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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.

Network13.40.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
13.40.0.0
Broadcast address
13.47.255.255
First usable
13.40.0.1
Last usable
13.47.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 0D280000 · Integer 220725248 to 221249535
Reverse DNS zones
40.13.in-addr.arpa
41.13.in-addr.arpa
42.13.in-addr.arpa
43.13.in-addr.arpa
44.13.in-addr.arpa
45.13.in-addr.arpa
46.13.in-addr.arpa
47.13.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001101.00101000.00000000.0000000013.40.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00001101.00101000.00000000.0000000013.40.0.0
Broadcast00001101.00101111.11111111.1111111113.47.255.255
Split into smaller subnets/25
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

13.40.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
113.40.0.0/2513.40.0.1 to 13.40.0.12613.40.0.127126
213.40.0.128/2513.40.0.129 to 13.40.0.25413.40.0.255126
313.40.1.0/2513.40.1.1 to 13.40.1.12613.40.1.127126
413.40.1.128/2513.40.1.129 to 13.40.1.25413.40.1.255126
513.40.2.0/2513.40.2.1 to 13.40.2.12613.40.2.127126
613.40.2.128/2513.40.2.129 to 13.40.2.25413.40.2.255126
713.40.3.0/2513.40.3.1 to 13.40.3.12613.40.3.127126
813.40.3.128/2513.40.3.129 to 13.40.3.25413.40.3.255126
913.40.4.0/2513.40.4.1 to 13.40.4.12613.40.4.127126
1013.40.4.128/2513.40.4.129 to 13.40.4.25413.40.4.255126
1113.40.5.0/2513.40.5.1 to 13.40.5.12613.40.5.127126
1213.40.5.128/2513.40.5.129 to 13.40.5.25413.40.5.255126
1313.40.6.0/2513.40.6.1 to 13.40.6.12613.40.6.127126
1413.40.6.128/2513.40.6.129 to 13.40.6.25413.40.6.255126
1513.40.7.0/2513.40.7.1 to 13.40.7.12613.40.7.127126
1613.40.7.128/2513.40.7.129 to 13.40.7.25413.40.7.255126
1713.40.8.0/2513.40.8.1 to 13.40.8.12613.40.8.127126
1813.40.8.128/2513.40.8.129 to 13.40.8.25413.40.8.255126
1913.40.9.0/2513.40.9.1 to 13.40.9.12613.40.9.127126
2013.40.9.128/2513.40.9.129 to 13.40.9.25413.40.9.255126
2113.40.10.0/2513.40.10.1 to 13.40.10.12613.40.10.127126
2213.40.10.128/2513.40.10.129 to 13.40.10.25413.40.10.255126
2313.40.11.0/2513.40.11.1 to 13.40.11.12613.40.11.127126
2413.40.11.128/2513.40.11.129 to 13.40.11.25413.40.11.255126
2513.40.12.0/2513.40.12.1 to 13.40.12.12613.40.12.127126
2613.40.12.128/2513.40.12.129 to 13.40.12.25413.40.12.255126
2713.40.13.0/2513.40.13.1 to 13.40.13.12613.40.13.127126
2813.40.13.128/2513.40.13.129 to 13.40.13.25413.40.13.255126
2913.40.14.0/2513.40.14.1 to 13.40.14.12613.40.14.127126
3013.40.14.128/2513.40.14.129 to 13.40.14.25413.40.14.255126
3113.40.15.0/2513.40.15.1 to 13.40.15.12613.40.15.127126
3213.40.15.128/2513.40.15.129 to 13.40.15.25413.40.15.255126
3313.40.16.0/2513.40.16.1 to 13.40.16.12613.40.16.127126
3413.40.16.128/2513.40.16.129 to 13.40.16.25413.40.16.255126
3513.40.17.0/2513.40.17.1 to 13.40.17.12613.40.17.127126
3613.40.17.128/2513.40.17.129 to 13.40.17.25413.40.17.255126
3713.40.18.0/2513.40.18.1 to 13.40.18.12613.40.18.127126
3813.40.18.128/2513.40.18.129 to 13.40.18.25413.40.18.255126
3913.40.19.0/2513.40.19.1 to 13.40.19.12613.40.19.127126
4013.40.19.128/2513.40.19.129 to 13.40.19.25413.40.19.255126
4113.40.20.0/2513.40.20.1 to 13.40.20.12613.40.20.127126
4213.40.20.128/2513.40.20.129 to 13.40.20.25413.40.20.255126
4313.40.21.0/2513.40.21.1 to 13.40.21.12613.40.21.127126
4413.40.21.128/2513.40.21.129 to 13.40.21.25413.40.21.255126
4513.40.22.0/2513.40.22.1 to 13.40.22.12613.40.22.127126
4613.40.22.128/2513.40.22.129 to 13.40.22.25413.40.22.255126
4713.40.23.0/2513.40.23.1 to 13.40.23.12613.40.23.127126
4813.40.23.128/2513.40.23.129 to 13.40.23.25413.40.23.255126
4913.40.24.0/2513.40.24.1 to 13.40.24.12613.40.24.127126
5013.40.24.128/2513.40.24.129 to 13.40.24.25413.40.24.255126
5113.40.25.0/2513.40.25.1 to 13.40.25.12613.40.25.127126
5213.40.25.128/2513.40.25.129 to 13.40.25.25413.40.25.255126
5313.40.26.0/2513.40.26.1 to 13.40.26.12613.40.26.127126
5413.40.26.128/2513.40.26.129 to 13.40.26.25413.40.26.255126
5513.40.27.0/2513.40.27.1 to 13.40.27.12613.40.27.127126
5613.40.27.128/2513.40.27.129 to 13.40.27.25413.40.27.255126
5713.40.28.0/2513.40.28.1 to 13.40.28.12613.40.28.127126
5813.40.28.128/2513.40.28.129 to 13.40.28.25413.40.28.255126
5913.40.29.0/2513.40.29.1 to 13.40.29.12613.40.29.127126
6013.40.29.128/2513.40.29.129 to 13.40.29.25413.40.29.255126
6113.40.30.0/2513.40.30.1 to 13.40.30.12613.40.30.127126
6213.40.30.128/2513.40.30.129 to 13.40.30.25413.40.30.255126
6313.40.31.0/2513.40.31.1 to 13.40.31.12613.40.31.127126
6413.40.31.128/2513.40.31.129 to 13.40.31.25413.40.31.255126
6513.40.32.0/2513.40.32.1 to 13.40.32.12613.40.32.127126
6613.40.32.128/2513.40.32.129 to 13.40.32.25413.40.32.255126
6713.40.33.0/2513.40.33.1 to 13.40.33.12613.40.33.127126
6813.40.33.128/2513.40.33.129 to 13.40.33.25413.40.33.255126
6913.40.34.0/2513.40.34.1 to 13.40.34.12613.40.34.127126
7013.40.34.128/2513.40.34.129 to 13.40.34.25413.40.34.255126
7113.40.35.0/2513.40.35.1 to 13.40.35.12613.40.35.127126
7213.40.35.128/2513.40.35.129 to 13.40.35.25413.40.35.255126
7313.40.36.0/2513.40.36.1 to 13.40.36.12613.40.36.127126
7413.40.36.128/2513.40.36.129 to 13.40.36.25413.40.36.255126
7513.40.37.0/2513.40.37.1 to 13.40.37.12613.40.37.127126
7613.40.37.128/2513.40.37.129 to 13.40.37.25413.40.37.255126
7713.40.38.0/2513.40.38.1 to 13.40.38.12613.40.38.127126
7813.40.38.128/2513.40.38.129 to 13.40.38.25413.40.38.255126
7913.40.39.0/2513.40.39.1 to 13.40.39.12613.40.39.127126
8013.40.39.128/2513.40.39.129 to 13.40.39.25413.40.39.255126
8113.40.40.0/2513.40.40.1 to 13.40.40.12613.40.40.127126
8213.40.40.128/2513.40.40.129 to 13.40.40.25413.40.40.255126
8313.40.41.0/2513.40.41.1 to 13.40.41.12613.40.41.127126
8413.40.41.128/2513.40.41.129 to 13.40.41.25413.40.41.255126
8513.40.42.0/2513.40.42.1 to 13.40.42.12613.40.42.127126
8613.40.42.128/2513.40.42.129 to 13.40.42.25413.40.42.255126
8713.40.43.0/2513.40.43.1 to 13.40.43.12613.40.43.127126
8813.40.43.128/2513.40.43.129 to 13.40.43.25413.40.43.255126
8913.40.44.0/2513.40.44.1 to 13.40.44.12613.40.44.127126
9013.40.44.128/2513.40.44.129 to 13.40.44.25413.40.44.255126
9113.40.45.0/2513.40.45.1 to 13.40.45.12613.40.45.127126
9213.40.45.128/2513.40.45.129 to 13.40.45.25413.40.45.255126
9313.40.46.0/2513.40.46.1 to 13.40.46.12613.40.46.127126
9413.40.46.128/2513.40.46.129 to 13.40.46.25413.40.46.255126
9513.40.47.0/2513.40.47.1 to 13.40.47.12613.40.47.127126
9613.40.47.128/2513.40.47.129 to 13.40.47.25413.40.47.255126
9713.40.48.0/2513.40.48.1 to 13.40.48.12613.40.48.127126
9813.40.48.128/2513.40.48.129 to 13.40.48.25413.40.48.255126
9913.40.49.0/2513.40.49.1 to 13.40.49.12613.40.49.127126
10013.40.49.128/2513.40.49.129 to 13.40.49.25413.40.49.255126
10113.40.50.0/2513.40.50.1 to 13.40.50.12613.40.50.127126
10213.40.50.128/2513.40.50.129 to 13.40.50.25413.40.50.255126
10313.40.51.0/2513.40.51.1 to 13.40.51.12613.40.51.127126
10413.40.51.128/2513.40.51.129 to 13.40.51.25413.40.51.255126
10513.40.52.0/2513.40.52.1 to 13.40.52.12613.40.52.127126
10613.40.52.128/2513.40.52.129 to 13.40.52.25413.40.52.255126
10713.40.53.0/2513.40.53.1 to 13.40.53.12613.40.53.127126
10813.40.53.128/2513.40.53.129 to 13.40.53.25413.40.53.255126
10913.40.54.0/2513.40.54.1 to 13.40.54.12613.40.54.127126
11013.40.54.128/2513.40.54.129 to 13.40.54.25413.40.54.255126
11113.40.55.0/2513.40.55.1 to 13.40.55.12613.40.55.127126
11213.40.55.128/2513.40.55.129 to 13.40.55.25413.40.55.255126
11313.40.56.0/2513.40.56.1 to 13.40.56.12613.40.56.127126
11413.40.56.128/2513.40.56.129 to 13.40.56.25413.40.56.255126
11513.40.57.0/2513.40.57.1 to 13.40.57.12613.40.57.127126
11613.40.57.128/2513.40.57.129 to 13.40.57.25413.40.57.255126
11713.40.58.0/2513.40.58.1 to 13.40.58.12613.40.58.127126
11813.40.58.128/2513.40.58.129 to 13.40.58.25413.40.58.255126
11913.40.59.0/2513.40.59.1 to 13.40.59.12613.40.59.127126
12013.40.59.128/2513.40.59.129 to 13.40.59.25413.40.59.255126
12113.40.60.0/2513.40.60.1 to 13.40.60.12613.40.60.127126
12213.40.60.128/2513.40.60.129 to 13.40.60.25413.40.60.255126
12313.40.61.0/2513.40.61.1 to 13.40.61.12613.40.61.127126
12413.40.61.128/2513.40.61.129 to 13.40.61.25413.40.61.255126
12513.40.62.0/2513.40.62.1 to 13.40.62.12613.40.62.127126
12613.40.62.128/2513.40.62.129 to 13.40.62.25413.40.62.255126
12713.40.63.0/2513.40.63.1 to 13.40.63.12613.40.63.127126
12813.40.63.128/2513.40.63.129 to 13.40.63.25413.40.63.255126
12913.40.64.0/2513.40.64.1 to 13.40.64.12613.40.64.127126
13013.40.64.128/2513.40.64.129 to 13.40.64.25413.40.64.255126
13113.40.65.0/2513.40.65.1 to 13.40.65.12613.40.65.127126
13213.40.65.128/2513.40.65.129 to 13.40.65.25413.40.65.255126
13313.40.66.0/2513.40.66.1 to 13.40.66.12613.40.66.127126
13413.40.66.128/2513.40.66.129 to 13.40.66.25413.40.66.255126
13513.40.67.0/2513.40.67.1 to 13.40.67.12613.40.67.127126
13613.40.67.128/2513.40.67.129 to 13.40.67.25413.40.67.255126
13713.40.68.0/2513.40.68.1 to 13.40.68.12613.40.68.127126
13813.40.68.128/2513.40.68.129 to 13.40.68.25413.40.68.255126
13913.40.69.0/2513.40.69.1 to 13.40.69.12613.40.69.127126
14013.40.69.128/2513.40.69.129 to 13.40.69.25413.40.69.255126
14113.40.70.0/2513.40.70.1 to 13.40.70.12613.40.70.127126
14213.40.70.128/2513.40.70.129 to 13.40.70.25413.40.70.255126
14313.40.71.0/2513.40.71.1 to 13.40.71.12613.40.71.127126
14413.40.71.128/2513.40.71.129 to 13.40.71.25413.40.71.255126
14513.40.72.0/2513.40.72.1 to 13.40.72.12613.40.72.127126
14613.40.72.128/2513.40.72.129 to 13.40.72.25413.40.72.255126
14713.40.73.0/2513.40.73.1 to 13.40.73.12613.40.73.127126
14813.40.73.128/2513.40.73.129 to 13.40.73.25413.40.73.255126
14913.40.74.0/2513.40.74.1 to 13.40.74.12613.40.74.127126
15013.40.74.128/2513.40.74.129 to 13.40.74.25413.40.74.255126
15113.40.75.0/2513.40.75.1 to 13.40.75.12613.40.75.127126
15213.40.75.128/2513.40.75.129 to 13.40.75.25413.40.75.255126
15313.40.76.0/2513.40.76.1 to 13.40.76.12613.40.76.127126
15413.40.76.128/2513.40.76.129 to 13.40.76.25413.40.76.255126
15513.40.77.0/2513.40.77.1 to 13.40.77.12613.40.77.127126
15613.40.77.128/2513.40.77.129 to 13.40.77.25413.40.77.255126
15713.40.78.0/2513.40.78.1 to 13.40.78.12613.40.78.127126
15813.40.78.128/2513.40.78.129 to 13.40.78.25413.40.78.255126
15913.40.79.0/2513.40.79.1 to 13.40.79.12613.40.79.127126
16013.40.79.128/2513.40.79.129 to 13.40.79.25413.40.79.255126
16113.40.80.0/2513.40.80.1 to 13.40.80.12613.40.80.127126
16213.40.80.128/2513.40.80.129 to 13.40.80.25413.40.80.255126
16313.40.81.0/2513.40.81.1 to 13.40.81.12613.40.81.127126
16413.40.81.128/2513.40.81.129 to 13.40.81.25413.40.81.255126
16513.40.82.0/2513.40.82.1 to 13.40.82.12613.40.82.127126
16613.40.82.128/2513.40.82.129 to 13.40.82.25413.40.82.255126
16713.40.83.0/2513.40.83.1 to 13.40.83.12613.40.83.127126
16813.40.83.128/2513.40.83.129 to 13.40.83.25413.40.83.255126
16913.40.84.0/2513.40.84.1 to 13.40.84.12613.40.84.127126
17013.40.84.128/2513.40.84.129 to 13.40.84.25413.40.84.255126
17113.40.85.0/2513.40.85.1 to 13.40.85.12613.40.85.127126
17213.40.85.128/2513.40.85.129 to 13.40.85.25413.40.85.255126
17313.40.86.0/2513.40.86.1 to 13.40.86.12613.40.86.127126
17413.40.86.128/2513.40.86.129 to 13.40.86.25413.40.86.255126
17513.40.87.0/2513.40.87.1 to 13.40.87.12613.40.87.127126
17613.40.87.128/2513.40.87.129 to 13.40.87.25413.40.87.255126
17713.40.88.0/2513.40.88.1 to 13.40.88.12613.40.88.127126
17813.40.88.128/2513.40.88.129 to 13.40.88.25413.40.88.255126
17913.40.89.0/2513.40.89.1 to 13.40.89.12613.40.89.127126
18013.40.89.128/2513.40.89.129 to 13.40.89.25413.40.89.255126
18113.40.90.0/2513.40.90.1 to 13.40.90.12613.40.90.127126
18213.40.90.128/2513.40.90.129 to 13.40.90.25413.40.90.255126
18313.40.91.0/2513.40.91.1 to 13.40.91.12613.40.91.127126
18413.40.91.128/2513.40.91.129 to 13.40.91.25413.40.91.255126
18513.40.92.0/2513.40.92.1 to 13.40.92.12613.40.92.127126
18613.40.92.128/2513.40.92.129 to 13.40.92.25413.40.92.255126
18713.40.93.0/2513.40.93.1 to 13.40.93.12613.40.93.127126
18813.40.93.128/2513.40.93.129 to 13.40.93.25413.40.93.255126
18913.40.94.0/2513.40.94.1 to 13.40.94.12613.40.94.127126
19013.40.94.128/2513.40.94.129 to 13.40.94.25413.40.94.255126
19113.40.95.0/2513.40.95.1 to 13.40.95.12613.40.95.127126
19213.40.95.128/2513.40.95.129 to 13.40.95.25413.40.95.255126
19313.40.96.0/2513.40.96.1 to 13.40.96.12613.40.96.127126
19413.40.96.128/2513.40.96.129 to 13.40.96.25413.40.96.255126
19513.40.97.0/2513.40.97.1 to 13.40.97.12613.40.97.127126
19613.40.97.128/2513.40.97.129 to 13.40.97.25413.40.97.255126
19713.40.98.0/2513.40.98.1 to 13.40.98.12613.40.98.127126
19813.40.98.128/2513.40.98.129 to 13.40.98.25413.40.98.255126
19913.40.99.0/2513.40.99.1 to 13.40.99.12613.40.99.127126
20013.40.99.128/2513.40.99.129 to 13.40.99.25413.40.99.255126
20113.40.100.0/2513.40.100.1 to 13.40.100.12613.40.100.127126
20213.40.100.128/2513.40.100.129 to 13.40.100.25413.40.100.255126
20313.40.101.0/2513.40.101.1 to 13.40.101.12613.40.101.127126
20413.40.101.128/2513.40.101.129 to 13.40.101.25413.40.101.255126
20513.40.102.0/2513.40.102.1 to 13.40.102.12613.40.102.127126
20613.40.102.128/2513.40.102.129 to 13.40.102.25413.40.102.255126
20713.40.103.0/2513.40.103.1 to 13.40.103.12613.40.103.127126
20813.40.103.128/2513.40.103.129 to 13.40.103.25413.40.103.255126
20913.40.104.0/2513.40.104.1 to 13.40.104.12613.40.104.127126
21013.40.104.128/2513.40.104.129 to 13.40.104.25413.40.104.255126
21113.40.105.0/2513.40.105.1 to 13.40.105.12613.40.105.127126
21213.40.105.128/2513.40.105.129 to 13.40.105.25413.40.105.255126
21313.40.106.0/2513.40.106.1 to 13.40.106.12613.40.106.127126
21413.40.106.128/2513.40.106.129 to 13.40.106.25413.40.106.255126
21513.40.107.0/2513.40.107.1 to 13.40.107.12613.40.107.127126
21613.40.107.128/2513.40.107.129 to 13.40.107.25413.40.107.255126
21713.40.108.0/2513.40.108.1 to 13.40.108.12613.40.108.127126
21813.40.108.128/2513.40.108.129 to 13.40.108.25413.40.108.255126
21913.40.109.0/2513.40.109.1 to 13.40.109.12613.40.109.127126
22013.40.109.128/2513.40.109.129 to 13.40.109.25413.40.109.255126
22113.40.110.0/2513.40.110.1 to 13.40.110.12613.40.110.127126
22213.40.110.128/2513.40.110.129 to 13.40.110.25413.40.110.255126
22313.40.111.0/2513.40.111.1 to 13.40.111.12613.40.111.127126
22413.40.111.128/2513.40.111.129 to 13.40.111.25413.40.111.255126
22513.40.112.0/2513.40.112.1 to 13.40.112.12613.40.112.127126
22613.40.112.128/2513.40.112.129 to 13.40.112.25413.40.112.255126
22713.40.113.0/2513.40.113.1 to 13.40.113.12613.40.113.127126
22813.40.113.128/2513.40.113.129 to 13.40.113.25413.40.113.255126
22913.40.114.0/2513.40.114.1 to 13.40.114.12613.40.114.127126
23013.40.114.128/2513.40.114.129 to 13.40.114.25413.40.114.255126
23113.40.115.0/2513.40.115.1 to 13.40.115.12613.40.115.127126
23213.40.115.128/2513.40.115.129 to 13.40.115.25413.40.115.255126
23313.40.116.0/2513.40.116.1 to 13.40.116.12613.40.116.127126
23413.40.116.128/2513.40.116.129 to 13.40.116.25413.40.116.255126
23513.40.117.0/2513.40.117.1 to 13.40.117.12613.40.117.127126
23613.40.117.128/2513.40.117.129 to 13.40.117.25413.40.117.255126
23713.40.118.0/2513.40.118.1 to 13.40.118.12613.40.118.127126
23813.40.118.128/2513.40.118.129 to 13.40.118.25413.40.118.255126
23913.40.119.0/2513.40.119.1 to 13.40.119.12613.40.119.127126
24013.40.119.128/2513.40.119.129 to 13.40.119.25413.40.119.255126
24113.40.120.0/2513.40.120.1 to 13.40.120.12613.40.120.127126
24213.40.120.128/2513.40.120.129 to 13.40.120.25413.40.120.255126
24313.40.121.0/2513.40.121.1 to 13.40.121.12613.40.121.127126
24413.40.121.128/2513.40.121.129 to 13.40.121.25413.40.121.255126
24513.40.122.0/2513.40.122.1 to 13.40.122.12613.40.122.127126
24613.40.122.128/2513.40.122.129 to 13.40.122.25413.40.122.255126
24713.40.123.0/2513.40.123.1 to 13.40.123.12613.40.123.127126
24813.40.123.128/2513.40.123.129 to 13.40.123.25413.40.123.255126
24913.40.124.0/2513.40.124.1 to 13.40.124.12613.40.124.127126
25013.40.124.128/2513.40.124.129 to 13.40.124.25413.40.124.255126
25113.40.125.0/2513.40.125.1 to 13.40.125.12613.40.125.127126
25213.40.125.128/2513.40.125.129 to 13.40.125.25413.40.125.255126
25313.40.126.0/2513.40.126.1 to 13.40.126.12613.40.126.127126
25413.40.126.128/2513.40.126.129 to 13.40.126.25413.40.126.255126
25513.40.127.0/2513.40.127.1 to 13.40.127.12613.40.127.127126
25613.40.127.128/2513.40.127.129 to 13.40.127.25413.40.127.255126

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.