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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.

Network19.89.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
19.89.0.0
Broadcast address
19.89.31.255
First usable
19.89.0.1
Last usable
19.89.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 13590000 · Integer 324599808 to 324607999
Reverse DNS zones
0.89.19.in-addr.arpa
1.89.19.in-addr.arpa
2.89.19.in-addr.arpa
3.89.19.in-addr.arpa
4.89.19.in-addr.arpa
5.89.19.in-addr.arpa
6.89.19.in-addr.arpa
7.89.19.in-addr.arpa
8.89.19.in-addr.arpa
9.89.19.in-addr.arpa
10.89.19.in-addr.arpa
11.89.19.in-addr.arpa
12.89.19.in-addr.arpa
13.89.19.in-addr.arpa
14.89.19.in-addr.arpa
15.89.19.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010011.01011001.00000000.0000000019.89.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00010011.01011001.00000000.0000000019.89.0.0
Broadcast00010011.01011001.00011111.1111111119.89.31.255
Split into smaller subnets/26
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

19.89.0.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
119.89.0.0/2619.89.0.1 to 19.89.0.6219.89.0.6362
219.89.0.64/2619.89.0.65 to 19.89.0.12619.89.0.12762
319.89.0.128/2619.89.0.129 to 19.89.0.19019.89.0.19162
419.89.0.192/2619.89.0.193 to 19.89.0.25419.89.0.25562
519.89.1.0/2619.89.1.1 to 19.89.1.6219.89.1.6362
619.89.1.64/2619.89.1.65 to 19.89.1.12619.89.1.12762
719.89.1.128/2619.89.1.129 to 19.89.1.19019.89.1.19162
819.89.1.192/2619.89.1.193 to 19.89.1.25419.89.1.25562
919.89.2.0/2619.89.2.1 to 19.89.2.6219.89.2.6362
1019.89.2.64/2619.89.2.65 to 19.89.2.12619.89.2.12762
1119.89.2.128/2619.89.2.129 to 19.89.2.19019.89.2.19162
1219.89.2.192/2619.89.2.193 to 19.89.2.25419.89.2.25562
1319.89.3.0/2619.89.3.1 to 19.89.3.6219.89.3.6362
1419.89.3.64/2619.89.3.65 to 19.89.3.12619.89.3.12762
1519.89.3.128/2619.89.3.129 to 19.89.3.19019.89.3.19162
1619.89.3.192/2619.89.3.193 to 19.89.3.25419.89.3.25562
1719.89.4.0/2619.89.4.1 to 19.89.4.6219.89.4.6362
1819.89.4.64/2619.89.4.65 to 19.89.4.12619.89.4.12762
1919.89.4.128/2619.89.4.129 to 19.89.4.19019.89.4.19162
2019.89.4.192/2619.89.4.193 to 19.89.4.25419.89.4.25562
2119.89.5.0/2619.89.5.1 to 19.89.5.6219.89.5.6362
2219.89.5.64/2619.89.5.65 to 19.89.5.12619.89.5.12762
2319.89.5.128/2619.89.5.129 to 19.89.5.19019.89.5.19162
2419.89.5.192/2619.89.5.193 to 19.89.5.25419.89.5.25562
2519.89.6.0/2619.89.6.1 to 19.89.6.6219.89.6.6362
2619.89.6.64/2619.89.6.65 to 19.89.6.12619.89.6.12762
2719.89.6.128/2619.89.6.129 to 19.89.6.19019.89.6.19162
2819.89.6.192/2619.89.6.193 to 19.89.6.25419.89.6.25562
2919.89.7.0/2619.89.7.1 to 19.89.7.6219.89.7.6362
3019.89.7.64/2619.89.7.65 to 19.89.7.12619.89.7.12762
3119.89.7.128/2619.89.7.129 to 19.89.7.19019.89.7.19162
3219.89.7.192/2619.89.7.193 to 19.89.7.25419.89.7.25562
3319.89.8.0/2619.89.8.1 to 19.89.8.6219.89.8.6362
3419.89.8.64/2619.89.8.65 to 19.89.8.12619.89.8.12762
3519.89.8.128/2619.89.8.129 to 19.89.8.19019.89.8.19162
3619.89.8.192/2619.89.8.193 to 19.89.8.25419.89.8.25562
3719.89.9.0/2619.89.9.1 to 19.89.9.6219.89.9.6362
3819.89.9.64/2619.89.9.65 to 19.89.9.12619.89.9.12762
3919.89.9.128/2619.89.9.129 to 19.89.9.19019.89.9.19162
4019.89.9.192/2619.89.9.193 to 19.89.9.25419.89.9.25562
4119.89.10.0/2619.89.10.1 to 19.89.10.6219.89.10.6362
4219.89.10.64/2619.89.10.65 to 19.89.10.12619.89.10.12762
4319.89.10.128/2619.89.10.129 to 19.89.10.19019.89.10.19162
4419.89.10.192/2619.89.10.193 to 19.89.10.25419.89.10.25562
4519.89.11.0/2619.89.11.1 to 19.89.11.6219.89.11.6362
4619.89.11.64/2619.89.11.65 to 19.89.11.12619.89.11.12762
4719.89.11.128/2619.89.11.129 to 19.89.11.19019.89.11.19162
4819.89.11.192/2619.89.11.193 to 19.89.11.25419.89.11.25562
4919.89.12.0/2619.89.12.1 to 19.89.12.6219.89.12.6362
5019.89.12.64/2619.89.12.65 to 19.89.12.12619.89.12.12762
5119.89.12.128/2619.89.12.129 to 19.89.12.19019.89.12.19162
5219.89.12.192/2619.89.12.193 to 19.89.12.25419.89.12.25562
5319.89.13.0/2619.89.13.1 to 19.89.13.6219.89.13.6362
5419.89.13.64/2619.89.13.65 to 19.89.13.12619.89.13.12762
5519.89.13.128/2619.89.13.129 to 19.89.13.19019.89.13.19162
5619.89.13.192/2619.89.13.193 to 19.89.13.25419.89.13.25562
5719.89.14.0/2619.89.14.1 to 19.89.14.6219.89.14.6362
5819.89.14.64/2619.89.14.65 to 19.89.14.12619.89.14.12762
5919.89.14.128/2619.89.14.129 to 19.89.14.19019.89.14.19162
6019.89.14.192/2619.89.14.193 to 19.89.14.25419.89.14.25562
6119.89.15.0/2619.89.15.1 to 19.89.15.6219.89.15.6362
6219.89.15.64/2619.89.15.65 to 19.89.15.12619.89.15.12762
6319.89.15.128/2619.89.15.129 to 19.89.15.19019.89.15.19162
6419.89.15.192/2619.89.15.193 to 19.89.15.25419.89.15.25562
6519.89.16.0/2619.89.16.1 to 19.89.16.6219.89.16.6362
6619.89.16.64/2619.89.16.65 to 19.89.16.12619.89.16.12762
6719.89.16.128/2619.89.16.129 to 19.89.16.19019.89.16.19162
6819.89.16.192/2619.89.16.193 to 19.89.16.25419.89.16.25562
6919.89.17.0/2619.89.17.1 to 19.89.17.6219.89.17.6362
7019.89.17.64/2619.89.17.65 to 19.89.17.12619.89.17.12762
7119.89.17.128/2619.89.17.129 to 19.89.17.19019.89.17.19162
7219.89.17.192/2619.89.17.193 to 19.89.17.25419.89.17.25562
7319.89.18.0/2619.89.18.1 to 19.89.18.6219.89.18.6362
7419.89.18.64/2619.89.18.65 to 19.89.18.12619.89.18.12762
7519.89.18.128/2619.89.18.129 to 19.89.18.19019.89.18.19162
7619.89.18.192/2619.89.18.193 to 19.89.18.25419.89.18.25562
7719.89.19.0/2619.89.19.1 to 19.89.19.6219.89.19.6362
7819.89.19.64/2619.89.19.65 to 19.89.19.12619.89.19.12762
7919.89.19.128/2619.89.19.129 to 19.89.19.19019.89.19.19162
8019.89.19.192/2619.89.19.193 to 19.89.19.25419.89.19.25562
8119.89.20.0/2619.89.20.1 to 19.89.20.6219.89.20.6362
8219.89.20.64/2619.89.20.65 to 19.89.20.12619.89.20.12762
8319.89.20.128/2619.89.20.129 to 19.89.20.19019.89.20.19162
8419.89.20.192/2619.89.20.193 to 19.89.20.25419.89.20.25562
8519.89.21.0/2619.89.21.1 to 19.89.21.6219.89.21.6362
8619.89.21.64/2619.89.21.65 to 19.89.21.12619.89.21.12762
8719.89.21.128/2619.89.21.129 to 19.89.21.19019.89.21.19162
8819.89.21.192/2619.89.21.193 to 19.89.21.25419.89.21.25562
8919.89.22.0/2619.89.22.1 to 19.89.22.6219.89.22.6362
9019.89.22.64/2619.89.22.65 to 19.89.22.12619.89.22.12762
9119.89.22.128/2619.89.22.129 to 19.89.22.19019.89.22.19162
9219.89.22.192/2619.89.22.193 to 19.89.22.25419.89.22.25562
9319.89.23.0/2619.89.23.1 to 19.89.23.6219.89.23.6362
9419.89.23.64/2619.89.23.65 to 19.89.23.12619.89.23.12762
9519.89.23.128/2619.89.23.129 to 19.89.23.19019.89.23.19162
9619.89.23.192/2619.89.23.193 to 19.89.23.25419.89.23.25562
9719.89.24.0/2619.89.24.1 to 19.89.24.6219.89.24.6362
9819.89.24.64/2619.89.24.65 to 19.89.24.12619.89.24.12762
9919.89.24.128/2619.89.24.129 to 19.89.24.19019.89.24.19162
10019.89.24.192/2619.89.24.193 to 19.89.24.25419.89.24.25562
10119.89.25.0/2619.89.25.1 to 19.89.25.6219.89.25.6362
10219.89.25.64/2619.89.25.65 to 19.89.25.12619.89.25.12762
10319.89.25.128/2619.89.25.129 to 19.89.25.19019.89.25.19162
10419.89.25.192/2619.89.25.193 to 19.89.25.25419.89.25.25562
10519.89.26.0/2619.89.26.1 to 19.89.26.6219.89.26.6362
10619.89.26.64/2619.89.26.65 to 19.89.26.12619.89.26.12762
10719.89.26.128/2619.89.26.129 to 19.89.26.19019.89.26.19162
10819.89.26.192/2619.89.26.193 to 19.89.26.25419.89.26.25562
10919.89.27.0/2619.89.27.1 to 19.89.27.6219.89.27.6362
11019.89.27.64/2619.89.27.65 to 19.89.27.12619.89.27.12762
11119.89.27.128/2619.89.27.129 to 19.89.27.19019.89.27.19162
11219.89.27.192/2619.89.27.193 to 19.89.27.25419.89.27.25562
11319.89.28.0/2619.89.28.1 to 19.89.28.6219.89.28.6362
11419.89.28.64/2619.89.28.65 to 19.89.28.12619.89.28.12762
11519.89.28.128/2619.89.28.129 to 19.89.28.19019.89.28.19162
11619.89.28.192/2619.89.28.193 to 19.89.28.25419.89.28.25562
11719.89.29.0/2619.89.29.1 to 19.89.29.6219.89.29.6362
11819.89.29.64/2619.89.29.65 to 19.89.29.12619.89.29.12762
11919.89.29.128/2619.89.29.129 to 19.89.29.19019.89.29.19162
12019.89.29.192/2619.89.29.193 to 19.89.29.25419.89.29.25562
12119.89.30.0/2619.89.30.1 to 19.89.30.6219.89.30.6362
12219.89.30.64/2619.89.30.65 to 19.89.30.12619.89.30.12762
12319.89.30.128/2619.89.30.129 to 19.89.30.19019.89.30.19162
12419.89.30.192/2619.89.30.193 to 19.89.30.25419.89.30.25562
12519.89.31.0/2619.89.31.1 to 19.89.31.6219.89.31.6362
12619.89.31.64/2619.89.31.65 to 19.89.31.12619.89.31.12762
12719.89.31.128/2619.89.31.129 to 19.89.31.19019.89.31.19162
12819.89.31.192/2619.89.31.193 to 19.89.31.25419.89.31.25562

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.