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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.

Network27.167.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
27.167.0.0
Broadcast address
27.167.127.255
First usable
27.167.0.1
Last usable
27.167.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 1BA70000 · Integer 463929344 to 463962111
Reverse DNS zones
0.167.27.in-addr.arpa
1.167.27.in-addr.arpa
2.167.27.in-addr.arpa
3.167.27.in-addr.arpa
4.167.27.in-addr.arpa
5.167.27.in-addr.arpa
6.167.27.in-addr.arpa
7.167.27.in-addr.arpa
8.167.27.in-addr.arpa
9.167.27.in-addr.arpa
10.167.27.in-addr.arpa
11.167.27.in-addr.arpa
12.167.27.in-addr.arpa
13.167.27.in-addr.arpa
14.167.27.in-addr.arpa
15.167.27.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011011.10100111.00000000.0000000027.167.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00011011.10100111.00000000.0000000027.167.0.0
Broadcast00011011.10100111.01111111.1111111127.167.127.255
Split into smaller subnets/25
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

27.167.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
127.167.0.0/2527.167.0.1 to 27.167.0.12627.167.0.127126
227.167.0.128/2527.167.0.129 to 27.167.0.25427.167.0.255126
327.167.1.0/2527.167.1.1 to 27.167.1.12627.167.1.127126
427.167.1.128/2527.167.1.129 to 27.167.1.25427.167.1.255126
527.167.2.0/2527.167.2.1 to 27.167.2.12627.167.2.127126
627.167.2.128/2527.167.2.129 to 27.167.2.25427.167.2.255126
727.167.3.0/2527.167.3.1 to 27.167.3.12627.167.3.127126
827.167.3.128/2527.167.3.129 to 27.167.3.25427.167.3.255126
927.167.4.0/2527.167.4.1 to 27.167.4.12627.167.4.127126
1027.167.4.128/2527.167.4.129 to 27.167.4.25427.167.4.255126
1127.167.5.0/2527.167.5.1 to 27.167.5.12627.167.5.127126
1227.167.5.128/2527.167.5.129 to 27.167.5.25427.167.5.255126
1327.167.6.0/2527.167.6.1 to 27.167.6.12627.167.6.127126
1427.167.6.128/2527.167.6.129 to 27.167.6.25427.167.6.255126
1527.167.7.0/2527.167.7.1 to 27.167.7.12627.167.7.127126
1627.167.7.128/2527.167.7.129 to 27.167.7.25427.167.7.255126
1727.167.8.0/2527.167.8.1 to 27.167.8.12627.167.8.127126
1827.167.8.128/2527.167.8.129 to 27.167.8.25427.167.8.255126
1927.167.9.0/2527.167.9.1 to 27.167.9.12627.167.9.127126
2027.167.9.128/2527.167.9.129 to 27.167.9.25427.167.9.255126
2127.167.10.0/2527.167.10.1 to 27.167.10.12627.167.10.127126
2227.167.10.128/2527.167.10.129 to 27.167.10.25427.167.10.255126
2327.167.11.0/2527.167.11.1 to 27.167.11.12627.167.11.127126
2427.167.11.128/2527.167.11.129 to 27.167.11.25427.167.11.255126
2527.167.12.0/2527.167.12.1 to 27.167.12.12627.167.12.127126
2627.167.12.128/2527.167.12.129 to 27.167.12.25427.167.12.255126
2727.167.13.0/2527.167.13.1 to 27.167.13.12627.167.13.127126
2827.167.13.128/2527.167.13.129 to 27.167.13.25427.167.13.255126
2927.167.14.0/2527.167.14.1 to 27.167.14.12627.167.14.127126
3027.167.14.128/2527.167.14.129 to 27.167.14.25427.167.14.255126
3127.167.15.0/2527.167.15.1 to 27.167.15.12627.167.15.127126
3227.167.15.128/2527.167.15.129 to 27.167.15.25427.167.15.255126
3327.167.16.0/2527.167.16.1 to 27.167.16.12627.167.16.127126
3427.167.16.128/2527.167.16.129 to 27.167.16.25427.167.16.255126
3527.167.17.0/2527.167.17.1 to 27.167.17.12627.167.17.127126
3627.167.17.128/2527.167.17.129 to 27.167.17.25427.167.17.255126
3727.167.18.0/2527.167.18.1 to 27.167.18.12627.167.18.127126
3827.167.18.128/2527.167.18.129 to 27.167.18.25427.167.18.255126
3927.167.19.0/2527.167.19.1 to 27.167.19.12627.167.19.127126
4027.167.19.128/2527.167.19.129 to 27.167.19.25427.167.19.255126
4127.167.20.0/2527.167.20.1 to 27.167.20.12627.167.20.127126
4227.167.20.128/2527.167.20.129 to 27.167.20.25427.167.20.255126
4327.167.21.0/2527.167.21.1 to 27.167.21.12627.167.21.127126
4427.167.21.128/2527.167.21.129 to 27.167.21.25427.167.21.255126
4527.167.22.0/2527.167.22.1 to 27.167.22.12627.167.22.127126
4627.167.22.128/2527.167.22.129 to 27.167.22.25427.167.22.255126
4727.167.23.0/2527.167.23.1 to 27.167.23.12627.167.23.127126
4827.167.23.128/2527.167.23.129 to 27.167.23.25427.167.23.255126
4927.167.24.0/2527.167.24.1 to 27.167.24.12627.167.24.127126
5027.167.24.128/2527.167.24.129 to 27.167.24.25427.167.24.255126
5127.167.25.0/2527.167.25.1 to 27.167.25.12627.167.25.127126
5227.167.25.128/2527.167.25.129 to 27.167.25.25427.167.25.255126
5327.167.26.0/2527.167.26.1 to 27.167.26.12627.167.26.127126
5427.167.26.128/2527.167.26.129 to 27.167.26.25427.167.26.255126
5527.167.27.0/2527.167.27.1 to 27.167.27.12627.167.27.127126
5627.167.27.128/2527.167.27.129 to 27.167.27.25427.167.27.255126
5727.167.28.0/2527.167.28.1 to 27.167.28.12627.167.28.127126
5827.167.28.128/2527.167.28.129 to 27.167.28.25427.167.28.255126
5927.167.29.0/2527.167.29.1 to 27.167.29.12627.167.29.127126
6027.167.29.128/2527.167.29.129 to 27.167.29.25427.167.29.255126
6127.167.30.0/2527.167.30.1 to 27.167.30.12627.167.30.127126
6227.167.30.128/2527.167.30.129 to 27.167.30.25427.167.30.255126
6327.167.31.0/2527.167.31.1 to 27.167.31.12627.167.31.127126
6427.167.31.128/2527.167.31.129 to 27.167.31.25427.167.31.255126
6527.167.32.0/2527.167.32.1 to 27.167.32.12627.167.32.127126
6627.167.32.128/2527.167.32.129 to 27.167.32.25427.167.32.255126
6727.167.33.0/2527.167.33.1 to 27.167.33.12627.167.33.127126
6827.167.33.128/2527.167.33.129 to 27.167.33.25427.167.33.255126
6927.167.34.0/2527.167.34.1 to 27.167.34.12627.167.34.127126
7027.167.34.128/2527.167.34.129 to 27.167.34.25427.167.34.255126
7127.167.35.0/2527.167.35.1 to 27.167.35.12627.167.35.127126
7227.167.35.128/2527.167.35.129 to 27.167.35.25427.167.35.255126
7327.167.36.0/2527.167.36.1 to 27.167.36.12627.167.36.127126
7427.167.36.128/2527.167.36.129 to 27.167.36.25427.167.36.255126
7527.167.37.0/2527.167.37.1 to 27.167.37.12627.167.37.127126
7627.167.37.128/2527.167.37.129 to 27.167.37.25427.167.37.255126
7727.167.38.0/2527.167.38.1 to 27.167.38.12627.167.38.127126
7827.167.38.128/2527.167.38.129 to 27.167.38.25427.167.38.255126
7927.167.39.0/2527.167.39.1 to 27.167.39.12627.167.39.127126
8027.167.39.128/2527.167.39.129 to 27.167.39.25427.167.39.255126
8127.167.40.0/2527.167.40.1 to 27.167.40.12627.167.40.127126
8227.167.40.128/2527.167.40.129 to 27.167.40.25427.167.40.255126
8327.167.41.0/2527.167.41.1 to 27.167.41.12627.167.41.127126
8427.167.41.128/2527.167.41.129 to 27.167.41.25427.167.41.255126
8527.167.42.0/2527.167.42.1 to 27.167.42.12627.167.42.127126
8627.167.42.128/2527.167.42.129 to 27.167.42.25427.167.42.255126
8727.167.43.0/2527.167.43.1 to 27.167.43.12627.167.43.127126
8827.167.43.128/2527.167.43.129 to 27.167.43.25427.167.43.255126
8927.167.44.0/2527.167.44.1 to 27.167.44.12627.167.44.127126
9027.167.44.128/2527.167.44.129 to 27.167.44.25427.167.44.255126
9127.167.45.0/2527.167.45.1 to 27.167.45.12627.167.45.127126
9227.167.45.128/2527.167.45.129 to 27.167.45.25427.167.45.255126
9327.167.46.0/2527.167.46.1 to 27.167.46.12627.167.46.127126
9427.167.46.128/2527.167.46.129 to 27.167.46.25427.167.46.255126
9527.167.47.0/2527.167.47.1 to 27.167.47.12627.167.47.127126
9627.167.47.128/2527.167.47.129 to 27.167.47.25427.167.47.255126
9727.167.48.0/2527.167.48.1 to 27.167.48.12627.167.48.127126
9827.167.48.128/2527.167.48.129 to 27.167.48.25427.167.48.255126
9927.167.49.0/2527.167.49.1 to 27.167.49.12627.167.49.127126
10027.167.49.128/2527.167.49.129 to 27.167.49.25427.167.49.255126
10127.167.50.0/2527.167.50.1 to 27.167.50.12627.167.50.127126
10227.167.50.128/2527.167.50.129 to 27.167.50.25427.167.50.255126
10327.167.51.0/2527.167.51.1 to 27.167.51.12627.167.51.127126
10427.167.51.128/2527.167.51.129 to 27.167.51.25427.167.51.255126
10527.167.52.0/2527.167.52.1 to 27.167.52.12627.167.52.127126
10627.167.52.128/2527.167.52.129 to 27.167.52.25427.167.52.255126
10727.167.53.0/2527.167.53.1 to 27.167.53.12627.167.53.127126
10827.167.53.128/2527.167.53.129 to 27.167.53.25427.167.53.255126
10927.167.54.0/2527.167.54.1 to 27.167.54.12627.167.54.127126
11027.167.54.128/2527.167.54.129 to 27.167.54.25427.167.54.255126
11127.167.55.0/2527.167.55.1 to 27.167.55.12627.167.55.127126
11227.167.55.128/2527.167.55.129 to 27.167.55.25427.167.55.255126
11327.167.56.0/2527.167.56.1 to 27.167.56.12627.167.56.127126
11427.167.56.128/2527.167.56.129 to 27.167.56.25427.167.56.255126
11527.167.57.0/2527.167.57.1 to 27.167.57.12627.167.57.127126
11627.167.57.128/2527.167.57.129 to 27.167.57.25427.167.57.255126
11727.167.58.0/2527.167.58.1 to 27.167.58.12627.167.58.127126
11827.167.58.128/2527.167.58.129 to 27.167.58.25427.167.58.255126
11927.167.59.0/2527.167.59.1 to 27.167.59.12627.167.59.127126
12027.167.59.128/2527.167.59.129 to 27.167.59.25427.167.59.255126
12127.167.60.0/2527.167.60.1 to 27.167.60.12627.167.60.127126
12227.167.60.128/2527.167.60.129 to 27.167.60.25427.167.60.255126
12327.167.61.0/2527.167.61.1 to 27.167.61.12627.167.61.127126
12427.167.61.128/2527.167.61.129 to 27.167.61.25427.167.61.255126
12527.167.62.0/2527.167.62.1 to 27.167.62.12627.167.62.127126
12627.167.62.128/2527.167.62.129 to 27.167.62.25427.167.62.255126
12727.167.63.0/2527.167.63.1 to 27.167.63.12627.167.63.127126
12827.167.63.128/2527.167.63.129 to 27.167.63.25427.167.63.255126
12927.167.64.0/2527.167.64.1 to 27.167.64.12627.167.64.127126
13027.167.64.128/2527.167.64.129 to 27.167.64.25427.167.64.255126
13127.167.65.0/2527.167.65.1 to 27.167.65.12627.167.65.127126
13227.167.65.128/2527.167.65.129 to 27.167.65.25427.167.65.255126
13327.167.66.0/2527.167.66.1 to 27.167.66.12627.167.66.127126
13427.167.66.128/2527.167.66.129 to 27.167.66.25427.167.66.255126
13527.167.67.0/2527.167.67.1 to 27.167.67.12627.167.67.127126
13627.167.67.128/2527.167.67.129 to 27.167.67.25427.167.67.255126
13727.167.68.0/2527.167.68.1 to 27.167.68.12627.167.68.127126
13827.167.68.128/2527.167.68.129 to 27.167.68.25427.167.68.255126
13927.167.69.0/2527.167.69.1 to 27.167.69.12627.167.69.127126
14027.167.69.128/2527.167.69.129 to 27.167.69.25427.167.69.255126
14127.167.70.0/2527.167.70.1 to 27.167.70.12627.167.70.127126
14227.167.70.128/2527.167.70.129 to 27.167.70.25427.167.70.255126
14327.167.71.0/2527.167.71.1 to 27.167.71.12627.167.71.127126
14427.167.71.128/2527.167.71.129 to 27.167.71.25427.167.71.255126
14527.167.72.0/2527.167.72.1 to 27.167.72.12627.167.72.127126
14627.167.72.128/2527.167.72.129 to 27.167.72.25427.167.72.255126
14727.167.73.0/2527.167.73.1 to 27.167.73.12627.167.73.127126
14827.167.73.128/2527.167.73.129 to 27.167.73.25427.167.73.255126
14927.167.74.0/2527.167.74.1 to 27.167.74.12627.167.74.127126
15027.167.74.128/2527.167.74.129 to 27.167.74.25427.167.74.255126
15127.167.75.0/2527.167.75.1 to 27.167.75.12627.167.75.127126
15227.167.75.128/2527.167.75.129 to 27.167.75.25427.167.75.255126
15327.167.76.0/2527.167.76.1 to 27.167.76.12627.167.76.127126
15427.167.76.128/2527.167.76.129 to 27.167.76.25427.167.76.255126
15527.167.77.0/2527.167.77.1 to 27.167.77.12627.167.77.127126
15627.167.77.128/2527.167.77.129 to 27.167.77.25427.167.77.255126
15727.167.78.0/2527.167.78.1 to 27.167.78.12627.167.78.127126
15827.167.78.128/2527.167.78.129 to 27.167.78.25427.167.78.255126
15927.167.79.0/2527.167.79.1 to 27.167.79.12627.167.79.127126
16027.167.79.128/2527.167.79.129 to 27.167.79.25427.167.79.255126
16127.167.80.0/2527.167.80.1 to 27.167.80.12627.167.80.127126
16227.167.80.128/2527.167.80.129 to 27.167.80.25427.167.80.255126
16327.167.81.0/2527.167.81.1 to 27.167.81.12627.167.81.127126
16427.167.81.128/2527.167.81.129 to 27.167.81.25427.167.81.255126
16527.167.82.0/2527.167.82.1 to 27.167.82.12627.167.82.127126
16627.167.82.128/2527.167.82.129 to 27.167.82.25427.167.82.255126
16727.167.83.0/2527.167.83.1 to 27.167.83.12627.167.83.127126
16827.167.83.128/2527.167.83.129 to 27.167.83.25427.167.83.255126
16927.167.84.0/2527.167.84.1 to 27.167.84.12627.167.84.127126
17027.167.84.128/2527.167.84.129 to 27.167.84.25427.167.84.255126
17127.167.85.0/2527.167.85.1 to 27.167.85.12627.167.85.127126
17227.167.85.128/2527.167.85.129 to 27.167.85.25427.167.85.255126
17327.167.86.0/2527.167.86.1 to 27.167.86.12627.167.86.127126
17427.167.86.128/2527.167.86.129 to 27.167.86.25427.167.86.255126
17527.167.87.0/2527.167.87.1 to 27.167.87.12627.167.87.127126
17627.167.87.128/2527.167.87.129 to 27.167.87.25427.167.87.255126
17727.167.88.0/2527.167.88.1 to 27.167.88.12627.167.88.127126
17827.167.88.128/2527.167.88.129 to 27.167.88.25427.167.88.255126
17927.167.89.0/2527.167.89.1 to 27.167.89.12627.167.89.127126
18027.167.89.128/2527.167.89.129 to 27.167.89.25427.167.89.255126
18127.167.90.0/2527.167.90.1 to 27.167.90.12627.167.90.127126
18227.167.90.128/2527.167.90.129 to 27.167.90.25427.167.90.255126
18327.167.91.0/2527.167.91.1 to 27.167.91.12627.167.91.127126
18427.167.91.128/2527.167.91.129 to 27.167.91.25427.167.91.255126
18527.167.92.0/2527.167.92.1 to 27.167.92.12627.167.92.127126
18627.167.92.128/2527.167.92.129 to 27.167.92.25427.167.92.255126
18727.167.93.0/2527.167.93.1 to 27.167.93.12627.167.93.127126
18827.167.93.128/2527.167.93.129 to 27.167.93.25427.167.93.255126
18927.167.94.0/2527.167.94.1 to 27.167.94.12627.167.94.127126
19027.167.94.128/2527.167.94.129 to 27.167.94.25427.167.94.255126
19127.167.95.0/2527.167.95.1 to 27.167.95.12627.167.95.127126
19227.167.95.128/2527.167.95.129 to 27.167.95.25427.167.95.255126
19327.167.96.0/2527.167.96.1 to 27.167.96.12627.167.96.127126
19427.167.96.128/2527.167.96.129 to 27.167.96.25427.167.96.255126
19527.167.97.0/2527.167.97.1 to 27.167.97.12627.167.97.127126
19627.167.97.128/2527.167.97.129 to 27.167.97.25427.167.97.255126
19727.167.98.0/2527.167.98.1 to 27.167.98.12627.167.98.127126
19827.167.98.128/2527.167.98.129 to 27.167.98.25427.167.98.255126
19927.167.99.0/2527.167.99.1 to 27.167.99.12627.167.99.127126
20027.167.99.128/2527.167.99.129 to 27.167.99.25427.167.99.255126
20127.167.100.0/2527.167.100.1 to 27.167.100.12627.167.100.127126
20227.167.100.128/2527.167.100.129 to 27.167.100.25427.167.100.255126
20327.167.101.0/2527.167.101.1 to 27.167.101.12627.167.101.127126
20427.167.101.128/2527.167.101.129 to 27.167.101.25427.167.101.255126
20527.167.102.0/2527.167.102.1 to 27.167.102.12627.167.102.127126
20627.167.102.128/2527.167.102.129 to 27.167.102.25427.167.102.255126
20727.167.103.0/2527.167.103.1 to 27.167.103.12627.167.103.127126
20827.167.103.128/2527.167.103.129 to 27.167.103.25427.167.103.255126
20927.167.104.0/2527.167.104.1 to 27.167.104.12627.167.104.127126
21027.167.104.128/2527.167.104.129 to 27.167.104.25427.167.104.255126
21127.167.105.0/2527.167.105.1 to 27.167.105.12627.167.105.127126
21227.167.105.128/2527.167.105.129 to 27.167.105.25427.167.105.255126
21327.167.106.0/2527.167.106.1 to 27.167.106.12627.167.106.127126
21427.167.106.128/2527.167.106.129 to 27.167.106.25427.167.106.255126
21527.167.107.0/2527.167.107.1 to 27.167.107.12627.167.107.127126
21627.167.107.128/2527.167.107.129 to 27.167.107.25427.167.107.255126
21727.167.108.0/2527.167.108.1 to 27.167.108.12627.167.108.127126
21827.167.108.128/2527.167.108.129 to 27.167.108.25427.167.108.255126
21927.167.109.0/2527.167.109.1 to 27.167.109.12627.167.109.127126
22027.167.109.128/2527.167.109.129 to 27.167.109.25427.167.109.255126
22127.167.110.0/2527.167.110.1 to 27.167.110.12627.167.110.127126
22227.167.110.128/2527.167.110.129 to 27.167.110.25427.167.110.255126
22327.167.111.0/2527.167.111.1 to 27.167.111.12627.167.111.127126
22427.167.111.128/2527.167.111.129 to 27.167.111.25427.167.111.255126
22527.167.112.0/2527.167.112.1 to 27.167.112.12627.167.112.127126
22627.167.112.128/2527.167.112.129 to 27.167.112.25427.167.112.255126
22727.167.113.0/2527.167.113.1 to 27.167.113.12627.167.113.127126
22827.167.113.128/2527.167.113.129 to 27.167.113.25427.167.113.255126
22927.167.114.0/2527.167.114.1 to 27.167.114.12627.167.114.127126
23027.167.114.128/2527.167.114.129 to 27.167.114.25427.167.114.255126
23127.167.115.0/2527.167.115.1 to 27.167.115.12627.167.115.127126
23227.167.115.128/2527.167.115.129 to 27.167.115.25427.167.115.255126
23327.167.116.0/2527.167.116.1 to 27.167.116.12627.167.116.127126
23427.167.116.128/2527.167.116.129 to 27.167.116.25427.167.116.255126
23527.167.117.0/2527.167.117.1 to 27.167.117.12627.167.117.127126
23627.167.117.128/2527.167.117.129 to 27.167.117.25427.167.117.255126
23727.167.118.0/2527.167.118.1 to 27.167.118.12627.167.118.127126
23827.167.118.128/2527.167.118.129 to 27.167.118.25427.167.118.255126
23927.167.119.0/2527.167.119.1 to 27.167.119.12627.167.119.127126
24027.167.119.128/2527.167.119.129 to 27.167.119.25427.167.119.255126
24127.167.120.0/2527.167.120.1 to 27.167.120.12627.167.120.127126
24227.167.120.128/2527.167.120.129 to 27.167.120.25427.167.120.255126
24327.167.121.0/2527.167.121.1 to 27.167.121.12627.167.121.127126
24427.167.121.128/2527.167.121.129 to 27.167.121.25427.167.121.255126
24527.167.122.0/2527.167.122.1 to 27.167.122.12627.167.122.127126
24627.167.122.128/2527.167.122.129 to 27.167.122.25427.167.122.255126
24727.167.123.0/2527.167.123.1 to 27.167.123.12627.167.123.127126
24827.167.123.128/2527.167.123.129 to 27.167.123.25427.167.123.255126
24927.167.124.0/2527.167.124.1 to 27.167.124.12627.167.124.127126
25027.167.124.128/2527.167.124.129 to 27.167.124.25427.167.124.255126
25127.167.125.0/2527.167.125.1 to 27.167.125.12627.167.125.127126
25227.167.125.128/2527.167.125.129 to 27.167.125.25427.167.125.255126
25327.167.126.0/2527.167.126.1 to 27.167.126.12627.167.126.127126
25427.167.126.128/2527.167.126.129 to 27.167.126.25427.167.126.255126
25527.167.127.0/2527.167.127.1 to 27.167.127.12627.167.127.127126
25627.167.127.128/2527.167.127.129 to 27.167.127.25427.167.127.255126

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.