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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.

Network50.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
50.64.0.0
Broadcast address
50.127.255.255
First usable
50.64.0.1
Last usable
50.127.255.254
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 32400000 · Integer 843055104 to 847249407
Reverse DNS zones
64.50.in-addr.arpa
65.50.in-addr.arpa
66.50.in-addr.arpa
67.50.in-addr.arpa
68.50.in-addr.arpa
69.50.in-addr.arpa
70.50.in-addr.arpa
71.50.in-addr.arpa
72.50.in-addr.arpa
73.50.in-addr.arpa
74.50.in-addr.arpa
75.50.in-addr.arpa
76.50.in-addr.arpa
77.50.in-addr.arpa
78.50.in-addr.arpa
79.50.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
Address00110010.01000000.00000000.0000000050.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00110010.01000000.00000000.0000000050.64.0.0
Broadcast00110010.01111111.11111111.1111111150.127.255.255
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)

50.64.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
150.64.0.0/1750.64.0.1 to 50.64.127.25450.64.127.25532,766
250.64.128.0/1750.64.128.1 to 50.64.255.25450.64.255.25532,766
350.65.0.0/1750.65.0.1 to 50.65.127.25450.65.127.25532,766
450.65.128.0/1750.65.128.1 to 50.65.255.25450.65.255.25532,766
550.66.0.0/1750.66.0.1 to 50.66.127.25450.66.127.25532,766
650.66.128.0/1750.66.128.1 to 50.66.255.25450.66.255.25532,766
750.67.0.0/1750.67.0.1 to 50.67.127.25450.67.127.25532,766
850.67.128.0/1750.67.128.1 to 50.67.255.25450.67.255.25532,766
950.68.0.0/1750.68.0.1 to 50.68.127.25450.68.127.25532,766
1050.68.128.0/1750.68.128.1 to 50.68.255.25450.68.255.25532,766
1150.69.0.0/1750.69.0.1 to 50.69.127.25450.69.127.25532,766
1250.69.128.0/1750.69.128.1 to 50.69.255.25450.69.255.25532,766
1350.70.0.0/1750.70.0.1 to 50.70.127.25450.70.127.25532,766
1450.70.128.0/1750.70.128.1 to 50.70.255.25450.70.255.25532,766
1550.71.0.0/1750.71.0.1 to 50.71.127.25450.71.127.25532,766
1650.71.128.0/1750.71.128.1 to 50.71.255.25450.71.255.25532,766
1750.72.0.0/1750.72.0.1 to 50.72.127.25450.72.127.25532,766
1850.72.128.0/1750.72.128.1 to 50.72.255.25450.72.255.25532,766
1950.73.0.0/1750.73.0.1 to 50.73.127.25450.73.127.25532,766
2050.73.128.0/1750.73.128.1 to 50.73.255.25450.73.255.25532,766
2150.74.0.0/1750.74.0.1 to 50.74.127.25450.74.127.25532,766
2250.74.128.0/1750.74.128.1 to 50.74.255.25450.74.255.25532,766
2350.75.0.0/1750.75.0.1 to 50.75.127.25450.75.127.25532,766
2450.75.128.0/1750.75.128.1 to 50.75.255.25450.75.255.25532,766
2550.76.0.0/1750.76.0.1 to 50.76.127.25450.76.127.25532,766
2650.76.128.0/1750.76.128.1 to 50.76.255.25450.76.255.25532,766
2750.77.0.0/1750.77.0.1 to 50.77.127.25450.77.127.25532,766
2850.77.128.0/1750.77.128.1 to 50.77.255.25450.77.255.25532,766
2950.78.0.0/1750.78.0.1 to 50.78.127.25450.78.127.25532,766
3050.78.128.0/1750.78.128.1 to 50.78.255.25450.78.255.25532,766
3150.79.0.0/1750.79.0.1 to 50.79.127.25450.79.127.25532,766
3250.79.128.0/1750.79.128.1 to 50.79.255.25450.79.255.25532,766
3350.80.0.0/1750.80.0.1 to 50.80.127.25450.80.127.25532,766
3450.80.128.0/1750.80.128.1 to 50.80.255.25450.80.255.25532,766
3550.81.0.0/1750.81.0.1 to 50.81.127.25450.81.127.25532,766
3650.81.128.0/1750.81.128.1 to 50.81.255.25450.81.255.25532,766
3750.82.0.0/1750.82.0.1 to 50.82.127.25450.82.127.25532,766
3850.82.128.0/1750.82.128.1 to 50.82.255.25450.82.255.25532,766
3950.83.0.0/1750.83.0.1 to 50.83.127.25450.83.127.25532,766
4050.83.128.0/1750.83.128.1 to 50.83.255.25450.83.255.25532,766
4150.84.0.0/1750.84.0.1 to 50.84.127.25450.84.127.25532,766
4250.84.128.0/1750.84.128.1 to 50.84.255.25450.84.255.25532,766
4350.85.0.0/1750.85.0.1 to 50.85.127.25450.85.127.25532,766
4450.85.128.0/1750.85.128.1 to 50.85.255.25450.85.255.25532,766
4550.86.0.0/1750.86.0.1 to 50.86.127.25450.86.127.25532,766
4650.86.128.0/1750.86.128.1 to 50.86.255.25450.86.255.25532,766
4750.87.0.0/1750.87.0.1 to 50.87.127.25450.87.127.25532,766
4850.87.128.0/1750.87.128.1 to 50.87.255.25450.87.255.25532,766
4950.88.0.0/1750.88.0.1 to 50.88.127.25450.88.127.25532,766
5050.88.128.0/1750.88.128.1 to 50.88.255.25450.88.255.25532,766
5150.89.0.0/1750.89.0.1 to 50.89.127.25450.89.127.25532,766
5250.89.128.0/1750.89.128.1 to 50.89.255.25450.89.255.25532,766
5350.90.0.0/1750.90.0.1 to 50.90.127.25450.90.127.25532,766
5450.90.128.0/1750.90.128.1 to 50.90.255.25450.90.255.25532,766
5550.91.0.0/1750.91.0.1 to 50.91.127.25450.91.127.25532,766
5650.91.128.0/1750.91.128.1 to 50.91.255.25450.91.255.25532,766
5750.92.0.0/1750.92.0.1 to 50.92.127.25450.92.127.25532,766
5850.92.128.0/1750.92.128.1 to 50.92.255.25450.92.255.25532,766
5950.93.0.0/1750.93.0.1 to 50.93.127.25450.93.127.25532,766
6050.93.128.0/1750.93.128.1 to 50.93.255.25450.93.255.25532,766
6150.94.0.0/1750.94.0.1 to 50.94.127.25450.94.127.25532,766
6250.94.128.0/1750.94.128.1 to 50.94.255.25450.94.255.25532,766
6350.95.0.0/1750.95.0.1 to 50.95.127.25450.95.127.25532,766
6450.95.128.0/1750.95.128.1 to 50.95.255.25450.95.255.25532,766
6550.96.0.0/1750.96.0.1 to 50.96.127.25450.96.127.25532,766
6650.96.128.0/1750.96.128.1 to 50.96.255.25450.96.255.25532,766
6750.97.0.0/1750.97.0.1 to 50.97.127.25450.97.127.25532,766
6850.97.128.0/1750.97.128.1 to 50.97.255.25450.97.255.25532,766
6950.98.0.0/1750.98.0.1 to 50.98.127.25450.98.127.25532,766
7050.98.128.0/1750.98.128.1 to 50.98.255.25450.98.255.25532,766
7150.99.0.0/1750.99.0.1 to 50.99.127.25450.99.127.25532,766
7250.99.128.0/1750.99.128.1 to 50.99.255.25450.99.255.25532,766
7350.100.0.0/1750.100.0.1 to 50.100.127.25450.100.127.25532,766
7450.100.128.0/1750.100.128.1 to 50.100.255.25450.100.255.25532,766
7550.101.0.0/1750.101.0.1 to 50.101.127.25450.101.127.25532,766
7650.101.128.0/1750.101.128.1 to 50.101.255.25450.101.255.25532,766
7750.102.0.0/1750.102.0.1 to 50.102.127.25450.102.127.25532,766
7850.102.128.0/1750.102.128.1 to 50.102.255.25450.102.255.25532,766
7950.103.0.0/1750.103.0.1 to 50.103.127.25450.103.127.25532,766
8050.103.128.0/1750.103.128.1 to 50.103.255.25450.103.255.25532,766
8150.104.0.0/1750.104.0.1 to 50.104.127.25450.104.127.25532,766
8250.104.128.0/1750.104.128.1 to 50.104.255.25450.104.255.25532,766
8350.105.0.0/1750.105.0.1 to 50.105.127.25450.105.127.25532,766
8450.105.128.0/1750.105.128.1 to 50.105.255.25450.105.255.25532,766
8550.106.0.0/1750.106.0.1 to 50.106.127.25450.106.127.25532,766
8650.106.128.0/1750.106.128.1 to 50.106.255.25450.106.255.25532,766
8750.107.0.0/1750.107.0.1 to 50.107.127.25450.107.127.25532,766
8850.107.128.0/1750.107.128.1 to 50.107.255.25450.107.255.25532,766
8950.108.0.0/1750.108.0.1 to 50.108.127.25450.108.127.25532,766
9050.108.128.0/1750.108.128.1 to 50.108.255.25450.108.255.25532,766
9150.109.0.0/1750.109.0.1 to 50.109.127.25450.109.127.25532,766
9250.109.128.0/1750.109.128.1 to 50.109.255.25450.109.255.25532,766
9350.110.0.0/1750.110.0.1 to 50.110.127.25450.110.127.25532,766
9450.110.128.0/1750.110.128.1 to 50.110.255.25450.110.255.25532,766
9550.111.0.0/1750.111.0.1 to 50.111.127.25450.111.127.25532,766
9650.111.128.0/1750.111.128.1 to 50.111.255.25450.111.255.25532,766
9750.112.0.0/1750.112.0.1 to 50.112.127.25450.112.127.25532,766
9850.112.128.0/1750.112.128.1 to 50.112.255.25450.112.255.25532,766
9950.113.0.0/1750.113.0.1 to 50.113.127.25450.113.127.25532,766
10050.113.128.0/1750.113.128.1 to 50.113.255.25450.113.255.25532,766
10150.114.0.0/1750.114.0.1 to 50.114.127.25450.114.127.25532,766
10250.114.128.0/1750.114.128.1 to 50.114.255.25450.114.255.25532,766
10350.115.0.0/1750.115.0.1 to 50.115.127.25450.115.127.25532,766
10450.115.128.0/1750.115.128.1 to 50.115.255.25450.115.255.25532,766
10550.116.0.0/1750.116.0.1 to 50.116.127.25450.116.127.25532,766
10650.116.128.0/1750.116.128.1 to 50.116.255.25450.116.255.25532,766
10750.117.0.0/1750.117.0.1 to 50.117.127.25450.117.127.25532,766
10850.117.128.0/1750.117.128.1 to 50.117.255.25450.117.255.25532,766
10950.118.0.0/1750.118.0.1 to 50.118.127.25450.118.127.25532,766
11050.118.128.0/1750.118.128.1 to 50.118.255.25450.118.255.25532,766
11150.119.0.0/1750.119.0.1 to 50.119.127.25450.119.127.25532,766
11250.119.128.0/1750.119.128.1 to 50.119.255.25450.119.255.25532,766
11350.120.0.0/1750.120.0.1 to 50.120.127.25450.120.127.25532,766
11450.120.128.0/1750.120.128.1 to 50.120.255.25450.120.255.25532,766
11550.121.0.0/1750.121.0.1 to 50.121.127.25450.121.127.25532,766
11650.121.128.0/1750.121.128.1 to 50.121.255.25450.121.255.25532,766
11750.122.0.0/1750.122.0.1 to 50.122.127.25450.122.127.25532,766
11850.122.128.0/1750.122.128.1 to 50.122.255.25450.122.255.25532,766
11950.123.0.0/1750.123.0.1 to 50.123.127.25450.123.127.25532,766
12050.123.128.0/1750.123.128.1 to 50.123.255.25450.123.255.25532,766
12150.124.0.0/1750.124.0.1 to 50.124.127.25450.124.127.25532,766
12250.124.128.0/1750.124.128.1 to 50.124.255.25450.124.255.25532,766
12350.125.0.0/1750.125.0.1 to 50.125.127.25450.125.127.25532,766
12450.125.128.0/1750.125.128.1 to 50.125.255.25450.125.255.25532,766
12550.126.0.0/1750.126.0.1 to 50.126.127.25450.126.127.25532,766
12650.126.128.0/1750.126.128.1 to 50.126.255.25450.126.255.25532,766
12750.127.0.0/1750.127.0.1 to 50.127.127.25450.127.127.25532,766
12850.127.128.0/1750.127.128.1 to 50.127.255.25450.127.255.25532,766

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.