190.167.19.255126
41190.167.20.0/25190.167.20.1 to 190.167.20.126190.167.20.127126
42190.167.20.128/25190.167.20.129 to 190.167.20.254190.167.20.255126
43190.167.21.0/25190.167.21.1 to 190.167.21.126190.167.21.127126
44190.167.21.128/25190.167.21.129 to 190.167.21.254190.167.21.255126
45190.167.22.0/25190.167.22.1 to 190.167.22.126190.167.22.127126
46190.167.22.128/25190.167.22.129 to 190.167.22.254190.167.22.255126
47190.167.23.0/25190.167.23.1 to 190.167.23.126190.167.23.127126
48190.167.23.128/25190.167.23.129 to 190.167.23.254190.167.23.255126
49190.167.24.0/25190.167.24.1 to 190.167.24.126190.167.24.127126
50190.167.24.128/25190.167.24.129 to 190.167.24.254190.167.24.255126
51190.167.25.0/25190.167.25.1 to 190.167.25.126190.167.25.127126
52190.167.25.128/25190.167.25.129 to 190.167.25.254190.167.25.255126
53190.167.26.0/25190.167.26.1 to 190.167.26.126190.167.26.127126
54190.167.26.128/25190.167.26.129 to 190.167.26.254190.167.26.255126
55190.167.27.0/25190.167.27.1 to 190.167.27.126190.167.27.127126
56190.167.27.128/25190.167.27.129 to 190.167.27.254190.167.27.255126
57190.167.28.0/25190.167.28.1 to 190.167.28.126190.167.28.127126
58190.167.28.128/25190.167.28.129 to 190.167.28.254190.167.28.255126
59190.167.29.0/25190.167.29.1 to 190.167.29.126190.167.29.127126
60190.167.29.128/25190.167.29.129 to 190.167.29.254190.167.29.255126
61190.167.30.0/25190.167.30.1 to 190.167.30.126190.167.30.127126
62190.167.30.128/25190.167.30.129 to 190.167.30.254190.167.30.255126
63190.167.31.0/25190.167.31.1 to 190.167.31.126190.167.31.127126
64190.167.31.128/25190.167.31.129 to 190.167.31.254190.167.31.255126
65190.167.32.0/25190.167.32.1 to 190.167.32.126190.167.32.127126
66190.167.32.128/25190.167.32.129 to 190.167.32.254190.167.32.255126
67190.167.33.0/25190.167.33.1 to 190.167.33.126190.167.33.127126
68190.167.33.128/25190.167.33.129 to 190.167.33.254190.167.33.255126
69190.167.34.0/25190.167.34.1 to 190.167.34.126190.167.34.127126
70190.167.34.128/25190.167.34.129 to 190.167.34.254190.167.34.255126
71190.167.35.0/25190.167.35.1 to 190.167.35.126190.167.35.127126
72190.167.35.128/25190.167.35.129 to 190.167.35.254190.167.35.255126
73190.167.36.0/25190.167.36.1 to 190.167.36.126190.167.36.127126
74190.167.36.128/25190.167.36.129 to 190.167.36.254190.167.36.255126
75190.167.37.0/25190.167.37.1 to 190.167.37.126190.167.37.127126
76190.167.37.128/25190.167.37.129 to 190.167.37.254190.167.37.255126
77190.167.38.0/25190.167.38.1 to 190.167.38.126190.167.38.127126
78190.167.38.128/25190.167.38.129 to 190.167.38.254190.167.38.255126
79190.167.39.0/25190.167.39.1 to 190.167.39.126190.167.39.127126
80190.167.39.128/25190.167.39.129 to 190.167.39.254190.167.39.255126
81190.167.40.0/25190.167.40.1 to 190.167.40.126190.167.40.127126
82190.167.40.128/25190.167.40.129 to 190.167.40.254190.167.40.255126
83190.167.41.0/25190.167.41.1 to 190.167.41.126190.167.41.127126
84190.167.41.128/25190.167.41.129 to 190.167.41.254190.167.41.255126
85190.167.42.0/25190.167.42.1 to 190.167.42.126190.167.42.127126
86190.167.42.128/25190.167.42.129 to 190.167.42.254190.167.42.255126
87190.167.43.0/25190.167.43.1 to 190.167.43.126190.167.43.127126
88190.167.43.128/25190.167.43.129 to 190.167.43.254190.167.43.255126
89190.167.44.0/25190.167.44.1 to 190.167.44.126190.167.44.127126
90190.167.44.128/25190.167.44.129 to 190.167.44.254190.167.44.255126
91190.167.45.0/25190.167.45.1 to 190.167.45.126190.167.45.127126
92190.167.45.128/25190.167.45.129 to 190.167.45.254190.167.45.255126
93190.167.46.0/25190.167.46.1 to 190.167.46.126190.167.46.127126
94190.167.46.128/25190.167.46.129 to 190.167.46.254190.167.46.255126
95190.167.47.0/25190.167.47.1 to 190.167.47.126190.167.47.127126
96190.167.47.128/25190.167.47.129 to 190.167.47.254190.167.47.255126
97190.167.48.0/25190.167.48.1 to 190.167.48.126190.167.48.127126
98190.167.48.128/25190.167.48.129 to 190.167.48.254190.167.48.255126
99190.167.49.0/25190.167.49.1 to 190.167.49.126190.167.49.127126
100190.167.49.128/25190.167.49.129 to 190.167.49.254190.167.49.255126
101190.167.50.0/25190.167.50.1 to 190.167.50.126190.167.50.127126
102190.167.50.128/25190.167.50.129 to 190.167.50.254190.167.50.255126
103190.167.51.0/25190.167.51.1 to 190.167.51.126190.167.51.127126
104190.167.51.128/25190.167.51.129 to 190.167.51.254190.167.51.255126
105190.167.52.0/25190.167.52.1 to 190.167.52.126190.167.52.127126
106190.167.52.128/25190.167.52.129 to 190.167.52.254190.167.52.255126
107190.167.53.0/25190.167.53.1 to 190.167.53.126190.167.53.127126
108190.167.53.128/25190.167.53.129 to 190.167.53.254190.167.53.255126
109190.167.54.0/25190.167.54.1 to 190.167.54.126190.167.54.127126
110190.167.54.128/25190.167.54.129 to 190.167.54.254190.167.54.255126
111190.167.55.0/25190.167.55.1 to 190.167.55.126190.167.55.127126
112190.167.55.128/25190.167.55.129 to 190.167.55.254190.167.55.255126
113190.167.56.0/25190.167.56.1 to 190.167.56.126190.167.56.127126
114190.167.56.128/25190.167.56.129 to 190.167.56.254190.167.56.255126
115190.167.57.0/25190.167.57.1 to 190.167.57.126190.167.57.127126
116190.167.57.128/25190.167.57.129 to 190.167.57.254190.167.57.255126
117190.167.58.0/25190.167.58.1 to 190.167.58.126190.167.58.127126
118190.167.58.128/25190.167.58.129 to 190.167.58.254190.167.58.255126
119190.167.59.0/25190.167.59.1 to 190.167.59.126190.167.59.127126
120190.167.59.128/25190.167.59.129 to 190.167.59.254190.167.59.255126
121190.167.60.0/25190.167.60.1 to 190.167.60.126190.167.60.127126
122190.167.60.128/25190.167.60.129 to 190.167.60.254190.167.60.255126
123190.167.61.0/25190.167.61.1 to 190.167.61.126190.167.61.127126
124190.167.61.128/25190.167.61.129 to 190.167.61.254190.167.61.255126
125190.167.62.0/25190.167.62.1 to 190.167.62.126190.167.62.127126
126190.167.62.128/25190.167.62.129 to 190.167.62.254190.167.62.255126
127190.167.63.0/25190.167.63.1 to 190.167.63.126190.167.63.127126
128190.167.63.128/25190.167.63.129 to 190.167.63.254190.167.63.255126

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.