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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.

Network190.24.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
190.24.0.0
Broadcast address
190.31.255.255
First usable
190.24.0.1
Last usable
190.31.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
B (default /16)
As numbers
Hex BE180000 · Integer 3189243904 to 3189768191
Reverse DNS zones
24.190.in-addr.arpa
25.190.in-addr.arpa
26.190.in-addr.arpa
27.190.in-addr.arpa
28.190.in-addr.arpa
29.190.in-addr.arpa
30.190.in-addr.arpa
31.190.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111110.00011000.00000000.00000000190.24.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10111110.00011000.00000000.00000000190.24.0.0
Broadcast10111110.00011111.11111111.11111111190.31.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

190.24.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1190.24.0.0/20190.24.0.1 to 190.24.15.254190.24.15.2554,094
2190.24.16.0/20190.24.16.1 to 190.24.31.254190.24.31.2554,094
3190.24.32.0/20190.24.32.1 to 190.24.47.254190.24.47.2554,094
4190.24.48.0/20190.24.48.1 to 190.24.63.254190.24.63.2554,094
5190.24.64.0/20190.24.64.1 to 190.24.79.254190.24.79.2554,094
6190.24.80.0/20190.24.80.1 to 190.24.95.254190.24.95.2554,094
7190.24.96.0/20190.24.96.1 to 190.24.111.254190.24.111.2554,094
8190.24.112.0/20190.24.112.1 to 190.24.127.254190.24.127.2554,094
9190.24.128.0/20190.24.128.1 to 190.24.143.254190.24.143.2554,094
10190.24.144.0/20190.24.144.1 to 190.24.159.254190.24.159.2554,094
11190.24.160.0/20190.24.160.1 to 190.24.175.254190.24.175.2554,094
12190.24.176.0/20190.24.176.1 to 190.24.191.254190.24.191.2554,094
13190.24.192.0/20190.24.192.1 to 190.24.207.254190.24.207.2554,094
14190.24.208.0/20190.24.208.1 to 190.24.223.254190.24.223.2554,094
15190.24.224.0/20190.24.224.1 to 190.24.239.254190.24.239.2554,094
16190.24.240.0/20190.24.240.1 to 190.24.255.254190.24.255.2554,094
17190.25.0.0/20190.25.0.1 to 190.25.15.254190.25.15.2554,094
18190.25.16.0/20190.25.16.1 to 190.25.31.254190.25.31.2554,094
19190.25.32.0/20190.25.32.1 to 190.25.47.254190.25.47.2554,094
20190.25.48.0/20190.25.48.1 to 190.25.63.254190.25.63.2554,094
21190.25.64.0/20190.25.64.1 to 190.25.79.254190.25.79.2554,094
22190.25.80.0/20190.25.80.1 to 190.25.95.254190.25.95.2554,094
23190.25.96.0/20190.25.96.1 to 190.25.111.254190.25.111.2554,094
24190.25.112.0/20190.25.112.1 to 190.25.127.254190.25.127.2554,094
25190.25.128.0/20190.25.128.1 to 190.25.143.254190.25.143.2554,094
26190.25.144.0/20190.25.144.1 to 190.25.159.254190.25.159.2554,094
27190.25.160.0/20190.25.160.1 to 190.25.175.254190.25.175.2554,094
28190.25.176.0/20190.25.176.1 to 190.25.191.254190.25.191.2554,094
29190.25.192.0/20190.25.192.1 to 190.25.207.254190.25.207.2554,094
30190.25.208.0/20190.25.208.1 to 190.25.223.254190.25.223.2554,094
31190.25.224.0/20190.25.224.1 to 190.25.239.254190.25.239.2554,094
32190.25.240.0/20190.25.240.1 to 190.25.255.254190.25.255.2554,094
33190.26.0.0/20190.26.0.1 to 190.26.15.254190.26.15.2554,094
34190.26.16.0/20190.26.16.1 to 190.26.31.254190.26.31.2554,094
35190.26.32.0/20190.26.32.1 to 190.26.47.254190.26.47.2554,094
36190.26.48.0/20190.26.48.1 to 190.26.63.254190.26.63.2554,094
37190.26.64.0/20190.26.64.1 to 190.26.79.254190.26.79.2554,094
38190.26.80.0/20190.26.80.1 to 190.26.95.254190.26.95.2554,094
39190.26.96.0/20190.26.96.1 to 190.26.111.254190.26.111.2554,094
40190.26.112.0/20190.26.112.1 to 190.26.127.254190.26.127.2554,094
41190.26.128.0/20190.26.128.1 to 190.26.143.254190.26.143.2554,094
42190.26.144.0/20190.26.144.1 to 190.26.159.254190.26.159.2554,094
43190.26.160.0/20190.26.160.1 to 190.26.175.254190.26.175.2554,094
44190.26.176.0/20190.26.176.1 to 190.26.191.254190.26.191.2554,094
45190.26.192.0/20190.26.192.1 to 190.26.207.254190.26.207.2554,094
46190.26.208.0/20190.26.208.1 to 190.26.223.254190.26.223.2554,094
47190.26.224.0/20190.26.224.1 to 190.26.239.254190.26.239.2554,094
48190.26.240.0/20190.26.240.1 to 190.26.255.254190.26.255.2554,094
49190.27.0.0/20190.27.0.1 to 190.27.15.254190.27.15.2554,094
50190.27.16.0/20190.27.16.1 to 190.27.31.254190.27.31.2554,094
51190.27.32.0/20190.27.32.1 to 190.27.47.254190.27.47.2554,094
52190.27.48.0/20190.27.48.1 to 190.27.63.254190.27.63.2554,094
53190.27.64.0/20190.27.64.1 to 190.27.79.254190.27.79.2554,094
54190.27.80.0/20190.27.80.1 to 190.27.95.254190.27.95.2554,094
55190.27.96.0/20190.27.96.1 to 190.27.111.254190.27.111.2554,094
56190.27.112.0/20190.27.112.1 to 190.27.127.254190.27.127.2554,094
57190.27.128.0/20190.27.128.1 to 190.27.143.254190.27.143.2554,094
58190.27.144.0/20190.27.144.1 to 190.27.159.254190.27.159.2554,094
59190.27.160.0/20190.27.160.1 to 190.27.175.254190.27.175.2554,094
60190.27.176.0/20190.27.176.1 to 190.27.191.254190.27.191.2554,094
61190.27.192.0/20190.27.192.1 to 190.27.207.254190.27.207.2554,094
62190.27.208.0/20190.27.208.1 to 190.27.223.254190.27.223.2554,094
63190.27.224.0/20190.27.224.1 to 190.27.239.254190.27.239.2554,094
64190.27.240.0/20190.27.240.1 to 190.27.255.254190.27.255.2554,094
65190.28.0.0/20190.28.0.1 to 190.28.15.254190.28.15.2554,094
66190.28.16.0/20190.28.16.1 to 190.28.31.254190.28.31.2554,094
67190.28.32.0/20190.28.32.1 to 190.28.47.254190.28.47.2554,094
68190.28.48.0/20190.28.48.1 to 190.28.63.254190.28.63.2554,094
69190.28.64.0/20190.28.64.1 to 190.28.79.254190.28.79.2554,094
70190.28.80.0/20190.28.80.1 to 190.28.95.254190.28.95.2554,094
71190.28.96.0/20190.28.96.1 to 190.28.111.254190.28.111.2554,094
72190.28.112.0/20190.28.112.1 to 190.28.127.254190.28.127.2554,094
73190.28.128.0/20190.28.128.1 to 190.28.143.254190.28.143.2554,094
74190.28.144.0/20190.28.144.1 to 190.28.159.254190.28.159.2554,094
75190.28.160.0/20190.28.160.1 to 190.28.175.254190.28.175.2554,094
76190.28.176.0/20190.28.176.1 to 190.28.191.254190.28.191.2554,094
77190.28.192.0/20190.28.192.1 to 190.28.207.254190.28.207.2554,094
78190.28.208.0/20190.28.208.1 to 190.28.223.254190.28.223.2554,094
79190.28.224.0/20190.28.224.1 to 190.28.239.254190.28.239.2554,094
80190.28.240.0/20190.28.240.1 to 190.28.255.254190.28.255.2554,094
81190.29.0.0/20190.29.0.1 to 190.29.15.254190.29.15.2554,094
82190.29.16.0/20190.29.16.1 to 190.29.31.254190.29.31.2554,094
83190.29.32.0/20190.29.32.1 to 190.29.47.254190.29.47.2554,094
84190.29.48.0/20190.29.48.1 to 190.29.63.254190.29.63.2554,094
85190.29.64.0/20190.29.64.1 to 190.29.79.254190.29.79.2554,094
86190.29.80.0/20190.29.80.1 to 190.29.95.254190.29.95.2554,094
87190.29.96.0/20190.29.96.1 to 190.29.111.254190.29.111.2554,094
88190.29.112.0/20190.29.112.1 to 190.29.127.254190.29.127.2554,094
89190.29.128.0/20190.29.128.1 to 190.29.143.254190.29.143.2554,094
90190.29.144.0/20190.29.144.1 to 190.29.159.254190.29.159.2554,094
91190.29.160.0/20190.29.160.1 to 190.29.175.254190.29.175.2554,094
92190.29.176.0/20190.29.176.1 to 190.29.191.254190.29.191.2554,094
93190.29.192.0/20190.29.192.1 to 190.29.207.254190.29.207.2554,094
94190.29.208.0/20190.29.208.1 to 190.29.223.254190.29.223.2554,094
95190.29.224.0/20190.29.224.1 to 190.29.239.254190.29.239.2554,094
96190.29.240.0/20190.29.240.1 to 190.29.255.254190.29.255.2554,094
97190.30.0.0/20190.30.0.1 to 190.30.15.254190.30.15.2554,094
98190.30.16.0/20190.30.16.1 to 190.30.31.254190.30.31.2554,094
99190.30.32.0/20190.30.32.1 to 190.30.47.254190.30.47.2554,094
100190.30.48.0/20190.30.48.1 to 190.30.63.254190.30.63.2554,094
101190.30.64.0/20190.30.64.1 to 190.30.79.254190.30.79.2554,094
102190.30.80.0/20190.30.80.1 to 190.30.95.254190.30.95.2554,094
103190.30.96.0/20190.30.96.1 to 190.30.111.254190.30.111.2554,094
104190.30.112.0/20190.30.112.1 to 190.30.127.254190.30.127.2554,094
105190.30.128.0/20190.30.128.1 to 190.30.143.254190.30.143.2554,094
106190.30.144.0/20190.30.144.1 to 190.30.159.254190.30.159.2554,094
107190.30.160.0/20190.30.160.1 to 190.30.175.254190.30.175.2554,094
108190.30.176.0/20190.30.176.1 to 190.30.191.254190.30.191.2554,094
109190.30.192.0/20190.30.192.1 to 190.30.207.254190.30.207.2554,094
110190.30.208.0/20190.30.208.1 to 190.30.223.254190.30.223.2554,094
111190.30.224.0/20190.30.224.1 to 190.30.239.254190.30.239.2554,094
112190.30.240.0/20190.30.240.1 to 190.30.255.254190.30.255.2554,094
113190.31.0.0/20190.31.0.1 to 190.31.15.254190.31.15.2554,094
114190.31.16.0/20190.31.16.1 to 190.31.31.254190.31.31.2554,094
115190.31.32.0/20190.31.32.1 to 190.31.47.254190.31.47.2554,094
116190.31.48.0/20190.31.48.1 to 190.31.63.254190.31.63.2554,094
117190.31.64.0/20190.31.64.1 to 190.31.79.254190.31.79.2554,094
118190.31.80.0/20190.31.80.1 to 190.31.95.254190.31.95.2554,094
119190.31.96.0/20190.31.96.1 to 190.31.111.254190.31.111.2554,094
120190.31.112.0/20190.31.112.1 to 190.31.127.254190.31.127.2554,094
121190.31.128.0/20190.31.128.1 to 190.31.143.254190.31.143.2554,094
122190.31.144.0/20190.31.144.1 to 190.31.159.254190.31.159.2554,094
123190.31.160.0/20190.31.160.1 to 190.31.175.254190.31.175.2554,094
124190.31.176.0/20190.31.176.1 to 190.31.191.254190.31.191.2554,094
125190.31.192.0/20190.31.192.1 to 190.31.207.254190.31.207.2554,094
126190.31.208.0/20190.31.208.1 to 190.31.223.254190.31.223.2554,094
127190.31.224.0/20190.31.224.1 to 190.31.239.254190.31.239.2554,094
128190.31.240.0/20190.31.240.1 to 190.31.255.254190.31.255.2554,094

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.