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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.

Network164.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
164.78.0.0
Broadcast address
164.78.127.255
First usable
164.78.0.1
Last usable
164.78.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex A44E0000 · Integer 2756575232 to 2756607999
Reverse DNS zones
0.78.164.in-addr.arpa
1.78.164.in-addr.arpa
2.78.164.in-addr.arpa
3.78.164.in-addr.arpa
4.78.164.in-addr.arpa
5.78.164.in-addr.arpa
6.78.164.in-addr.arpa
7.78.164.in-addr.arpa
8.78.164.in-addr.arpa
9.78.164.in-addr.arpa
10.78.164.in-addr.arpa
11.78.164.in-addr.arpa
12.78.164.in-addr.arpa
13.78.164.in-addr.arpa
14.78.164.in-addr.arpa
15.78.164.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100100.01001110.00000000.00000000164.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10100100.01001110.00000000.00000000164.78.0.0
Broadcast10100100.01001110.01111111.11111111164.78.127.255
Split into smaller subnets/24

164.78.0.0/17 makes 128 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.78.0.0/24164.78.0.1 to 164.78.0.254164.78.0.255254
2164.78.1.0/24164.78.1.1 to 164.78.1.254164.78.1.255254
3164.78.2.0/24164.78.2.1 to 164.78.2.254164.78.2.255254
4164.78.3.0/24164.78.3.1 to 164.78.3.254164.78.3.255254
5164.78.4.0/24164.78.4.1 to 164.78.4.254164.78.4.255254
6164.78.5.0/24164.78.5.1 to 164.78.5.254164.78.5.255254
7164.78.6.0/24164.78.6.1 to 164.78.6.254164.78.6.255254
8164.78.7.0/24164.78.7.1 to 164.78.7.254164.78.7.255254
9164.78.8.0/24164.78.8.1 to 164.78.8.254164.78.8.255254
10164.78.9.0/24164.78.9.1 to 164.78.9.254164.78.9.255254
11164.78.10.0/24164.78.10.1 to 164.78.10.254164.78.10.255254
12164.78.11.0/24164.78.11.1 to 164.78.11.254164.78.11.255254
13164.78.12.0/24164.78.12.1 to 164.78.12.254164.78.12.255254
14164.78.13.0/24164.78.13.1 to 164.78.13.254164.78.13.255254
15164.78.14.0/24164.78.14.1 to 164.78.14.254164.78.14.255254
16164.78.15.0/24164.78.15.1 to 164.78.15.254164.78.15.255254
17164.78.16.0/24164.78.16.1 to 164.78.16.254164.78.16.255254
18164.78.17.0/24164.78.17.1 to 164.78.17.254164.78.17.255254
19164.78.18.0/24164.78.18.1 to 164.78.18.254164.78.18.255254
20164.78.19.0/24164.78.19.1 to 164.78.19.254164.78.19.255254
21164.78.20.0/24164.78.20.1 to 164.78.20.254164.78.20.255254
22164.78.21.0/24164.78.21.1 to 164.78.21.254164.78.21.255254
23164.78.22.0/24164.78.22.1 to 164.78.22.254164.78.22.255254
24164.78.23.0/24164.78.23.1 to 164.78.23.254164.78.23.255254
25164.78.24.0/24164.78.24.1 to 164.78.24.254164.78.24.255254
26164.78.25.0/24164.78.25.1 to 164.78.25.254164.78.25.255254
27164.78.26.0/24164.78.26.1 to 164.78.26.254164.78.26.255254
28164.78.27.0/24164.78.27.1 to 164.78.27.254164.78.27.255254
29164.78.28.0/24164.78.28.1 to 164.78.28.254164.78.28.255254
30164.78.29.0/24164.78.29.1 to 164.78.29.254164.78.29.255254
31164.78.30.0/24164.78.30.1 to 164.78.30.254164.78.30.255254
32164.78.31.0/24164.78.31.1 to 164.78.31.254164.78.31.255254
33164.78.32.0/24164.78.32.1 to 164.78.32.254164.78.32.255254
34164.78.33.0/24164.78.33.1 to 164.78.33.254164.78.33.255254
35164.78.34.0/24164.78.34.1 to 164.78.34.254164.78.34.255254
36164.78.35.0/24164.78.35.1 to 164.78.35.254164.78.35.255254
37164.78.36.0/24164.78.36.1 to 164.78.36.254164.78.36.255254
38164.78.37.0/24164.78.37.1 to 164.78.37.254164.78.37.255254
39164.78.38.0/24164.78.38.1 to 164.78.38.254164.78.38.255254
40164.78.39.0/24164.78.39.1 to 164.78.39.254164.78.39.255254
41164.78.40.0/24164.78.40.1 to 164.78.40.254164.78.40.255254
42164.78.41.0/24164.78.41.1 to 164.78.41.254164.78.41.255254
43164.78.42.0/24164.78.42.1 to 164.78.42.254164.78.42.255254
44164.78.43.0/24164.78.43.1 to 164.78.43.254164.78.43.255254
45164.78.44.0/24164.78.44.1 to 164.78.44.254164.78.44.255254
46164.78.45.0/24164.78.45.1 to 164.78.45.254164.78.45.255254
47164.78.46.0/24164.78.46.1 to 164.78.46.254164.78.46.255254
48164.78.47.0/24164.78.47.1 to 164.78.47.254164.78.47.255254
49164.78.48.0/24164.78.48.1 to 164.78.48.254164.78.48.255254
50164.78.49.0/24164.78.49.1 to 164.78.49.254164.78.49.255254
51164.78.50.0/24164.78.50.1 to 164.78.50.254164.78.50.255254
52164.78.51.0/24164.78.51.1 to 164.78.51.254164.78.51.255254
53164.78.52.0/24164.78.52.1 to 164.78.52.254164.78.52.255254
54164.78.53.0/24164.78.53.1 to 164.78.53.254164.78.53.255254
55164.78.54.0/24164.78.54.1 to 164.78.54.254164.78.54.255254
56164.78.55.0/24164.78.55.1 to 164.78.55.254164.78.55.255254
57164.78.56.0/24164.78.56.1 to 164.78.56.254164.78.56.255254
58164.78.57.0/24164.78.57.1 to 164.78.57.254164.78.57.255254
59164.78.58.0/24164.78.58.1 to 164.78.58.254164.78.58.255254
60164.78.59.0/24164.78.59.1 to 164.78.59.254164.78.59.255254
61164.78.60.0/24164.78.60.1 to 164.78.60.254164.78.60.255254
62164.78.61.0/24164.78.61.1 to 164.78.61.254164.78.61.255254
63164.78.62.0/24164.78.62.1 to 164.78.62.254164.78.62.255254
64164.78.63.0/24164.78.63.1 to 164.78.63.254164.78.63.255254
65164.78.64.0/24164.78.64.1 to 164.78.64.254164.78.64.255254
66164.78.65.0/24164.78.65.1 to 164.78.65.254164.78.65.255254
67164.78.66.0/24164.78.66.1 to 164.78.66.254164.78.66.255254
68164.78.67.0/24164.78.67.1 to 164.78.67.254164.78.67.255254
69164.78.68.0/24164.78.68.1 to 164.78.68.254164.78.68.255254
70164.78.69.0/24164.78.69.1 to 164.78.69.254164.78.69.255254
71164.78.70.0/24164.78.70.1 to 164.78.70.254164.78.70.255254
72164.78.71.0/24164.78.71.1 to 164.78.71.254164.78.71.255254
73164.78.72.0/24164.78.72.1 to 164.78.72.254164.78.72.255254
74164.78.73.0/24164.78.73.1 to 164.78.73.254164.78.73.255254
75164.78.74.0/24164.78.74.1 to 164.78.74.254164.78.74.255254
76164.78.75.0/24164.78.75.1 to 164.78.75.254164.78.75.255254
77164.78.76.0/24164.78.76.1 to 164.78.76.254164.78.76.255254
78164.78.77.0/24164.78.77.1 to 164.78.77.254164.78.77.255254
79164.78.78.0/24164.78.78.1 to 164.78.78.254164.78.78.255254
80164.78.79.0/24164.78.79.1 to 164.78.79.254164.78.79.255254
81164.78.80.0/24164.78.80.1 to 164.78.80.254164.78.80.255254
82164.78.81.0/24164.78.81.1 to 164.78.81.254164.78.81.255254
83164.78.82.0/24164.78.82.1 to 164.78.82.254164.78.82.255254
84164.78.83.0/24164.78.83.1 to 164.78.83.254164.78.83.255254
85164.78.84.0/24164.78.84.1 to 164.78.84.254164.78.84.255254
86164.78.85.0/24164.78.85.1 to 164.78.85.254164.78.85.255254
87164.78.86.0/24164.78.86.1 to 164.78.86.254164.78.86.255254
88164.78.87.0/24164.78.87.1 to 164.78.87.254164.78.87.255254
89164.78.88.0/24164.78.88.1 to 164.78.88.254164.78.88.255254
90164.78.89.0/24164.78.89.1 to 164.78.89.254164.78.89.255254
91164.78.90.0/24164.78.90.1 to 164.78.90.254164.78.90.255254
92164.78.91.0/24164.78.91.1 to 164.78.91.254164.78.91.255254
93164.78.92.0/24164.78.92.1 to 164.78.92.254164.78.92.255254
94164.78.93.0/24164.78.93.1 to 164.78.93.254164.78.93.255254
95164.78.94.0/24164.78.94.1 to 164.78.94.254164.78.94.255254
96164.78.95.0/24164.78.95.1 to 164.78.95.254164.78.95.255254
97164.78.96.0/24164.78.96.1 to 164.78.96.254164.78.96.255254
98164.78.97.0/24164.78.97.1 to 164.78.97.254164.78.97.255254
99164.78.98.0/24164.78.98.1 to 164.78.98.254164.78.98.255254
100164.78.99.0/24164.78.99.1 to 164.78.99.254164.78.99.255254
101164.78.100.0/24164.78.100.1 to 164.78.100.254164.78.100.255254
102164.78.101.0/24164.78.101.1 to 164.78.101.254164.78.101.255254
103164.78.102.0/24164.78.102.1 to 164.78.102.254164.78.102.255254
104164.78.103.0/24164.78.103.1 to 164.78.103.254164.78.103.255254
105164.78.104.0/24164.78.104.1 to 164.78.104.254164.78.104.255254
106164.78.105.0/24164.78.105.1 to 164.78.105.254164.78.105.255254
107164.78.106.0/24164.78.106.1 to 164.78.106.254164.78.106.255254
108164.78.107.0/24164.78.107.1 to 164.78.107.254164.78.107.255254
109164.78.108.0/24164.78.108.1 to 164.78.108.254164.78.108.255254
110164.78.109.0/24164.78.109.1 to 164.78.109.254164.78.109.255254
111164.78.110.0/24164.78.110.1 to 164.78.110.254164.78.110.255254
112164.78.111.0/24164.78.111.1 to 164.78.111.254164.78.111.255254
113164.78.112.0/24164.78.112.1 to 164.78.112.254164.78.112.255254
114164.78.113.0/24164.78.113.1 to 164.78.113.254164.78.113.255254
115164.78.114.0/24164.78.114.1 to 164.78.114.254164.78.114.255254
116164.78.115.0/24164.78.115.1 to 164.78.115.254164.78.115.255254
117164.78.116.0/24164.78.116.1 to 164.78.116.254164.78.116.255254
118164.78.117.0/24164.78.117.1 to 164.78.117.254164.78.117.255254
119164.78.118.0/24164.78.118.1 to 164.78.118.254164.78.118.255254
120164.78.119.0/24164.78.119.1 to 164.78.119.254164.78.119.255254
121164.78.120.0/24164.78.120.1 to 164.78.120.254164.78.120.255254
122164.78.121.0/24164.78.121.1 to 164.78.121.254164.78.121.255254
123164.78.122.0/24164.78.122.1 to 164.78.122.254164.78.122.255254
124164.78.123.0/24164.78.123.1 to 164.78.123.254164.78.123.255254
125164.78.124.0/24164.78.124.1 to 164.78.124.254164.78.124.255254
126164.78.125.0/24164.78.125.1 to 164.78.125.254164.78.125.255254
127164.78.126.0/24164.78.126.1 to 164.78.126.254164.78.126.255254
128164.78.127.0/24164.78.127.1 to 164.78.127.254164.78.127.255254

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