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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.

Network70.87.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
70.87.0.0
Broadcast address
70.87.255.255
First usable
70.87.0.1
Last usable
70.87.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 46570000 · Integer 1180106752 to 1180172287
Reverse DNS zone
87.70.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000110.01010111..00000000.0000000070.87.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01000110.01010111..00000000.0000000070.87.0.0
Broadcast01000110.01010111..11111111.1111111170.87.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

70.87.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
170.87.0.0/2570.87.0.1 to 70.87.0.12670.87.0.127126
270.87.0.128/2570.87.0.129 to 70.87.0.25470.87.0.255126
370.87.1.0/2570.87.1.1 to 70.87.1.12670.87.1.127126
470.87.1.128/2570.87.1.129 to 70.87.1.25470.87.1.255126
570.87.2.0/2570.87.2.1 to 70.87.2.12670.87.2.127126
670.87.2.128/2570.87.2.129 to 70.87.2.25470.87.2.255126
770.87.3.0/2570.87.3.1 to 70.87.3.12670.87.3.127126
870.87.3.128/2570.87.3.129 to 70.87.3.25470.87.3.255126
970.87.4.0/2570.87.4.1 to 70.87.4.12670.87.4.127126
1070.87.4.128/2570.87.4.129 to 70.87.4.25470.87.4.255126
1170.87.5.0/2570.87.5.1 to 70.87.5.12670.87.5.127126
1270.87.5.128/2570.87.5.129 to 70.87.5.25470.87.5.255126
1370.87.6.0/2570.87.6.1 to 70.87.6.12670.87.6.127126
1470.87.6.128/2570.87.6.129 to 70.87.6.25470.87.6.255126
1570.87.7.0/2570.87.7.1 to 70.87.7.12670.87.7.127126
1670.87.7.128/2570.87.7.129 to 70.87.7.25470.87.7.255126
1770.87.8.0/2570.87.8.1 to 70.87.8.12670.87.8.127126
1870.87.8.128/2570.87.8.129 to 70.87.8.25470.87.8.255126
1970.87.9.0/2570.87.9.1 to 70.87.9.12670.87.9.127126
2070.87.9.128/2570.87.9.129 to 70.87.9.25470.87.9.255126
2170.87.10.0/2570.87.10.1 to 70.87.10.12670.87.10.127126
2270.87.10.128/2570.87.10.129 to 70.87.10.25470.87.10.255126
2370.87.11.0/2570.87.11.1 to 70.87.11.12670.87.11.127126
2470.87.11.128/2570.87.11.129 to 70.87.11.25470.87.11.255126
2570.87.12.0/2570.87.12.1 to 70.87.12.12670.87.12.127126
2670.87.12.128/2570.87.12.129 to 70.87.12.25470.87.12.255126
2770.87.13.0/2570.87.13.1 to 70.87.13.12670.87.13.127126
2870.87.13.128/2570.87.13.129 to 70.87.13.25470.87.13.255126
2970.87.14.0/2570.87.14.1 to 70.87.14.12670.87.14.127126
3070.87.14.128/2570.87.14.129 to 70.87.14.25470.87.14.255126
3170.87.15.0/2570.87.15.1 to 70.87.15.12670.87.15.127126
3270.87.15.128/2570.87.15.129 to 70.87.15.25470.87.15.255126
3370.87.16.0/2570.87.16.1 to 70.87.16.12670.87.16.127126
3470.87.16.128/2570.87.16.129 to 70.87.16.25470.87.16.255126
3570.87.17.0/2570.87.17.1 to 70.87.17.12670.87.17.127126
3670.87.17.128/2570.87.17.129 to 70.87.17.25470.87.17.255126
3770.87.18.0/2570.87.18.1 to 70.87.18.12670.87.18.127126
3870.87.18.128/2570.87.18.129 to 70.87.18.25470.87.18.255126
3970.87.19.0/2570.87.19.1 to 70.87.19.12670.87.19.127126
4070.87.19.128/2570.87.19.129 to 70.87.19.25470.87.19.255126
4170.87.20.0/2570.87.20.1 to 70.87.20.12670.87.20.127126
4270.87.20.128/2570.87.20.129 to 70.87.20.25470.87.20.255126
4370.87.21.0/2570.87.21.1 to 70.87.21.12670.87.21.127126
4470.87.21.128/2570.87.21.129 to 70.87.21.25470.87.21.255126
4570.87.22.0/2570.87.22.1 to 70.87.22.12670.87.22.127126
4670.87.22.128/2570.87.22.129 to 70.87.22.25470.87.22.255126
4770.87.23.0/2570.87.23.1 to 70.87.23.12670.87.23.127126
4870.87.23.128/2570.87.23.129 to 70.87.23.25470.87.23.255126
4970.87.24.0/2570.87.24.1 to 70.87.24.12670.87.24.127126
5070.87.24.128/2570.87.24.129 to 70.87.24.25470.87.24.255126
5170.87.25.0/2570.87.25.1 to 70.87.25.12670.87.25.127126
5270.87.25.128/2570.87.25.129 to 70.87.25.25470.87.25.255126
5370.87.26.0/2570.87.26.1 to 70.87.26.12670.87.26.127126
5470.87.26.128/2570.87.26.129 to 70.87.26.25470.87.26.255126
5570.87.27.0/2570.87.27.1 to 70.87.27.12670.87.27.127126
5670.87.27.128/2570.87.27.129 to 70.87.27.25470.87.27.255126
5770.87.28.0/2570.87.28.1 to 70.87.28.12670.87.28.127126
5870.87.28.128/2570.87.28.129 to 70.87.28.25470.87.28.255126
5970.87.29.0/2570.87.29.1 to 70.87.29.12670.87.29.127126
6070.87.29.128/2570.87.29.129 to 70.87.29.25470.87.29.255126
6170.87.30.0/2570.87.30.1 to 70.87.30.12670.87.30.127126
6270.87.30.128/2570.87.30.129 to 70.87.30.25470.87.30.255126
6370.87.31.0/2570.87.31.1 to 70.87.31.12670.87.31.127126
6470.87.31.128/2570.87.31.129 to 70.87.31.25470.87.31.255126
6570.87.32.0/2570.87.32.1 to 70.87.32.12670.87.32.127126
6670.87.32.128/2570.87.32.129 to 70.87.32.25470.87.32.255126
6770.87.33.0/2570.87.33.1 to 70.87.33.12670.87.33.127126
6870.87.33.128/2570.87.33.129 to 70.87.33.25470.87.33.255126
6970.87.34.0/2570.87.34.1 to 70.87.34.12670.87.34.127126
7070.87.34.128/2570.87.34.129 to 70.87.34.25470.87.34.255126
7170.87.35.0/2570.87.35.1 to 70.87.35.12670.87.35.127126
7270.87.35.128/2570.87.35.129 to 70.87.35.25470.87.35.255126
7370.87.36.0/2570.87.36.1 to 70.87.36.12670.87.36.127126
7470.87.36.128/2570.87.36.129 to 70.87.36.25470.87.36.255126
7570.87.37.0/2570.87.37.1 to 70.87.37.12670.87.37.127126
7670.87.37.128/2570.87.37.129 to 70.87.37.25470.87.37.255126
7770.87.38.0/2570.87.38.1 to 70.87.38.12670.87.38.127126
7870.87.38.128/2570.87.38.129 to 70.87.38.25470.87.38.255126
7970.87.39.0/2570.87.39.1 to 70.87.39.12670.87.39.127126
8070.87.39.128/2570.87.39.129 to 70.87.39.25470.87.39.255126
8170.87.40.0/2570.87.40.1 to 70.87.40.12670.87.40.127126
8270.87.40.128/2570.87.40.129 to 70.87.40.25470.87.40.255126
8370.87.41.0/2570.87.41.1 to 70.87.41.12670.87.41.127126
8470.87.41.128/2570.87.41.129 to 70.87.41.25470.87.41.255126
8570.87.42.0/2570.87.42.1 to 70.87.42.12670.87.42.127126
8670.87.42.128/2570.87.42.129 to 70.87.42.25470.87.42.255126
8770.87.43.0/2570.87.43.1 to 70.87.43.12670.87.43.127126
8870.87.43.128/2570.87.43.129 to 70.87.43.25470.87.43.255126
8970.87.44.0/2570.87.44.1 to 70.87.44.12670.87.44.127126
9070.87.44.128/2570.87.44.129 to 70.87.44.25470.87.44.255126
9170.87.45.0/2570.87.45.1 to 70.87.45.12670.87.45.127126
9270.87.45.128/2570.87.45.129 to 70.87.45.25470.87.45.255126
9370.87.46.0/2570.87.46.1 to 70.87.46.12670.87.46.127126
9470.87.46.128/2570.87.46.129 to 70.87.46.25470.87.46.255126
9570.87.47.0/2570.87.47.1 to 70.87.47.12670.87.47.127126
9670.87.47.128/2570.87.47.129 to 70.87.47.25470.87.47.255126
9770.87.48.0/2570.87.48.1 to 70.87.48.12670.87.48.127126
9870.87.48.128/2570.87.48.129 to 70.87.48.25470.87.48.255126
9970.87.49.0/2570.87.49.1 to 70.87.49.12670.87.49.127126
10070.87.49.128/2570.87.49.129 to 70.87.49.25470.87.49.255126
10170.87.50.0/2570.87.50.1 to 70.87.50.12670.87.50.127126
10270.87.50.128/2570.87.50.129 to 70.87.50.25470.87.50.255126
10370.87.51.0/2570.87.51.1 to 70.87.51.12670.87.51.127126
10470.87.51.128/2570.87.51.129 to 70.87.51.25470.87.51.255126
10570.87.52.0/2570.87.52.1 to 70.87.52.12670.87.52.127126
10670.87.52.128/2570.87.52.129 to 70.87.52.25470.87.52.255126
10770.87.53.0/2570.87.53.1 to 70.87.53.12670.87.53.127126
10870.87.53.128/2570.87.53.129 to 70.87.53.25470.87.53.255126
10970.87.54.0/2570.87.54.1 to 70.87.54.12670.87.54.127126
11070.87.54.128/2570.87.54.129 to 70.87.54.25470.87.54.255126
11170.87.55.0/2570.87.55.1 to 70.87.55.12670.87.55.127126
11270.87.55.128/2570.87.55.129 to 70.87.55.25470.87.55.255126
11370.87.56.0/2570.87.56.1 to 70.87.56.12670.87.56.127126
11470.87.56.128/2570.87.56.129 to 70.87.56.25470.87.56.255126
11570.87.57.0/2570.87.57.1 to 70.87.57.12670.87.57.127126
11670.87.57.128/2570.87.57.129 to 70.87.57.25470.87.57.255126
11770.87.58.0/2570.87.58.1 to 70.87.58.12670.87.58.127126
11870.87.58.128/2570.87.58.129 to 70.87.58.25470.87.58.255126
11970.87.59.0/2570.87.59.1 to 70.87.59.12670.87.59.127126
12070.87.59.128/2570.87.59.129 to 70.87.59.25470.87.59.255126
12170.87.60.0/2570.87.60.1 to 70.87.60.12670.87.60.127126
12270.87.60.128/2570.87.60.129 to 70.87.60.25470.87.60.255126
12370.87.61.0/2570.87.61.1 to 70.87.61.12670.87.61.127126
12470.87.61.128/2570.87.61.129 to 70.87.61.25470.87.61.255126
12570.87.62.0/2570.87.62.1 to 70.87.62.12670.87.62.127126
12670.87.62.128/2570.87.62.129 to 70.87.62.25470.87.62.255126
12770.87.63.0/2570.87.63.1 to 70.87.63.12670.87.63.127126
12870.87.63.128/2570.87.63.129 to 70.87.63.25470.87.63.255126
12970.87.64.0/2570.87.64.1 to 70.87.64.12670.87.64.127126
13070.87.64.128/2570.87.64.129 to 70.87.64.25470.87.64.255126
13170.87.65.0/2570.87.65.1 to 70.87.65.12670.87.65.127126
13270.87.65.128/2570.87.65.129 to 70.87.65.25470.87.65.255126
13370.87.66.0/2570.87.66.1 to 70.87.66.12670.87.66.127126
13470.87.66.128/2570.87.66.129 to 70.87.66.25470.87.66.255126
13570.87.67.0/2570.87.67.1 to 70.87.67.12670.87.67.127126
13670.87.67.128/2570.87.67.129 to 70.87.67.25470.87.67.255126
13770.87.68.0/2570.87.68.1 to 70.87.68.12670.87.68.127126
13870.87.68.128/2570.87.68.129 to 70.87.68.25470.87.68.255126
13970.87.69.0/2570.87.69.1 to 70.87.69.12670.87.69.127126
14070.87.69.128/2570.87.69.129 to 70.87.69.25470.87.69.255126
14170.87.70.0/2570.87.70.1 to 70.87.70.12670.87.70.127126
14270.87.70.128/2570.87.70.129 to 70.87.70.25470.87.70.255126
14370.87.71.0/2570.87.71.1 to 70.87.71.12670.87.71.127126
14470.87.71.128/2570.87.71.129 to 70.87.71.25470.87.71.255126
14570.87.72.0/2570.87.72.1 to 70.87.72.12670.87.72.127126
14670.87.72.128/2570.87.72.129 to 70.87.72.25470.87.72.255126
14770.87.73.0/2570.87.73.1 to 70.87.73.12670.87.73.127126
14870.87.73.128/2570.87.73.129 to 70.87.73.25470.87.73.255126
14970.87.74.0/2570.87.74.1 to 70.87.74.12670.87.74.127126
15070.87.74.128/2570.87.74.129 to 70.87.74.25470.87.74.255126
15170.87.75.0/2570.87.75.1 to 70.87.75.12670.87.75.127126
15270.87.75.128/2570.87.75.129 to 70.87.75.25470.87.75.255126
15370.87.76.0/2570.87.76.1 to 70.87.76.12670.87.76.127126
15470.87.76.128/2570.87.76.129 to 70.87.76.25470.87.76.255126
15570.87.77.0/2570.87.77.1 to 70.87.77.12670.87.77.127126
15670.87.77.128/2570.87.77.129 to 70.87.77.25470.87.77.255126
15770.87.78.0/2570.87.78.1 to 70.87.78.12670.87.78.127126
15870.87.78.128/2570.87.78.129 to 70.87.78.25470.87.78.255126
15970.87.79.0/2570.87.79.1 to 70.87.79.12670.87.79.127126
16070.87.79.128/2570.87.79.129 to 70.87.79.25470.87.79.255126
16170.87.80.0/2570.87.80.1 to 70.87.80.12670.87.80.127126
16270.87.80.128/2570.87.80.129 to 70.87.80.25470.87.80.255126
16370.87.81.0/2570.87.81.1 to 70.87.81.12670.87.81.127126
16470.87.81.128/2570.87.81.129 to 70.87.81.25470.87.81.255126
16570.87.82.0/2570.87.82.1 to 70.87.82.12670.87.82.127126
16670.87.82.128/2570.87.82.129 to 70.87.82.25470.87.82.255126
16770.87.83.0/2570.87.83.1 to 70.87.83.12670.87.83.127126
16870.87.83.128/2570.87.83.129 to 70.87.83.25470.87.83.255126
16970.87.84.0/2570.87.84.1 to 70.87.84.12670.87.84.127126
17070.87.84.128/2570.87.84.129 to 70.87.84.25470.87.84.255126
17170.87.85.0/2570.87.85.1 to 70.87.85.12670.87.85.127126
17270.87.85.128/2570.87.85.129 to 70.87.85.25470.87.85.255126
17370.87.86.0/2570.87.86.1 to 70.87.86.12670.87.86.127126
17470.87.86.128/2570.87.86.129 to 70.87.86.25470.87.86.255126
17570.87.87.0/2570.87.87.1 to 70.87.87.12670.87.87.127126
17670.87.87.128/2570.87.87.129 to 70.87.87.25470.87.87.255126
17770.87.88.0/2570.87.88.1 to 70.87.88.12670.87.88.127126
17870.87.88.128/2570.87.88.129 to 70.87.88.25470.87.88.255126
17970.87.89.0/2570.87.89.1 to 70.87.89.12670.87.89.127126
18070.87.89.128/2570.87.89.129 to 70.87.89.25470.87.89.255126
18170.87.90.0/2570.87.90.1 to 70.87.90.12670.87.90.127126
18270.87.90.128/2570.87.90.129 to 70.87.90.25470.87.90.255126
18370.87.91.0/2570.87.91.1 to 70.87.91.12670.87.91.127126
18470.87.91.128/2570.87.91.129 to 70.87.91.25470.87.91.255126
18570.87.92.0/2570.87.92.1 to 70.87.92.12670.87.92.127126
18670.87.92.128/2570.87.92.129 to 70.87.92.25470.87.92.255126
18770.87.93.0/2570.87.93.1 to 70.87.93.12670.87.93.127126
18870.87.93.128/2570.87.93.129 to 70.87.93.25470.87.93.255126
18970.87.94.0/2570.87.94.1 to 70.87.94.12670.87.94.127126
19070.87.94.128/2570.87.94.129 to 70.87.94.25470.87.94.255126
19170.87.95.0/2570.87.95.1 to 70.87.95.12670.87.95.127126
19270.87.95.128/2570.87.95.129 to 70.87.95.25470.87.95.255126
19370.87.96.0/2570.87.96.1 to 70.87.96.12670.87.96.127126
19470.87.96.128/2570.87.96.129 to 70.87.96.25470.87.96.255126
19570.87.97.0/2570.87.97.1 to 70.87.97.12670.87.97.127126
19670.87.97.128/2570.87.97.129 to 70.87.97.25470.87.97.255126
19770.87.98.0/2570.87.98.1 to 70.87.98.12670.87.98.127126
19870.87.98.128/2570.87.98.129 to 70.87.98.25470.87.98.255126
19970.87.99.0/2570.87.99.1 to 70.87.99.12670.87.99.127126
20070.87.99.128/2570.87.99.129 to 70.87.99.25470.87.99.255126
20170.87.100.0/2570.87.100.1 to 70.87.100.12670.87.100.127126
20270.87.100.128/2570.87.100.129 to 70.87.100.25470.87.100.255126
20370.87.101.0/2570.87.101.1 to 70.87.101.12670.87.101.127126
20470.87.101.128/2570.87.101.129 to 70.87.101.25470.87.101.255126
20570.87.102.0/2570.87.102.1 to 70.87.102.12670.87.102.127126
20670.87.102.128/2570.87.102.129 to 70.87.102.25470.87.102.255126
20770.87.103.0/2570.87.103.1 to 70.87.103.12670.87.103.127126
20870.87.103.128/2570.87.103.129 to 70.87.103.25470.87.103.255126
20970.87.104.0/2570.87.104.1 to 70.87.104.12670.87.104.127126
21070.87.104.128/2570.87.104.129 to 70.87.104.25470.87.104.255126
21170.87.105.0/2570.87.105.1 to 70.87.105.12670.87.105.127126
21270.87.105.128/2570.87.105.129 to 70.87.105.25470.87.105.255126
21370.87.106.0/2570.87.106.1 to 70.87.106.12670.87.106.127126
21470.87.106.128/2570.87.106.129 to 70.87.106.25470.87.106.255126
21570.87.107.0/2570.87.107.1 to 70.87.107.12670.87.107.127126
21670.87.107.128/2570.87.107.129 to 70.87.107.25470.87.107.255126
21770.87.108.0/2570.87.108.1 to 70.87.108.12670.87.108.127126
21870.87.108.128/2570.87.108.129 to 70.87.108.25470.87.108.255126
21970.87.109.0/2570.87.109.1 to 70.87.109.12670.87.109.127126
22070.87.109.128/2570.87.109.129 to 70.87.109.25470.87.109.255126
22170.87.110.0/2570.87.110.1 to 70.87.110.12670.87.110.127126
22270.87.110.128/2570.87.110.129 to 70.87.110.25470.87.110.255126
22370.87.111.0/2570.87.111.1 to 70.87.111.12670.87.111.127126
22470.87.111.128/2570.87.111.129 to 70.87.111.25470.87.111.255126
22570.87.112.0/2570.87.112.1 to 70.87.112.12670.87.112.127126
22670.87.112.128/2570.87.112.129 to 70.87.112.25470.87.112.255126
22770.87.113.0/2570.87.113.1 to 70.87.113.12670.87.113.127126
22870.87.113.128/2570.87.113.129 to 70.87.113.25470.87.113.255126
22970.87.114.0/2570.87.114.1 to 70.87.114.12670.87.114.127126
23070.87.114.128/2570.87.114.129 to 70.87.114.25470.87.114.255126
23170.87.115.0/2570.87.115.1 to 70.87.115.12670.87.115.127126
23270.87.115.128/2570.87.115.129 to 70.87.115.25470.87.115.255126
23370.87.116.0/2570.87.116.1 to 70.87.116.12670.87.116.127126
23470.87.116.128/2570.87.116.129 to 70.87.116.25470.87.116.255126
23570.87.117.0/2570.87.117.1 to 70.87.117.12670.87.117.127126
23670.87.117.128/2570.87.117.129 to 70.87.117.25470.87.117.255126
23770.87.118.0/2570.87.118.1 to 70.87.118.12670.87.118.127126
23870.87.118.128/2570.87.118.129 to 70.87.118.25470.87.118.255126
23970.87.119.0/2570.87.119.1 to 70.87.119.12670.87.119.127126
24070.87.119.128/2570.87.119.129 to 70.87.119.25470.87.119.255126
24170.87.120.0/2570.87.120.1 to 70.87.120.12670.87.120.127126
24270.87.120.128/2570.87.120.129 to 70.87.120.25470.87.120.255126
24370.87.121.0/2570.87.121.1 to 70.87.121.12670.87.121.127126
24470.87.121.128/2570.87.121.129 to 70.87.121.25470.87.121.255126
24570.87.122.0/2570.87.122.1 to 70.87.122.12670.87.122.127126
24670.87.122.128/2570.87.122.129 to 70.87.122.25470.87.122.255126
24770.87.123.0/2570.87.123.1 to 70.87.123.12670.87.123.127126
24870.87.123.128/2570.87.123.129 to 70.87.123.25470.87.123.255126
24970.87.124.0/2570.87.124.1 to 70.87.124.12670.87.124.127126
25070.87.124.128/2570.87.124.129 to 70.87.124.25470.87.124.255126
25170.87.125.0/2570.87.125.1 to 70.87.125.12670.87.125.127126
25270.87.125.128/2570.87.125.129 to 70.87.125.25470.87.125.255126
25370.87.126.0/2570.87.126.1 to 70.87.126.12670.87.126.127126
25470.87.126.128/2570.87.126.129 to 70.87.126.25470.87.126.255126
25570.87.127.0/2570.87.127.1 to 70.87.127.12670.87.127.127126
25670.87.127.128/2570.87.127.129 to 70.87.127.25470.87.127.255126

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.