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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.

Network75.53.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
75.53.64.0
Broadcast address
75.53.127.255
First usable
75.53.64.1
Last usable
75.53.127.254
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 4B354000 · Integer 1261780992 to 1261797375
Reverse DNS zones
64.53.75.in-addr.arpa
65.53.75.in-addr.arpa
66.53.75.in-addr.arpa
67.53.75.in-addr.arpa
68.53.75.in-addr.arpa
69.53.75.in-addr.arpa
70.53.75.in-addr.arpa
71.53.75.in-addr.arpa
72.53.75.in-addr.arpa
73.53.75.in-addr.arpa
74.53.75.in-addr.arpa
75.53.75.in-addr.arpa
76.53.75.in-addr.arpa
77.53.75.in-addr.arpa
78.53.75.in-addr.arpa
79.53.75.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
Address01001011.00110101.01000000.0000000075.53.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01001011.00110101.01000000.0000000075.53.64.0
Broadcast01001011.00110101.01111111.1111111175.53.127.255
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)

75.53.64.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
175.53.64.0/2575.53.64.1 to 75.53.64.12675.53.64.127126
275.53.64.128/2575.53.64.129 to 75.53.64.25475.53.64.255126
375.53.65.0/2575.53.65.1 to 75.53.65.12675.53.65.127126
475.53.65.128/2575.53.65.129 to 75.53.65.25475.53.65.255126
575.53.66.0/2575.53.66.1 to 75.53.66.12675.53.66.127126
675.53.66.128/2575.53.66.129 to 75.53.66.25475.53.66.255126
775.53.67.0/2575.53.67.1 to 75.53.67.12675.53.67.127126
875.53.67.128/2575.53.67.129 to 75.53.67.25475.53.67.255126
975.53.68.0/2575.53.68.1 to 75.53.68.12675.53.68.127126
1075.53.68.128/2575.53.68.129 to 75.53.68.25475.53.68.255126
1175.53.69.0/2575.53.69.1 to 75.53.69.12675.53.69.127126
1275.53.69.128/2575.53.69.129 to 75.53.69.25475.53.69.255126
1375.53.70.0/2575.53.70.1 to 75.53.70.12675.53.70.127126
1475.53.70.128/2575.53.70.129 to 75.53.70.25475.53.70.255126
1575.53.71.0/2575.53.71.1 to 75.53.71.12675.53.71.127126
1675.53.71.128/2575.53.71.129 to 75.53.71.25475.53.71.255126
1775.53.72.0/2575.53.72.1 to 75.53.72.12675.53.72.127126
1875.53.72.128/2575.53.72.129 to 75.53.72.25475.53.72.255126
1975.53.73.0/2575.53.73.1 to 75.53.73.12675.53.73.127126
2075.53.73.128/2575.53.73.129 to 75.53.73.25475.53.73.255126
2175.53.74.0/2575.53.74.1 to 75.53.74.12675.53.74.127126
2275.53.74.128/2575.53.74.129 to 75.53.74.25475.53.74.255126
2375.53.75.0/2575.53.75.1 to 75.53.75.12675.53.75.127126
2475.53.75.128/2575.53.75.129 to 75.53.75.25475.53.75.255126
2575.53.76.0/2575.53.76.1 to 75.53.76.12675.53.76.127126
2675.53.76.128/2575.53.76.129 to 75.53.76.25475.53.76.255126
2775.53.77.0/2575.53.77.1 to 75.53.77.12675.53.77.127126
2875.53.77.128/2575.53.77.129 to 75.53.77.25475.53.77.255126
2975.53.78.0/2575.53.78.1 to 75.53.78.12675.53.78.127126
3075.53.78.128/2575.53.78.129 to 75.53.78.25475.53.78.255126
3175.53.79.0/2575.53.79.1 to 75.53.79.12675.53.79.127126
3275.53.79.128/2575.53.79.129 to 75.53.79.25475.53.79.255126
3375.53.80.0/2575.53.80.1 to 75.53.80.12675.53.80.127126
3475.53.80.128/2575.53.80.129 to 75.53.80.25475.53.80.255126
3575.53.81.0/2575.53.81.1 to 75.53.81.12675.53.81.127126
3675.53.81.128/2575.53.81.129 to 75.53.81.25475.53.81.255126
3775.53.82.0/2575.53.82.1 to 75.53.82.12675.53.82.127126
3875.53.82.128/2575.53.82.129 to 75.53.82.25475.53.82.255126
3975.53.83.0/2575.53.83.1 to 75.53.83.12675.53.83.127126
4075.53.83.128/2575.53.83.129 to 75.53.83.25475.53.83.255126
4175.53.84.0/2575.53.84.1 to 75.53.84.12675.53.84.127126
4275.53.84.128/2575.53.84.129 to 75.53.84.25475.53.84.255126
4375.53.85.0/2575.53.85.1 to 75.53.85.12675.53.85.127126
4475.53.85.128/2575.53.85.129 to 75.53.85.25475.53.85.255126
4575.53.86.0/2575.53.86.1 to 75.53.86.12675.53.86.127126
4675.53.86.128/2575.53.86.129 to 75.53.86.25475.53.86.255126
4775.53.87.0/2575.53.87.1 to 75.53.87.12675.53.87.127126
4875.53.87.128/2575.53.87.129 to 75.53.87.25475.53.87.255126
4975.53.88.0/2575.53.88.1 to 75.53.88.12675.53.88.127126
5075.53.88.128/2575.53.88.129 to 75.53.88.25475.53.88.255126
5175.53.89.0/2575.53.89.1 to 75.53.89.12675.53.89.127126
5275.53.89.128/2575.53.89.129 to 75.53.89.25475.53.89.255126
5375.53.90.0/2575.53.90.1 to 75.53.90.12675.53.90.127126
5475.53.90.128/2575.53.90.129 to 75.53.90.25475.53.90.255126
5575.53.91.0/2575.53.91.1 to 75.53.91.12675.53.91.127126
5675.53.91.128/2575.53.91.129 to 75.53.91.25475.53.91.255126
5775.53.92.0/2575.53.92.1 to 75.53.92.12675.53.92.127126
5875.53.92.128/2575.53.92.129 to 75.53.92.25475.53.92.255126
5975.53.93.0/2575.53.93.1 to 75.53.93.12675.53.93.127126
6075.53.93.128/2575.53.93.129 to 75.53.93.25475.53.93.255126
6175.53.94.0/2575.53.94.1 to 75.53.94.12675.53.94.127126
6275.53.94.128/2575.53.94.129 to 75.53.94.25475.53.94.255126
6375.53.95.0/2575.53.95.1 to 75.53.95.12675.53.95.127126
6475.53.95.128/2575.53.95.129 to 75.53.95.25475.53.95.255126
6575.53.96.0/2575.53.96.1 to 75.53.96.12675.53.96.127126
6675.53.96.128/2575.53.96.129 to 75.53.96.25475.53.96.255126
6775.53.97.0/2575.53.97.1 to 75.53.97.12675.53.97.127126
6875.53.97.128/2575.53.97.129 to 75.53.97.25475.53.97.255126
6975.53.98.0/2575.53.98.1 to 75.53.98.12675.53.98.127126
7075.53.98.128/2575.53.98.129 to 75.53.98.25475.53.98.255126
7175.53.99.0/2575.53.99.1 to 75.53.99.12675.53.99.127126
7275.53.99.128/2575.53.99.129 to 75.53.99.25475.53.99.255126
7375.53.100.0/2575.53.100.1 to 75.53.100.12675.53.100.127126
7475.53.100.128/2575.53.100.129 to 75.53.100.25475.53.100.255126
7575.53.101.0/2575.53.101.1 to 75.53.101.12675.53.101.127126
7675.53.101.128/2575.53.101.129 to 75.53.101.25475.53.101.255126
7775.53.102.0/2575.53.102.1 to 75.53.102.12675.53.102.127126
7875.53.102.128/2575.53.102.129 to 75.53.102.25475.53.102.255126
7975.53.103.0/2575.53.103.1 to 75.53.103.12675.53.103.127126
8075.53.103.128/2575.53.103.129 to 75.53.103.25475.53.103.255126
8175.53.104.0/2575.53.104.1 to 75.53.104.12675.53.104.127126
8275.53.104.128/2575.53.104.129 to 75.53.104.25475.53.104.255126
8375.53.105.0/2575.53.105.1 to 75.53.105.12675.53.105.127126
8475.53.105.128/2575.53.105.129 to 75.53.105.25475.53.105.255126
8575.53.106.0/2575.53.106.1 to 75.53.106.12675.53.106.127126
8675.53.106.128/2575.53.106.129 to 75.53.106.25475.53.106.255126
8775.53.107.0/2575.53.107.1 to 75.53.107.12675.53.107.127126
8875.53.107.128/2575.53.107.129 to 75.53.107.25475.53.107.255126
8975.53.108.0/2575.53.108.1 to 75.53.108.12675.53.108.127126
9075.53.108.128/2575.53.108.129 to 75.53.108.25475.53.108.255126
9175.53.109.0/2575.53.109.1 to 75.53.109.12675.53.109.127126
9275.53.109.128/2575.53.109.129 to 75.53.109.25475.53.109.255126
9375.53.110.0/2575.53.110.1 to 75.53.110.12675.53.110.127126
9475.53.110.128/2575.53.110.129 to 75.53.110.25475.53.110.255126
9575.53.111.0/2575.53.111.1 to 75.53.111.12675.53.111.127126
9675.53.111.128/2575.53.111.129 to 75.53.111.25475.53.111.255126
9775.53.112.0/2575.53.112.1 to 75.53.112.12675.53.112.127126
9875.53.112.128/2575.53.112.129 to 75.53.112.25475.53.112.255126
9975.53.113.0/2575.53.113.1 to 75.53.113.12675.53.113.127126
10075.53.113.128/2575.53.113.129 to 75.53.113.25475.53.113.255126
10175.53.114.0/2575.53.114.1 to 75.53.114.12675.53.114.127126
10275.53.114.128/2575.53.114.129 to 75.53.114.25475.53.114.255126
10375.53.115.0/2575.53.115.1 to 75.53.115.12675.53.115.127126
10475.53.115.128/2575.53.115.129 to 75.53.115.25475.53.115.255126
10575.53.116.0/2575.53.116.1 to 75.53.116.12675.53.116.127126
10675.53.116.128/2575.53.116.129 to 75.53.116.25475.53.116.255126
10775.53.117.0/2575.53.117.1 to 75.53.117.12675.53.117.127126
10875.53.117.128/2575.53.117.129 to 75.53.117.25475.53.117.255126
10975.53.118.0/2575.53.118.1 to 75.53.118.12675.53.118.127126
11075.53.118.128/2575.53.118.129 to 75.53.118.25475.53.118.255126
11175.53.119.0/2575.53.119.1 to 75.53.119.12675.53.119.127126
11275.53.119.128/2575.53.119.129 to 75.53.119.25475.53.119.255126
11375.53.120.0/2575.53.120.1 to 75.53.120.12675.53.120.127126
11475.53.120.128/2575.53.120.129 to 75.53.120.25475.53.120.255126
11575.53.121.0/2575.53.121.1 to 75.53.121.12675.53.121.127126
11675.53.121.128/2575.53.121.129 to 75.53.121.25475.53.121.255126
11775.53.122.0/2575.53.122.1 to 75.53.122.12675.53.122.127126
11875.53.122.128/2575.53.122.129 to 75.53.122.25475.53.122.255126
11975.53.123.0/2575.53.123.1 to 75.53.123.12675.53.123.127126
12075.53.123.128/2575.53.123.129 to 75.53.123.25475.53.123.255126
12175.53.124.0/2575.53.124.1 to 75.53.124.12675.53.124.127126
12275.53.124.128/2575.53.124.129 to 75.53.124.25475.53.124.255126
12375.53.125.0/2575.53.125.1 to 75.53.125.12675.53.125.127126
12475.53.125.128/2575.53.125.129 to 75.53.125.25475.53.125.255126
12575.53.126.0/2575.53.126.1 to 75.53.126.12675.53.126.127126
12675.53.126.128/2575.53.126.129 to 75.53.126.25475.53.126.255126
12775.53.127.0/2575.53.127.1 to 75.53.127.12675.53.127.127126
12875.53.127.128/2575.53.127.129 to 75.53.127.25475.53.127.255126

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.