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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.

Network68.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
68.0.0.0
Broadcast address
71.255.255.255
First usable
68.0.0.1
Last usable
71.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 44000000 · Integer 1140850688 to 1207959551
Reverse DNS zones
68.in-addr.arpa
69.in-addr.arpa
70.in-addr.arpa
71.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000100.00000000.00000000.0000000068.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01000100.00000000.00000000.0000000068.0.0.0
Broadcast01000111.11111111.11111111.1111111171.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

68.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.0.0.0/1768.0.0.1 to 68.0.127.25468.0.127.25532,766
268.0.128.0/1768.0.128.1 to 68.0.255.25468.0.255.25532,766
368.1.0.0/1768.1.0.1 to 68.1.127.25468.1.127.25532,766
468.1.128.0/1768.1.128.1 to 68.1.255.25468.1.255.25532,766
568.2.0.0/1768.2.0.1 to 68.2.127.25468.2.127.25532,766
668.2.128.0/1768.2.128.1 to 68.2.255.25468.2.255.25532,766
768.3.0.0/1768.3.0.1 to 68.3.127.25468.3.127.25532,766
868.3.128.0/1768.3.128.1 to 68.3.255.25468.3.255.25532,766
968.4.0.0/1768.4.0.1 to 68.4.127.25468.4.127.25532,766
1068.4.128.0/1768.4.128.1 to 68.4.255.25468.4.255.25532,766
1168.5.0.0/1768.5.0.1 to 68.5.127.25468.5.127.25532,766
1268.5.128.0/1768.5.128.1 to 68.5.255.25468.5.255.25532,766
1368.6.0.0/1768.6.0.1 to 68.6.127.25468.6.127.25532,766
1468.6.128.0/1768.6.128.1 to 68.6.255.25468.6.255.25532,766
1568.7.0.0/1768.7.0.1 to 68.7.127.25468.7.127.25532,766
1668.7.128.0/1768.7.128.1 to 68.7.255.25468.7.255.25532,766
1768.8.0.0/1768.8.0.1 to 68.8.127.25468.8.127.25532,766
1868.8.128.0/1768.8.128.1 to 68.8.255.25468.8.255.25532,766
1968.9.0.0/1768.9.0.1 to 68.9.127.25468.9.127.25532,766
2068.9.128.0/1768.9.128.1 to 68.9.255.25468.9.255.25532,766
2168.10.0.0/1768.10.0.1 to 68.10.127.25468.10.127.25532,766
2268.10.128.0/1768.10.128.1 to 68.10.255.25468.10.255.25532,766
2368.11.0.0/1768.11.0.1 to 68.11.127.25468.11.127.25532,766
2468.11.128.0/1768.11.128.1 to 68.11.255.25468.11.255.25532,766
2568.12.0.0/1768.12.0.1 to 68.12.127.25468.12.127.25532,766
2668.12.128.0/1768.12.128.1 to 68.12.255.25468.12.255.25532,766
2768.13.0.0/1768.13.0.1 to 68.13.127.25468.13.127.25532,766
2868.13.128.0/1768.13.128.1 to 68.13.255.25468.13.255.25532,766
2968.14.0.0/1768.14.0.1 to 68.14.127.25468.14.127.25532,766
3068.14.128.0/1768.14.128.1 to 68.14.255.25468.14.255.25532,766
3168.15.0.0/1768.15.0.1 to 68.15.127.25468.15.127.25532,766
3268.15.128.0/1768.15.128.1 to 68.15.255.25468.15.255.25532,766
3368.16.0.0/1768.16.0.1 to 68.16.127.25468.16.127.25532,766
3468.16.128.0/1768.16.128.1 to 68.16.255.25468.16.255.25532,766
3568.17.0.0/1768.17.0.1 to 68.17.127.25468.17.127.25532,766
3668.17.128.0/1768.17.128.1 to 68.17.255.25468.17.255.25532,766
3768.18.0.0/1768.18.0.1 to 68.18.127.25468.18.127.25532,766
3868.18.128.0/1768.18.128.1 to 68.18.255.25468.18.255.25532,766
3968.19.0.0/1768.19.0.1 to 68.19.127.25468.19.127.25532,766
4068.19.128.0/1768.19.128.1 to 68.19.255.25468.19.255.25532,766
4168.20.0.0/1768.20.0.1 to 68.20.127.25468.20.127.25532,766
4268.20.128.0/1768.20.128.1 to 68.20.255.25468.20.255.25532,766
4368.21.0.0/1768.21.0.1 to 68.21.127.25468.21.127.25532,766
4468.21.128.0/1768.21.128.1 to 68.21.255.25468.21.255.25532,766
4568.22.0.0/1768.22.0.1 to 68.22.127.25468.22.127.25532,766
4668.22.128.0/1768.22.128.1 to 68.22.255.25468.22.255.25532,766
4768.23.0.0/1768.23.0.1 to 68.23.127.25468.23.127.25532,766
4868.23.128.0/1768.23.128.1 to 68.23.255.25468.23.255.25532,766
4968.24.0.0/1768.24.0.1 to 68.24.127.25468.24.127.25532,766
5068.24.128.0/1768.24.128.1 to 68.24.255.25468.24.255.25532,766
5168.25.0.0/1768.25.0.1 to 68.25.127.25468.25.127.25532,766
5268.25.128.0/1768.25.128.1 to 68.25.255.25468.25.255.25532,766
5368.26.0.0/1768.26.0.1 to 68.26.127.25468.26.127.25532,766
5468.26.128.0/1768.26.128.1 to 68.26.255.25468.26.255.25532,766
5568.27.0.0/1768.27.0.1 to 68.27.127.25468.27.127.25532,766
5668.27.128.0/1768.27.128.1 to 68.27.255.25468.27.255.25532,766
5768.28.0.0/1768.28.0.1 to 68.28.127.25468.28.127.25532,766
5868.28.128.0/1768.28.128.1 to 68.28.255.25468.28.255.25532,766
5968.29.0.0/1768.29.0.1 to 68.29.127.25468.29.127.25532,766
6068.29.128.0/1768.29.128.1 to 68.29.255.25468.29.255.25532,766
6168.30.0.0/1768.30.0.1 to 68.30.127.25468.30.127.25532,766
6268.30.128.0/1768.30.128.1 to 68.30.255.25468.30.255.25532,766
6368.31.0.0/1768.31.0.1 to 68.31.127.25468.31.127.25532,766
6468.31.128.0/1768.31.128.1 to 68.31.255.25468.31.255.25532,766
6568.32.0.0/1768.32.0.1 to 68.32.127.25468.32.127.25532,766
6668.32.128.0/1768.32.128.1 to 68.32.255.25468.32.255.25532,766
6768.33.0.0/1768.33.0.1 to 68.33.127.25468.33.127.25532,766
6868.33.128.0/1768.33.128.1 to 68.33.255.25468.33.255.25532,766
6968.34.0.0/1768.34.0.1 to 68.34.127.25468.34.127.25532,766
7068.34.128.0/1768.34.128.1 to 68.34.255.25468.34.255.25532,766
7168.35.0.0/1768.35.0.1 to 68.35.127.25468.35.127.25532,766
7268.35.128.0/1768.35.128.1 to 68.35.255.25468.35.255.25532,766
7368.36.0.0/1768.36.0.1 to 68.36.127.25468.36.127.25532,766
7468.36.128.0/1768.36.128.1 to 68.36.255.25468.36.255.25532,766
7568.37.0.0/1768.37.0.1 to 68.37.127.25468.37.127.25532,766
7668.37.128.0/1768.37.128.1 to 68.37.255.25468.37.255.25532,766
7768.38.0.0/1768.38.0.1 to 68.38.127.25468.38.127.25532,766
7868.38.128.0/1768.38.128.1 to 68.38.255.25468.38.255.25532,766
7968.39.0.0/1768.39.0.1 to 68.39.127.25468.39.127.25532,766
8068.39.128.0/1768.39.128.1 to 68.39.255.25468.39.255.25532,766
8168.40.0.0/1768.40.0.1 to 68.40.127.25468.40.127.25532,766
8268.40.128.0/1768.40.128.1 to 68.40.255.25468.40.255.25532,766
8368.41.0.0/1768.41.0.1 to 68.41.127.25468.41.127.25532,766
8468.41.128.0/1768.41.128.1 to 68.41.255.25468.41.255.25532,766
8568.42.0.0/1768.42.0.1 to 68.42.127.25468.42.127.25532,766
8668.42.128.0/1768.42.128.1 to 68.42.255.25468.42.255.25532,766
8768.43.0.0/1768.43.0.1 to 68.43.127.25468.43.127.25532,766
8868.43.128.0/1768.43.128.1 to 68.43.255.25468.43.255.25532,766
8968.44.0.0/1768.44.0.1 to 68.44.127.25468.44.127.25532,766
9068.44.128.0/1768.44.128.1 to 68.44.255.25468.44.255.25532,766
9168.45.0.0/1768.45.0.1 to 68.45.127.25468.45.127.25532,766
9268.45.128.0/1768.45.128.1 to 68.45.255.25468.45.255.25532,766
9368.46.0.0/1768.46.0.1 to 68.46.127.25468.46.127.25532,766
9468.46.128.0/1768.46.128.1 to 68.46.255.25468.46.255.25532,766
9568.47.0.0/1768.47.0.1 to 68.47.127.25468.47.127.25532,766
9668.47.128.0/1768.47.128.1 to 68.47.255.25468.47.255.25532,766
9768.48.0.0/1768.48.0.1 to 68.48.127.25468.48.127.25532,766
9868.48.128.0/1768.48.128.1 to 68.48.255.25468.48.255.25532,766
9968.49.0.0/1768.49.0.1 to 68.49.127.25468.49.127.25532,766
10068.49.128.0/1768.49.128.1 to 68.49.255.25468.49.255.25532,766
10168.50.0.0/1768.50.0.1 to 68.50.127.25468.50.127.25532,766
10268.50.128.0/1768.50.128.1 to 68.50.255.25468.50.255.25532,766
10368.51.0.0/1768.51.0.1 to 68.51.127.25468.51.127.25532,766
10468.51.128.0/1768.51.128.1 to 68.51.255.25468.51.255.25532,766
10568.52.0.0/1768.52.0.1 to 68.52.127.25468.52.127.25532,766
10668.52.128.0/1768.52.128.1 to 68.52.255.25468.52.255.25532,766
10768.53.0.0/1768.53.0.1 to 68.53.127.25468.53.127.25532,766
10868.53.128.0/1768.53.128.1 to 68.53.255.25468.53.255.25532,766
10968.54.0.0/1768.54.0.1 to 68.54.127.25468.54.127.25532,766
11068.54.128.0/1768.54.128.1 to 68.54.255.25468.54.255.25532,766
11168.55.0.0/1768.55.0.1 to 68.55.127.25468.55.127.25532,766
11268.55.128.0/1768.55.128.1 to 68.55.255.25468.55.255.25532,766
11368.56.0.0/1768.56.0.1 to 68.56.127.25468.56.127.25532,766
11468.56.128.0/1768.56.128.1 to 68.56.255.25468.56.255.25532,766
11568.57.0.0/1768.57.0.1 to 68.57.127.25468.57.127.25532,766
11668.57.128.0/1768.57.128.1 to 68.57.255.25468.57.255.25532,766
11768.58.0.0/1768.58.0.1 to 68.58.127.25468.58.127.25532,766
11868.58.128.0/1768.58.128.1 to 68.58.255.25468.58.255.25532,766
11968.59.0.0/1768.59.0.1 to 68.59.127.25468.59.127.25532,766
12068.59.128.0/1768.59.128.1 to 68.59.255.25468.59.255.25532,766
12168.60.0.0/1768.60.0.1 to 68.60.127.25468.60.127.25532,766
12268.60.128.0/1768.60.128.1 to 68.60.255.25468.60.255.25532,766
12368.61.0.0/1768.61.0.1 to 68.61.127.25468.61.127.25532,766
12468.61.128.0/1768.61.128.1 to 68.61.255.25468.61.255.25532,766
12568.62.0.0/1768.62.0.1 to 68.62.127.25468.62.127.25532,766
12668.62.128.0/1768.62.128.1 to 68.62.255.25468.62.255.25532,766
12768.63.0.0/1768.63.0.1 to 68.63.127.25468.63.127.25532,766
12868.63.128.0/1768.63.128.1 to 68.63.255.25468.63.255.25532,766
12968.64.0.0/1768.64.0.1 to 68.64.127.25468.64.127.25532,766
13068.64.128.0/1768.64.128.1 to 68.64.255.25468.64.255.25532,766
13168.65.0.0/1768.65.0.1 to 68.65.127.25468.65.127.25532,766
13268.65.128.0/1768.65.128.1 to 68.65.255.25468.65.255.25532,766
13368.66.0.0/1768.66.0.1 to 68.66.127.25468.66.127.25532,766
13468.66.128.0/1768.66.128.1 to 68.66.255.25468.66.255.25532,766
13568.67.0.0/1768.67.0.1 to 68.67.127.25468.67.127.25532,766
13668.67.128.0/1768.67.128.1 to 68.67.255.25468.67.255.25532,766
13768.68.0.0/1768.68.0.1 to 68.68.127.25468.68.127.25532,766
13868.68.128.0/1768.68.128.1 to 68.68.255.25468.68.255.25532,766
13968.69.0.0/1768.69.0.1 to 68.69.127.25468.69.127.25532,766
14068.69.128.0/1768.69.128.1 to 68.69.255.25468.69.255.25532,766
14168.70.0.0/1768.70.0.1 to 68.70.127.25468.70.127.25532,766
14268.70.128.0/1768.70.128.1 to 68.70.255.25468.70.255.25532,766
14368.71.0.0/1768.71.0.1 to 68.71.127.25468.71.127.25532,766
14468.71.128.0/1768.71.128.1 to 68.71.255.25468.71.255.25532,766
14568.72.0.0/1768.72.0.1 to 68.72.127.25468.72.127.25532,766
14668.72.128.0/1768.72.128.1 to 68.72.255.25468.72.255.25532,766
14768.73.0.0/1768.73.0.1 to 68.73.127.25468.73.127.25532,766
14868.73.128.0/1768.73.128.1 to 68.73.255.25468.73.255.25532,766
14968.74.0.0/1768.74.0.1 to 68.74.127.25468.74.127.25532,766
15068.74.128.0/1768.74.128.1 to 68.74.255.25468.74.255.25532,766
15168.75.0.0/1768.75.0.1 to 68.75.127.25468.75.127.25532,766
15268.75.128.0/1768.75.128.1 to 68.75.255.25468.75.255.25532,766
15368.76.0.0/1768.76.0.1 to 68.76.127.25468.76.127.25532,766
15468.76.128.0/1768.76.128.1 to 68.76.255.25468.76.255.25532,766
15568.77.0.0/1768.77.0.1 to 68.77.127.25468.77.127.25532,766
15668.77.128.0/1768.77.128.1 to 68.77.255.25468.77.255.25532,766
15768.78.0.0/1768.78.0.1 to 68.78.127.25468.78.127.25532,766
15868.78.128.0/1768.78.128.1 to 68.78.255.25468.78.255.25532,766
15968.79.0.0/1768.79.0.1 to 68.79.127.25468.79.127.25532,766
16068.79.128.0/1768.79.128.1 to 68.79.255.25468.79.255.25532,766
16168.80.0.0/1768.80.0.1 to 68.80.127.25468.80.127.25532,766
16268.80.128.0/1768.80.128.1 to 68.80.255.25468.80.255.25532,766
16368.81.0.0/1768.81.0.1 to 68.81.127.25468.81.127.25532,766
16468.81.128.0/1768.81.128.1 to 68.81.255.25468.81.255.25532,766
16568.82.0.0/1768.82.0.1 to 68.82.127.25468.82.127.25532,766
16668.82.128.0/1768.82.128.1 to 68.82.255.25468.82.255.25532,766
16768.83.0.0/1768.83.0.1 to 68.83.127.25468.83.127.25532,766
16868.83.128.0/1768.83.128.1 to 68.83.255.25468.83.255.25532,766
16968.84.0.0/1768.84.0.1 to 68.84.127.25468.84.127.25532,766
17068.84.128.0/1768.84.128.1 to 68.84.255.25468.84.255.25532,766
17168.85.0.0/1768.85.0.1 to 68.85.127.25468.85.127.25532,766
17268.85.128.0/1768.85.128.1 to 68.85.255.25468.85.255.25532,766
17368.86.0.0/1768.86.0.1 to 68.86.127.25468.86.127.25532,766
17468.86.128.0/1768.86.128.1 to 68.86.255.25468.86.255.25532,766
17568.87.0.0/1768.87.0.1 to 68.87.127.25468.87.127.25532,766
17668.87.128.0/1768.87.128.1 to 68.87.255.25468.87.255.25532,766
17768.88.0.0/1768.88.0.1 to 68.88.127.25468.88.127.25532,766
17868.88.128.0/1768.88.128.1 to 68.88.255.25468.88.255.25532,766
17968.89.0.0/1768.89.0.1 to 68.89.127.25468.89.127.25532,766
18068.89.128.0/1768.89.128.1 to 68.89.255.25468.89.255.25532,766
18168.90.0.0/1768.90.0.1 to 68.90.127.25468.90.127.25532,766
18268.90.128.0/1768.90.128.1 to 68.90.255.25468.90.255.25532,766
18368.91.0.0/1768.91.0.1 to 68.91.127.25468.91.127.25532,766
18468.91.128.0/1768.91.128.1 to 68.91.255.25468.91.255.25532,766
18568.92.0.0/1768.92.0.1 to 68.92.127.25468.92.127.25532,766
18668.92.128.0/1768.92.128.1 to 68.92.255.25468.92.255.25532,766
18768.93.0.0/1768.93.0.1 to 68.93.127.25468.93.127.25532,766
18868.93.128.0/1768.93.128.1 to 68.93.255.25468.93.255.25532,766
18968.94.0.0/1768.94.0.1 to 68.94.127.25468.94.127.25532,766
19068.94.128.0/1768.94.128.1 to 68.94.255.25468.94.255.25532,766
19168.95.0.0/1768.95.0.1 to 68.95.127.25468.95.127.25532,766
19268.95.128.0/1768.95.128.1 to 68.95.255.25468.95.255.25532,766
19368.96.0.0/1768.96.0.1 to 68.96.127.25468.96.127.25532,766
19468.96.128.0/1768.96.128.1 to 68.96.255.25468.96.255.25532,766
19568.97.0.0/1768.97.0.1 to 68.97.127.25468.97.127.25532,766
19668.97.128.0/1768.97.128.1 to 68.97.255.25468.97.255.25532,766
19768.98.0.0/1768.98.0.1 to 68.98.127.25468.98.127.25532,766
19868.98.128.0/1768.98.128.1 to 68.98.255.25468.98.255.25532,766
19968.99.0.0/1768.99.0.1 to 68.99.127.25468.99.127.25532,766
20068.99.128.0/1768.99.128.1 to 68.99.255.25468.99.255.25532,766
20168.100.0.0/1768.100.0.1 to 68.100.127.25468.100.127.25532,766
20268.100.128.0/1768.100.128.1 to 68.100.255.25468.100.255.25532,766
20368.101.0.0/1768.101.0.1 to 68.101.127.25468.101.127.25532,766
20468.101.128.0/1768.101.128.1 to 68.101.255.25468.101.255.25532,766
20568.102.0.0/1768.102.0.1 to 68.102.127.25468.102.127.25532,766
20668.102.128.0/1768.102.128.1 to 68.102.255.25468.102.255.25532,766
20768.103.0.0/1768.103.0.1 to 68.103.127.25468.103.127.25532,766
20868.103.128.0/1768.103.128.1 to 68.103.255.25468.103.255.25532,766
20968.104.0.0/1768.104.0.1 to 68.104.127.25468.104.127.25532,766
21068.104.128.0/1768.104.128.1 to 68.104.255.25468.104.255.25532,766
21168.105.0.0/1768.105.0.1 to 68.105.127.25468.105.127.25532,766
21268.105.128.0/1768.105.128.1 to 68.105.255.25468.105.255.25532,766
21368.106.0.0/1768.106.0.1 to 68.106.127.25468.106.127.25532,766
21468.106.128.0/1768.106.128.1 to 68.106.255.25468.106.255.25532,766
21568.107.0.0/1768.107.0.1 to 68.107.127.25468.107.127.25532,766
21668.107.128.0/1768.107.128.1 to 68.107.255.25468.107.255.25532,766
21768.108.0.0/1768.108.0.1 to 68.108.127.25468.108.127.25532,766
21868.108.128.0/1768.108.128.1 to 68.108.255.25468.108.255.25532,766
21968.109.0.0/1768.109.0.1 to 68.109.127.25468.109.127.25532,766
22068.109.128.0/1768.109.128.1 to 68.109.255.25468.109.255.25532,766
22168.110.0.0/1768.110.0.1 to 68.110.127.25468.110.127.25532,766
22268.110.128.0/1768.110.128.1 to 68.110.255.25468.110.255.25532,766
22368.111.0.0/1768.111.0.1 to 68.111.127.25468.111.127.25532,766
22468.111.128.0/1768.111.128.1 to 68.111.255.25468.111.255.25532,766
22568.112.0.0/1768.112.0.1 to 68.112.127.25468.112.127.25532,766
22668.112.128.0/1768.112.128.1 to 68.112.255.25468.112.255.25532,766
22768.113.0.0/1768.113.0.1 to 68.113.127.25468.113.127.25532,766
22868.113.128.0/1768.113.128.1 to 68.113.255.25468.113.255.25532,766
22968.114.0.0/1768.114.0.1 to 68.114.127.25468.114.127.25532,766
23068.114.128.0/1768.114.128.1 to 68.114.255.25468.114.255.25532,766
23168.115.0.0/1768.115.0.1 to 68.115.127.25468.115.127.25532,766
23268.115.128.0/1768.115.128.1 to 68.115.255.25468.115.255.25532,766
23368.116.0.0/1768.116.0.1 to 68.116.127.25468.116.127.25532,766
23468.116.128.0/1768.116.128.1 to 68.116.255.25468.116.255.25532,766
23568.117.0.0/1768.117.0.1 to 68.117.127.25468.117.127.25532,766
23668.117.128.0/1768.117.128.1 to 68.117.255.25468.117.255.25532,766
23768.118.0.0/1768.118.0.1 to 68.118.127.25468.118.127.25532,766
23868.118.128.0/1768.118.128.1 to 68.118.255.25468.118.255.25532,766
23968.119.0.0/1768.119.0.1 to 68.119.127.25468.119.127.25532,766
24068.119.128.0/1768.119.128.1 to 68.119.255.25468.119.255.25532,766
24168.120.0.0/1768.120.0.1 to 68.120.127.25468.120.127.25532,766
24268.120.128.0/1768.120.128.1 to 68.120.255.25468.120.255.25532,766
24368.121.0.0/1768.121.0.1 to 68.121.127.25468.121.127.25532,766
24468.121.128.0/1768.121.128.1 to 68.121.255.25468.121.255.25532,766
24568.122.0.0/1768.122.0.1 to 68.122.127.25468.122.127.25532,766
24668.122.128.0/1768.122.128.1 to 68.122.255.25468.122.255.25532,766
24768.123.0.0/1768.123.0.1 to 68.123.127.25468.123.127.25532,766
24868.123.128.0/1768.123.128.1 to 68.123.255.25468.123.255.25532,766
24968.124.0.0/1768.124.0.1 to 68.124.127.25468.124.127.25532,766
25068.124.128.0/1768.124.128.1 to 68.124.255.25468.124.255.25532,766
25168.125.0.0/1768.125.0.1 to 68.125.127.25468.125.127.25532,766
25268.125.128.0/1768.125.128.1 to 68.125.255.25468.125.255.25532,766
25368.126.0.0/1768.126.0.1 to 68.126.127.25468.126.127.25532,766
25468.126.128.0/1768.126.128.1 to 68.126.255.25468.126.255.25532,766
25568.127.0.0/1768.127.0.1 to 68.127.127.25468.127.127.25532,766
25668.127.128.0/1768.127.128.1 to 68.127.255.25468.127.255.25532,766

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.