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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.

Network16.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
16.0.0.0
Broadcast address
19.255.255.255
First usable
16.0.0.1
Last usable
19.255.255.254
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 10000000 · Integer 268435456 to 335544319
Reverse DNS zones
16.in-addr.arpa
17.in-addr.arpa
18.in-addr.arpa
19.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
Address00010000.00000000.00000000.0000000016.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network00010000.00000000.00000000.0000000016.0.0.0
Broadcast00010011.11111111.11111111.1111111119.255.255.255
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)

16.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.0.0.0/1716.0.0.1 to 16.0.127.25416.0.127.25532,766
216.0.128.0/1716.0.128.1 to 16.0.255.25416.0.255.25532,766
316.1.0.0/1716.1.0.1 to 16.1.127.25416.1.127.25532,766
416.1.128.0/1716.1.128.1 to 16.1.255.25416.1.255.25532,766
516.2.0.0/1716.2.0.1 to 16.2.127.25416.2.127.25532,766
616.2.128.0/1716.2.128.1 to 16.2.255.25416.2.255.25532,766
716.3.0.0/1716.3.0.1 to 16.3.127.25416.3.127.25532,766
816.3.128.0/1716.3.128.1 to 16.3.255.25416.3.255.25532,766
916.4.0.0/1716.4.0.1 to 16.4.127.25416.4.127.25532,766
1016.4.128.0/1716.4.128.1 to 16.4.255.25416.4.255.25532,766
1116.5.0.0/1716.5.0.1 to 16.5.127.25416.5.127.25532,766
1216.5.128.0/1716.5.128.1 to 16.5.255.25416.5.255.25532,766
1316.6.0.0/1716.6.0.1 to 16.6.127.25416.6.127.25532,766
1416.6.128.0/1716.6.128.1 to 16.6.255.25416.6.255.25532,766
1516.7.0.0/1716.7.0.1 to 16.7.127.25416.7.127.25532,766
1616.7.128.0/1716.7.128.1 to 16.7.255.25416.7.255.25532,766
1716.8.0.0/1716.8.0.1 to 16.8.127.25416.8.127.25532,766
1816.8.128.0/1716.8.128.1 to 16.8.255.25416.8.255.25532,766
1916.9.0.0/1716.9.0.1 to 16.9.127.25416.9.127.25532,766
2016.9.128.0/1716.9.128.1 to 16.9.255.25416.9.255.25532,766
2116.10.0.0/1716.10.0.1 to 16.10.127.25416.10.127.25532,766
2216.10.128.0/1716.10.128.1 to 16.10.255.25416.10.255.25532,766
2316.11.0.0/1716.11.0.1 to 16.11.127.25416.11.127.25532,766
2416.11.128.0/1716.11.128.1 to 16.11.255.25416.11.255.25532,766
2516.12.0.0/1716.12.0.1 to 16.12.127.25416.12.127.25532,766
2616.12.128.0/1716.12.128.1 to 16.12.255.25416.12.255.25532,766
2716.13.0.0/1716.13.0.1 to 16.13.127.25416.13.127.25532,766
2816.13.128.0/1716.13.128.1 to 16.13.255.25416.13.255.25532,766
2916.14.0.0/1716.14.0.1 to 16.14.127.25416.14.127.25532,766
3016.14.128.0/1716.14.128.1 to 16.14.255.25416.14.255.25532,766
3116.15.0.0/1716.15.0.1 to 16.15.127.25416.15.127.25532,766
3216.15.128.0/1716.15.128.1 to 16.15.255.25416.15.255.25532,766
3316.16.0.0/1716.16.0.1 to 16.16.127.25416.16.127.25532,766
3416.16.128.0/1716.16.128.1 to 16.16.255.25416.16.255.25532,766
3516.17.0.0/1716.17.0.1 to 16.17.127.25416.17.127.25532,766
3616.17.128.0/1716.17.128.1 to 16.17.255.25416.17.255.25532,766
3716.18.0.0/1716.18.0.1 to 16.18.127.25416.18.127.25532,766
3816.18.128.0/1716.18.128.1 to 16.18.255.25416.18.255.25532,766
3916.19.0.0/1716.19.0.1 to 16.19.127.25416.19.127.25532,766
4016.19.128.0/1716.19.128.1 to 16.19.255.25416.19.255.25532,766
4116.20.0.0/1716.20.0.1 to 16.20.127.25416.20.127.25532,766
4216.20.128.0/1716.20.128.1 to 16.20.255.25416.20.255.25532,766
4316.21.0.0/1716.21.0.1 to 16.21.127.25416.21.127.25532,766
4416.21.128.0/1716.21.128.1 to 16.21.255.25416.21.255.25532,766
4516.22.0.0/1716.22.0.1 to 16.22.127.25416.22.127.25532,766
4616.22.128.0/1716.22.128.1 to 16.22.255.25416.22.255.25532,766
4716.23.0.0/1716.23.0.1 to 16.23.127.25416.23.127.25532,766
4816.23.128.0/1716.23.128.1 to 16.23.255.25416.23.255.25532,766
4916.24.0.0/1716.24.0.1 to 16.24.127.25416.24.127.25532,766
5016.24.128.0/1716.24.128.1 to 16.24.255.25416.24.255.25532,766
5116.25.0.0/1716.25.0.1 to 16.25.127.25416.25.127.25532,766
5216.25.128.0/1716.25.128.1 to 16.25.255.25416.25.255.25532,766
5316.26.0.0/1716.26.0.1 to 16.26.127.25416.26.127.25532,766
5416.26.128.0/1716.26.128.1 to 16.26.255.25416.26.255.25532,766
5516.27.0.0/1716.27.0.1 to 16.27.127.25416.27.127.25532,766
5616.27.128.0/1716.27.128.1 to 16.27.255.25416.27.255.25532,766
5716.28.0.0/1716.28.0.1 to 16.28.127.25416.28.127.25532,766
5816.28.128.0/1716.28.128.1 to 16.28.255.25416.28.255.25532,766
5916.29.0.0/1716.29.0.1 to 16.29.127.25416.29.127.25532,766
6016.29.128.0/1716.29.128.1 to 16.29.255.25416.29.255.25532,766
6116.30.0.0/1716.30.0.1 to 16.30.127.25416.30.127.25532,766
6216.30.128.0/1716.30.128.1 to 16.30.255.25416.30.255.25532,766
6316.31.0.0/1716.31.0.1 to 16.31.127.25416.31.127.25532,766
6416.31.128.0/1716.31.128.1 to 16.31.255.25416.31.255.25532,766
6516.32.0.0/1716.32.0.1 to 16.32.127.25416.32.127.25532,766
6616.32.128.0/1716.32.128.1 to 16.32.255.25416.32.255.25532,766
6716.33.0.0/1716.33.0.1 to 16.33.127.25416.33.127.25532,766
6816.33.128.0/1716.33.128.1 to 16.33.255.25416.33.255.25532,766
6916.34.0.0/1716.34.0.1 to 16.34.127.25416.34.127.25532,766
7016.34.128.0/1716.34.128.1 to 16.34.255.25416.34.255.25532,766
7116.35.0.0/1716.35.0.1 to 16.35.127.25416.35.127.25532,766
7216.35.128.0/1716.35.128.1 to 16.35.255.25416.35.255.25532,766
7316.36.0.0/1716.36.0.1 to 16.36.127.25416.36.127.25532,766
7416.36.128.0/1716.36.128.1 to 16.36.255.25416.36.255.25532,766
7516.37.0.0/1716.37.0.1 to 16.37.127.25416.37.127.25532,766
7616.37.128.0/1716.37.128.1 to 16.37.255.25416.37.255.25532,766
7716.38.0.0/1716.38.0.1 to 16.38.127.25416.38.127.25532,766
7816.38.128.0/1716.38.128.1 to 16.38.255.25416.38.255.25532,766
7916.39.0.0/1716.39.0.1 to 16.39.127.25416.39.127.25532,766
8016.39.128.0/1716.39.128.1 to 16.39.255.25416.39.255.25532,766
8116.40.0.0/1716.40.0.1 to 16.40.127.25416.40.127.25532,766
8216.40.128.0/1716.40.128.1 to 16.40.255.25416.40.255.25532,766
8316.41.0.0/1716.41.0.1 to 16.41.127.25416.41.127.25532,766
8416.41.128.0/1716.41.128.1 to 16.41.255.25416.41.255.25532,766
8516.42.0.0/1716.42.0.1 to 16.42.127.25416.42.127.25532,766
8616.42.128.0/1716.42.128.1 to 16.42.255.25416.42.255.25532,766
8716.43.0.0/1716.43.0.1 to 16.43.127.25416.43.127.25532,766
8816.43.128.0/1716.43.128.1 to 16.43.255.25416.43.255.25532,766
8916.44.0.0/1716.44.0.1 to 16.44.127.25416.44.127.25532,766
9016.44.128.0/1716.44.128.1 to 16.44.255.25416.44.255.25532,766
9116.45.0.0/1716.45.0.1 to 16.45.127.25416.45.127.25532,766
9216.45.128.0/1716.45.128.1 to 16.45.255.25416.45.255.25532,766
9316.46.0.0/1716.46.0.1 to 16.46.127.25416.46.127.25532,766
9416.46.128.0/1716.46.128.1 to 16.46.255.25416.46.255.25532,766
9516.47.0.0/1716.47.0.1 to 16.47.127.25416.47.127.25532,766
9616.47.128.0/1716.47.128.1 to 16.47.255.25416.47.255.25532,766
9716.48.0.0/1716.48.0.1 to 16.48.127.25416.48.127.25532,766
9816.48.128.0/1716.48.128.1 to 16.48.255.25416.48.255.25532,766
9916.49.0.0/1716.49.0.1 to 16.49.127.25416.49.127.25532,766
10016.49.128.0/1716.49.128.1 to 16.49.255.25416.49.255.25532,766
10116.50.0.0/1716.50.0.1 to 16.50.127.25416.50.127.25532,766
10216.50.128.0/1716.50.128.1 to 16.50.255.25416.50.255.25532,766
10316.51.0.0/1716.51.0.1 to 16.51.127.25416.51.127.25532,766
10416.51.128.0/1716.51.128.1 to 16.51.255.25416.51.255.25532,766
10516.52.0.0/1716.52.0.1 to 16.52.127.25416.52.127.25532,766
10616.52.128.0/1716.52.128.1 to 16.52.255.25416.52.255.25532,766
10716.53.0.0/1716.53.0.1 to 16.53.127.25416.53.127.25532,766
10816.53.128.0/1716.53.128.1 to 16.53.255.25416.53.255.25532,766
10916.54.0.0/1716.54.0.1 to 16.54.127.25416.54.127.25532,766
11016.54.128.0/1716.54.128.1 to 16.54.255.25416.54.255.25532,766
11116.55.0.0/1716.55.0.1 to 16.55.127.25416.55.127.25532,766
11216.55.128.0/1716.55.128.1 to 16.55.255.25416.55.255.25532,766
11316.56.0.0/1716.56.0.1 to 16.56.127.25416.56.127.25532,766
11416.56.128.0/1716.56.128.1 to 16.56.255.25416.56.255.25532,766
11516.57.0.0/1716.57.0.1 to 16.57.127.25416.57.127.25532,766
11616.57.128.0/1716.57.128.1 to 16.57.255.25416.57.255.25532,766
11716.58.0.0/1716.58.0.1 to 16.58.127.25416.58.127.25532,766
11816.58.128.0/1716.58.128.1 to 16.58.255.25416.58.255.25532,766
11916.59.0.0/1716.59.0.1 to 16.59.127.25416.59.127.25532,766
12016.59.128.0/1716.59.128.1 to 16.59.255.25416.59.255.25532,766
12116.60.0.0/1716.60.0.1 to 16.60.127.25416.60.127.25532,766
12216.60.128.0/1716.60.128.1 to 16.60.255.25416.60.255.25532,766
12316.61.0.0/1716.61.0.1 to 16.61.127.25416.61.127.25532,766
12416.61.128.0/1716.61.128.1 to 16.61.255.25416.61.255.25532,766
12516.62.0.0/1716.62.0.1 to 16.62.127.25416.62.127.25532,766
12616.62.128.0/1716.62.128.1 to 16.62.255.25416.62.255.25532,766
12716.63.0.0/1716.63.0.1 to 16.63.127.25416.63.127.25532,766
12816.63.128.0/1716.63.128.1 to 16.63.255.25416.63.255.25532,766
12916.64.0.0/1716.64.0.1 to 16.64.127.25416.64.127.25532,766
13016.64.128.0/1716.64.128.1 to 16.64.255.25416.64.255.25532,766
13116.65.0.0/1716.65.0.1 to 16.65.127.25416.65.127.25532,766
13216.65.128.0/1716.65.128.1 to 16.65.255.25416.65.255.25532,766
13316.66.0.0/1716.66.0.1 to 16.66.127.25416.66.127.25532,766
13416.66.128.0/1716.66.128.1 to 16.66.255.25416.66.255.25532,766
13516.67.0.0/1716.67.0.1 to 16.67.127.25416.67.127.25532,766
13616.67.128.0/1716.67.128.1 to 16.67.255.25416.67.255.25532,766
13716.68.0.0/1716.68.0.1 to 16.68.127.25416.68.127.25532,766
13816.68.128.0/1716.68.128.1 to 16.68.255.25416.68.255.25532,766
13916.69.0.0/1716.69.0.1 to 16.69.127.25416.69.127.25532,766
14016.69.128.0/1716.69.128.1 to 16.69.255.25416.69.255.25532,766
14116.70.0.0/1716.70.0.1 to 16.70.127.25416.70.127.25532,766
14216.70.128.0/1716.70.128.1 to 16.70.255.25416.70.255.25532,766
14316.71.0.0/1716.71.0.1 to 16.71.127.25416.71.127.25532,766
14416.71.128.0/1716.71.128.1 to 16.71.255.25416.71.255.25532,766
14516.72.0.0/1716.72.0.1 to 16.72.127.25416.72.127.25532,766
14616.72.128.0/1716.72.128.1 to 16.72.255.25416.72.255.25532,766
14716.73.0.0/1716.73.0.1 to 16.73.127.25416.73.127.25532,766
14816.73.128.0/1716.73.128.1 to 16.73.255.25416.73.255.25532,766
14916.74.0.0/1716.74.0.1 to 16.74.127.25416.74.127.25532,766
15016.74.128.0/1716.74.128.1 to 16.74.255.25416.74.255.25532,766
15116.75.0.0/1716.75.0.1 to 16.75.127.25416.75.127.25532,766
15216.75.128.0/1716.75.128.1 to 16.75.255.25416.75.255.25532,766
15316.76.0.0/1716.76.0.1 to 16.76.127.25416.76.127.25532,766
15416.76.128.0/1716.76.128.1 to 16.76.255.25416.76.255.25532,766
15516.77.0.0/1716.77.0.1 to 16.77.127.25416.77.127.25532,766
15616.77.128.0/1716.77.128.1 to 16.77.255.25416.77.255.25532,766
15716.78.0.0/1716.78.0.1 to 16.78.127.25416.78.127.25532,766
15816.78.128.0/1716.78.128.1 to 16.78.255.25416.78.255.25532,766
15916.79.0.0/1716.79.0.1 to 16.79.127.25416.79.127.25532,766
16016.79.128.0/1716.79.128.1 to 16.79.255.25416.79.255.25532,766
16116.80.0.0/1716.80.0.1 to 16.80.127.25416.80.127.25532,766
16216.80.128.0/1716.80.128.1 to 16.80.255.25416.80.255.25532,766
16316.81.0.0/1716.81.0.1 to 16.81.127.25416.81.127.25532,766
16416.81.128.0/1716.81.128.1 to 16.81.255.25416.81.255.25532,766
16516.82.0.0/1716.82.0.1 to 16.82.127.25416.82.127.25532,766
16616.82.128.0/1716.82.128.1 to 16.82.255.25416.82.255.25532,766
16716.83.0.0/1716.83.0.1 to 16.83.127.25416.83.127.25532,766
16816.83.128.0/1716.83.128.1 to 16.83.255.25416.83.255.25532,766
16916.84.0.0/1716.84.0.1 to 16.84.127.25416.84.127.25532,766
17016.84.128.0/1716.84.128.1 to 16.84.255.25416.84.255.25532,766
17116.85.0.0/1716.85.0.1 to 16.85.127.25416.85.127.25532,766
17216.85.128.0/1716.85.128.1 to 16.85.255.25416.85.255.25532,766
17316.86.0.0/1716.86.0.1 to 16.86.127.25416.86.127.25532,766
17416.86.128.0/1716.86.128.1 to 16.86.255.25416.86.255.25532,766
17516.87.0.0/1716.87.0.1 to 16.87.127.25416.87.127.25532,766
17616.87.128.0/1716.87.128.1 to 16.87.255.25416.87.255.25532,766
17716.88.0.0/1716.88.0.1 to 16.88.127.25416.88.127.25532,766
17816.88.128.0/1716.88.128.1 to 16.88.255.25416.88.255.25532,766
17916.89.0.0/1716.89.0.1 to 16.89.127.25416.89.127.25532,766
18016.89.128.0/1716.89.128.1 to 16.89.255.25416.89.255.25532,766
18116.90.0.0/1716.90.0.1 to 16.90.127.25416.90.127.25532,766
18216.90.128.0/1716.90.128.1 to 16.90.255.25416.90.255.25532,766
18316.91.0.0/1716.91.0.1 to 16.91.127.25416.91.127.25532,766
18416.91.128.0/1716.91.128.1 to 16.91.255.25416.91.255.25532,766
18516.92.0.0/1716.92.0.1 to 16.92.127.25416.92.127.25532,766
18616.92.128.0/1716.92.128.1 to 16.92.255.25416.92.255.25532,766
18716.93.0.0/1716.93.0.1 to 16.93.127.25416.93.127.25532,766
18816.93.128.0/1716.93.128.1 to 16.93.255.25416.93.255.25532,766
18916.94.0.0/1716.94.0.1 to 16.94.127.25416.94.127.25532,766
19016.94.128.0/1716.94.128.1 to 16.94.255.25416.94.255.25532,766
19116.95.0.0/1716.95.0.1 to 16.95.127.25416.95.127.25532,766
19216.95.128.0/1716.95.128.1 to 16.95.255.25416.95.255.25532,766
19316.96.0.0/1716.96.0.1 to 16.96.127.25416.96.127.25532,766
19416.96.128.0/1716.96.128.1 to 16.96.255.25416.96.255.25532,766
19516.97.0.0/1716.97.0.1 to 16.97.127.25416.97.127.25532,766
19616.97.128.0/1716.97.128.1 to 16.97.255.25416.97.255.25532,766
19716.98.0.0/1716.98.0.1 to 16.98.127.25416.98.127.25532,766
19816.98.128.0/1716.98.128.1 to 16.98.255.25416.98.255.25532,766
19916.99.0.0/1716.99.0.1 to 16.99.127.25416.99.127.25532,766
20016.99.128.0/1716.99.128.1 to 16.99.255.25416.99.255.25532,766
20116.100.0.0/1716.100.0.1 to 16.100.127.25416.100.127.25532,766
20216.100.128.0/1716.100.128.1 to 16.100.255.25416.100.255.25532,766
20316.101.0.0/1716.101.0.1 to 16.101.127.25416.101.127.25532,766
20416.101.128.0/1716.101.128.1 to 16.101.255.25416.101.255.25532,766
20516.102.0.0/1716.102.0.1 to 16.102.127.25416.102.127.25532,766
20616.102.128.0/1716.102.128.1 to 16.102.255.25416.102.255.25532,766
20716.103.0.0/1716.103.0.1 to 16.103.127.25416.103.127.25532,766
20816.103.128.0/1716.103.128.1 to 16.103.255.25416.103.255.25532,766
20916.104.0.0/1716.104.0.1 to 16.104.127.25416.104.127.25532,766
21016.104.128.0/1716.104.128.1 to 16.104.255.25416.104.255.25532,766
21116.105.0.0/1716.105.0.1 to 16.105.127.25416.105.127.25532,766
21216.105.128.0/1716.105.128.1 to 16.105.255.25416.105.255.25532,766
21316.106.0.0/1716.106.0.1 to 16.106.127.25416.106.127.25532,766
21416.106.128.0/1716.106.128.1 to 16.106.255.25416.106.255.25532,766
21516.107.0.0/1716.107.0.1 to 16.107.127.25416.107.127.25532,766
21616.107.128.0/1716.107.128.1 to 16.107.255.25416.107.255.25532,766
21716.108.0.0/1716.108.0.1 to 16.108.127.25416.108.127.25532,766
21816.108.128.0/1716.108.128.1 to 16.108.255.25416.108.255.25532,766
21916.109.0.0/1716.109.0.1 to 16.109.127.25416.109.127.25532,766
22016.109.128.0/1716.109.128.1 to 16.109.255.25416.109.255.25532,766
22116.110.0.0/1716.110.0.1 to 16.110.127.25416.110.127.25532,766
22216.110.128.0/1716.110.128.1 to 16.110.255.25416.110.255.25532,766
22316.111.0.0/1716.111.0.1 to 16.111.127.25416.111.127.25532,766
22416.111.128.0/1716.111.128.1 to 16.111.255.25416.111.255.25532,766
22516.112.0.0/1716.112.0.1 to 16.112.127.25416.112.127.25532,766
22616.112.128.0/1716.112.128.1 to 16.112.255.25416.112.255.25532,766
22716.113.0.0/1716.113.0.1 to 16.113.127.25416.113.127.25532,766
22816.113.128.0/1716.113.128.1 to 16.113.255.25416.113.255.25532,766
22916.114.0.0/1716.114.0.1 to 16.114.127.25416.114.127.25532,766
23016.114.128.0/1716.114.128.1 to 16.114.255.25416.114.255.25532,766
23116.115.0.0/1716.115.0.1 to 16.115.127.25416.115.127.25532,766
23216.115.128.0/1716.115.128.1 to 16.115.255.25416.115.255.25532,766
23316.116.0.0/1716.116.0.1 to 16.116.127.25416.116.127.25532,766
23416.116.128.0/1716.116.128.1 to 16.116.255.25416.116.255.25532,766
23516.117.0.0/1716.117.0.1 to 16.117.127.25416.117.127.25532,766
23616.117.128.0/1716.117.128.1 to 16.117.255.25416.117.255.25532,766
23716.118.0.0/1716.118.0.1 to 16.118.127.25416.118.127.25532,766
23816.118.128.0/1716.118.128.1 to 16.118.255.25416.118.255.25532,766
23916.119.0.0/1716.119.0.1 to 16.119.127.25416.119.127.25532,766
24016.119.128.0/1716.119.128.1 to 16.119.255.25416.119.255.25532,766
24116.120.0.0/1716.120.0.1 to 16.120.127.25416.120.127.25532,766
24216.120.128.0/1716.120.128.1 to 16.120.255.25416.120.255.25532,766
24316.121.0.0/1716.121.0.1 to 16.121.127.25416.121.127.25532,766
24416.121.128.0/1716.121.128.1 to 16.121.255.25416.121.255.25532,766
24516.122.0.0/1716.122.0.1 to 16.122.127.25416.122.127.25532,766
24616.122.128.0/1716.122.128.1 to 16.122.255.25416.122.255.25532,766
24716.123.0.0/1716.123.0.1 to 16.123.127.25416.123.127.25532,766
24816.123.128.0/1716.123.128.1 to 16.123.255.25416.123.255.25532,766
24916.124.0.0/1716.124.0.1 to 16.124.127.25416.124.127.25532,766
25016.124.128.0/1716.124.128.1 to 16.124.255.25416.124.255.25532,766
25116.125.0.0/1716.125.0.1 to 16.125.127.25416.125.127.25532,766
25216.125.128.0/1716.125.128.1 to 16.125.255.25416.125.255.25532,766
25316.126.0.0/1716.126.0.1 to 16.126.127.25416.126.127.25532,766
25416.126.128.0/1716.126.128.1 to 16.126.255.25416.126.255.25532,766
25516.127.0.0/1716.127.0.1 to 16.127.127.25416.127.127.25532,766
25616.127.128.0/1716.127.128.1 to 16.127.255.25416.127.255.25532,766

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.