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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.

Network5.248.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
5.248.0.0
Broadcast address
5.255.255.255
First usable
5.248.0.1
Last usable
5.255.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 05F80000 · Integer 100139008 to 100663295
Reverse DNS zones
248.5.in-addr.arpa
249.5.in-addr.arpa
250.5.in-addr.arpa
251.5.in-addr.arpa
252.5.in-addr.arpa
253.5.in-addr.arpa
254.5.in-addr.arpa
255.5.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000101.11111000.00000000.000000005.248.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00000101.11111000.00000000.000000005.248.0.0
Broadcast00000101.11111111.11111111.111111115.255.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

5.248.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
15.248.0.0/205.248.0.1 to 5.248.15.2545.248.15.2554,094
25.248.16.0/205.248.16.1 to 5.248.31.2545.248.31.2554,094
35.248.32.0/205.248.32.1 to 5.248.47.2545.248.47.2554,094
45.248.48.0/205.248.48.1 to 5.248.63.2545.248.63.2554,094
55.248.64.0/205.248.64.1 to 5.248.79.2545.248.79.2554,094
65.248.80.0/205.248.80.1 to 5.248.95.2545.248.95.2554,094
75.248.96.0/205.248.96.1 to 5.248.111.2545.248.111.2554,094
85.248.112.0/205.248.112.1 to 5.248.127.2545.248.127.2554,094
95.248.128.0/205.248.128.1 to 5.248.143.2545.248.143.2554,094
105.248.144.0/205.248.144.1 to 5.248.159.2545.248.159.2554,094
115.248.160.0/205.248.160.1 to 5.248.175.2545.248.175.2554,094
125.248.176.0/205.248.176.1 to 5.248.191.2545.248.191.2554,094
135.248.192.0/205.248.192.1 to 5.248.207.2545.248.207.2554,094
145.248.208.0/205.248.208.1 to 5.248.223.2545.248.223.2554,094
155.248.224.0/205.248.224.1 to 5.248.239.2545.248.239.2554,094
165.248.240.0/205.248.240.1 to 5.248.255.2545.248.255.2554,094
175.249.0.0/205.249.0.1 to 5.249.15.2545.249.15.2554,094
185.249.16.0/205.249.16.1 to 5.249.31.2545.249.31.2554,094
195.249.32.0/205.249.32.1 to 5.249.47.2545.249.47.2554,094
205.249.48.0/205.249.48.1 to 5.249.63.2545.249.63.2554,094
215.249.64.0/205.249.64.1 to 5.249.79.2545.249.79.2554,094
225.249.80.0/205.249.80.1 to 5.249.95.2545.249.95.2554,094
235.249.96.0/205.249.96.1 to 5.249.111.2545.249.111.2554,094
245.249.112.0/205.249.112.1 to 5.249.127.2545.249.127.2554,094
255.249.128.0/205.249.128.1 to 5.249.143.2545.249.143.2554,094
265.249.144.0/205.249.144.1 to 5.249.159.2545.249.159.2554,094
275.249.160.0/205.249.160.1 to 5.249.175.2545.249.175.2554,094
285.249.176.0/205.249.176.1 to 5.249.191.2545.249.191.2554,094
295.249.192.0/205.249.192.1 to 5.249.207.2545.249.207.2554,094
305.249.208.0/205.249.208.1 to 5.249.223.2545.249.223.2554,094
315.249.224.0/205.249.224.1 to 5.249.239.2545.249.239.2554,094
325.249.240.0/205.249.240.1 to 5.249.255.2545.249.255.2554,094
335.250.0.0/205.250.0.1 to 5.250.15.2545.250.15.2554,094
345.250.16.0/205.250.16.1 to 5.250.31.2545.250.31.2554,094
355.250.32.0/205.250.32.1 to 5.250.47.2545.250.47.2554,094
365.250.48.0/205.250.48.1 to 5.250.63.2545.250.63.2554,094
375.250.64.0/205.250.64.1 to 5.250.79.2545.250.79.2554,094
385.250.80.0/205.250.80.1 to 5.250.95.2545.250.95.2554,094
395.250.96.0/205.250.96.1 to 5.250.111.2545.250.111.2554,094
405.250.112.0/205.250.112.1 to 5.250.127.2545.250.127.2554,094
415.250.128.0/205.250.128.1 to 5.250.143.2545.250.143.2554,094
425.250.144.0/205.250.144.1 to 5.250.159.2545.250.159.2554,094
435.250.160.0/205.250.160.1 to 5.250.175.2545.250.175.2554,094
445.250.176.0/205.250.176.1 to 5.250.191.2545.250.191.2554,094
455.250.192.0/205.250.192.1 to 5.250.207.2545.250.207.2554,094
465.250.208.0/205.250.208.1 to 5.250.223.2545.250.223.2554,094
475.250.224.0/205.250.224.1 to 5.250.239.2545.250.239.2554,094
485.250.240.0/205.250.240.1 to 5.250.255.2545.250.255.2554,094
495.251.0.0/205.251.0.1 to 5.251.15.2545.251.15.2554,094
505.251.16.0/205.251.16.1 to 5.251.31.2545.251.31.2554,094
515.251.32.0/205.251.32.1 to 5.251.47.2545.251.47.2554,094
525.251.48.0/205.251.48.1 to 5.251.63.2545.251.63.2554,094
535.251.64.0/205.251.64.1 to 5.251.79.2545.251.79.2554,094
545.251.80.0/205.251.80.1 to 5.251.95.2545.251.95.2554,094
555.251.96.0/205.251.96.1 to 5.251.111.2545.251.111.2554,094
565.251.112.0/205.251.112.1 to 5.251.127.2545.251.127.2554,094
575.251.128.0/205.251.128.1 to 5.251.143.2545.251.143.2554,094
585.251.144.0/205.251.144.1 to 5.251.159.2545.251.159.2554,094
595.251.160.0/205.251.160.1 to 5.251.175.2545.251.175.2554,094
605.251.176.0/205.251.176.1 to 5.251.191.2545.251.191.2554,094
615.251.192.0/205.251.192.1 to 5.251.207.2545.251.207.2554,094
625.251.208.0/205.251.208.1 to 5.251.223.2545.251.223.2554,094
635.251.224.0/205.251.224.1 to 5.251.239.2545.251.239.2554,094
645.251.240.0/205.251.240.1 to 5.251.255.2545.251.255.2554,094
655.252.0.0/205.252.0.1 to 5.252.15.2545.252.15.2554,094
665.252.16.0/205.252.16.1 to 5.252.31.2545.252.31.2554,094
675.252.32.0/205.252.32.1 to 5.252.47.2545.252.47.2554,094
685.252.48.0/205.252.48.1 to 5.252.63.2545.252.63.2554,094
695.252.64.0/205.252.64.1 to 5.252.79.2545.252.79.2554,094
705.252.80.0/205.252.80.1 to 5.252.95.2545.252.95.2554,094
715.252.96.0/205.252.96.1 to 5.252.111.2545.252.111.2554,094
725.252.112.0/205.252.112.1 to 5.252.127.2545.252.127.2554,094
735.252.128.0/205.252.128.1 to 5.252.143.2545.252.143.2554,094
745.252.144.0/205.252.144.1 to 5.252.159.2545.252.159.2554,094
755.252.160.0/205.252.160.1 to 5.252.175.2545.252.175.2554,094
765.252.176.0/205.252.176.1 to 5.252.191.2545.252.191.2554,094
775.252.192.0/205.252.192.1 to 5.252.207.2545.252.207.2554,094
785.252.208.0/205.252.208.1 to 5.252.223.2545.252.223.2554,094
795.252.224.0/205.252.224.1 to 5.252.239.2545.252.239.2554,094
805.252.240.0/205.252.240.1 to 5.252.255.2545.252.255.2554,094
815.253.0.0/205.253.0.1 to 5.253.15.2545.253.15.2554,094
825.253.16.0/205.253.16.1 to 5.253.31.2545.253.31.2554,094
835.253.32.0/205.253.32.1 to 5.253.47.2545.253.47.2554,094
845.253.48.0/205.253.48.1 to 5.253.63.2545.253.63.2554,094
855.253.64.0/205.253.64.1 to 5.253.79.2545.253.79.2554,094
865.253.80.0/205.253.80.1 to 5.253.95.2545.253.95.2554,094
875.253.96.0/205.253.96.1 to 5.253.111.2545.253.111.2554,094
885.253.112.0/205.253.112.1 to 5.253.127.2545.253.127.2554,094
895.253.128.0/205.253.128.1 to 5.253.143.2545.253.143.2554,094
905.253.144.0/205.253.144.1 to 5.253.159.2545.253.159.2554,094
915.253.160.0/205.253.160.1 to 5.253.175.2545.253.175.2554,094
925.253.176.0/205.253.176.1 to 5.253.191.2545.253.191.2554,094
935.253.192.0/205.253.192.1 to 5.253.207.2545.253.207.2554,094
945.253.208.0/205.253.208.1 to 5.253.223.2545.253.223.2554,094
955.253.224.0/205.253.224.1 to 5.253.239.2545.253.239.2554,094
965.253.240.0/205.253.240.1 to 5.253.255.2545.253.255.2554,094
975.254.0.0/205.254.0.1 to 5.254.15.2545.254.15.2554,094
985.254.16.0/205.254.16.1 to 5.254.31.2545.254.31.2554,094
995.254.32.0/205.254.32.1 to 5.254.47.2545.254.47.2554,094
1005.254.48.0/205.254.48.1 to 5.254.63.2545.254.63.2554,094
1015.254.64.0/205.254.64.1 to 5.254.79.2545.254.79.2554,094
1025.254.80.0/205.254.80.1 to 5.254.95.2545.254.95.2554,094
1035.254.96.0/205.254.96.1 to 5.254.111.2545.254.111.2554,094
1045.254.112.0/205.254.112.1 to 5.254.127.2545.254.127.2554,094
1055.254.128.0/205.254.128.1 to 5.254.143.2545.254.143.2554,094
1065.254.144.0/205.254.144.1 to 5.254.159.2545.254.159.2554,094
1075.254.160.0/205.254.160.1 to 5.254.175.2545.254.175.2554,094
1085.254.176.0/205.254.176.1 to 5.254.191.2545.254.191.2554,094
1095.254.192.0/205.254.192.1 to 5.254.207.2545.254.207.2554,094
1105.254.208.0/205.254.208.1 to 5.254.223.2545.254.223.2554,094
1115.254.224.0/205.254.224.1 to 5.254.239.2545.254.239.2554,094
1125.254.240.0/205.254.240.1 to 5.254.255.2545.254.255.2554,094
1135.255.0.0/205.255.0.1 to 5.255.15.2545.255.15.2554,094
1145.255.16.0/205.255.16.1 to 5.255.31.2545.255.31.2554,094
1155.255.32.0/205.255.32.1 to 5.255.47.2545.255.47.2554,094
1165.255.48.0/205.255.48.1 to 5.255.63.2545.255.63.2554,094
1175.255.64.0/205.255.64.1 to 5.255.79.2545.255.79.2554,094
1185.255.80.0/205.255.80.1 to 5.255.95.2545.255.95.2554,094
1195.255.96.0/205.255.96.1 to 5.255.111.2545.255.111.2554,094
1205.255.112.0/205.255.112.1 to 5.255.127.2545.255.127.2554,094
1215.255.128.0/205.255.128.1 to 5.255.143.2545.255.143.2554,094
1225.255.144.0/205.255.144.1 to 5.255.159.2545.255.159.2554,094
1235.255.160.0/205.255.160.1 to 5.255.175.2545.255.175.2554,094
1245.255.176.0/205.255.176.1 to 5.255.191.2545.255.191.2554,094
1255.255.192.0/205.255.192.1 to 5.255.207.2545.255.207.2554,094
1265.255.208.0/205.255.208.1 to 5.255.223.2545.255.223.2554,094
1275.255.224.0/205.255.224.1 to 5.255.239.2545.255.239.2554,094
1285.255.240.0/205.255.240.1 to 5.255.255.2545.255.255.2554,094

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.