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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.

Network56.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
56.0.0.0
Broadcast address
63.255.255.255
First usable
56.0.0.1
Last usable
63.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
A (default /8)
As numbers
Hex 38000000 · Integer 939524096 to 1073741823
Reverse DNS zones
56.in-addr.arpa
57.in-addr.arpa
58.in-addr.arpa
59.in-addr.arpa
60.in-addr.arpa
61.in-addr.arpa
62.in-addr.arpa
63.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111000.00000000.00000000.0000000056.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network00111000.00000000.00000000.0000000056.0.0.0
Broadcast00111111.11111111.11111111.1111111163.255.255.255
Split into smaller subnets/17
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

56.0.0.0/5 makes 4,096 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
156.0.0.0/1756.0.0.1 to 56.0.127.25456.0.127.25532,766
256.0.128.0/1756.0.128.1 to 56.0.255.25456.0.255.25532,766
356.1.0.0/1756.1.0.1 to 56.1.127.25456.1.127.25532,766
456.1.128.0/1756.1.128.1 to 56.1.255.25456.1.255.25532,766
556.2.0.0/1756.2.0.1 to 56.2.127.25456.2.127.25532,766
656.2.128.0/1756.2.128.1 to 56.2.255.25456.2.255.25532,766
756.3.0.0/1756.3.0.1 to 56.3.127.25456.3.127.25532,766
856.3.128.0/1756.3.128.1 to 56.3.255.25456.3.255.25532,766
956.4.0.0/1756.4.0.1 to 56.4.127.25456.4.127.25532,766
1056.4.128.0/1756.4.128.1 to 56.4.255.25456.4.255.25532,766
1156.5.0.0/1756.5.0.1 to 56.5.127.25456.5.127.25532,766
1256.5.128.0/1756.5.128.1 to 56.5.255.25456.5.255.25532,766
1356.6.0.0/1756.6.0.1 to 56.6.127.25456.6.127.25532,766
1456.6.128.0/1756.6.128.1 to 56.6.255.25456.6.255.25532,766
1556.7.0.0/1756.7.0.1 to 56.7.127.25456.7.127.25532,766
1656.7.128.0/1756.7.128.1 to 56.7.255.25456.7.255.25532,766
1756.8.0.0/1756.8.0.1 to 56.8.127.25456.8.127.25532,766
1856.8.128.0/1756.8.128.1 to 56.8.255.25456.8.255.25532,766
1956.9.0.0/1756.9.0.1 to 56.9.127.25456.9.127.25532,766
2056.9.128.0/1756.9.128.1 to 56.9.255.25456.9.255.25532,766
2156.10.0.0/1756.10.0.1 to 56.10.127.25456.10.127.25532,766
2256.10.128.0/1756.10.128.1 to 56.10.255.25456.10.255.25532,766
2356.11.0.0/1756.11.0.1 to 56.11.127.25456.11.127.25532,766
2456.11.128.0/1756.11.128.1 to 56.11.255.25456.11.255.25532,766
2556.12.0.0/1756.12.0.1 to 56.12.127.25456.12.127.25532,766
2656.12.128.0/1756.12.128.1 to 56.12.255.25456.12.255.25532,766
2756.13.0.0/1756.13.0.1 to 56.13.127.25456.13.127.25532,766
2856.13.128.0/1756.13.128.1 to 56.13.255.25456.13.255.25532,766
2956.14.0.0/1756.14.0.1 to 56.14.127.25456.14.127.25532,766
3056.14.128.0/1756.14.128.1 to 56.14.255.25456.14.255.25532,766
3156.15.0.0/1756.15.0.1 to 56.15.127.25456.15.127.25532,766
3256.15.128.0/1756.15.128.1 to 56.15.255.25456.15.255.25532,766
3356.16.0.0/1756.16.0.1 to 56.16.127.25456.16.127.25532,766
3456.16.128.0/1756.16.128.1 to 56.16.255.25456.16.255.25532,766
3556.17.0.0/1756.17.0.1 to 56.17.127.25456.17.127.25532,766
3656.17.128.0/1756.17.128.1 to 56.17.255.25456.17.255.25532,766
3756.18.0.0/1756.18.0.1 to 56.18.127.25456.18.127.25532,766
3856.18.128.0/1756.18.128.1 to 56.18.255.25456.18.255.25532,766
3956.19.0.0/1756.19.0.1 to 56.19.127.25456.19.127.25532,766
4056.19.128.0/1756.19.128.1 to 56.19.255.25456.19.255.25532,766
4156.20.0.0/1756.20.0.1 to 56.20.127.25456.20.127.25532,766
4256.20.128.0/1756.20.128.1 to 56.20.255.25456.20.255.25532,766
4356.21.0.0/1756.21.0.1 to 56.21.127.25456.21.127.25532,766
4456.21.128.0/1756.21.128.1 to 56.21.255.25456.21.255.25532,766
4556.22.0.0/1756.22.0.1 to 56.22.127.25456.22.127.25532,766
4656.22.128.0/1756.22.128.1 to 56.22.255.25456.22.255.25532,766
4756.23.0.0/1756.23.0.1 to 56.23.127.25456.23.127.25532,766
4856.23.128.0/1756.23.128.1 to 56.23.255.25456.23.255.25532,766
4956.24.0.0/1756.24.0.1 to 56.24.127.25456.24.127.25532,766
5056.24.128.0/1756.24.128.1 to 56.24.255.25456.24.255.25532,766
5156.25.0.0/1756.25.0.1 to 56.25.127.25456.25.127.25532,766
5256.25.128.0/1756.25.128.1 to 56.25.255.25456.25.255.25532,766
5356.26.0.0/1756.26.0.1 to 56.26.127.25456.26.127.25532,766
5456.26.128.0/1756.26.128.1 to 56.26.255.25456.26.255.25532,766
5556.27.0.0/1756.27.0.1 to 56.27.127.25456.27.127.25532,766
5656.27.128.0/1756.27.128.1 to 56.27.255.25456.27.255.25532,766
5756.28.0.0/1756.28.0.1 to 56.28.127.25456.28.127.25532,766
5856.28.128.0/1756.28.128.1 to 56.28.255.25456.28.255.25532,766
5956.29.0.0/1756.29.0.1 to 56.29.127.25456.29.127.25532,766
6056.29.128.0/1756.29.128.1 to 56.29.255.25456.29.255.25532,766
6156.30.0.0/1756.30.0.1 to 56.30.127.25456.30.127.25532,766
6256.30.128.0/1756.30.128.1 to 56.30.255.25456.30.255.25532,766
6356.31.0.0/1756.31.0.1 to 56.31.127.25456.31.127.25532,766
6456.31.128.0/1756.31.128.1 to 56.31.255.25456.31.255.25532,766
6556.32.0.0/1756.32.0.1 to 56.32.127.25456.32.127.25532,766
6656.32.128.0/1756.32.128.1 to 56.32.255.25456.32.255.25532,766
6756.33.0.0/1756.33.0.1 to 56.33.127.25456.33.127.25532,766
6856.33.128.0/1756.33.128.1 to 56.33.255.25456.33.255.25532,766
6956.34.0.0/1756.34.0.1 to 56.34.127.25456.34.127.25532,766
7056.34.128.0/1756.34.128.1 to 56.34.255.25456.34.255.25532,766
7156.35.0.0/1756.35.0.1 to 56.35.127.25456.35.127.25532,766
7256.35.128.0/1756.35.128.1 to 56.35.255.25456.35.255.25532,766
7356.36.0.0/1756.36.0.1 to 56.36.127.25456.36.127.25532,766
7456.36.128.0/1756.36.128.1 to 56.36.255.25456.36.255.25532,766
7556.37.0.0/1756.37.0.1 to 56.37.127.25456.37.127.25532,766
7656.37.128.0/1756.37.128.1 to 56.37.255.25456.37.255.25532,766
7756.38.0.0/1756.38.0.1 to 56.38.127.25456.38.127.25532,766
7856.38.128.0/1756.38.128.1 to 56.38.255.25456.38.255.25532,766
7956.39.0.0/1756.39.0.1 to 56.39.127.25456.39.127.25532,766
8056.39.128.0/1756.39.128.1 to 56.39.255.25456.39.255.25532,766
8156.40.0.0/1756.40.0.1 to 56.40.127.25456.40.127.25532,766
8256.40.128.0/1756.40.128.1 to 56.40.255.25456.40.255.25532,766
8356.41.0.0/1756.41.0.1 to 56.41.127.25456.41.127.25532,766
8456.41.128.0/1756.41.128.1 to 56.41.255.25456.41.255.25532,766
8556.42.0.0/1756.42.0.1 to 56.42.127.25456.42.127.25532,766
8656.42.128.0/1756.42.128.1 to 56.42.255.25456.42.255.25532,766
8756.43.0.0/1756.43.0.1 to 56.43.127.25456.43.127.25532,766
8856.43.128.0/1756.43.128.1 to 56.43.255.25456.43.255.25532,766
8956.44.0.0/1756.44.0.1 to 56.44.127.25456.44.127.25532,766
9056.44.128.0/1756.44.128.1 to 56.44.255.25456.44.255.25532,766
9156.45.0.0/1756.45.0.1 to 56.45.127.25456.45.127.25532,766
9256.45.128.0/1756.45.128.1 to 56.45.255.25456.45.255.25532,766
9356.46.0.0/1756.46.0.1 to 56.46.127.25456.46.127.25532,766
9456.46.128.0/1756.46.128.1 to 56.46.255.25456.46.255.25532,766
9556.47.0.0/1756.47.0.1 to 56.47.127.25456.47.127.25532,766
9656.47.128.0/1756.47.128.1 to 56.47.255.25456.47.255.25532,766
9756.48.0.0/1756.48.0.1 to 56.48.127.25456.48.127.25532,766
9856.48.128.0/1756.48.128.1 to 56.48.255.25456.48.255.25532,766
9956.49.0.0/1756.49.0.1 to 56.49.127.25456.49.127.25532,766
10056.49.128.0/1756.49.128.1 to 56.49.255.25456.49.255.25532,766
10156.50.0.0/1756.50.0.1 to 56.50.127.25456.50.127.25532,766
10256.50.128.0/1756.50.128.1 to 56.50.255.25456.50.255.25532,766
10356.51.0.0/1756.51.0.1 to 56.51.127.25456.51.127.25532,766
10456.51.128.0/1756.51.128.1 to 56.51.255.25456.51.255.25532,766
10556.52.0.0/1756.52.0.1 to 56.52.127.25456.52.127.25532,766
10656.52.128.0/1756.52.128.1 to 56.52.255.25456.52.255.25532,766
10756.53.0.0/1756.53.0.1 to 56.53.127.25456.53.127.25532,766
10856.53.128.0/1756.53.128.1 to 56.53.255.25456.53.255.25532,766
10956.54.0.0/1756.54.0.1 to 56.54.127.25456.54.127.25532,766
11056.54.128.0/1756.54.128.1 to 56.54.255.25456.54.255.25532,766
11156.55.0.0/1756.55.0.1 to 56.55.127.25456.55.127.25532,766
11256.55.128.0/1756.55.128.1 to 56.55.255.25456.55.255.25532,766
11356.56.0.0/1756.56.0.1 to 56.56.127.25456.56.127.25532,766
11456.56.128.0/1756.56.128.1 to 56.56.255.25456.56.255.25532,766
11556.57.0.0/1756.57.0.1 to 56.57.127.25456.57.127.25532,766
11656.57.128.0/1756.57.128.1 to 56.57.255.25456.57.255.25532,766
11756.58.0.0/1756.58.0.1 to 56.58.127.25456.58.127.25532,766
11856.58.128.0/1756.58.128.1 to 56.58.255.25456.58.255.25532,766
11956.59.0.0/1756.59.0.1 to 56.59.127.25456.59.127.25532,766
12056.59.128.0/1756.59.128.1 to 56.59.255.25456.59.255.25532,766
12156.60.0.0/1756.60.0.1 to 56.60.127.25456.60.127.25532,766
12256.60.128.0/1756.60.128.1 to 56.60.255.25456.60.255.25532,766
12356.61.0.0/1756.61.0.1 to 56.61.127.25456.61.127.25532,766
12456.61.128.0/1756.61.128.1 to 56.61.255.25456.61.255.25532,766
12556.62.0.0/1756.62.0.1 to 56.62.127.25456.62.127.25532,766
12656.62.128.0/1756.62.128.1 to 56.62.255.25456.62.255.25532,766
12756.63.0.0/1756.63.0.1 to 56.63.127.25456.63.127.25532,766
12856.63.128.0/1756.63.128.1 to 56.63.255.25456.63.255.25532,766
12956.64.0.0/1756.64.0.1 to 56.64.127.25456.64.127.25532,766
13056.64.128.0/1756.64.128.1 to 56.64.255.25456.64.255.25532,766
13156.65.0.0/1756.65.0.1 to 56.65.127.25456.65.127.25532,766
13256.65.128.0/1756.65.128.1 to 56.65.255.25456.65.255.25532,766
13356.66.0.0/1756.66.0.1 to 56.66.127.25456.66.127.25532,766
13456.66.128.0/1756.66.128.1 to 56.66.255.25456.66.255.25532,766
13556.67.0.0/1756.67.0.1 to 56.67.127.25456.67.127.25532,766
13656.67.128.0/1756.67.128.1 to 56.67.255.25456.67.255.25532,766
13756.68.0.0/1756.68.0.1 to 56.68.127.25456.68.127.25532,766
13856.68.128.0/1756.68.128.1 to 56.68.255.25456.68.255.25532,766
13956.69.0.0/1756.69.0.1 to 56.69.127.25456.69.127.25532,766
14056.69.128.0/1756.69.128.1 to 56.69.255.25456.69.255.25532,766
14156.70.0.0/1756.70.0.1 to 56.70.127.25456.70.127.25532,766
14256.70.128.0/1756.70.128.1 to 56.70.255.25456.70.255.25532,766
14356.71.0.0/1756.71.0.1 to 56.71.127.25456.71.127.25532,766
14456.71.128.0/1756.71.128.1 to 56.71.255.25456.71.255.25532,766
14556.72.0.0/1756.72.0.1 to 56.72.127.25456.72.127.25532,766
14656.72.128.0/1756.72.128.1 to 56.72.255.25456.72.255.25532,766
14756.73.0.0/1756.73.0.1 to 56.73.127.25456.73.127.25532,766
14856.73.128.0/1756.73.128.1 to 56.73.255.25456.73.255.25532,766
14956.74.0.0/1756.74.0.1 to 56.74.127.25456.74.127.25532,766
15056.74.128.0/1756.74.128.1 to 56.74.255.25456.74.255.25532,766
15156.75.0.0/1756.75.0.1 to 56.75.127.25456.75.127.25532,766
15256.75.128.0/1756.75.128.1 to 56.75.255.25456.75.255.25532,766
15356.76.0.0/1756.76.0.1 to 56.76.127.25456.76.127.25532,766
15456.76.128.0/1756.76.128.1 to 56.76.255.25456.76.255.25532,766
15556.77.0.0/1756.77.0.1 to 56.77.127.25456.77.127.25532,766
15656.77.128.0/1756.77.128.1 to 56.77.255.25456.77.255.25532,766
15756.78.0.0/1756.78.0.1 to 56.78.127.25456.78.127.25532,766
15856.78.128.0/1756.78.128.1 to 56.78.255.25456.78.255.25532,766
15956.79.0.0/1756.79.0.1 to 56.79.127.25456.79.127.25532,766
16056.79.128.0/1756.79.128.1 to 56.79.255.25456.79.255.25532,766
16156.80.0.0/1756.80.0.1 to 56.80.127.25456.80.127.25532,766
16256.80.128.0/1756.80.128.1 to 56.80.255.25456.80.255.25532,766
16356.81.0.0/1756.81.0.1 to 56.81.127.25456.81.127.25532,766
16456.81.128.0/1756.81.128.1 to 56.81.255.25456.81.255.25532,766
16556.82.0.0/1756.82.0.1 to 56.82.127.25456.82.127.25532,766
16656.82.128.0/1756.82.128.1 to 56.82.255.25456.82.255.25532,766
16756.83.0.0/1756.83.0.1 to 56.83.127.25456.83.127.25532,766
16856.83.128.0/1756.83.128.1 to 56.83.255.25456.83.255.25532,766
16956.84.0.0/1756.84.0.1 to 56.84.127.25456.84.127.25532,766
17056.84.128.0/1756.84.128.1 to 56.84.255.25456.84.255.25532,766
17156.85.0.0/1756.85.0.1 to 56.85.127.25456.85.127.25532,766
17256.85.128.0/1756.85.128.1 to 56.85.255.25456.85.255.25532,766
17356.86.0.0/1756.86.0.1 to 56.86.127.25456.86.127.25532,766
17456.86.128.0/1756.86.128.1 to 56.86.255.25456.86.255.25532,766
17556.87.0.0/1756.87.0.1 to 56.87.127.25456.87.127.25532,766
17656.87.128.0/1756.87.128.1 to 56.87.255.25456.87.255.25532,766
17756.88.0.0/1756.88.0.1 to 56.88.127.25456.88.127.25532,766
17856.88.128.0/1756.88.128.1 to 56.88.255.25456.88.255.25532,766
17956.89.0.0/1756.89.0.1 to 56.89.127.25456.89.127.25532,766
18056.89.128.0/1756.89.128.1 to 56.89.255.25456.89.255.25532,766
18156.90.0.0/1756.90.0.1 to 56.90.127.25456.90.127.25532,766
18256.90.128.0/1756.90.128.1 to 56.90.255.25456.90.255.25532,766
18356.91.0.0/1756.91.0.1 to 56.91.127.25456.91.127.25532,766
18456.91.128.0/1756.91.128.1 to 56.91.255.25456.91.255.25532,766
18556.92.0.0/1756.92.0.1 to 56.92.127.25456.92.127.25532,766
18656.92.128.0/1756.92.128.1 to 56.92.255.25456.92.255.25532,766
18756.93.0.0/1756.93.0.1 to 56.93.127.25456.93.127.25532,766
18856.93.128.0/1756.93.128.1 to 56.93.255.25456.93.255.25532,766
18956.94.0.0/1756.94.0.1 to 56.94.127.25456.94.127.25532,766
19056.94.128.0/1756.94.128.1 to 56.94.255.25456.94.255.25532,766
19156.95.0.0/1756.95.0.1 to 56.95.127.25456.95.127.25532,766
19256.95.128.0/1756.95.128.1 to 56.95.255.25456.95.255.25532,766
19356.96.0.0/1756.96.0.1 to 56.96.127.25456.96.127.25532,766
19456.96.128.0/1756.96.128.1 to 56.96.255.25456.96.255.25532,766
19556.97.0.0/1756.97.0.1 to 56.97.127.25456.97.127.25532,766
19656.97.128.0/1756.97.128.1 to 56.97.255.25456.97.255.25532,766
19756.98.0.0/1756.98.0.1 to 56.98.127.25456.98.127.25532,766
19856.98.128.0/1756.98.128.1 to 56.98.255.25456.98.255.25532,766
19956.99.0.0/1756.99.0.1 to 56.99.127.25456.99.127.25532,766
20056.99.128.0/1756.99.128.1 to 56.99.255.25456.99.255.25532,766
20156.100.0.0/1756.100.0.1 to 56.100.127.25456.100.127.25532,766
20256.100.128.0/1756.100.128.1 to 56.100.255.25456.100.255.25532,766
20356.101.0.0/1756.101.0.1 to 56.101.127.25456.101.127.25532,766
20456.101.128.0/1756.101.128.1 to 56.101.255.25456.101.255.25532,766
20556.102.0.0/1756.102.0.1 to 56.102.127.25456.102.127.25532,766
20656.102.128.0/1756.102.128.1 to 56.102.255.25456.102.255.25532,766
20756.103.0.0/1756.103.0.1 to 56.103.127.25456.103.127.25532,766
20856.103.128.0/1756.103.128.1 to 56.103.255.25456.103.255.25532,766
20956.104.0.0/1756.104.0.1 to 56.104.127.25456.104.127.25532,766
21056.104.128.0/1756.104.128.1 to 56.104.255.25456.104.255.25532,766
21156.105.0.0/1756.105.0.1 to 56.105.127.25456.105.127.25532,766
21256.105.128.0/1756.105.128.1 to 56.105.255.25456.105.255.25532,766
21356.106.0.0/1756.106.0.1 to 56.106.127.25456.106.127.25532,766
21456.106.128.0/1756.106.128.1 to 56.106.255.25456.106.255.25532,766
21556.107.0.0/1756.107.0.1 to 56.107.127.25456.107.127.25532,766
21656.107.128.0/1756.107.128.1 to 56.107.255.25456.107.255.25532,766
21756.108.0.0/1756.108.0.1 to 56.108.127.25456.108.127.25532,766
21856.108.128.0/1756.108.128.1 to 56.108.255.25456.108.255.25532,766
21956.109.0.0/1756.109.0.1 to 56.109.127.25456.109.127.25532,766
22056.109.128.0/1756.109.128.1 to 56.109.255.25456.109.255.25532,766
22156.110.0.0/1756.110.0.1 to 56.110.127.25456.110.127.25532,766
22256.110.128.0/1756.110.128.1 to 56.110.255.25456.110.255.25532,766
22356.111.0.0/1756.111.0.1 to 56.111.127.25456.111.127.25532,766
22456.111.128.0/1756.111.128.1 to 56.111.255.25456.111.255.25532,766
22556.112.0.0/1756.112.0.1 to 56.112.127.25456.112.127.25532,766
22656.112.128.0/1756.112.128.1 to 56.112.255.25456.112.255.25532,766
22756.113.0.0/1756.113.0.1 to 56.113.127.25456.113.127.25532,766
22856.113.128.0/1756.113.128.1 to 56.113.255.25456.113.255.25532,766
22956.114.0.0/1756.114.0.1 to 56.114.127.25456.114.127.25532,766
23056.114.128.0/1756.114.128.1 to 56.114.255.25456.114.255.25532,766
23156.115.0.0/1756.115.0.1 to 56.115.127.25456.115.127.25532,766
23256.115.128.0/1756.115.128.1 to 56.115.255.25456.115.255.25532,766
23356.116.0.0/1756.116.0.1 to 56.116.127.25456.116.127.25532,766
23456.116.128.0/1756.116.128.1 to 56.116.255.25456.116.255.25532,766
23556.117.0.0/1756.117.0.1 to 56.117.127.25456.117.127.25532,766
23656.117.128.0/1756.117.128.1 to 56.117.255.25456.117.255.25532,766
23756.118.0.0/1756.118.0.1 to 56.118.127.25456.118.127.25532,766
23856.118.128.0/1756.118.128.1 to 56.118.255.25456.118.255.25532,766
23956.119.0.0/1756.119.0.1 to 56.119.127.25456.119.127.25532,766
24056.119.128.0/1756.119.128.1 to 56.119.255.25456.119.255.25532,766
24156.120.0.0/1756.120.0.1 to 56.120.127.25456.120.127.25532,766
24256.120.128.0/1756.120.128.1 to 56.120.255.25456.120.255.25532,766
24356.121.0.0/1756.121.0.1 to 56.121.127.25456.121.127.25532,766
24456.121.128.0/1756.121.128.1 to 56.121.255.25456.121.255.25532,766
24556.122.0.0/1756.122.0.1 to 56.122.127.25456.122.127.25532,766
24656.122.128.0/1756.122.128.1 to 56.122.255.25456.122.255.25532,766
24756.123.0.0/1756.123.0.1 to 56.123.127.25456.123.127.25532,766
24856.123.128.0/1756.123.128.1 to 56.123.255.25456.123.255.25532,766
24956.124.0.0/1756.124.0.1 to 56.124.127.25456.124.127.25532,766
25056.124.128.0/1756.124.128.1 to 56.124.255.25456.124.255.25532,766
25156.125.0.0/1756.125.0.1 to 56.125.127.25456.125.127.25532,766
25256.125.128.0/1756.125.128.1 to 56.125.255.25456.125.255.25532,766
25356.126.0.0/1756.126.0.1 to 56.126.127.25456.126.127.25532,766
25456.126.128.0/1756.126.128.1 to 56.126.255.25456.126.255.25532,766
25556.127.0.0/1756.127.0.1 to 56.127.127.25456.127.127.25532,766
25656.127.128.0/1756.127.128.1 to 56.127.255.25456.127.255.25532,766

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.