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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.

Network228.99.76.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
228.99.76.0
Broadcast address
228.99.79.255
First usable
228.99.76.1
Last usable
228.99.79.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4634C00 · Integer 3831712768 to 3831713791
Reverse DNS zones
76.99.228.in-addr.arpa
77.99.228.in-addr.arpa
78.99.228.in-addr.arpa
79.99.228.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
Address11100100.01100011.01001100.00000000228.99.76.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network11100100.01100011.01001100.00000000228.99.76.0
Broadcast11100100.01100011.01001111.11111111228.99.79.255
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)

228.99.76.0/22 makes 64 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.99.76.0/28228.99.76.1 to 228.99.76.14228.99.76.1514
2228.99.76.16/28228.99.76.17 to 228.99.76.30228.99.76.3114
3228.99.76.32/28228.99.76.33 to 228.99.76.46228.99.76.4714
4228.99.76.48/28228.99.76.49 to 228.99.76.62228.99.76.6314
5228.99.76.64/28228.99.76.65 to 228.99.76.78228.99.76.7914
6228.99.76.80/28228.99.76.81 to 228.99.76.94228.99.76.9514
7228.99.76.96/28228.99.76.97 to 228.99.76.110228.99.76.11114
8228.99.76.112/28228.99.76.113 to 228.99.76.126228.99.76.12714
9228.99.76.128/28228.99.76.129 to 228.99.76.142228.99.76.14314
10228.99.76.144/28228.99.76.145 to 228.99.76.158228.99.76.15914
11228.99.76.160/28228.99.76.161 to 228.99.76.174228.99.76.17514
12228.99.76.176/28228.99.76.177 to 228.99.76.190228.99.76.19114
13228.99.76.192/28228.99.76.193 to 228.99.76.206228.99.76.20714
14228.99.76.208/28228.99.76.209 to 228.99.76.222228.99.76.22314
15228.99.76.224/28228.99.76.225 to 228.99.76.238228.99.76.23914
16228.99.76.240/28228.99.76.241 to 228.99.76.254228.99.76.25514
17228.99.77.0/28228.99.77.1 to 228.99.77.14228.99.77.1514
18228.99.77.16/28228.99.77.17 to 228.99.77.30228.99.77.3114
19228.99.77.32/28228.99.77.33 to 228.99.77.46228.99.77.4714
20228.99.77.48/28228.99.77.49 to 228.99.77.62228.99.77.6314
21228.99.77.64/28228.99.77.65 to 228.99.77.78228.99.77.7914
22228.99.77.80/28228.99.77.81 to 228.99.77.94228.99.77.9514
23228.99.77.96/28228.99.77.97 to 228.99.77.110228.99.77.11114
24228.99.77.112/28228.99.77.113 to 228.99.77.126228.99.77.12714
25228.99.77.128/28228.99.77.129 to 228.99.77.142228.99.77.14314
26228.99.77.144/28228.99.77.145 to 228.99.77.158228.99.77.15914
27228.99.77.160/28228.99.77.161 to 228.99.77.174228.99.77.17514
28228.99.77.176/28228.99.77.177 to 228.99.77.190228.99.77.19114
29228.99.77.192/28228.99.77.193 to 228.99.77.206228.99.77.20714
30228.99.77.208/28228.99.77.209 to 228.99.77.222228.99.77.22314
31228.99.77.224/28228.99.77.225 to 228.99.77.238228.99.77.23914
32228.99.77.240/28228.99.77.241 to 228.99.77.254228.99.77.25514
33228.99.78.0/28228.99.78.1 to 228.99.78.14228.99.78.1514
34228.99.78.16/28228.99.78.17 to 228.99.78.30228.99.78.3114
35228.99.78.32/28228.99.78.33 to 228.99.78.46228.99.78.4714
36228.99.78.48/28228.99.78.49 to 228.99.78.62228.99.78.6314
37228.99.78.64/28228.99.78.65 to 228.99.78.78228.99.78.7914
38228.99.78.80/28228.99.78.81 to 228.99.78.94228.99.78.9514
39228.99.78.96/28228.99.78.97 to 228.99.78.110228.99.78.11114
40228.99.78.112/28228.99.78.113 to 228.99.78.126228.99.78.12714
41228.99.78.128/28228.99.78.129 to 228.99.78.142228.99.78.14314
42228.99.78.144/28228.99.78.145 to 228.99.78.158228.99.78.15914
43228.99.78.160/28228.99.78.161 to 228.99.78.174228.99.78.17514
44228.99.78.176/28228.99.78.177 to 228.99.78.190228.99.78.19114
45228.99.78.192/28228.99.78.193 to 228.99.78.206228.99.78.20714
46228.99.78.208/28228.99.78.209 to 228.99.78.222228.99.78.22314
47228.99.78.224/28228.99.78.225 to 228.99.78.238228.99.78.23914
48228.99.78.240/28228.99.78.241 to 228.99.78.254228.99.78.25514
49228.99.79.0/28228.99.79.1 to 228.99.79.14228.99.79.1514
50228.99.79.16/28228.99.79.17 to 228.99.79.30228.99.79.3114
51228.99.79.32/28228.99.79.33 to 228.99.79.46228.99.79.4714
52228.99.79.48/28228.99.79.49 to 228.99.79.62228.99.79.6314
53228.99.79.64/28228.99.79.65 to 228.99.79.78228.99.79.7914
54228.99.79.80/28228.99.79.81 to 228.99.79.94228.99.79.9514
55228.99.79.96/28228.99.79.97 to 228.99.79.110228.99.79.11114
56228.99.79.112/28228.99.79.113 to 228.99.79.126228.99.79.12714
57228.99.79.128/28228.99.79.129 to 228.99.79.142228.99.79.14314
58228.99.79.144/28228.99.79.145 to 228.99.79.158228.99.79.15914
59228.99.79.160/28228.99.79.161 to 228.99.79.174228.99.79.17514
60228.99.79.176/28228.99.79.177 to 228.99.79.190228.99.79.19114
61228.99.79.192/28228.99.79.193 to 228.99.79.206228.99.79.20714
62228.99.79.208/28228.99.79.209 to 228.99.79.222228.99.79.22314
63228.99.79.224/28228.99.79.225 to 228.99.79.238228.99.79.23914
64228.99.79.240/28228.99.79.241 to 228.99.79.254228.99.79.25514

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.