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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.

Network2.77.136.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
2.77.136.0
Broadcast address
2.77.139.255
First usable
2.77.136.1
Last usable
2.77.139.254
Usable hosts
1,022 (1,024 less the network and broadcast addresses)
Subnet mask
255.255.252.0
Wildcard mask
0.0.3.255 (Cisco ACLs, OSPF)
Prefix length
/22
Type
Public public
Old class
A (default /8)
As numbers
Hex 024D8800 · Integer 38635520 to 38636543
Reverse DNS zones
136.77.2.in-addr.arpa
137.77.2.in-addr.arpa
138.77.2.in-addr.arpa
139.77.2.in-addr.arpa
/22 is not on a 8-bit boundary, so it takes 4 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000010.01001101.10001000.000000002.77.136.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00000010.01001101.10001000.000000002.77.136.0
Broadcast00000010.01001101.10001011.111111112.77.139.255
Split into smaller subnets/28
/23 (2)/24 (4)/25 (8)/26 (16)/27 (32)/28 (64)/29 (128)/30 (256)/31 (512)/32 (1,024)

2.77.136.0/22 makes 64 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.77.136.0/282.77.136.1 to 2.77.136.142.77.136.1514
22.77.136.16/282.77.136.17 to 2.77.136.302.77.136.3114
32.77.136.32/282.77.136.33 to 2.77.136.462.77.136.4714
42.77.136.48/282.77.136.49 to 2.77.136.622.77.136.6314
52.77.136.64/282.77.136.65 to 2.77.136.782.77.136.7914
62.77.136.80/282.77.136.81 to 2.77.136.942.77.136.9514
72.77.136.96/282.77.136.97 to 2.77.136.1102.77.136.11114
82.77.136.112/282.77.136.113 to 2.77.136.1262.77.136.12714
92.77.136.128/282.77.136.129 to 2.77.136.1422.77.136.14314
102.77.136.144/282.77.136.145 to 2.77.136.1582.77.136.15914
112.77.136.160/282.77.136.161 to 2.77.136.1742.77.136.17514
122.77.136.176/282.77.136.177 to 2.77.136.1902.77.136.19114
132.77.136.192/282.77.136.193 to 2.77.136.2062.77.136.20714
142.77.136.208/282.77.136.209 to 2.77.136.2222.77.136.22314
152.77.136.224/282.77.136.225 to 2.77.136.2382.77.136.23914
162.77.136.240/282.77.136.241 to 2.77.136.2542.77.136.25514
172.77.137.0/282.77.137.1 to 2.77.137.142.77.137.1514
182.77.137.16/282.77.137.17 to 2.77.137.302.77.137.3114
192.77.137.32/282.77.137.33 to 2.77.137.462.77.137.4714
202.77.137.48/282.77.137.49 to 2.77.137.622.77.137.6314
212.77.137.64/282.77.137.65 to 2.77.137.782.77.137.7914
222.77.137.80/282.77.137.81 to 2.77.137.942.77.137.9514
232.77.137.96/282.77.137.97 to 2.77.137.1102.77.137.11114
242.77.137.112/282.77.137.113 to 2.77.137.1262.77.137.12714
252.77.137.128/282.77.137.129 to 2.77.137.1422.77.137.14314
262.77.137.144/282.77.137.145 to 2.77.137.1582.77.137.15914
272.77.137.160/282.77.137.161 to 2.77.137.1742.77.137.17514
282.77.137.176/282.77.137.177 to 2.77.137.1902.77.137.19114
292.77.137.192/282.77.137.193 to 2.77.137.2062.77.137.20714
302.77.137.208/282.77.137.209 to 2.77.137.2222.77.137.22314
312.77.137.224/282.77.137.225 to 2.77.137.2382.77.137.23914
322.77.137.240/282.77.137.241 to 2.77.137.2542.77.137.25514
332.77.138.0/282.77.138.1 to 2.77.138.142.77.138.1514
342.77.138.16/282.77.138.17 to 2.77.138.302.77.138.3114
352.77.138.32/282.77.138.33 to 2.77.138.462.77.138.4714
362.77.138.48/282.77.138.49 to 2.77.138.622.77.138.6314
372.77.138.64/282.77.138.65 to 2.77.138.782.77.138.7914
382.77.138.80/282.77.138.81 to 2.77.138.942.77.138.9514
392.77.138.96/282.77.138.97 to 2.77.138.1102.77.138.11114
402.77.138.112/282.77.138.113 to 2.77.138.1262.77.138.12714
412.77.138.128/282.77.138.129 to 2.77.138.1422.77.138.14314
422.77.138.144/282.77.138.145 to 2.77.138.1582.77.138.15914
432.77.138.160/282.77.138.161 to 2.77.138.1742.77.138.17514
442.77.138.176/282.77.138.177 to 2.77.138.1902.77.138.19114
452.77.138.192/282.77.138.193 to 2.77.138.2062.77.138.20714
462.77.138.208/282.77.138.209 to 2.77.138.2222.77.138.22314
472.77.138.224/282.77.138.225 to 2.77.138.2382.77.138.23914
482.77.138.240/282.77.138.241 to 2.77.138.2542.77.138.25514
492.77.139.0/282.77.139.1 to 2.77.139.142.77.139.1514
502.77.139.16/282.77.139.17 to 2.77.139.302.77.139.3114
512.77.139.32/282.77.139.33 to 2.77.139.462.77.139.4714
522.77.139.48/282.77.139.49 to 2.77.139.622.77.139.6314
532.77.139.64/282.77.139.65 to 2.77.139.782.77.139.7914
542.77.139.80/282.77.139.81 to 2.77.139.942.77.139.9514
552.77.139.96/282.77.139.97 to 2.77.139.1102.77.139.11114
562.77.139.112/282.77.139.113 to 2.77.139.1262.77.139.12714
572.77.139.128/282.77.139.129 to 2.77.139.1422.77.139.14314
582.77.139.144/282.77.139.145 to 2.77.139.1582.77.139.15914
592.77.139.160/282.77.139.161 to 2.77.139.1742.77.139.17514
602.77.139.176/282.77.139.177 to 2.77.139.1902.77.139.19114
612.77.139.192/282.77.139.193 to 2.77.139.2062.77.139.20714
622.77.139.208/282.77.139.209 to 2.77.139.2222.77.139.22314
632.77.139.224/282.77.139.225 to 2.77.139.2382.77.139.23914
642.77.139.240/282.77.139.241 to 2.77.139.2542.77.139.25514

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.