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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.

Network58.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
58.64.0.0
Broadcast address
58.127.255.255
First usable
58.64.0.1
Last usable
58.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 3A400000 · Integer 977272832 to 981467135
Reverse DNS zones
64.58.in-addr.arpa
65.58.in-addr.arpa
66.58.in-addr.arpa
67.58.in-addr.arpa
68.58.in-addr.arpa
69.58.in-addr.arpa
70.58.in-addr.arpa
71.58.in-addr.arpa
72.58.in-addr.arpa
73.58.in-addr.arpa
74.58.in-addr.arpa
75.58.in-addr.arpa
76.58.in-addr.arpa
77.58.in-addr.arpa
78.58.in-addr.arpa
79.58.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111010.01000000.00000000.0000000058.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00111010.01000000.00000000.0000000058.64.0.0
Broadcast00111010.01111111.11111111.1111111158.127.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

58.64.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
158.64.0.0/1758.64.0.1 to 58.64.127.25458.64.127.25532,766
258.64.128.0/1758.64.128.1 to 58.64.255.25458.64.255.25532,766
358.65.0.0/1758.65.0.1 to 58.65.127.25458.65.127.25532,766
458.65.128.0/1758.65.128.1 to 58.65.255.25458.65.255.25532,766
558.66.0.0/1758.66.0.1 to 58.66.127.25458.66.127.25532,766
658.66.128.0/1758.66.128.1 to 58.66.255.25458.66.255.25532,766
758.67.0.0/1758.67.0.1 to 58.67.127.25458.67.127.25532,766
858.67.128.0/1758.67.128.1 to 58.67.255.25458.67.255.25532,766
958.68.0.0/1758.68.0.1 to 58.68.127.25458.68.127.25532,766
1058.68.128.0/1758.68.128.1 to 58.68.255.25458.68.255.25532,766
1158.69.0.0/1758.69.0.1 to 58.69.127.25458.69.127.25532,766
1258.69.128.0/1758.69.128.1 to 58.69.255.25458.69.255.25532,766
1358.70.0.0/1758.70.0.1 to 58.70.127.25458.70.127.25532,766
1458.70.128.0/1758.70.128.1 to 58.70.255.25458.70.255.25532,766
1558.71.0.0/1758.71.0.1 to 58.71.127.25458.71.127.25532,766
1658.71.128.0/1758.71.128.1 to 58.71.255.25458.71.255.25532,766
1758.72.0.0/1758.72.0.1 to 58.72.127.25458.72.127.25532,766
1858.72.128.0/1758.72.128.1 to 58.72.255.25458.72.255.25532,766
1958.73.0.0/1758.73.0.1 to 58.73.127.25458.73.127.25532,766
2058.73.128.0/1758.73.128.1 to 58.73.255.25458.73.255.25532,766
2158.74.0.0/1758.74.0.1 to 58.74.127.25458.74.127.25532,766
2258.74.128.0/1758.74.128.1 to 58.74.255.25458.74.255.25532,766
2358.75.0.0/1758.75.0.1 to 58.75.127.25458.75.127.25532,766
2458.75.128.0/1758.75.128.1 to 58.75.255.25458.75.255.25532,766
2558.76.0.0/1758.76.0.1 to 58.76.127.25458.76.127.25532,766
2658.76.128.0/1758.76.128.1 to 58.76.255.25458.76.255.25532,766
2758.77.0.0/1758.77.0.1 to 58.77.127.25458.77.127.25532,766
2858.77.128.0/1758.77.128.1 to 58.77.255.25458.77.255.25532,766
2958.78.0.0/1758.78.0.1 to 58.78.127.25458.78.127.25532,766
3058.78.128.0/1758.78.128.1 to 58.78.255.25458.78.255.25532,766
3158.79.0.0/1758.79.0.1 to 58.79.127.25458.79.127.25532,766
3258.79.128.0/1758.79.128.1 to 58.79.255.25458.79.255.25532,766
3358.80.0.0/1758.80.0.1 to 58.80.127.25458.80.127.25532,766
3458.80.128.0/1758.80.128.1 to 58.80.255.25458.80.255.25532,766
3558.81.0.0/1758.81.0.1 to 58.81.127.25458.81.127.25532,766
3658.81.128.0/1758.81.128.1 to 58.81.255.25458.81.255.25532,766
3758.82.0.0/1758.82.0.1 to 58.82.127.25458.82.127.25532,766
3858.82.128.0/1758.82.128.1 to 58.82.255.25458.82.255.25532,766
3958.83.0.0/1758.83.0.1 to 58.83.127.25458.83.127.25532,766
4058.83.128.0/1758.83.128.1 to 58.83.255.25458.83.255.25532,766
4158.84.0.0/1758.84.0.1 to 58.84.127.25458.84.127.25532,766
4258.84.128.0/1758.84.128.1 to 58.84.255.25458.84.255.25532,766
4358.85.0.0/1758.85.0.1 to 58.85.127.25458.85.127.25532,766
4458.85.128.0/1758.85.128.1 to 58.85.255.25458.85.255.25532,766
4558.86.0.0/1758.86.0.1 to 58.86.127.25458.86.127.25532,766
4658.86.128.0/1758.86.128.1 to 58.86.255.25458.86.255.25532,766
4758.87.0.0/1758.87.0.1 to 58.87.127.25458.87.127.25532,766
4858.87.128.0/1758.87.128.1 to 58.87.255.25458.87.255.25532,766
4958.88.0.0/1758.88.0.1 to 58.88.127.25458.88.127.25532,766
5058.88.128.0/1758.88.128.1 to 58.88.255.25458.88.255.25532,766
5158.89.0.0/1758.89.0.1 to 58.89.127.25458.89.127.25532,766
5258.89.128.0/1758.89.128.1 to 58.89.255.25458.89.255.25532,766
5358.90.0.0/1758.90.0.1 to 58.90.127.25458.90.127.25532,766
5458.90.128.0/1758.90.128.1 to 58.90.255.25458.90.255.25532,766
5558.91.0.0/1758.91.0.1 to 58.91.127.25458.91.127.25532,766
5658.91.128.0/1758.91.128.1 to 58.91.255.25458.91.255.25532,766
5758.92.0.0/1758.92.0.1 to 58.92.127.25458.92.127.25532,766
5858.92.128.0/1758.92.128.1 to 58.92.255.25458.92.255.25532,766
5958.93.0.0/1758.93.0.1 to 58.93.127.25458.93.127.25532,766
6058.93.128.0/1758.93.128.1 to 58.93.255.25458.93.255.25532,766
6158.94.0.0/1758.94.0.1 to 58.94.127.25458.94.127.25532,766
6258.94.128.0/1758.94.128.1 to 58.94.255.25458.94.255.25532,766
6358.95.0.0/1758.95.0.1 to 58.95.127.25458.95.127.25532,766
6458.95.128.0/1758.95.128.1 to 58.95.255.25458.95.255.25532,766
6558.96.0.0/1758.96.0.1 to 58.96.127.25458.96.127.25532,766
6658.96.128.0/1758.96.128.1 to 58.96.255.25458.96.255.25532,766
6758.97.0.0/1758.97.0.1 to 58.97.127.25458.97.127.25532,766
6858.97.128.0/1758.97.128.1 to 58.97.255.25458.97.255.25532,766
6958.98.0.0/1758.98.0.1 to 58.98.127.25458.98.127.25532,766
7058.98.128.0/1758.98.128.1 to 58.98.255.25458.98.255.25532,766
7158.99.0.0/1758.99.0.1 to 58.99.127.25458.99.127.25532,766
7258.99.128.0/1758.99.128.1 to 58.99.255.25458.99.255.25532,766
7358.100.0.0/1758.100.0.1 to 58.100.127.25458.100.127.25532,766
7458.100.128.0/1758.100.128.1 to 58.100.255.25458.100.255.25532,766
7558.101.0.0/1758.101.0.1 to 58.101.127.25458.101.127.25532,766
7658.101.128.0/1758.101.128.1 to 58.101.255.25458.101.255.25532,766
7758.102.0.0/1758.102.0.1 to 58.102.127.25458.102.127.25532,766
7858.102.128.0/1758.102.128.1 to 58.102.255.25458.102.255.25532,766
7958.103.0.0/1758.103.0.1 to 58.103.127.25458.103.127.25532,766
8058.103.128.0/1758.103.128.1 to 58.103.255.25458.103.255.25532,766
8158.104.0.0/1758.104.0.1 to 58.104.127.25458.104.127.25532,766
8258.104.128.0/1758.104.128.1 to 58.104.255.25458.104.255.25532,766
8358.105.0.0/1758.105.0.1 to 58.105.127.25458.105.127.25532,766
8458.105.128.0/1758.105.128.1 to 58.105.255.25458.105.255.25532,766
8558.106.0.0/1758.106.0.1 to 58.106.127.25458.106.127.25532,766
8658.106.128.0/1758.106.128.1 to 58.106.255.25458.106.255.25532,766
8758.107.0.0/1758.107.0.1 to 58.107.127.25458.107.127.25532,766
8858.107.128.0/1758.107.128.1 to 58.107.255.25458.107.255.25532,766
8958.108.0.0/1758.108.0.1 to 58.108.127.25458.108.127.25532,766
9058.108.128.0/1758.108.128.1 to 58.108.255.25458.108.255.25532,766
9158.109.0.0/1758.109.0.1 to 58.109.127.25458.109.127.25532,766
9258.109.128.0/1758.109.128.1 to 58.109.255.25458.109.255.25532,766
9358.110.0.0/1758.110.0.1 to 58.110.127.25458.110.127.25532,766
9458.110.128.0/1758.110.128.1 to 58.110.255.25458.110.255.25532,766
9558.111.0.0/1758.111.0.1 to 58.111.127.25458.111.127.25532,766
9658.111.128.0/1758.111.128.1 to 58.111.255.25458.111.255.25532,766
9758.112.0.0/1758.112.0.1 to 58.112.127.25458.112.127.25532,766
9858.112.128.0/1758.112.128.1 to 58.112.255.25458.112.255.25532,766
9958.113.0.0/1758.113.0.1 to 58.113.127.25458.113.127.25532,766
10058.113.128.0/1758.113.128.1 to 58.113.255.25458.113.255.25532,766
10158.114.0.0/1758.114.0.1 to 58.114.127.25458.114.127.25532,766
10258.114.128.0/1758.114.128.1 to 58.114.255.25458.114.255.25532,766
10358.115.0.0/1758.115.0.1 to 58.115.127.25458.115.127.25532,766
10458.115.128.0/1758.115.128.1 to 58.115.255.25458.115.255.25532,766
10558.116.0.0/1758.116.0.1 to 58.116.127.25458.116.127.25532,766
10658.116.128.0/1758.116.128.1 to 58.116.255.25458.116.255.25532,766
10758.117.0.0/1758.117.0.1 to 58.117.127.25458.117.127.25532,766
10858.117.128.0/1758.117.128.1 to 58.117.255.25458.117.255.25532,766
10958.118.0.0/1758.118.0.1 to 58.118.127.25458.118.127.25532,766
11058.118.128.0/1758.118.128.1 to 58.118.255.25458.118.255.25532,766
11158.119.0.0/1758.119.0.1 to 58.119.127.25458.119.127.25532,766
11258.119.128.0/1758.119.128.1 to 58.119.255.25458.119.255.25532,766
11358.120.0.0/1758.120.0.1 to 58.120.127.25458.120.127.25532,766
11458.120.128.0/1758.120.128.1 to 58.120.255.25458.120.255.25532,766
11558.121.0.0/1758.121.0.1 to 58.121.127.25458.121.127.25532,766
11658.121.128.0/1758.121.128.1 to 58.121.255.25458.121.255.25532,766
11758.122.0.0/1758.122.0.1 to 58.122.127.25458.122.127.25532,766
11858.122.128.0/1758.122.128.1 to 58.122.255.25458.122.255.25532,766
11958.123.0.0/1758.123.0.1 to 58.123.127.25458.123.127.25532,766
12058.123.128.0/1758.123.128.1 to 58.123.255.25458.123.255.25532,766
12158.124.0.0/1758.124.0.1 to 58.124.127.25458.124.127.25532,766
12258.124.128.0/1758.124.128.1 to 58.124.255.25458.124.255.25532,766
12358.125.0.0/1758.125.0.1 to 58.125.127.25458.125.127.25532,766
12458.125.128.0/1758.125.128.1 to 58.125.255.25458.125.255.25532,766
12558.126.0.0/1758.126.0.1 to 58.126.127.25458.126.127.25532,766
12658.126.128.0/1758.126.128.1 to 58.126.255.25458.126.255.25532,766
12758.127.0.0/1758.127.0.1 to 58.127.127.25458.127.127.25532,766
12858.127.128.0/1758.127.128.1 to 58.127.255.25458.127.255.25532,766

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.