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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.

Network134.3.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
134.3.64.0
Broadcast address
134.3.95.255
First usable
134.3.64.1
Last usable
134.3.95.254
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 86034000 · Integer 2248359936 to 2248368127
Reverse DNS zones
64.3.134.in-addr.arpa
65.3.134.in-addr.arpa
66.3.134.in-addr.arpa
67.3.134.in-addr.arpa
68.3.134.in-addr.arpa
69.3.134.in-addr.arpa
70.3.134.in-addr.arpa
71.3.134.in-addr.arpa
72.3.134.in-addr.arpa
73.3.134.in-addr.arpa
74.3.134.in-addr.arpa
75.3.134.in-addr.arpa
76.3.134.in-addr.arpa
77.3.134.in-addr.arpa
78.3.134.in-addr.arpa
79.3.134.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
Address10000110.00000011.01000000.00000000134.3.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10000110.00000011.01000000.00000000134.3.64.0
Broadcast10000110.00000011.01011111.11111111134.3.95.255
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)

134.3.64.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1134.3.64.0/26134.3.64.1 to 134.3.64.62134.3.64.6362
2134.3.64.64/26134.3.64.65 to 134.3.64.126134.3.64.12762
3134.3.64.128/26134.3.64.129 to 134.3.64.190134.3.64.19162
4134.3.64.192/26134.3.64.193 to 134.3.64.254134.3.64.25562
5134.3.65.0/26134.3.65.1 to 134.3.65.62134.3.65.6362
6134.3.65.64/26134.3.65.65 to 134.3.65.126134.3.65.12762
7134.3.65.128/26134.3.65.129 to 134.3.65.190134.3.65.19162
8134.3.65.192/26134.3.65.193 to 134.3.65.254134.3.65.25562
9134.3.66.0/26134.3.66.1 to 134.3.66.62134.3.66.6362
10134.3.66.64/26134.3.66.65 to 134.3.66.126134.3.66.12762
11134.3.66.128/26134.3.66.129 to 134.3.66.190134.3.66.19162
12134.3.66.192/26134.3.66.193 to 134.3.66.254134.3.66.25562
13134.3.67.0/26134.3.67.1 to 134.3.67.62134.3.67.6362
14134.3.67.64/26134.3.67.65 to 134.3.67.126134.3.67.12762
15134.3.67.128/26134.3.67.129 to 134.3.67.190134.3.67.19162
16134.3.67.192/26134.3.67.193 to 134.3.67.254134.3.67.25562
17134.3.68.0/26134.3.68.1 to 134.3.68.62134.3.68.6362
18134.3.68.64/26134.3.68.65 to 134.3.68.126134.3.68.12762
19134.3.68.128/26134.3.68.129 to 134.3.68.190134.3.68.19162
20134.3.68.192/26134.3.68.193 to 134.3.68.254134.3.68.25562
21134.3.69.0/26134.3.69.1 to 134.3.69.62134.3.69.6362
22134.3.69.64/26134.3.69.65 to 134.3.69.126134.3.69.12762
23134.3.69.128/26134.3.69.129 to 134.3.69.190134.3.69.19162
24134.3.69.192/26134.3.69.193 to 134.3.69.254134.3.69.25562
25134.3.70.0/26134.3.70.1 to 134.3.70.62134.3.70.6362
26134.3.70.64/26134.3.70.65 to 134.3.70.126134.3.70.12762
27134.3.70.128/26134.3.70.129 to 134.3.70.190134.3.70.19162
28134.3.70.192/26134.3.70.193 to 134.3.70.254134.3.70.25562
29134.3.71.0/26134.3.71.1 to 134.3.71.62134.3.71.6362
30134.3.71.64/26134.3.71.65 to 134.3.71.126134.3.71.12762
31134.3.71.128/26134.3.71.129 to 134.3.71.190134.3.71.19162
32134.3.71.192/26134.3.71.193 to 134.3.71.254134.3.71.25562
33134.3.72.0/26134.3.72.1 to 134.3.72.62134.3.72.6362
34134.3.72.64/26134.3.72.65 to 134.3.72.126134.3.72.12762
35134.3.72.128/26134.3.72.129 to 134.3.72.190134.3.72.19162
36134.3.72.192/26134.3.72.193 to 134.3.72.254134.3.72.25562
37134.3.73.0/26134.3.73.1 to 134.3.73.62134.3.73.6362
38134.3.73.64/26134.3.73.65 to 134.3.73.126134.3.73.12762
39134.3.73.128/26134.3.73.129 to 134.3.73.190134.3.73.19162
40134.3.73.192/26134.3.73.193 to 134.3.73.254134.3.73.25562
41134.3.74.0/26134.3.74.1 to 134.3.74.62134.3.74.6362
42134.3.74.64/26134.3.74.65 to 134.3.74.126134.3.74.12762
43134.3.74.128/26134.3.74.129 to 134.3.74.190134.3.74.19162
44134.3.74.192/26134.3.74.193 to 134.3.74.254134.3.74.25562
45134.3.75.0/26134.3.75.1 to 134.3.75.62134.3.75.6362
46134.3.75.64/26134.3.75.65 to 134.3.75.126134.3.75.12762
47134.3.75.128/26134.3.75.129 to 134.3.75.190134.3.75.19162
48134.3.75.192/26134.3.75.193 to 134.3.75.254134.3.75.25562
49134.3.76.0/26134.3.76.1 to 134.3.76.62134.3.76.6362
50134.3.76.64/26134.3.76.65 to 134.3.76.126134.3.76.12762
51134.3.76.128/26134.3.76.129 to 134.3.76.190134.3.76.19162
52134.3.76.192/26134.3.76.193 to 134.3.76.254134.3.76.25562
53134.3.77.0/26134.3.77.1 to 134.3.77.62134.3.77.6362
54134.3.77.64/26134.3.77.65 to 134.3.77.126134.3.77.12762
55134.3.77.128/26134.3.77.129 to 134.3.77.190134.3.77.19162
56134.3.77.192/26134.3.77.193 to 134.3.77.254134.3.77.25562
57134.3.78.0/26134.3.78.1 to 134.3.78.62134.3.78.6362
58134.3.78.64/26134.3.78.65 to 134.3.78.126134.3.78.12762
59134.3.78.128/26134.3.78.129 to 134.3.78.190134.3.78.19162
60134.3.78.192/26134.3.78.193 to 134.3.78.254134.3.78.25562
61134.3.79.0/26134.3.79.1 to 134.3.79.62134.3.79.6362
62134.3.79.64/26134.3.79.65 to 134.3.79.126134.3.79.12762
63134.3.79.128/26134.3.79.129 to 134.3.79.190134.3.79.19162
64134.3.79.192/26134.3.79.193 to 134.3.79.254134.3.79.25562
65134.3.80.0/26134.3.80.1 to 134.3.80.62134.3.80.6362
66134.3.80.64/26134.3.80.65 to 134.3.80.126134.3.80.12762
67134.3.80.128/26134.3.80.129 to 134.3.80.190134.3.80.19162
68134.3.80.192/26134.3.80.193 to 134.3.80.254134.3.80.25562
69134.3.81.0/26134.3.81.1 to 134.3.81.62134.3.81.6362
70134.3.81.64/26134.3.81.65 to 134.3.81.126134.3.81.12762
71134.3.81.128/26134.3.81.129 to 134.3.81.190134.3.81.19162
72134.3.81.192/26134.3.81.193 to 134.3.81.254134.3.81.25562
73134.3.82.0/26134.3.82.1 to 134.3.82.62134.3.82.6362
74134.3.82.64/26134.3.82.65 to 134.3.82.126134.3.82.12762
75134.3.82.128/26134.3.82.129 to 134.3.82.190134.3.82.19162
76134.3.82.192/26134.3.82.193 to 134.3.82.254134.3.82.25562
77134.3.83.0/26134.3.83.1 to 134.3.83.62134.3.83.6362
78134.3.83.64/26134.3.83.65 to 134.3.83.126134.3.83.12762
79134.3.83.128/26134.3.83.129 to 134.3.83.190134.3.83.19162
80134.3.83.192/26134.3.83.193 to 134.3.83.254134.3.83.25562
81134.3.84.0/26134.3.84.1 to 134.3.84.62134.3.84.6362
82134.3.84.64/26134.3.84.65 to 134.3.84.126134.3.84.12762
83134.3.84.128/26134.3.84.129 to 134.3.84.190134.3.84.19162
84134.3.84.192/26134.3.84.193 to 134.3.84.254134.3.84.25562
85134.3.85.0/26134.3.85.1 to 134.3.85.62134.3.85.6362
86134.3.85.64/26134.3.85.65 to 134.3.85.126134.3.85.12762
87134.3.85.128/26134.3.85.129 to 134.3.85.190134.3.85.19162
88134.3.85.192/26134.3.85.193 to 134.3.85.254134.3.85.25562
89134.3.86.0/26134.3.86.1 to 134.3.86.62134.3.86.6362
90134.3.86.64/26134.3.86.65 to 134.3.86.126134.3.86.12762
91134.3.86.128/26134.3.86.129 to 134.3.86.190134.3.86.19162
92134.3.86.192/26134.3.86.193 to 134.3.86.254134.3.86.25562
93134.3.87.0/26134.3.87.1 to 134.3.87.62134.3.87.6362
94134.3.87.64/26134.3.87.65 to 134.3.87.126134.3.87.12762
95134.3.87.128/26134.3.87.129 to 134.3.87.190134.3.87.19162
96134.3.87.192/26134.3.87.193 to 134.3.87.254134.3.87.25562
97134.3.88.0/26134.3.88.1 to 134.3.88.62134.3.88.6362
98134.3.88.64/26134.3.88.65 to 134.3.88.126134.3.88.12762
99134.3.88.128/26134.3.88.129 to 134.3.88.190134.3.88.19162
100134.3.88.192/26134.3.88.193 to 134.3.88.254134.3.88.25562
101134.3.89.0/26134.3.89.1 to 134.3.89.62134.3.89.6362
102134.3.89.64/26134.3.89.65 to 134.3.89.126134.3.89.12762
103134.3.89.128/26134.3.89.129 to 134.3.89.190134.3.89.19162
104134.3.89.192/26134.3.89.193 to 134.3.89.254134.3.89.25562
105134.3.90.0/26134.3.90.1 to 134.3.90.62134.3.90.6362
106134.3.90.64/26134.3.90.65 to 134.3.90.126134.3.90.12762
107134.3.90.128/26134.3.90.129 to 134.3.90.190134.3.90.19162
108134.3.90.192/26134.3.90.193 to 134.3.90.254134.3.90.25562
109134.3.91.0/26134.3.91.1 to 134.3.91.62134.3.91.6362
110134.3.91.64/26134.3.91.65 to 134.3.91.126134.3.91.12762
111134.3.91.128/26134.3.91.129 to 134.3.91.190134.3.91.19162
112134.3.91.192/26134.3.91.193 to 134.3.91.254134.3.91.25562
113134.3.92.0/26134.3.92.1 to 134.3.92.62134.3.92.6362
114134.3.92.64/26134.3.92.65 to 134.3.92.126134.3.92.12762
115134.3.92.128/26134.3.92.129 to 134.3.92.190134.3.92.19162
116134.3.92.192/26134.3.92.193 to 134.3.92.254134.3.92.25562
117134.3.93.0/26134.3.93.1 to 134.3.93.62134.3.93.6362
118134.3.93.64/26134.3.93.65 to 134.3.93.126134.3.93.12762
119134.3.93.128/26134.3.93.129 to 134.3.93.190134.3.93.19162
120134.3.93.192/26134.3.93.193 to 134.3.93.254134.3.93.25562
121134.3.94.0/26134.3.94.1 to 134.3.94.62134.3.94.6362
122134.3.94.64/26134.3.94.65 to 134.3.94.126134.3.94.12762
123134.3.94.128/26134.3.94.129 to 134.3.94.190134.3.94.19162
124134.3.94.192/26134.3.94.193 to 134.3.94.254134.3.94.25562
125134.3.95.0/26134.3.95.1 to 134.3.95.62134.3.95.6362
126134.3.95.64/26134.3.95.65 to 134.3.95.126134.3.95.12762
127134.3.95.128/26134.3.95.129 to 134.3.95.190134.3.95.19162
128134.3.95.192/26134.3.95.193 to 134.3.95.254134.3.95.25562

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.