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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.

Network94.3.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
94.3.64.0
Broadcast address
94.3.127.255
First usable
94.3.64.1
Last usable
94.3.127.254
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
A (default /8)
As numbers
Hex 5E034000 · Integer 1577271296 to 1577287679
Reverse DNS zones
64.3.94.in-addr.arpa
65.3.94.in-addr.arpa
66.3.94.in-addr.arpa
67.3.94.in-addr.arpa
68.3.94.in-addr.arpa
69.3.94.in-addr.arpa
70.3.94.in-addr.arpa
71.3.94.in-addr.arpa
72.3.94.in-addr.arpa
73.3.94.in-addr.arpa
74.3.94.in-addr.arpa
75.3.94.in-addr.arpa
76.3.94.in-addr.arpa
77.3.94.in-addr.arpa
78.3.94.in-addr.arpa
79.3.94.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
Address01011110.00000011.01000000.0000000094.3.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01011110.00000011.01000000.0000000094.3.64.0
Broadcast01011110.00000011.01111111.1111111194.3.127.255
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)

94.3.64.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
194.3.64.0/2594.3.64.1 to 94.3.64.12694.3.64.127126
294.3.64.128/2594.3.64.129 to 94.3.64.25494.3.64.255126
394.3.65.0/2594.3.65.1 to 94.3.65.12694.3.65.127126
494.3.65.128/2594.3.65.129 to 94.3.65.25494.3.65.255126
594.3.66.0/2594.3.66.1 to 94.3.66.12694.3.66.127126
694.3.66.128/2594.3.66.129 to 94.3.66.25494.3.66.255126
794.3.67.0/2594.3.67.1 to 94.3.67.12694.3.67.127126
894.3.67.128/2594.3.67.129 to 94.3.67.25494.3.67.255126
994.3.68.0/2594.3.68.1 to 94.3.68.12694.3.68.127126
1094.3.68.128/2594.3.68.129 to 94.3.68.25494.3.68.255126
1194.3.69.0/2594.3.69.1 to 94.3.69.12694.3.69.127126
1294.3.69.128/2594.3.69.129 to 94.3.69.25494.3.69.255126
1394.3.70.0/2594.3.70.1 to 94.3.70.12694.3.70.127126
1494.3.70.128/2594.3.70.129 to 94.3.70.25494.3.70.255126
1594.3.71.0/2594.3.71.1 to 94.3.71.12694.3.71.127126
1694.3.71.128/2594.3.71.129 to 94.3.71.25494.3.71.255126
1794.3.72.0/2594.3.72.1 to 94.3.72.12694.3.72.127126
1894.3.72.128/2594.3.72.129 to 94.3.72.25494.3.72.255126
1994.3.73.0/2594.3.73.1 to 94.3.73.12694.3.73.127126
2094.3.73.128/2594.3.73.129 to 94.3.73.25494.3.73.255126
2194.3.74.0/2594.3.74.1 to 94.3.74.12694.3.74.127126
2294.3.74.128/2594.3.74.129 to 94.3.74.25494.3.74.255126
2394.3.75.0/2594.3.75.1 to 94.3.75.12694.3.75.127126
2494.3.75.128/2594.3.75.129 to 94.3.75.25494.3.75.255126
2594.3.76.0/2594.3.76.1 to 94.3.76.12694.3.76.127126
2694.3.76.128/2594.3.76.129 to 94.3.76.25494.3.76.255126
2794.3.77.0/2594.3.77.1 to 94.3.77.12694.3.77.127126
2894.3.77.128/2594.3.77.129 to 94.3.77.25494.3.77.255126
2994.3.78.0/2594.3.78.1 to 94.3.78.12694.3.78.127126
3094.3.78.128/2594.3.78.129 to 94.3.78.25494.3.78.255126
3194.3.79.0/2594.3.79.1 to 94.3.79.12694.3.79.127126
3294.3.79.128/2594.3.79.129 to 94.3.79.25494.3.79.255126
3394.3.80.0/2594.3.80.1 to 94.3.80.12694.3.80.127126
3494.3.80.128/2594.3.80.129 to 94.3.80.25494.3.80.255126
3594.3.81.0/2594.3.81.1 to 94.3.81.12694.3.81.127126
3694.3.81.128/2594.3.81.129 to 94.3.81.25494.3.81.255126
3794.3.82.0/2594.3.82.1 to 94.3.82.12694.3.82.127126
3894.3.82.128/2594.3.82.129 to 94.3.82.25494.3.82.255126
3994.3.83.0/2594.3.83.1 to 94.3.83.12694.3.83.127126
4094.3.83.128/2594.3.83.129 to 94.3.83.25494.3.83.255126
4194.3.84.0/2594.3.84.1 to 94.3.84.12694.3.84.127126
4294.3.84.128/2594.3.84.129 to 94.3.84.25494.3.84.255126
4394.3.85.0/2594.3.85.1 to 94.3.85.12694.3.85.127126
4494.3.85.128/2594.3.85.129 to 94.3.85.25494.3.85.255126
4594.3.86.0/2594.3.86.1 to 94.3.86.12694.3.86.127126
4694.3.86.128/2594.3.86.129 to 94.3.86.25494.3.86.255126
4794.3.87.0/2594.3.87.1 to 94.3.87.12694.3.87.127126
4894.3.87.128/2594.3.87.129 to 94.3.87.25494.3.87.255126
4994.3.88.0/2594.3.88.1 to 94.3.88.12694.3.88.127126
5094.3.88.128/2594.3.88.129 to 94.3.88.25494.3.88.255126
5194.3.89.0/2594.3.89.1 to 94.3.89.12694.3.89.127126
5294.3.89.128/2594.3.89.129 to 94.3.89.25494.3.89.255126
5394.3.90.0/2594.3.90.1 to 94.3.90.12694.3.90.127126
5494.3.90.128/2594.3.90.129 to 94.3.90.25494.3.90.255126
5594.3.91.0/2594.3.91.1 to 94.3.91.12694.3.91.127126
5694.3.91.128/2594.3.91.129 to 94.3.91.25494.3.91.255126
5794.3.92.0/2594.3.92.1 to 94.3.92.12694.3.92.127126
5894.3.92.128/2594.3.92.129 to 94.3.92.25494.3.92.255126
5994.3.93.0/2594.3.93.1 to 94.3.93.12694.3.93.127126
6094.3.93.128/2594.3.93.129 to 94.3.93.25494.3.93.255126
6194.3.94.0/2594.3.94.1 to 94.3.94.12694.3.94.127126
6294.3.94.128/2594.3.94.129 to 94.3.94.25494.3.94.255126
6394.3.95.0/2594.3.95.1 to 94.3.95.12694.3.95.127126
6494.3.95.128/2594.3.95.129 to 94.3.95.25494.3.95.255126
6594.3.96.0/2594.3.96.1 to 94.3.96.12694.3.96.127126
6694.3.96.128/2594.3.96.129 to 94.3.96.25494.3.96.255126
6794.3.97.0/2594.3.97.1 to 94.3.97.12694.3.97.127126
6894.3.97.128/2594.3.97.129 to 94.3.97.25494.3.97.255126
6994.3.98.0/2594.3.98.1 to 94.3.98.12694.3.98.127126
7094.3.98.128/2594.3.98.129 to 94.3.98.25494.3.98.255126
7194.3.99.0/2594.3.99.1 to 94.3.99.12694.3.99.127126
7294.3.99.128/2594.3.99.129 to 94.3.99.25494.3.99.255126
7394.3.100.0/2594.3.100.1 to 94.3.100.12694.3.100.127126
7494.3.100.128/2594.3.100.129 to 94.3.100.25494.3.100.255126
7594.3.101.0/2594.3.101.1 to 94.3.101.12694.3.101.127126
7694.3.101.128/2594.3.101.129 to 94.3.101.25494.3.101.255126
7794.3.102.0/2594.3.102.1 to 94.3.102.12694.3.102.127126
7894.3.102.128/2594.3.102.129 to 94.3.102.25494.3.102.255126
7994.3.103.0/2594.3.103.1 to 94.3.103.12694.3.103.127126
8094.3.103.128/2594.3.103.129 to 94.3.103.25494.3.103.255126
8194.3.104.0/2594.3.104.1 to 94.3.104.12694.3.104.127126
8294.3.104.128/2594.3.104.129 to 94.3.104.25494.3.104.255126
8394.3.105.0/2594.3.105.1 to 94.3.105.12694.3.105.127126
8494.3.105.128/2594.3.105.129 to 94.3.105.25494.3.105.255126
8594.3.106.0/2594.3.106.1 to 94.3.106.12694.3.106.127126
8694.3.106.128/2594.3.106.129 to 94.3.106.25494.3.106.255126
8794.3.107.0/2594.3.107.1 to 94.3.107.12694.3.107.127126
8894.3.107.128/2594.3.107.129 to 94.3.107.25494.3.107.255126
8994.3.108.0/2594.3.108.1 to 94.3.108.12694.3.108.127126
9094.3.108.128/2594.3.108.129 to 94.3.108.25494.3.108.255126
9194.3.109.0/2594.3.109.1 to 94.3.109.12694.3.109.127126
9294.3.109.128/2594.3.109.129 to 94.3.109.25494.3.109.255126
9394.3.110.0/2594.3.110.1 to 94.3.110.12694.3.110.127126
9494.3.110.128/2594.3.110.129 to 94.3.110.25494.3.110.255126
9594.3.111.0/2594.3.111.1 to 94.3.111.12694.3.111.127126
9694.3.111.128/2594.3.111.129 to 94.3.111.25494.3.111.255126
9794.3.112.0/2594.3.112.1 to 94.3.112.12694.3.112.127126
9894.3.112.128/2594.3.112.129 to 94.3.112.25494.3.112.255126
9994.3.113.0/2594.3.113.1 to 94.3.113.12694.3.113.127126
10094.3.113.128/2594.3.113.129 to 94.3.113.25494.3.113.255126
10194.3.114.0/2594.3.114.1 to 94.3.114.12694.3.114.127126
10294.3.114.128/2594.3.114.129 to 94.3.114.25494.3.114.255126
10394.3.115.0/2594.3.115.1 to 94.3.115.12694.3.115.127126
10494.3.115.128/2594.3.115.129 to 94.3.115.25494.3.115.255126
10594.3.116.0/2594.3.116.1 to 94.3.116.12694.3.116.127126
10694.3.116.128/2594.3.116.129 to 94.3.116.25494.3.116.255126
10794.3.117.0/2594.3.117.1 to 94.3.117.12694.3.117.127126
10894.3.117.128/2594.3.117.129 to 94.3.117.25494.3.117.255126
10994.3.118.0/2594.3.118.1 to 94.3.118.12694.3.118.127126
11094.3.118.128/2594.3.118.129 to 94.3.118.25494.3.118.255126
11194.3.119.0/2594.3.119.1 to 94.3.119.12694.3.119.127126
11294.3.119.128/2594.3.119.129 to 94.3.119.25494.3.119.255126
11394.3.120.0/2594.3.120.1 to 94.3.120.12694.3.120.127126
11494.3.120.128/2594.3.120.129 to 94.3.120.25494.3.120.255126
11594.3.121.0/2594.3.121.1 to 94.3.121.12694.3.121.127126
11694.3.121.128/2594.3.121.129 to 94.3.121.25494.3.121.255126
11794.3.122.0/2594.3.122.1 to 94.3.122.12694.3.122.127126
11894.3.122.128/2594.3.122.129 to 94.3.122.25494.3.122.255126
11994.3.123.0/2594.3.123.1 to 94.3.123.12694.3.123.127126
12094.3.123.128/2594.3.123.129 to 94.3.123.25494.3.123.255126
12194.3.124.0/2594.3.124.1 to 94.3.124.12694.3.124.127126
12294.3.124.128/2594.3.124.129 to 94.3.124.25494.3.124.255126
12394.3.125.0/2594.3.125.1 to 94.3.125.12694.3.125.127126
12494.3.125.128/2594.3.125.129 to 94.3.125.25494.3.125.255126
12594.3.126.0/2594.3.126.1 to 94.3.126.12694.3.126.127126
12694.3.126.128/2594.3.126.129 to 94.3.126.25494.3.126.255126
12794.3.127.0/2594.3.127.1 to 94.3.127.12694.3.127.127126
12894.3.127.128/2594.3.127.129 to 94.3.127.25494.3.127.255126

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.