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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.

Network6.232.96.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
6.232.96.0
Broadcast address
6.232.111.255
First usable
6.232.96.1
Last usable
6.232.111.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
A (default /8)
As numbers
Hex 06E86000 · Integer 115892224 to 115896319
Reverse DNS zones
96.232.6.in-addr.arpa
97.232.6.in-addr.arpa
98.232.6.in-addr.arpa
99.232.6.in-addr.arpa
100.232.6.in-addr.arpa
101.232.6.in-addr.arpa
102.232.6.in-addr.arpa
103.232.6.in-addr.arpa
104.232.6.in-addr.arpa
105.232.6.in-addr.arpa
106.232.6.in-addr.arpa
107.232.6.in-addr.arpa
108.232.6.in-addr.arpa
109.232.6.in-addr.arpa
110.232.6.in-addr.arpa
111.232.6.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000110.11101000.01100000.000000006.232.96.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network00000110.11101000.01100000.000000006.232.96.0
Broadcast00000110.11101000.01101111.111111116.232.111.255
Split into smaller subnets/27
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

6.232.96.0/20 makes 128 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.232.96.0/276.232.96.1 to 6.232.96.306.232.96.3130
26.232.96.32/276.232.96.33 to 6.232.96.626.232.96.6330
36.232.96.64/276.232.96.65 to 6.232.96.946.232.96.9530
46.232.96.96/276.232.96.97 to 6.232.96.1266.232.96.12730
56.232.96.128/276.232.96.129 to 6.232.96.1586.232.96.15930
66.232.96.160/276.232.96.161 to 6.232.96.1906.232.96.19130
76.232.96.192/276.232.96.193 to 6.232.96.2226.232.96.22330
86.232.96.224/276.232.96.225 to 6.232.96.2546.232.96.25530
96.232.97.0/276.232.97.1 to 6.232.97.306.232.97.3130
106.232.97.32/276.232.97.33 to 6.232.97.626.232.97.6330
116.232.97.64/276.232.97.65 to 6.232.97.946.232.97.9530
126.232.97.96/276.232.97.97 to 6.232.97.1266.232.97.12730
136.232.97.128/276.232.97.129 to 6.232.97.1586.232.97.15930
146.232.97.160/276.232.97.161 to 6.232.97.1906.232.97.19130
156.232.97.192/276.232.97.193 to 6.232.97.2226.232.97.22330
166.232.97.224/276.232.97.225 to 6.232.97.2546.232.97.25530
176.232.98.0/276.232.98.1 to 6.232.98.306.232.98.3130
186.232.98.32/276.232.98.33 to 6.232.98.626.232.98.6330
196.232.98.64/276.232.98.65 to 6.232.98.946.232.98.9530
206.232.98.96/276.232.98.97 to 6.232.98.1266.232.98.12730
216.232.98.128/276.232.98.129 to 6.232.98.1586.232.98.15930
226.232.98.160/276.232.98.161 to 6.232.98.1906.232.98.19130
236.232.98.192/276.232.98.193 to 6.232.98.2226.232.98.22330
246.232.98.224/276.232.98.225 to 6.232.98.2546.232.98.25530
256.232.99.0/276.232.99.1 to 6.232.99.306.232.99.3130
266.232.99.32/276.232.99.33 to 6.232.99.626.232.99.6330
276.232.99.64/276.232.99.65 to 6.232.99.946.232.99.9530
286.232.99.96/276.232.99.97 to 6.232.99.1266.232.99.12730
296.232.99.128/276.232.99.129 to 6.232.99.1586.232.99.15930
306.232.99.160/276.232.99.161 to 6.232.99.1906.232.99.19130
316.232.99.192/276.232.99.193 to 6.232.99.2226.232.99.22330
326.232.99.224/276.232.99.225 to 6.232.99.2546.232.99.25530
336.232.100.0/276.232.100.1 to 6.232.100.306.232.100.3130
346.232.100.32/276.232.100.33 to 6.232.100.626.232.100.6330
356.232.100.64/276.232.100.65 to 6.232.100.946.232.100.9530
366.232.100.96/276.232.100.97 to 6.232.100.1266.232.100.12730
376.232.100.128/276.232.100.129 to 6.232.100.1586.232.100.15930
386.232.100.160/276.232.100.161 to 6.232.100.1906.232.100.19130
396.232.100.192/276.232.100.193 to 6.232.100.2226.232.100.22330
406.232.100.224/276.232.100.225 to 6.232.100.2546.232.100.25530
416.232.101.0/276.232.101.1 to 6.232.101.306.232.101.3130
426.232.101.32/276.232.101.33 to 6.232.101.626.232.101.6330
436.232.101.64/276.232.101.65 to 6.232.101.946.232.101.9530
446.232.101.96/276.232.101.97 to 6.232.101.1266.232.101.12730
456.232.101.128/276.232.101.129 to 6.232.101.1586.232.101.15930
466.232.101.160/276.232.101.161 to 6.232.101.1906.232.101.19130
476.232.101.192/276.232.101.193 to 6.232.101.2226.232.101.22330
486.232.101.224/276.232.101.225 to 6.232.101.2546.232.101.25530
496.232.102.0/276.232.102.1 to 6.232.102.306.232.102.3130
506.232.102.32/276.232.102.33 to 6.232.102.626.232.102.6330
516.232.102.64/276.232.102.65 to 6.232.102.946.232.102.9530
526.232.102.96/276.232.102.97 to 6.232.102.1266.232.102.12730
536.232.102.128/276.232.102.129 to 6.232.102.1586.232.102.15930
546.232.102.160/276.232.102.161 to 6.232.102.1906.232.102.19130
556.232.102.192/276.232.102.193 to 6.232.102.2226.232.102.22330
566.232.102.224/276.232.102.225 to 6.232.102.2546.232.102.25530
576.232.103.0/276.232.103.1 to 6.232.103.306.232.103.3130
586.232.103.32/276.232.103.33 to 6.232.103.626.232.103.6330
596.232.103.64/276.232.103.65 to 6.232.103.946.232.103.9530
606.232.103.96/276.232.103.97 to 6.232.103.1266.232.103.12730
616.232.103.128/276.232.103.129 to 6.232.103.1586.232.103.15930
626.232.103.160/276.232.103.161 to 6.232.103.1906.232.103.19130
636.232.103.192/276.232.103.193 to 6.232.103.2226.232.103.22330
646.232.103.224/276.232.103.225 to 6.232.103.2546.232.103.25530
656.232.104.0/276.232.104.1 to 6.232.104.306.232.104.3130
666.232.104.32/276.232.104.33 to 6.232.104.626.232.104.6330
676.232.104.64/276.232.104.65 to 6.232.104.946.232.104.9530
686.232.104.96/276.232.104.97 to 6.232.104.1266.232.104.12730
696.232.104.128/276.232.104.129 to 6.232.104.1586.232.104.15930
706.232.104.160/276.232.104.161 to 6.232.104.1906.232.104.19130
716.232.104.192/276.232.104.193 to 6.232.104.2226.232.104.22330
726.232.104.224/276.232.104.225 to 6.232.104.2546.232.104.25530
736.232.105.0/276.232.105.1 to 6.232.105.306.232.105.3130
746.232.105.32/276.232.105.33 to 6.232.105.626.232.105.6330
756.232.105.64/276.232.105.65 to 6.232.105.946.232.105.9530
766.232.105.96/276.232.105.97 to 6.232.105.1266.232.105.12730
776.232.105.128/276.232.105.129 to 6.232.105.1586.232.105.15930
786.232.105.160/276.232.105.161 to 6.232.105.1906.232.105.19130
796.232.105.192/276.232.105.193 to 6.232.105.2226.232.105.22330
806.232.105.224/276.232.105.225 to 6.232.105.2546.232.105.25530
816.232.106.0/276.232.106.1 to 6.232.106.306.232.106.3130
826.232.106.32/276.232.106.33 to 6.232.106.626.232.106.6330
836.232.106.64/276.232.106.65 to 6.232.106.946.232.106.9530
846.232.106.96/276.232.106.97 to 6.232.106.1266.232.106.12730
856.232.106.128/276.232.106.129 to 6.232.106.1586.232.106.15930
866.232.106.160/276.232.106.161 to 6.232.106.1906.232.106.19130
876.232.106.192/276.232.106.193 to 6.232.106.2226.232.106.22330
886.232.106.224/276.232.106.225 to 6.232.106.2546.232.106.25530
896.232.107.0/276.232.107.1 to 6.232.107.306.232.107.3130
906.232.107.32/276.232.107.33 to 6.232.107.626.232.107.6330
916.232.107.64/276.232.107.65 to 6.232.107.946.232.107.9530
926.232.107.96/276.232.107.97 to 6.232.107.1266.232.107.12730
936.232.107.128/276.232.107.129 to 6.232.107.1586.232.107.15930
946.232.107.160/276.232.107.161 to 6.232.107.1906.232.107.19130
956.232.107.192/276.232.107.193 to 6.232.107.2226.232.107.22330
966.232.107.224/276.232.107.225 to 6.232.107.2546.232.107.25530
976.232.108.0/276.232.108.1 to 6.232.108.306.232.108.3130
986.232.108.32/276.232.108.33 to 6.232.108.626.232.108.6330
996.232.108.64/276.232.108.65 to 6.232.108.946.232.108.9530
1006.232.108.96/276.232.108.97 to 6.232.108.1266.232.108.12730
1016.232.108.128/276.232.108.129 to 6.232.108.1586.232.108.15930
1026.232.108.160/276.232.108.161 to 6.232.108.1906.232.108.19130
1036.232.108.192/276.232.108.193 to 6.232.108.2226.232.108.22330
1046.232.108.224/276.232.108.225 to 6.232.108.2546.232.108.25530
1056.232.109.0/276.232.109.1 to 6.232.109.306.232.109.3130
1066.232.109.32/276.232.109.33 to 6.232.109.626.232.109.6330
1076.232.109.64/276.232.109.65 to 6.232.109.946.232.109.9530
1086.232.109.96/276.232.109.97 to 6.232.109.1266.232.109.12730
1096.232.109.128/276.232.109.129 to 6.232.109.1586.232.109.15930
1106.232.109.160/276.232.109.161 to 6.232.109.1906.232.109.19130
1116.232.109.192/276.232.109.193 to 6.232.109.2226.232.109.22330
1126.232.109.224/276.232.109.225 to 6.232.109.2546.232.109.25530
1136.232.110.0/276.232.110.1 to 6.232.110.306.232.110.3130
1146.232.110.32/276.232.110.33 to 6.232.110.626.232.110.6330
1156.232.110.64/276.232.110.65 to 6.232.110.946.232.110.9530
1166.232.110.96/276.232.110.97 to 6.232.110.1266.232.110.12730
1176.232.110.128/276.232.110.129 to 6.232.110.1586.232.110.15930
1186.232.110.160/276.232.110.161 to 6.232.110.1906.232.110.19130
1196.232.110.192/276.232.110.193 to 6.232.110.2226.232.110.22330
1206.232.110.224/276.232.110.225 to 6.232.110.2546.232.110.25530
1216.232.111.0/276.232.111.1 to 6.232.111.306.232.111.3130
1226.232.111.32/276.232.111.33 to 6.232.111.626.232.111.6330
1236.232.111.64/276.232.111.65 to 6.232.111.946.232.111.9530
1246.232.111.96/276.232.111.97 to 6.232.111.1266.232.111.12730
1256.232.111.128/276.232.111.129 to 6.232.111.1586.232.111.15930
1266.232.111.160/276.232.111.161 to 6.232.111.1906.232.111.19130
1276.232.111.192/276.232.111.193 to 6.232.111.2226.232.111.22330
1286.232.111.224/276.232.111.225 to 6.232.111.2546.232.111.25530

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.