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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.

Network34.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
34.0.0.0
Broadcast address
34.63.255.255
First usable
34.0.0.1
Last usable
34.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 22000000 · Integer 570425344 to 574619647
Reverse DNS zones
0.34.in-addr.arpa
1.34.in-addr.arpa
2.34.in-addr.arpa
3.34.in-addr.arpa
4.34.in-addr.arpa
5.34.in-addr.arpa
6.34.in-addr.arpa
7.34.in-addr.arpa
8.34.in-addr.arpa
9.34.in-addr.arpa
10.34.in-addr.arpa
11.34.in-addr.arpa
12.34.in-addr.arpa
13.34.in-addr.arpa
14.34.in-addr.arpa
15.34.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100010.00000000.00000000.0000000034.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00100010.00000000.00000000.0000000034.0.0.0
Broadcast00100010.00111111.11111111.1111111134.63.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

34.0.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
134.0.0.0/1734.0.0.1 to 34.0.127.25434.0.127.25532,766
234.0.128.0/1734.0.128.1 to 34.0.255.25434.0.255.25532,766
334.1.0.0/1734.1.0.1 to 34.1.127.25434.1.127.25532,766
434.1.128.0/1734.1.128.1 to 34.1.255.25434.1.255.25532,766
534.2.0.0/1734.2.0.1 to 34.2.127.25434.2.127.25532,766
634.2.128.0/1734.2.128.1 to 34.2.255.25434.2.255.25532,766
734.3.0.0/1734.3.0.1 to 34.3.127.25434.3.127.25532,766
834.3.128.0/1734.3.128.1 to 34.3.255.25434.3.255.25532,766
934.4.0.0/1734.4.0.1 to 34.4.127.25434.4.127.25532,766
1034.4.128.0/1734.4.128.1 to 34.4.255.25434.4.255.25532,766
1134.5.0.0/1734.5.0.1 to 34.5.127.25434.5.127.25532,766
1234.5.128.0/1734.5.128.1 to 34.5.255.25434.5.255.25532,766
1334.6.0.0/1734.6.0.1 to 34.6.127.25434.6.127.25532,766
1434.6.128.0/1734.6.128.1 to 34.6.255.25434.6.255.25532,766
1534.7.0.0/1734.7.0.1 to 34.7.127.25434.7.127.25532,766
1634.7.128.0/1734.7.128.1 to 34.7.255.25434.7.255.25532,766
1734.8.0.0/1734.8.0.1 to 34.8.127.25434.8.127.25532,766
1834.8.128.0/1734.8.128.1 to 34.8.255.25434.8.255.25532,766
1934.9.0.0/1734.9.0.1 to 34.9.127.25434.9.127.25532,766
2034.9.128.0/1734.9.128.1 to 34.9.255.25434.9.255.25532,766
2134.10.0.0/1734.10.0.1 to 34.10.127.25434.10.127.25532,766
2234.10.128.0/1734.10.128.1 to 34.10.255.25434.10.255.25532,766
2334.11.0.0/1734.11.0.1 to 34.11.127.25434.11.127.25532,766
2434.11.128.0/1734.11.128.1 to 34.11.255.25434.11.255.25532,766
2534.12.0.0/1734.12.0.1 to 34.12.127.25434.12.127.25532,766
2634.12.128.0/1734.12.128.1 to 34.12.255.25434.12.255.25532,766
2734.13.0.0/1734.13.0.1 to 34.13.127.25434.13.127.25532,766
2834.13.128.0/1734.13.128.1 to 34.13.255.25434.13.255.25532,766
2934.14.0.0/1734.14.0.1 to 34.14.127.25434.14.127.25532,766
3034.14.128.0/1734.14.128.1 to 34.14.255.25434.14.255.25532,766
3134.15.0.0/1734.15.0.1 to 34.15.127.25434.15.127.25532,766
3234.15.128.0/1734.15.128.1 to 34.15.255.25434.15.255.25532,766
3334.16.0.0/1734.16.0.1 to 34.16.127.25434.16.127.25532,766
3434.16.128.0/1734.16.128.1 to 34.16.255.25434.16.255.25532,766
3534.17.0.0/1734.17.0.1 to 34.17.127.25434.17.127.25532,766
3634.17.128.0/1734.17.128.1 to 34.17.255.25434.17.255.25532,766
3734.18.0.0/1734.18.0.1 to 34.18.127.25434.18.127.25532,766
3834.18.128.0/1734.18.128.1 to 34.18.255.25434.18.255.25532,766
3934.19.0.0/1734.19.0.1 to 34.19.127.25434.19.127.25532,766
4034.19.128.0/1734.19.128.1 to 34.19.255.25434.19.255.25532,766
4134.20.0.0/1734.20.0.1 to 34.20.127.25434.20.127.25532,766
4234.20.128.0/1734.20.128.1 to 34.20.255.25434.20.255.25532,766
4334.21.0.0/1734.21.0.1 to 34.21.127.25434.21.127.25532,766
4434.21.128.0/1734.21.128.1 to 34.21.255.25434.21.255.25532,766
4534.22.0.0/1734.22.0.1 to 34.22.127.25434.22.127.25532,766
4634.22.128.0/1734.22.128.1 to 34.22.255.25434.22.255.25532,766
4734.23.0.0/1734.23.0.1 to 34.23.127.25434.23.127.25532,766
4834.23.128.0/1734.23.128.1 to 34.23.255.25434.23.255.25532,766
4934.24.0.0/1734.24.0.1 to 34.24.127.25434.24.127.25532,766
5034.24.128.0/1734.24.128.1 to 34.24.255.25434.24.255.25532,766
5134.25.0.0/1734.25.0.1 to 34.25.127.25434.25.127.25532,766
5234.25.128.0/1734.25.128.1 to 34.25.255.25434.25.255.25532,766
5334.26.0.0/1734.26.0.1 to 34.26.127.25434.26.127.25532,766
5434.26.128.0/1734.26.128.1 to 34.26.255.25434.26.255.25532,766
5534.27.0.0/1734.27.0.1 to 34.27.127.25434.27.127.25532,766
5634.27.128.0/1734.27.128.1 to 34.27.255.25434.27.255.25532,766
5734.28.0.0/1734.28.0.1 to 34.28.127.25434.28.127.25532,766
5834.28.128.0/1734.28.128.1 to 34.28.255.25434.28.255.25532,766
5934.29.0.0/1734.29.0.1 to 34.29.127.25434.29.127.25532,766
6034.29.128.0/1734.29.128.1 to 34.29.255.25434.29.255.25532,766
6134.30.0.0/1734.30.0.1 to 34.30.127.25434.30.127.25532,766
6234.30.128.0/1734.30.128.1 to 34.30.255.25434.30.255.25532,766
6334.31.0.0/1734.31.0.1 to 34.31.127.25434.31.127.25532,766
6434.31.128.0/1734.31.128.1 to 34.31.255.25434.31.255.25532,766
6534.32.0.0/1734.32.0.1 to 34.32.127.25434.32.127.25532,766
6634.32.128.0/1734.32.128.1 to 34.32.255.25434.32.255.25532,766
6734.33.0.0/1734.33.0.1 to 34.33.127.25434.33.127.25532,766
6834.33.128.0/1734.33.128.1 to 34.33.255.25434.33.255.25532,766
6934.34.0.0/1734.34.0.1 to 34.34.127.25434.34.127.25532,766
7034.34.128.0/1734.34.128.1 to 34.34.255.25434.34.255.25532,766
7134.35.0.0/1734.35.0.1 to 34.35.127.25434.35.127.25532,766
7234.35.128.0/1734.35.128.1 to 34.35.255.25434.35.255.25532,766
7334.36.0.0/1734.36.0.1 to 34.36.127.25434.36.127.25532,766
7434.36.128.0/1734.36.128.1 to 34.36.255.25434.36.255.25532,766
7534.37.0.0/1734.37.0.1 to 34.37.127.25434.37.127.25532,766
7634.37.128.0/1734.37.128.1 to 34.37.255.25434.37.255.25532,766
7734.38.0.0/1734.38.0.1 to 34.38.127.25434.38.127.25532,766
7834.38.128.0/1734.38.128.1 to 34.38.255.25434.38.255.25532,766
7934.39.0.0/1734.39.0.1 to 34.39.127.25434.39.127.25532,766
8034.39.128.0/1734.39.128.1 to 34.39.255.25434.39.255.25532,766
8134.40.0.0/1734.40.0.1 to 34.40.127.25434.40.127.25532,766
8234.40.128.0/1734.40.128.1 to 34.40.255.25434.40.255.25532,766
8334.41.0.0/1734.41.0.1 to 34.41.127.25434.41.127.25532,766
8434.41.128.0/1734.41.128.1 to 34.41.255.25434.41.255.25532,766
8534.42.0.0/1734.42.0.1 to 34.42.127.25434.42.127.25532,766
8634.42.128.0/1734.42.128.1 to 34.42.255.25434.42.255.25532,766
8734.43.0.0/1734.43.0.1 to 34.43.127.25434.43.127.25532,766
8834.43.128.0/1734.43.128.1 to 34.43.255.25434.43.255.25532,766
8934.44.0.0/1734.44.0.1 to 34.44.127.25434.44.127.25532,766
9034.44.128.0/1734.44.128.1 to 34.44.255.25434.44.255.25532,766
9134.45.0.0/1734.45.0.1 to 34.45.127.25434.45.127.25532,766
9234.45.128.0/1734.45.128.1 to 34.45.255.25434.45.255.25532,766
9334.46.0.0/1734.46.0.1 to 34.46.127.25434.46.127.25532,766
9434.46.128.0/1734.46.128.1 to 34.46.255.25434.46.255.25532,766
9534.47.0.0/1734.47.0.1 to 34.47.127.25434.47.127.25532,766
9634.47.128.0/1734.47.128.1 to 34.47.255.25434.47.255.25532,766
9734.48.0.0/1734.48.0.1 to 34.48.127.25434.48.127.25532,766
9834.48.128.0/1734.48.128.1 to 34.48.255.25434.48.255.25532,766
9934.49.0.0/1734.49.0.1 to 34.49.127.25434.49.127.25532,766
10034.49.128.0/1734.49.128.1 to 34.49.255.25434.49.255.25532,766
10134.50.0.0/1734.50.0.1 to 34.50.127.25434.50.127.25532,766
10234.50.128.0/1734.50.128.1 to 34.50.255.25434.50.255.25532,766
10334.51.0.0/1734.51.0.1 to 34.51.127.25434.51.127.25532,766
10434.51.128.0/1734.51.128.1 to 34.51.255.25434.51.255.25532,766
10534.52.0.0/1734.52.0.1 to 34.52.127.25434.52.127.25532,766
10634.52.128.0/1734.52.128.1 to 34.52.255.25434.52.255.25532,766
10734.53.0.0/1734.53.0.1 to 34.53.127.25434.53.127.25532,766
10834.53.128.0/1734.53.128.1 to 34.53.255.25434.53.255.25532,766
10934.54.0.0/1734.54.0.1 to 34.54.127.25434.54.127.25532,766
11034.54.128.0/1734.54.128.1 to 34.54.255.25434.54.255.25532,766
11134.55.0.0/1734.55.0.1 to 34.55.127.25434.55.127.25532,766
11234.55.128.0/1734.55.128.1 to 34.55.255.25434.55.255.25532,766
11334.56.0.0/1734.56.0.1 to 34.56.127.25434.56.127.25532,766
11434.56.128.0/1734.56.128.1 to 34.56.255.25434.56.255.25532,766
11534.57.0.0/1734.57.0.1 to 34.57.127.25434.57.127.25532,766
11634.57.128.0/1734.57.128.1 to 34.57.255.25434.57.255.25532,766
11734.58.0.0/1734.58.0.1 to 34.58.127.25434.58.127.25532,766
11834.58.128.0/1734.58.128.1 to 34.58.255.25434.58.255.25532,766
11934.59.0.0/1734.59.0.1 to 34.59.127.25434.59.127.25532,766
12034.59.128.0/1734.59.128.1 to 34.59.255.25434.59.255.25532,766
12134.60.0.0/1734.60.0.1 to 34.60.127.25434.60.127.25532,766
12234.60.128.0/1734.60.128.1 to 34.60.255.25434.60.255.25532,766
12334.61.0.0/1734.61.0.1 to 34.61.127.25434.61.127.25532,766
12434.61.128.0/1734.61.128.1 to 34.61.255.25434.61.255.25532,766
12534.62.0.0/1734.62.0.1 to 34.62.127.25434.62.127.25532,766
12634.62.128.0/1734.62.128.1 to 34.62.255.25434.62.255.25532,766
12734.63.0.0/1734.63.0.1 to 34.63.127.25434.63.127.25532,766
12834.63.128.0/1734.63.128.1 to 34.63.255.25434.63.255.25532,766

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.