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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.

Network122.244.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
122.244.0.0
Broadcast address
122.245.255.255
First usable
122.244.0.1
Last usable
122.245.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 7AF40000 · Integer 2062811136 to 2062942207
Reverse DNS zones
244.122.in-addr.arpa
245.122.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111010.11110100.00000000.00000000122.244.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01111010.11110100.00000000.00000000122.244.0.0
Broadcast01111010.11110101.11111111.11111111122.245.255.255
Split into smaller subnets/24
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

122.244.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1122.244.0.0/24122.244.0.1 to 122.244.0.254122.244.0.255254
2122.244.1.0/24122.244.1.1 to 122.244.1.254122.244.1.255254
3122.244.2.0/24122.244.2.1 to 122.244.2.254122.244.2.255254
4122.244.3.0/24122.244.3.1 to 122.244.3.254122.244.3.255254
5122.244.4.0/24122.244.4.1 to 122.244.4.254122.244.4.255254
6122.244.5.0/24122.244.5.1 to 122.244.5.254122.244.5.255254
7122.244.6.0/24122.244.6.1 to 122.244.6.254122.244.6.255254
8122.244.7.0/24122.244.7.1 to 122.244.7.254122.244.7.255254
9122.244.8.0/24122.244.8.1 to 122.244.8.254122.244.8.255254
10122.244.9.0/24122.244.9.1 to 122.244.9.254122.244.9.255254
11122.244.10.0/24122.244.10.1 to 122.244.10.254122.244.10.255254
12122.244.11.0/24122.244.11.1 to 122.244.11.254122.244.11.255254
13122.244.12.0/24122.244.12.1 to 122.244.12.254122.244.12.255254
14122.244.13.0/24122.244.13.1 to 122.244.13.254122.244.13.255254
15122.244.14.0/24122.244.14.1 to 122.244.14.254122.244.14.255254
16122.244.15.0/24122.244.15.1 to 122.244.15.254122.244.15.255254
17122.244.16.0/24122.244.16.1 to 122.244.16.254122.244.16.255254
18122.244.17.0/24122.244.17.1 to 122.244.17.254122.244.17.255254
19122.244.18.0/24122.244.18.1 to 122.244.18.254122.244.18.255254
20122.244.19.0/24122.244.19.1 to 122.244.19.254122.244.19.255254
21122.244.20.0/24122.244.20.1 to 122.244.20.254122.244.20.255254
22122.244.21.0/24122.244.21.1 to 122.244.21.254122.244.21.255254
23122.244.22.0/24122.244.22.1 to 122.244.22.254122.244.22.255254
24122.244.23.0/24122.244.23.1 to 122.244.23.254122.244.23.255254
25122.244.24.0/24122.244.24.1 to 122.244.24.254122.244.24.255254
26122.244.25.0/24122.244.25.1 to 122.244.25.254122.244.25.255254
27122.244.26.0/24122.244.26.1 to 122.244.26.254122.244.26.255254
28122.244.27.0/24122.244.27.1 to 122.244.27.254122.244.27.255254
29122.244.28.0/24122.244.28.1 to 122.244.28.254122.244.28.255254
30122.244.29.0/24122.244.29.1 to 122.244.29.254122.244.29.255254
31122.244.30.0/24122.244.30.1 to 122.244.30.254122.244.30.255254
32122.244.31.0/24122.244.31.1 to 122.244.31.254122.244.31.255254
33122.244.32.0/24122.244.32.1 to 122.244.32.254122.244.32.255254
34122.244.33.0/24122.244.33.1 to 122.244.33.254122.244.33.255254
35122.244.34.0/24122.244.34.1 to 122.244.34.254122.244.34.255254
36122.244.35.0/24122.244.35.1 to 122.244.35.254122.244.35.255254
37122.244.36.0/24122.244.36.1 to 122.244.36.254122.244.36.255254
38122.244.37.0/24122.244.37.1 to 122.244.37.254122.244.37.255254
39122.244.38.0/24122.244.38.1 to 122.244.38.254122.244.38.255254
40122.244.39.0/24122.244.39.1 to 122.244.39.254122.244.39.255254
41122.244.40.0/24122.244.40.1 to 122.244.40.254122.244.40.255254
42122.244.41.0/24122.244.41.1 to 122.244.41.254122.244.41.255254
43122.244.42.0/24122.244.42.1 to 122.244.42.254122.244.42.255254
44122.244.43.0/24122.244.43.1 to 122.244.43.254122.244.43.255254
45122.244.44.0/24122.244.44.1 to 122.244.44.254122.244.44.255254
46122.244.45.0/24122.244.45.1 to 122.244.45.254122.244.45.255254
47122.244.46.0/24122.244.46.1 to 122.244.46.254122.244.46.255254
48122.244.47.0/24122.244.47.1 to 122.244.47.254122.244.47.255254
49122.244.48.0/24122.244.48.1 to 122.244.48.254122.244.48.255254
50122.244.49.0/24122.244.49.1 to 122.244.49.254122.244.49.255254
51122.244.50.0/24122.244.50.1 to 122.244.50.254122.244.50.255254
52122.244.51.0/24122.244.51.1 to 122.244.51.254122.244.51.255254
53122.244.52.0/24122.244.52.1 to 122.244.52.254122.244.52.255254
54122.244.53.0/24122.244.53.1 to 122.244.53.254122.244.53.255254
55122.244.54.0/24122.244.54.1 to 122.244.54.254122.244.54.255254
56122.244.55.0/24122.244.55.1 to 122.244.55.254122.244.55.255254
57122.244.56.0/24122.244.56.1 to 122.244.56.254122.244.56.255254
58122.244.57.0/24122.244.57.1 to 122.244.57.254122.244.57.255254
59122.244.58.0/24122.244.58.1 to 122.244.58.254122.244.58.255254
60122.244.59.0/24122.244.59.1 to 122.244.59.254122.244.59.255254
61122.244.60.0/24122.244.60.1 to 122.244.60.254122.244.60.255254
62122.244.61.0/24122.244.61.1 to 122.244.61.254122.244.61.255254
63122.244.62.0/24122.244.62.1 to 122.244.62.254122.244.62.255254
64122.244.63.0/24122.244.63.1 to 122.244.63.254122.244.63.255254
65122.244.64.0/24122.244.64.1 to 122.244.64.254122.244.64.255254
66122.244.65.0/24122.244.65.1 to 122.244.65.254122.244.65.255254
67122.244.66.0/24122.244.66.1 to 122.244.66.254122.244.66.255254
68122.244.67.0/24122.244.67.1 to 122.244.67.254122.244.67.255254
69122.244.68.0/24122.244.68.1 to 122.244.68.254122.244.68.255254
70122.244.69.0/24122.244.69.1 to 122.244.69.254122.244.69.255254
71122.244.70.0/24122.244.70.1 to 122.244.70.254122.244.70.255254
72122.244.71.0/24122.244.71.1 to 122.244.71.254122.244.71.255254
73122.244.72.0/24122.244.72.1 to 122.244.72.254122.244.72.255254
74122.244.73.0/24122.244.73.1 to 122.244.73.254122.244.73.255254
75122.244.74.0/24122.244.74.1 to 122.244.74.254122.244.74.255254
76122.244.75.0/24122.244.75.1 to 122.244.75.254122.244.75.255254
77122.244.76.0/24122.244.76.1 to 122.244.76.254122.244.76.255254
78122.244.77.0/24122.244.77.1 to 122.244.77.254122.244.77.255254
79122.244.78.0/24122.244.78.1 to 122.244.78.254122.244.78.255254
80122.244.79.0/24122.244.79.1 to 122.244.79.254122.244.79.255254
81122.244.80.0/24122.244.80.1 to 122.244.80.254122.244.80.255254
82122.244.81.0/24122.244.81.1 to 122.244.81.254122.244.81.255254
83122.244.82.0/24122.244.82.1 to 122.244.82.254122.244.82.255254
84122.244.83.0/24122.244.83.1 to 122.244.83.254122.244.83.255254
85122.244.84.0/24122.244.84.1 to 122.244.84.254122.244.84.255254
86122.244.85.0/24122.244.85.1 to 122.244.85.254122.244.85.255254
87122.244.86.0/24122.244.86.1 to 122.244.86.254122.244.86.255254
88122.244.87.0/24122.244.87.1 to 122.244.87.254122.244.87.255254
89122.244.88.0/24122.244.88.1 to 122.244.88.254122.244.88.255254
90122.244.89.0/24122.244.89.1 to 122.244.89.254122.244.89.255254
91122.244.90.0/24122.244.90.1 to 122.244.90.254122.244.90.255254
92122.244.91.0/24122.244.91.1 to 122.244.91.254122.244.91.255254
93122.244.92.0/24122.244.92.1 to 122.244.92.254122.244.92.255254
94122.244.93.0/24122.244.93.1 to 122.244.93.254122.244.93.255254
95122.244.94.0/24122.244.94.1 to 122.244.94.254122.244.94.255254
96122.244.95.0/24122.244.95.1 to 122.244.95.254122.244.95.255254
97122.244.96.0/24122.244.96.1 to 122.244.96.254122.244.96.255254
98122.244.97.0/24122.244.97.1 to 122.244.97.254122.244.97.255254
99122.244.98.0/24122.244.98.1 to 122.244.98.254122.244.98.255254
100122.244.99.0/24122.244.99.1 to 122.244.99.254122.244.99.255254
101122.244.100.0/24122.244.100.1 to 122.244.100.254122.244.100.255254
102122.244.101.0/24122.244.101.1 to 122.244.101.254122.244.101.255254
103122.244.102.0/24122.244.102.1 to 122.244.102.254122.244.102.255254
104122.244.103.0/24122.244.103.1 to 122.244.103.254122.244.103.255254
105122.244.104.0/24122.244.104.1 to 122.244.104.254122.244.104.255254
106122.244.105.0/24122.244.105.1 to 122.244.105.254122.244.105.255254
107122.244.106.0/24122.244.106.1 to 122.244.106.254122.244.106.255254
108122.244.107.0/24122.244.107.1 to 122.244.107.254122.244.107.255254
109122.244.108.0/24122.244.108.1 to 122.244.108.254122.244.108.255254
110122.244.109.0/24122.244.109.1 to 122.244.109.254122.244.109.255254
111122.244.110.0/24122.244.110.1 to 122.244.110.254122.244.110.255254
112122.244.111.0/24122.244.111.1 to 122.244.111.254122.244.111.255254
113122.244.112.0/24122.244.112.1 to 122.244.112.254122.244.112.255254
114122.244.113.0/24122.244.113.1 to 122.244.113.254122.244.113.255254
115122.244.114.0/24122.244.114.1 to 122.244.114.254122.244.114.255254
116122.244.115.0/24122.244.115.1 to 122.244.115.254122.244.115.255254
117122.244.116.0/24122.244.116.1 to 122.244.116.254122.244.116.255254
118122.244.117.0/24122.244.117.1 to 122.244.117.254122.244.117.255254
119122.244.118.0/24122.244.118.1 to 122.244.118.254122.244.118.255254
120122.244.119.0/24122.244.119.1 to 122.244.119.254122.244.119.255254
121122.244.120.0/24122.244.120.1 to 122.244.120.254122.244.120.255254
122122.244.121.0/24122.244.121.1 to 122.244.121.254122.244.121.255254
123122.244.122.0/24122.244.122.1 to 122.244.122.254122.244.122.255254
124122.244.123.0/24122.244.123.1 to 122.244.123.254122.244.123.255254
125122.244.124.0/24122.244.124.1 to 122.244.124.254122.244.124.255254
126122.244.125.0/24122.244.125.1 to 122.244.125.254122.244.125.255254
127122.244.126.0/24122.244.126.1 to 122.244.126.254122.244.126.255254
128122.244.127.0/24122.244.127.1 to 122.244.127.254122.244.127.255254
129122.244.128.0/24122.244.128.1 to 122.244.128.254122.244.128.255254
130122.244.129.0/24122.244.129.1 to 122.244.129.254122.244.129.255254
131122.244.130.0/24122.244.130.1 to 122.244.130.254122.244.130.255254
132122.244.131.0/24122.244.131.1 to 122.244.131.254122.244.131.255254
133122.244.132.0/24122.244.132.1 to 122.244.132.254122.244.132.255254
134122.244.133.0/24122.244.133.1 to 122.244.133.254122.244.133.255254
135122.244.134.0/24122.244.134.1 to 122.244.134.254122.244.134.255254
136122.244.135.0/24122.244.135.1 to 122.244.135.254122.244.135.255254
137122.244.136.0/24122.244.136.1 to 122.244.136.254122.244.136.255254
138122.244.137.0/24122.244.137.1 to 122.244.137.254122.244.137.255254
139122.244.138.0/24122.244.138.1 to 122.244.138.254122.244.138.255254
140122.244.139.0/24122.244.139.1 to 122.244.139.254122.244.139.255254
141122.244.140.0/24122.244.140.1 to 122.244.140.254122.244.140.255254
142122.244.141.0/24122.244.141.1 to 122.244.141.254122.244.141.255254
143122.244.142.0/24122.244.142.1 to 122.244.142.254122.244.142.255254
144122.244.143.0/24122.244.143.1 to 122.244.143.254122.244.143.255254
145122.244.144.0/24122.244.144.1 to 122.244.144.254122.244.144.255254
146122.244.145.0/24122.244.145.1 to 122.244.145.254122.244.145.255254
147122.244.146.0/24122.244.146.1 to 122.244.146.254122.244.146.255254
148122.244.147.0/24122.244.147.1 to 122.244.147.254122.244.147.255254
149122.244.148.0/24122.244.148.1 to 122.244.148.254122.244.148.255254
150122.244.149.0/24122.244.149.1 to 122.244.149.254122.244.149.255254
151122.244.150.0/24122.244.150.1 to 122.244.150.254122.244.150.255254
152122.244.151.0/24122.244.151.1 to 122.244.151.254122.244.151.255254
153122.244.152.0/24122.244.152.1 to 122.244.152.254122.244.152.255254
154122.244.153.0/24122.244.153.1 to 122.244.153.254122.244.153.255254
155122.244.154.0/24122.244.154.1 to 122.244.154.254122.244.154.255254
156122.244.155.0/24122.244.155.1 to 122.244.155.254122.244.155.255254
157122.244.156.0/24122.244.156.1 to 122.244.156.254122.244.156.255254
158122.244.157.0/24122.244.157.1 to 122.244.157.254122.244.157.255254
159122.244.158.0/24122.244.158.1 to 122.244.158.254122.244.158.255254
160122.244.159.0/24122.244.159.1 to 122.244.159.254122.244.159.255254
161122.244.160.0/24122.244.160.1 to 122.244.160.254122.244.160.255254
162122.244.161.0/24122.244.161.1 to 122.244.161.254122.244.161.255254
163122.244.162.0/24122.244.162.1 to 122.244.162.254122.244.162.255254
164122.244.163.0/24122.244.163.1 to 122.244.163.254122.244.163.255254
165122.244.164.0/24122.244.164.1 to 122.244.164.254122.244.164.255254
166122.244.165.0/24122.244.165.1 to 122.244.165.254122.244.165.255254
167122.244.166.0/24122.244.166.1 to 122.244.166.254122.244.166.255254
168122.244.167.0/24122.244.167.1 to 122.244.167.254122.244.167.255254
169122.244.168.0/24122.244.168.1 to 122.244.168.254122.244.168.255254
170122.244.169.0/24122.244.169.1 to 122.244.169.254122.244.169.255254
171122.244.170.0/24122.244.170.1 to 122.244.170.254122.244.170.255254
172122.244.171.0/24122.244.171.1 to 122.244.171.254122.244.171.255254
173122.244.172.0/24122.244.172.1 to 122.244.172.254122.244.172.255254
174122.244.173.0/24122.244.173.1 to 122.244.173.254122.244.173.255254
175122.244.174.0/24122.244.174.1 to 122.244.174.254122.244.174.255254
176122.244.175.0/24122.244.175.1 to 122.244.175.254122.244.175.255254
177122.244.176.0/24122.244.176.1 to 122.244.176.254122.244.176.255254
178122.244.177.0/24122.244.177.1 to 122.244.177.254122.244.177.255254
179122.244.178.0/24122.244.178.1 to 122.244.178.254122.244.178.255254
180122.244.179.0/24122.244.179.1 to 122.244.179.254122.244.179.255254
181122.244.180.0/24122.244.180.1 to 122.244.180.254122.244.180.255254
182122.244.181.0/24122.244.181.1 to 122.244.181.254122.244.181.255254
183122.244.182.0/24122.244.182.1 to 122.244.182.254122.244.182.255254
184122.244.183.0/24122.244.183.1 to 122.244.183.254122.244.183.255254
185122.244.184.0/24122.244.184.1 to 122.244.184.254122.244.184.255254
186122.244.185.0/24122.244.185.1 to 122.244.185.254122.244.185.255254
187122.244.186.0/24122.244.186.1 to 122.244.186.254122.244.186.255254
188122.244.187.0/24122.244.187.1 to 122.244.187.254122.244.187.255254
189122.244.188.0/24122.244.188.1 to 122.244.188.254122.244.188.255254
190122.244.189.0/24122.244.189.1 to 122.244.189.254122.244.189.255254
191122.244.190.0/24122.244.190.1 to 122.244.190.254122.244.190.255254
192122.244.191.0/24122.244.191.1 to 122.244.191.254122.244.191.255254
193122.244.192.0/24122.244.192.1 to 122.244.192.254122.244.192.255254
194122.244.193.0/24122.244.193.1 to 122.244.193.254122.244.193.255254
195122.244.194.0/24122.244.194.1 to 122.244.194.254122.244.194.255254
196122.244.195.0/24122.244.195.1 to 122.244.195.254122.244.195.255254
197122.244.196.0/24122.244.196.1 to 122.244.196.254122.244.196.255254
198122.244.197.0/24122.244.197.1 to 122.244.197.254122.244.197.255254
199122.244.198.0/24122.244.198.1 to 122.244.198.254122.244.198.255254
200122.244.199.0/24122.244.199.1 to 122.244.199.254122.244.199.255254
201122.244.200.0/24122.244.200.1 to 122.244.200.254122.244.200.255254
202122.244.201.0/24122.244.201.1 to 122.244.201.254122.244.201.255254
203122.244.202.0/24122.244.202.1 to 122.244.202.254122.244.202.255254
204122.244.203.0/24122.244.203.1 to 122.244.203.254122.244.203.255254
205122.244.204.0/24122.244.204.1 to 122.244.204.254122.244.204.255254
206122.244.205.0/24122.244.205.1 to 122.244.205.254122.244.205.255254
207122.244.206.0/24122.244.206.1 to 122.244.206.254122.244.206.255254
208122.244.207.0/24122.244.207.1 to 122.244.207.254122.244.207.255254
209122.244.208.0/24122.244.208.1 to 122.244.208.254122.244.208.255254
210122.244.209.0/24122.244.209.1 to 122.244.209.254122.244.209.255254
211122.244.210.0/24122.244.210.1 to 122.244.210.254122.244.210.255254
212122.244.211.0/24122.244.211.1 to 122.244.211.254122.244.211.255254
213122.244.212.0/24122.244.212.1 to 122.244.212.254122.244.212.255254
214122.244.213.0/24122.244.213.1 to 122.244.213.254122.244.213.255254
215122.244.214.0/24122.244.214.1 to 122.244.214.254122.244.214.255254
216122.244.215.0/24122.244.215.1 to 122.244.215.254122.244.215.255254
217122.244.216.0/24122.244.216.1 to 122.244.216.254122.244.216.255254
218122.244.217.0/24122.244.217.1 to 122.244.217.254122.244.217.255254
219122.244.218.0/24122.244.218.1 to 122.244.218.254122.244.218.255254
220122.244.219.0/24122.244.219.1 to 122.244.219.254122.244.219.255254
221122.244.220.0/24122.244.220.1 to 122.244.220.254122.244.220.255254
222122.244.221.0/24122.244.221.1 to 122.244.221.254122.244.221.255254
223122.244.222.0/24122.244.222.1 to 122.244.222.254122.244.222.255254
224122.244.223.0/24122.244.223.1 to 122.244.223.254122.244.223.255254
225122.244.224.0/24122.244.224.1 to 122.244.224.254122.244.224.255254
226122.244.225.0/24122.244.225.1 to 122.244.225.254122.244.225.255254
227122.244.226.0/24122.244.226.1 to 122.244.226.254122.244.226.255254
228122.244.227.0/24122.244.227.1 to 122.244.227.254122.244.227.255254
229122.244.228.0/24122.244.228.1 to 122.244.228.254122.244.228.255254
230122.244.229.0/24122.244.229.1 to 122.244.229.254122.244.229.255254
231122.244.230.0/24122.244.230.1 to 122.244.230.254122.244.230.255254
232122.244.231.0/24122.244.231.1 to 122.244.231.254122.244.231.255254
233122.244.232.0/24122.244.232.1 to 122.244.232.254122.244.232.255254
234122.244.233.0/24122.244.233.1 to 122.244.233.254122.244.233.255254
235122.244.234.0/24122.244.234.1 to 122.244.234.254122.244.234.255254
236122.244.235.0/24122.244.235.1 to 122.244.235.254122.244.235.255254
237122.244.236.0/24122.244.236.1 to 122.244.236.254122.244.236.255254
238122.244.237.0/24122.244.237.1 to 122.244.237.254122.244.237.255254
239122.244.238.0/24122.244.238.1 to 122.244.238.254122.244.238.255254
240122.244.239.0/24122.244.239.1 to 122.244.239.254122.244.239.255254
241122.244.240.0/24122.244.240.1 to 122.244.240.254122.244.240.255254
242122.244.241.0/24122.244.241.1 to 122.244.241.254122.244.241.255254
243122.244.242.0/24122.244.242.1 to 122.244.242.254122.244.242.255254
244122.244.243.0/24122.244.243.1 to 122.244.243.254122.244.243.255254
245122.244.244.0/24122.244.244.1 to 122.244.244.254122.244.244.255254
246122.244.245.0/24122.244.245.1 to 122.244.245.254122.244.245.255254
247122.244.246.0/24122.244.246.1 to 122.244.246.254122.244.246.255254
248122.244.247.0/24122.244.247.1 to 122.244.247.254122.244.247.255254
249122.244.248.0/24122.244.248.1 to 122.244.248.254122.244.248.255254
250122.244.249.0/24122.244.249.1 to 122.244.249.254122.244.249.255254
251122.244.250.0/24122.244.250.1 to 122.244.250.254122.244.250.255254
252122.244.251.0/24122.244.251.1 to 122.244.251.254122.244.251.255254
253122.244.252.0/24122.244.252.1 to 122.244.252.254122.244.252.255254
254122.244.253.0/24122.244.253.1 to 122.244.253.254122.244.253.255254
255122.244.254.0/24122.244.254.1 to 122.244.254.254122.244.254.255254
256122.244.255.0/24122.244.255.1 to 122.244.255.254122.244.255.255254

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.