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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.

Network76.112.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
76.112.0.0
Broadcast address
76.127.255.255
First usable
76.112.0.1
Last usable
76.127.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 4C700000 · Integer 1282408448 to 1283457023
Reverse DNS zones
112.76.in-addr.arpa
113.76.in-addr.arpa
114.76.in-addr.arpa
115.76.in-addr.arpa
116.76.in-addr.arpa
117.76.in-addr.arpa
118.76.in-addr.arpa
119.76.in-addr.arpa
120.76.in-addr.arpa
121.76.in-addr.arpa
122.76.in-addr.arpa
123.76.in-addr.arpa
124.76.in-addr.arpa
125.76.in-addr.arpa
126.76.in-addr.arpa
127.76.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001100.01110000.00000000.0000000076.112.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01001100.01110000.00000000.0000000076.112.0.0
Broadcast01001100.01111111.11111111.1111111176.127.255.255
Split into smaller subnets/19
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

76.112.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
176.112.0.0/1976.112.0.1 to 76.112.31.25476.112.31.2558,190
276.112.32.0/1976.112.32.1 to 76.112.63.25476.112.63.2558,190
376.112.64.0/1976.112.64.1 to 76.112.95.25476.112.95.2558,190
476.112.96.0/1976.112.96.1 to 76.112.127.25476.112.127.2558,190
576.112.128.0/1976.112.128.1 to 76.112.159.25476.112.159.2558,190
676.112.160.0/1976.112.160.1 to 76.112.191.25476.112.191.2558,190
776.112.192.0/1976.112.192.1 to 76.112.223.25476.112.223.2558,190
876.112.224.0/1976.112.224.1 to 76.112.255.25476.112.255.2558,190
976.113.0.0/1976.113.0.1 to 76.113.31.25476.113.31.2558,190
1076.113.32.0/1976.113.32.1 to 76.113.63.25476.113.63.2558,190
1176.113.64.0/1976.113.64.1 to 76.113.95.25476.113.95.2558,190
1276.113.96.0/1976.113.96.1 to 76.113.127.25476.113.127.2558,190
1376.113.128.0/1976.113.128.1 to 76.113.159.25476.113.159.2558,190
1476.113.160.0/1976.113.160.1 to 76.113.191.25476.113.191.2558,190
1576.113.192.0/1976.113.192.1 to 76.113.223.25476.113.223.2558,190
1676.113.224.0/1976.113.224.1 to 76.113.255.25476.113.255.2558,190
1776.114.0.0/1976.114.0.1 to 76.114.31.25476.114.31.2558,190
1876.114.32.0/1976.114.32.1 to 76.114.63.25476.114.63.2558,190
1976.114.64.0/1976.114.64.1 to 76.114.95.25476.114.95.2558,190
2076.114.96.0/1976.114.96.1 to 76.114.127.25476.114.127.2558,190
2176.114.128.0/1976.114.128.1 to 76.114.159.25476.114.159.2558,190
2276.114.160.0/1976.114.160.1 to 76.114.191.25476.114.191.2558,190
2376.114.192.0/1976.114.192.1 to 76.114.223.25476.114.223.2558,190
2476.114.224.0/1976.114.224.1 to 76.114.255.25476.114.255.2558,190
2576.115.0.0/1976.115.0.1 to 76.115.31.25476.115.31.2558,190
2676.115.32.0/1976.115.32.1 to 76.115.63.25476.115.63.2558,190
2776.115.64.0/1976.115.64.1 to 76.115.95.25476.115.95.2558,190
2876.115.96.0/1976.115.96.1 to 76.115.127.25476.115.127.2558,190
2976.115.128.0/1976.115.128.1 to 76.115.159.25476.115.159.2558,190
3076.115.160.0/1976.115.160.1 to 76.115.191.25476.115.191.2558,190
3176.115.192.0/1976.115.192.1 to 76.115.223.25476.115.223.2558,190
3276.115.224.0/1976.115.224.1 to 76.115.255.25476.115.255.2558,190
3376.116.0.0/1976.116.0.1 to 76.116.31.25476.116.31.2558,190
3476.116.32.0/1976.116.32.1 to 76.116.63.25476.116.63.2558,190
3576.116.64.0/1976.116.64.1 to 76.116.95.25476.116.95.2558,190
3676.116.96.0/1976.116.96.1 to 76.116.127.25476.116.127.2558,190
3776.116.128.0/1976.116.128.1 to 76.116.159.25476.116.159.2558,190
3876.116.160.0/1976.116.160.1 to 76.116.191.25476.116.191.2558,190
3976.116.192.0/1976.116.192.1 to 76.116.223.25476.116.223.2558,190
4076.116.224.0/1976.116.224.1 to 76.116.255.25476.116.255.2558,190
4176.117.0.0/1976.117.0.1 to 76.117.31.25476.117.31.2558,190
4276.117.32.0/1976.117.32.1 to 76.117.63.25476.117.63.2558,190
4376.117.64.0/1976.117.64.1 to 76.117.95.25476.117.95.2558,190
4476.117.96.0/1976.117.96.1 to 76.117.127.25476.117.127.2558,190
4576.117.128.0/1976.117.128.1 to 76.117.159.25476.117.159.2558,190
4676.117.160.0/1976.117.160.1 to 76.117.191.25476.117.191.2558,190
4776.117.192.0/1976.117.192.1 to 76.117.223.25476.117.223.2558,190
4876.117.224.0/1976.117.224.1 to 76.117.255.25476.117.255.2558,190
4976.118.0.0/1976.118.0.1 to 76.118.31.25476.118.31.2558,190
5076.118.32.0/1976.118.32.1 to 76.118.63.25476.118.63.2558,190
5176.118.64.0/1976.118.64.1 to 76.118.95.25476.118.95.2558,190
5276.118.96.0/1976.118.96.1 to 76.118.127.25476.118.127.2558,190
5376.118.128.0/1976.118.128.1 to 76.118.159.25476.118.159.2558,190
5476.118.160.0/1976.118.160.1 to 76.118.191.25476.118.191.2558,190
5576.118.192.0/1976.118.192.1 to 76.118.223.25476.118.223.2558,190
5676.118.224.0/1976.118.224.1 to 76.118.255.25476.118.255.2558,190
5776.119.0.0/1976.119.0.1 to 76.119.31.25476.119.31.2558,190
5876.119.32.0/1976.119.32.1 to 76.119.63.25476.119.63.2558,190
5976.119.64.0/1976.119.64.1 to 76.119.95.25476.119.95.2558,190
6076.119.96.0/1976.119.96.1 to 76.119.127.25476.119.127.2558,190
6176.119.128.0/1976.119.128.1 to 76.119.159.25476.119.159.2558,190
6276.119.160.0/1976.119.160.1 to 76.119.191.25476.119.191.2558,190
6376.119.192.0/1976.119.192.1 to 76.119.223.25476.119.223.2558,190
6476.119.224.0/1976.119.224.1 to 76.119.255.25476.119.255.2558,190
6576.120.0.0/1976.120.0.1 to 76.120.31.25476.120.31.2558,190
6676.120.32.0/1976.120.32.1 to 76.120.63.25476.120.63.2558,190
6776.120.64.0/1976.120.64.1 to 76.120.95.25476.120.95.2558,190
6876.120.96.0/1976.120.96.1 to 76.120.127.25476.120.127.2558,190
6976.120.128.0/1976.120.128.1 to 76.120.159.25476.120.159.2558,190
7076.120.160.0/1976.120.160.1 to 76.120.191.25476.120.191.2558,190
7176.120.192.0/1976.120.192.1 to 76.120.223.25476.120.223.2558,190
7276.120.224.0/1976.120.224.1 to 76.120.255.25476.120.255.2558,190
7376.121.0.0/1976.121.0.1 to 76.121.31.25476.121.31.2558,190
7476.121.32.0/1976.121.32.1 to 76.121.63.25476.121.63.2558,190
7576.121.64.0/1976.121.64.1 to 76.121.95.25476.121.95.2558,190
7676.121.96.0/1976.121.96.1 to 76.121.127.25476.121.127.2558,190
7776.121.128.0/1976.121.128.1 to 76.121.159.25476.121.159.2558,190
7876.121.160.0/1976.121.160.1 to 76.121.191.25476.121.191.2558,190
7976.121.192.0/1976.121.192.1 to 76.121.223.25476.121.223.2558,190
8076.121.224.0/1976.121.224.1 to 76.121.255.25476.121.255.2558,190
8176.122.0.0/1976.122.0.1 to 76.122.31.25476.122.31.2558,190
8276.122.32.0/1976.122.32.1 to 76.122.63.25476.122.63.2558,190
8376.122.64.0/1976.122.64.1 to 76.122.95.25476.122.95.2558,190
8476.122.96.0/1976.122.96.1 to 76.122.127.25476.122.127.2558,190
8576.122.128.0/1976.122.128.1 to 76.122.159.25476.122.159.2558,190
8676.122.160.0/1976.122.160.1 to 76.122.191.25476.122.191.2558,190
8776.122.192.0/1976.122.192.1 to 76.122.223.25476.122.223.2558,190
8876.122.224.0/1976.122.224.1 to 76.122.255.25476.122.255.2558,190
8976.123.0.0/1976.123.0.1 to 76.123.31.25476.123.31.2558,190
9076.123.32.0/1976.123.32.1 to 76.123.63.25476.123.63.2558,190
9176.123.64.0/1976.123.64.1 to 76.123.95.25476.123.95.2558,190
9276.123.96.0/1976.123.96.1 to 76.123.127.25476.123.127.2558,190
9376.123.128.0/1976.123.128.1 to 76.123.159.25476.123.159.2558,190
9476.123.160.0/1976.123.160.1 to 76.123.191.25476.123.191.2558,190
9576.123.192.0/1976.123.192.1 to 76.123.223.25476.123.223.2558,190
9676.123.224.0/1976.123.224.1 to 76.123.255.25476.123.255.2558,190
9776.124.0.0/1976.124.0.1 to 76.124.31.25476.124.31.2558,190
9876.124.32.0/1976.124.32.1 to 76.124.63.25476.124.63.2558,190
9976.124.64.0/1976.124.64.1 to 76.124.95.25476.124.95.2558,190
10076.124.96.0/1976.124.96.1 to 76.124.127.25476.124.127.2558,190
10176.124.128.0/1976.124.128.1 to 76.124.159.25476.124.159.2558,190
10276.124.160.0/1976.124.160.1 to 76.124.191.25476.124.191.2558,190
10376.124.192.0/1976.124.192.1 to 76.124.223.25476.124.223.2558,190
10476.124.224.0/1976.124.224.1 to 76.124.255.25476.124.255.2558,190
10576.125.0.0/1976.125.0.1 to 76.125.31.25476.125.31.2558,190
10676.125.32.0/1976.125.32.1 to 76.125.63.25476.125.63.2558,190
10776.125.64.0/1976.125.64.1 to 76.125.95.25476.125.95.2558,190
10876.125.96.0/1976.125.96.1 to 76.125.127.25476.125.127.2558,190
10976.125.128.0/1976.125.128.1 to 76.125.159.25476.125.159.2558,190
11076.125.160.0/1976.125.160.1 to 76.125.191.25476.125.191.2558,190
11176.125.192.0/1976.125.192.1 to 76.125.223.25476.125.223.2558,190
11276.125.224.0/1976.125.224.1 to 76.125.255.25476.125.255.2558,190
11376.126.0.0/1976.126.0.1 to 76.126.31.25476.126.31.2558,190
11476.126.32.0/1976.126.32.1 to 76.126.63.25476.126.63.2558,190
11576.126.64.0/1976.126.64.1 to 76.126.95.25476.126.95.2558,190
11676.126.96.0/1976.126.96.1 to 76.126.127.25476.126.127.2558,190
11776.126.128.0/1976.126.128.1 to 76.126.159.25476.126.159.2558,190
11876.126.160.0/1976.126.160.1 to 76.126.191.25476.126.191.2558,190
11976.126.192.0/1976.126.192.1 to 76.126.223.25476.126.223.2558,190
12076.126.224.0/1976.126.224.1 to 76.126.255.25476.126.255.2558,190
12176.127.0.0/1976.127.0.1 to 76.127.31.25476.127.31.2558,190
12276.127.32.0/1976.127.32.1 to 76.127.63.25476.127.63.2558,190
12376.127.64.0/1976.127.64.1 to 76.127.95.25476.127.95.2558,190
12476.127.96.0/1976.127.96.1 to 76.127.127.25476.127.127.2558,190
12576.127.128.0/1976.127.128.1 to 76.127.159.25476.127.159.2558,190
12676.127.160.0/1976.127.160.1 to 76.127.191.25476.127.191.2558,190
12776.127.192.0/1976.127.192.1 to 76.127.223.25476.127.223.2558,190
12876.127.224.0/1976.127.224.1 to 76.127.255.25476.127.255.2558,190

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.