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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.

Network191.26.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
191.26.64.0
Broadcast address
191.26.95.255
First usable
191.26.64.1
Last usable
191.26.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex BF1A4000 · Integer 3206168576 to 3206176767
Reverse DNS zones
64.26.191.in-addr.arpa
65.26.191.in-addr.arpa
66.26.191.in-addr.arpa
67.26.191.in-addr.arpa
68.26.191.in-addr.arpa
69.26.191.in-addr.arpa
70.26.191.in-addr.arpa
71.26.191.in-addr.arpa
72.26.191.in-addr.arpa
73.26.191.in-addr.arpa
74.26.191.in-addr.arpa
75.26.191.in-addr.arpa
76.26.191.in-addr.arpa
77.26.191.in-addr.arpa
78.26.191.in-addr.arpa
79.26.191.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111111.00011010.01000000.00000000191.26.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10111111.00011010.01000000.00000000191.26.64.0
Broadcast10111111.00011010.01011111.11111111191.26.95.255
Split into smaller subnets/26
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

191.26.64.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1191.26.64.0/26191.26.64.1 to 191.26.64.62191.26.64.6362
2191.26.64.64/26191.26.64.65 to 191.26.64.126191.26.64.12762
3191.26.64.128/26191.26.64.129 to 191.26.64.190191.26.64.19162
4191.26.64.192/26191.26.64.193 to 191.26.64.254191.26.64.25562
5191.26.65.0/26191.26.65.1 to 191.26.65.62191.26.65.6362
6191.26.65.64/26191.26.65.65 to 191.26.65.126191.26.65.12762
7191.26.65.128/26191.26.65.129 to 191.26.65.190191.26.65.19162
8191.26.65.192/26191.26.65.193 to 191.26.65.254191.26.65.25562
9191.26.66.0/26191.26.66.1 to 191.26.66.62191.26.66.6362
10191.26.66.64/26191.26.66.65 to 191.26.66.126191.26.66.12762
11191.26.66.128/26191.26.66.129 to 191.26.66.190191.26.66.19162
12191.26.66.192/26191.26.66.193 to 191.26.66.254191.26.66.25562
13191.26.67.0/26191.26.67.1 to 191.26.67.62191.26.67.6362
14191.26.67.64/26191.26.67.65 to 191.26.67.126191.26.67.12762
15191.26.67.128/26191.26.67.129 to 191.26.67.190191.26.67.19162
16191.26.67.192/26191.26.67.193 to 191.26.67.254191.26.67.25562
17191.26.68.0/26191.26.68.1 to 191.26.68.62191.26.68.6362
18191.26.68.64/26191.26.68.65 to 191.26.68.126191.26.68.12762
19191.26.68.128/26191.26.68.129 to 191.26.68.190191.26.68.19162
20191.26.68.192/26191.26.68.193 to 191.26.68.254191.26.68.25562
21191.26.69.0/26191.26.69.1 to 191.26.69.62191.26.69.6362
22191.26.69.64/26191.26.69.65 to 191.26.69.126191.26.69.12762
23191.26.69.128/26191.26.69.129 to 191.26.69.190191.26.69.19162
24191.26.69.192/26191.26.69.193 to 191.26.69.254191.26.69.25562
25191.26.70.0/26191.26.70.1 to 191.26.70.62191.26.70.6362
26191.26.70.64/26191.26.70.65 to 191.26.70.126191.26.70.12762
27191.26.70.128/26191.26.70.129 to 191.26.70.190191.26.70.19162
28191.26.70.192/26191.26.70.193 to 191.26.70.254191.26.70.25562
29191.26.71.0/26191.26.71.1 to 191.26.71.62191.26.71.6362
30191.26.71.64/26191.26.71.65 to 191.26.71.126191.26.71.12762
31191.26.71.128/26191.26.71.129 to 191.26.71.190191.26.71.19162
32191.26.71.192/26191.26.71.193 to 191.26.71.254191.26.71.25562
33191.26.72.0/26191.26.72.1 to 191.26.72.62191.26.72.6362
34191.26.72.64/26191.26.72.65 to 191.26.72.126191.26.72.12762
35191.26.72.128/26191.26.72.129 to 191.26.72.190191.26.72.19162
36191.26.72.192/26191.26.72.193 to 191.26.72.254191.26.72.25562
37191.26.73.0/26191.26.73.1 to 191.26.73.62191.26.73.6362
38191.26.73.64/26191.26.73.65 to 191.26.73.126191.26.73.12762
39191.26.73.128/26191.26.73.129 to 191.26.73.190191.26.73.19162
40191.26.73.192/26191.26.73.193 to 191.26.73.254191.26.73.25562
41191.26.74.0/26191.26.74.1 to 191.26.74.62191.26.74.6362
42191.26.74.64/26191.26.74.65 to 191.26.74.126191.26.74.12762
43191.26.74.128/26191.26.74.129 to 191.26.74.190191.26.74.19162
44191.26.74.192/26191.26.74.193 to 191.26.74.254191.26.74.25562
45191.26.75.0/26191.26.75.1 to 191.26.75.62191.26.75.6362
46191.26.75.64/26191.26.75.65 to 191.26.75.126191.26.75.12762
47191.26.75.128/26191.26.75.129 to 191.26.75.190191.26.75.19162
48191.26.75.192/26191.26.75.193 to 191.26.75.254191.26.75.25562
49191.26.76.0/26191.26.76.1 to 191.26.76.62191.26.76.6362
50191.26.76.64/26191.26.76.65 to 191.26.76.126191.26.76.12762
51191.26.76.128/26191.26.76.129 to 191.26.76.190191.26.76.19162
52191.26.76.192/26191.26.76.193 to 191.26.76.254191.26.76.25562
53191.26.77.0/26191.26.77.1 to 191.26.77.62191.26.77.6362
54191.26.77.64/26191.26.77.65 to 191.26.77.126191.26.77.12762
55191.26.77.128/26191.26.77.129 to 191.26.77.190191.26.77.19162
56191.26.77.192/26191.26.77.193 to 191.26.77.254191.26.77.25562
57191.26.78.0/26191.26.78.1 to 191.26.78.62191.26.78.6362
58191.26.78.64/26191.26.78.65 to 191.26.78.126191.26.78.12762
59191.26.78.128/26191.26.78.129 to 191.26.78.190191.26.78.19162
60191.26.78.192/26191.26.78.193 to 191.26.78.254191.26.78.25562
61191.26.79.0/26191.26.79.1 to 191.26.79.62191.26.79.6362
62191.26.79.64/26191.26.79.65 to 191.26.79.126191.26.79.12762
63191.26.79.128/26191.26.79.129 to 191.26.79.190191.26.79.19162
64191.26.79.192/26191.26.79.193 to 191.26.79.254191.26.79.25562
65191.26.80.0/26191.26.80.1 to 191.26.80.62191.26.80.6362
66191.26.80.64/26191.26.80.65 to 191.26.80.126191.26.80.12762
67191.26.80.128/26191.26.80.129 to 191.26.80.190191.26.80.19162
68191.26.80.192/26191.26.80.193 to 191.26.80.254191.26.80.25562
69191.26.81.0/26191.26.81.1 to 191.26.81.62191.26.81.6362
70191.26.81.64/26191.26.81.65 to 191.26.81.126191.26.81.12762
71191.26.81.128/26191.26.81.129 to 191.26.81.190191.26.81.19162
72191.26.81.192/26191.26.81.193 to 191.26.81.254191.26.81.25562
73191.26.82.0/26191.26.82.1 to 191.26.82.62191.26.82.6362
74191.26.82.64/26191.26.82.65 to 191.26.82.126191.26.82.12762
75191.26.82.128/26191.26.82.129 to 191.26.82.190191.26.82.19162
76191.26.82.192/26191.26.82.193 to 191.26.82.254191.26.82.25562
77191.26.83.0/26191.26.83.1 to 191.26.83.62191.26.83.6362
78191.26.83.64/26191.26.83.65 to 191.26.83.126191.26.83.12762
79191.26.83.128/26191.26.83.129 to 191.26.83.190191.26.83.19162
80191.26.83.192/26191.26.83.193 to 191.26.83.254191.26.83.25562
81191.26.84.0/26191.26.84.1 to 191.26.84.62191.26.84.6362
82191.26.84.64/26191.26.84.65 to 191.26.84.126191.26.84.12762
83191.26.84.128/26191.26.84.129 to 191.26.84.190191.26.84.19162
84191.26.84.192/26191.26.84.193 to 191.26.84.254191.26.84.25562
85191.26.85.0/26191.26.85.1 to 191.26.85.62191.26.85.6362
86191.26.85.64/26191.26.85.65 to 191.26.85.126191.26.85.12762
87191.26.85.128/26191.26.85.129 to 191.26.85.190191.26.85.19162
88191.26.85.192/26191.26.85.193 to 191.26.85.254191.26.85.25562
89191.26.86.0/26191.26.86.1 to 191.26.86.62191.26.86.6362
90191.26.86.64/26191.26.86.65 to 191.26.86.126191.26.86.12762
91191.26.86.128/26191.26.86.129 to 191.26.86.190191.26.86.19162
92191.26.86.192/26191.26.86.193 to 191.26.86.254191.26.86.25562
93191.26.87.0/26191.26.87.1 to 191.26.87.62191.26.87.6362
94191.26.87.64/26191.26.87.65 to 191.26.87.126191.26.87.12762
95191.26.87.128/26191.26.87.129 to 191.26.87.190191.26.87.19162
96191.26.87.192/26191.26.87.193 to 191.26.87.254191.26.87.25562
97191.26.88.0/26191.26.88.1 to 191.26.88.62191.26.88.6362
98191.26.88.64/26191.26.88.65 to 191.26.88.126191.26.88.12762
99191.26.88.128/26191.26.88.129 to 191.26.88.190191.26.88.19162
100191.26.88.192/26191.26.88.193 to 191.26.88.254191.26.88.25562
101191.26.89.0/26191.26.89.1 to 191.26.89.62191.26.89.6362
102191.26.89.64/26191.26.89.65 to 191.26.89.126191.26.89.12762
103191.26.89.128/26191.26.89.129 to 191.26.89.190191.26.89.19162
104191.26.89.192/26191.26.89.193 to 191.26.89.254191.26.89.25562
105191.26.90.0/26191.26.90.1 to 191.26.90.62191.26.90.6362
106191.26.90.64/26191.26.90.65 to 191.26.90.126191.26.90.12762
107191.26.90.128/26191.26.90.129 to 191.26.90.190191.26.90.19162
108191.26.90.192/26191.26.90.193 to 191.26.90.254191.26.90.25562
109191.26.91.0/26191.26.91.1 to 191.26.91.62191.26.91.6362
110191.26.91.64/26191.26.91.65 to 191.26.91.126191.26.91.12762
111191.26.91.128/26191.26.91.129 to 191.26.91.190191.26.91.19162
112191.26.91.192/26191.26.91.193 to 191.26.91.254191.26.91.25562
113191.26.92.0/26191.26.92.1 to 191.26.92.62191.26.92.6362
114191.26.92.64/26191.26.92.65 to 191.26.92.126191.26.92.12762
115191.26.92.128/26191.26.92.129 to 191.26.92.190191.26.92.19162
116191.26.92.192/26191.26.92.193 to 191.26.92.254191.26.92.25562
117191.26.93.0/26191.26.93.1 to 191.26.93.62191.26.93.6362
118191.26.93.64/26191.26.93.65 to 191.26.93.126191.26.93.12762
119191.26.93.128/26191.26.93.129 to 191.26.93.190191.26.93.19162
120191.26.93.192/26191.26.93.193 to 191.26.93.254191.26.93.25562
121191.26.94.0/26191.26.94.1 to 191.26.94.62191.26.94.6362
122191.26.94.64/26191.26.94.65 to 191.26.94.126191.26.94.12762
123191.26.94.128/26191.26.94.129 to 191.26.94.190191.26.94.19162
124191.26.94.192/26191.26.94.193 to 191.26.94.254191.26.94.25562
125191.26.95.0/26191.26.95.1 to 191.26.95.62191.26.95.6362
126191.26.95.64/26191.26.95.65 to 191.26.95.126191.26.95.12762
127191.26.95.128/26191.26.95.129 to 191.26.95.190191.26.95.19162
128191.26.95.192/26191.26.95.193 to 191.26.95.254191.26.95.25562

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.