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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.

Network222.192.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
222.192.0.0
Broadcast address
222.207.255.255
First usable
222.192.0.1
Last usable
222.207.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
C (default /24)
As numbers
Hex DEC00000 · Integer 3737124864 to 3738173439
Reverse DNS zones
192.222.in-addr.arpa
193.222.in-addr.arpa
194.222.in-addr.arpa
195.222.in-addr.arpa
196.222.in-addr.arpa
197.222.in-addr.arpa
198.222.in-addr.arpa
199.222.in-addr.arpa
200.222.in-addr.arpa
201.222.in-addr.arpa
202.222.in-addr.arpa
203.222.in-addr.arpa
204.222.in-addr.arpa
205.222.in-addr.arpa
206.222.in-addr.arpa
207.222.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011110.11000000.00000000.00000000222.192.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11011110.11000000.00000000.00000000222.192.0.0
Broadcast11011110.11001111.11111111.11111111222.207.255.255
Split into smaller subnets/24
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

222.192.0.0/12 makes 4,096 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1222.192.0.0/24222.192.0.1 to 222.192.0.254222.192.0.255254
2222.192.1.0/24222.192.1.1 to 222.192.1.254222.192.1.255254
3222.192.2.0/24222.192.2.1 to 222.192.2.254222.192.2.255254
4222.192.3.0/24222.192.3.1 to 222.192.3.254222.192.3.255254
5222.192.4.0/24222.192.4.1 to 222.192.4.254222.192.4.255254
6222.192.5.0/24222.192.5.1 to 222.192.5.254222.192.5.255254
7222.192.6.0/24222.192.6.1 to 222.192.6.254222.192.6.255254
8222.192.7.0/24222.192.7.1 to 222.192.7.254222.192.7.255254
9222.192.8.0/24222.192.8.1 to 222.192.8.254222.192.8.255254
10222.192.9.0/24222.192.9.1 to 222.192.9.254222.192.9.255254
11222.192.10.0/24222.192.10.1 to 222.192.10.254222.192.10.255254
12222.192.11.0/24222.192.11.1 to 222.192.11.254222.192.11.255254
13222.192.12.0/24222.192.12.1 to 222.192.12.254222.192.12.255254
14222.192.13.0/24222.192.13.1 to 222.192.13.254222.192.13.255254
15222.192.14.0/24222.192.14.1 to 222.192.14.254222.192.14.255254
16222.192.15.0/24222.192.15.1 to 222.192.15.254222.192.15.255254
17222.192.16.0/24222.192.16.1 to 222.192.16.254222.192.16.255254
18222.192.17.0/24222.192.17.1 to 222.192.17.254222.192.17.255254
19222.192.18.0/24222.192.18.1 to 222.192.18.254222.192.18.255254
20222.192.19.0/24222.192.19.1 to 222.192.19.254222.192.19.255254
21222.192.20.0/24222.192.20.1 to 222.192.20.254222.192.20.255254
22222.192.21.0/24222.192.21.1 to 222.192.21.254222.192.21.255254
23222.192.22.0/24222.192.22.1 to 222.192.22.254222.192.22.255254
24222.192.23.0/24222.192.23.1 to 222.192.23.254222.192.23.255254
25222.192.24.0/24222.192.24.1 to 222.192.24.254222.192.24.255254
26222.192.25.0/24222.192.25.1 to 222.192.25.254222.192.25.255254
27222.192.26.0/24222.192.26.1 to 222.192.26.254222.192.26.255254
28222.192.27.0/24222.192.27.1 to 222.192.27.254222.192.27.255254
29222.192.28.0/24222.192.28.1 to 222.192.28.254222.192.28.255254
30222.192.29.0/24222.192.29.1 to 222.192.29.254222.192.29.255254
31222.192.30.0/24222.192.30.1 to 222.192.30.254222.192.30.255254
32222.192.31.0/24222.192.31.1 to 222.192.31.254222.192.31.255254
33222.192.32.0/24222.192.32.1 to 222.192.32.254222.192.32.255254
34222.192.33.0/24222.192.33.1 to 222.192.33.254222.192.33.255254
35222.192.34.0/24222.192.34.1 to 222.192.34.254222.192.34.255254
36222.192.35.0/24222.192.35.1 to 222.192.35.254222.192.35.255254
37222.192.36.0/24222.192.36.1 to 222.192.36.254222.192.36.255254
38222.192.37.0/24222.192.37.1 to 222.192.37.254222.192.37.255254
39222.192.38.0/24222.192.38.1 to 222.192.38.254222.192.38.255254
40222.192.39.0/24222.192.39.1 to 222.192.39.254222.192.39.255254
41222.192.40.0/24222.192.40.1 to 222.192.40.254222.192.40.255254
42222.192.41.0/24222.192.41.1 to 222.192.41.254222.192.41.255254
43222.192.42.0/24222.192.42.1 to 222.192.42.254222.192.42.255254
44222.192.43.0/24222.192.43.1 to 222.192.43.254222.192.43.255254
45222.192.44.0/24222.192.44.1 to 222.192.44.254222.192.44.255254
46222.192.45.0/24222.192.45.1 to 222.192.45.254222.192.45.255254
47222.192.46.0/24222.192.46.1 to 222.192.46.254222.192.46.255254
48222.192.47.0/24222.192.47.1 to 222.192.47.254222.192.47.255254
49222.192.48.0/24222.192.48.1 to 222.192.48.254222.192.48.255254
50222.192.49.0/24222.192.49.1 to 222.192.49.254222.192.49.255254
51222.192.50.0/24222.192.50.1 to 222.192.50.254222.192.50.255254
52222.192.51.0/24222.192.51.1 to 222.192.51.254222.192.51.255254
53222.192.52.0/24222.192.52.1 to 222.192.52.254222.192.52.255254
54222.192.53.0/24222.192.53.1 to 222.192.53.254222.192.53.255254
55222.192.54.0/24222.192.54.1 to 222.192.54.254222.192.54.255254
56222.192.55.0/24222.192.55.1 to 222.192.55.254222.192.55.255254
57222.192.56.0/24222.192.56.1 to 222.192.56.254222.192.56.255254
58222.192.57.0/24222.192.57.1 to 222.192.57.254222.192.57.255254
59222.192.58.0/24222.192.58.1 to 222.192.58.254222.192.58.255254
60222.192.59.0/24222.192.59.1 to 222.192.59.254222.192.59.255254
61222.192.60.0/24222.192.60.1 to 222.192.60.254222.192.60.255254
62222.192.61.0/24222.192.61.1 to 222.192.61.254222.192.61.255254
63222.192.62.0/24222.192.62.1 to 222.192.62.254222.192.62.255254
64222.192.63.0/24222.192.63.1 to 222.192.63.254222.192.63.255254
65222.192.64.0/24222.192.64.1 to 222.192.64.254222.192.64.255254
66222.192.65.0/24222.192.65.1 to 222.192.65.254222.192.65.255254
67222.192.66.0/24222.192.66.1 to 222.192.66.254222.192.66.255254
68222.192.67.0/24222.192.67.1 to 222.192.67.254222.192.67.255254
69222.192.68.0/24222.192.68.1 to 222.192.68.254222.192.68.255254
70222.192.69.0/24222.192.69.1 to 222.192.69.254222.192.69.255254
71222.192.70.0/24222.192.70.1 to 222.192.70.254222.192.70.255254
72222.192.71.0/24222.192.71.1 to 222.192.71.254222.192.71.255254
73222.192.72.0/24222.192.72.1 to 222.192.72.254222.192.72.255254
74222.192.73.0/24222.192.73.1 to 222.192.73.254222.192.73.255254
75222.192.74.0/24222.192.74.1 to 222.192.74.254222.192.74.255254
76222.192.75.0/24222.192.75.1 to 222.192.75.254222.192.75.255254
77222.192.76.0/24222.192.76.1 to 222.192.76.254222.192.76.255254
78222.192.77.0/24222.192.77.1 to 222.192.77.254222.192.77.255254
79222.192.78.0/24222.192.78.1 to 222.192.78.254222.192.78.255254
80222.192.79.0/24222.192.79.1 to 222.192.79.254222.192.79.255254
81222.192.80.0/24222.192.80.1 to 222.192.80.254222.192.80.255254
82222.192.81.0/24222.192.81.1 to 222.192.81.254222.192.81.255254
83222.192.82.0/24222.192.82.1 to 222.192.82.254222.192.82.255254
84222.192.83.0/24222.192.83.1 to 222.192.83.254222.192.83.255254
85222.192.84.0/24222.192.84.1 to 222.192.84.254222.192.84.255254
86222.192.85.0/24222.192.85.1 to 222.192.85.254222.192.85.255254
87222.192.86.0/24222.192.86.1 to 222.192.86.254222.192.86.255254
88222.192.87.0/24222.192.87.1 to 222.192.87.254222.192.87.255254
89222.192.88.0/24222.192.88.1 to 222.192.88.254222.192.88.255254
90222.192.89.0/24222.192.89.1 to 222.192.89.254222.192.89.255254
91222.192.90.0/24222.192.90.1 to 222.192.90.254222.192.90.255254
92222.192.91.0/24222.192.91.1 to 222.192.91.254222.192.91.255254
93222.192.92.0/24222.192.92.1 to 222.192.92.254222.192.92.255254
94222.192.93.0/24222.192.93.1 to 222.192.93.254222.192.93.255254
95222.192.94.0/24222.192.94.1 to 222.192.94.254222.192.94.255254
96222.192.95.0/24222.192.95.1 to 222.192.95.254222.192.95.255254
97222.192.96.0/24222.192.96.1 to 222.192.96.254222.192.96.255254
98222.192.97.0/24222.192.97.1 to 222.192.97.254222.192.97.255254
99222.192.98.0/24222.192.98.1 to 222.192.98.254222.192.98.255254
100222.192.99.0/24222.192.99.1 to 222.192.99.254222.192.99.255254
101222.192.100.0/24222.192.100.1 to 222.192.100.254222.192.100.255254
102222.192.101.0/24222.192.101.1 to 222.192.101.254222.192.101.255254
103222.192.102.0/24222.192.102.1 to 222.192.102.254222.192.102.255254
104222.192.103.0/24222.192.103.1 to 222.192.103.254222.192.103.255254
105222.192.104.0/24222.192.104.1 to 222.192.104.254222.192.104.255254
106222.192.105.0/24222.192.105.1 to 222.192.105.254222.192.105.255254
107222.192.106.0/24222.192.106.1 to 222.192.106.254222.192.106.255254
108222.192.107.0/24222.192.107.1 to 222.192.107.254222.192.107.255254
109222.192.108.0/24222.192.108.1 to 222.192.108.254222.192.108.255254
110222.192.109.0/24222.192.109.1 to 222.192.109.254222.192.109.255254
111222.192.110.0/24222.192.110.1 to 222.192.110.254222.192.110.255254
112222.192.111.0/24222.192.111.1 to 222.192.111.254222.192.111.255254
113222.192.112.0/24222.192.112.1 to 222.192.112.254222.192.112.255254
114222.192.113.0/24222.192.113.1 to 222.192.113.254222.192.113.255254
115222.192.114.0/24222.192.114.1 to 222.192.114.254222.192.114.255254
116222.192.115.0/24222.192.115.1 to 222.192.115.254222.192.115.255254
117222.192.116.0/24222.192.116.1 to 222.192.116.254222.192.116.255254
118222.192.117.0/24222.192.117.1 to 222.192.117.254222.192.117.255254
119222.192.118.0/24222.192.118.1 to 222.192.118.254222.192.118.255254
120222.192.119.0/24222.192.119.1 to 222.192.119.254222.192.119.255254
121222.192.120.0/24222.192.120.1 to 222.192.120.254222.192.120.255254
122222.192.121.0/24222.192.121.1 to 222.192.121.254222.192.121.255254
123222.192.122.0/24222.192.122.1 to 222.192.122.254222.192.122.255254
124222.192.123.0/24222.192.123.1 to 222.192.123.254222.192.123.255254
125222.192.124.0/24222.192.124.1 to 222.192.124.254222.192.124.255254
126222.192.125.0/24222.192.125.1 to 222.192.125.254222.192.125.255254
127222.192.126.0/24222.192.126.1 to 222.192.126.254222.192.126.255254
128222.192.127.0/24222.192.127.1 to 222.192.127.254222.192.127.255254
129222.192.128.0/24222.192.128.1 to 222.192.128.254222.192.128.255254
130222.192.129.0/24222.192.129.1 to 222.192.129.254222.192.129.255254
131222.192.130.0/24222.192.130.1 to 222.192.130.254222.192.130.255254
132222.192.131.0/24222.192.131.1 to 222.192.131.254222.192.131.255254
133222.192.132.0/24222.192.132.1 to 222.192.132.254222.192.132.255254
134222.192.133.0/24222.192.133.1 to 222.192.133.254222.192.133.255254
135222.192.134.0/24222.192.134.1 to 222.192.134.254222.192.134.255254
136222.192.135.0/24222.192.135.1 to 222.192.135.254222.192.135.255254
137222.192.136.0/24222.192.136.1 to 222.192.136.254222.192.136.255254
138222.192.137.0/24222.192.137.1 to 222.192.137.254222.192.137.255254
139222.192.138.0/24222.192.138.1 to 222.192.138.254222.192.138.255254
140222.192.139.0/24222.192.139.1 to 222.192.139.254222.192.139.255254
141222.192.140.0/24222.192.140.1 to 222.192.140.254222.192.140.255254
142222.192.141.0/24222.192.141.1 to 222.192.141.254222.192.141.255254
143222.192.142.0/24222.192.142.1 to 222.192.142.254222.192.142.255254
144222.192.143.0/24222.192.143.1 to 222.192.143.254222.192.143.255254
145222.192.144.0/24222.192.144.1 to 222.192.144.254222.192.144.255254
146222.192.145.0/24222.192.145.1 to 222.192.145.254222.192.145.255254
147222.192.146.0/24222.192.146.1 to 222.192.146.254222.192.146.255254
148222.192.147.0/24222.192.147.1 to 222.192.147.254222.192.147.255254
149222.192.148.0/24222.192.148.1 to 222.192.148.254222.192.148.255254
150222.192.149.0/24222.192.149.1 to 222.192.149.254222.192.149.255254
151222.192.150.0/24222.192.150.1 to 222.192.150.254222.192.150.255254
152222.192.151.0/24222.192.151.1 to 222.192.151.254222.192.151.255254
153222.192.152.0/24222.192.152.1 to 222.192.152.254222.192.152.255254
154222.192.153.0/24222.192.153.1 to 222.192.153.254222.192.153.255254
155222.192.154.0/24222.192.154.1 to 222.192.154.254222.192.154.255254
156222.192.155.0/24222.192.155.1 to 222.192.155.254222.192.155.255254
157222.192.156.0/24222.192.156.1 to 222.192.156.254222.192.156.255254
158222.192.157.0/24222.192.157.1 to 222.192.157.254222.192.157.255254
159222.192.158.0/24222.192.158.1 to 222.192.158.254222.192.158.255254
160222.192.159.0/24222.192.159.1 to 222.192.159.254222.192.159.255254
161222.192.160.0/24222.192.160.1 to 222.192.160.254222.192.160.255254
162222.192.161.0/24222.192.161.1 to 222.192.161.254222.192.161.255254
163222.192.162.0/24222.192.162.1 to 222.192.162.254222.192.162.255254
164222.192.163.0/24222.192.163.1 to 222.192.163.254222.192.163.255254
165222.192.164.0/24222.192.164.1 to 222.192.164.254222.192.164.255254
166222.192.165.0/24222.192.165.1 to 222.192.165.254222.192.165.255254
167222.192.166.0/24222.192.166.1 to 222.192.166.254222.192.166.255254
168222.192.167.0/24222.192.167.1 to 222.192.167.254222.192.167.255254
169222.192.168.0/24222.192.168.1 to 222.192.168.254222.192.168.255254
170222.192.169.0/24222.192.169.1 to 222.192.169.254222.192.169.255254
171222.192.170.0/24222.192.170.1 to 222.192.170.254222.192.170.255254
172222.192.171.0/24222.192.171.1 to 222.192.171.254222.192.171.255254
173222.192.172.0/24222.192.172.1 to 222.192.172.254222.192.172.255254
174222.192.173.0/24222.192.173.1 to 222.192.173.254222.192.173.255254
175222.192.174.0/24222.192.174.1 to 222.192.174.254222.192.174.255254
176222.192.175.0/24222.192.175.1 to 222.192.175.254222.192.175.255254
177222.192.176.0/24222.192.176.1 to 222.192.176.254222.192.176.255254
178222.192.177.0/24222.192.177.1 to 222.192.177.254222.192.177.255254
179222.192.178.0/24222.192.178.1 to 222.192.178.254222.192.178.255254
180222.192.179.0/24222.192.179.1 to 222.192.179.254222.192.179.255254
181222.192.180.0/24222.192.180.1 to 222.192.180.254222.192.180.255254
182222.192.181.0/24222.192.181.1 to 222.192.181.254222.192.181.255254
183222.192.182.0/24222.192.182.1 to 222.192.182.254222.192.182.255254
184222.192.183.0/24222.192.183.1 to 222.192.183.254222.192.183.255254
185222.192.184.0/24222.192.184.1 to 222.192.184.254222.192.184.255254
186222.192.185.0/24222.192.185.1 to 222.192.185.254222.192.185.255254
187222.192.186.0/24222.192.186.1 to 222.192.186.254222.192.186.255254
188222.192.187.0/24222.192.187.1 to 222.192.187.254222.192.187.255254
189222.192.188.0/24222.192.188.1 to 222.192.188.254222.192.188.255254
190222.192.189.0/24222.192.189.1 to 222.192.189.254222.192.189.255254
191222.192.190.0/24222.192.190.1 to 222.192.190.254222.192.190.255254
192222.192.191.0/24222.192.191.1 to 222.192.191.254222.192.191.255254
193222.192.192.0/24222.192.192.1 to 222.192.192.254222.192.192.255254
194222.192.193.0/24222.192.193.1 to 222.192.193.254222.192.193.255254
195222.192.194.0/24222.192.194.1 to 222.192.194.254222.192.194.255254
196222.192.195.0/24222.192.195.1 to 222.192.195.254222.192.195.255254
197222.192.196.0/24222.192.196.1 to 222.192.196.254222.192.196.255254
198222.192.197.0/24222.192.197.1 to 222.192.197.254222.192.197.255254
199222.192.198.0/24222.192.198.1 to 222.192.198.254222.192.198.255254
200222.192.199.0/24222.192.199.1 to 222.192.199.254222.192.199.255254
201222.192.200.0/24222.192.200.1 to 222.192.200.254222.192.200.255254
202222.192.201.0/24222.192.201.1 to 222.192.201.254222.192.201.255254
203222.192.202.0/24222.192.202.1 to 222.192.202.254222.192.202.255254
204222.192.203.0/24222.192.203.1 to 222.192.203.254222.192.203.255254
205222.192.204.0/24222.192.204.1 to 222.192.204.254222.192.204.255254
206222.192.205.0/24222.192.205.1 to 222.192.205.254222.192.205.255254
207222.192.206.0/24222.192.206.1 to 222.192.206.254222.192.206.255254
208222.192.207.0/24222.192.207.1 to 222.192.207.254222.192.207.255254
209222.192.208.0/24222.192.208.1 to 222.192.208.254222.192.208.255254
210222.192.209.0/24222.192.209.1 to 222.192.209.254222.192.209.255254
211222.192.210.0/24222.192.210.1 to 222.192.210.254222.192.210.255254
212222.192.211.0/24222.192.211.1 to 222.192.211.254222.192.211.255254
213222.192.212.0/24222.192.212.1 to 222.192.212.254222.192.212.255254
214222.192.213.0/24222.192.213.1 to 222.192.213.254222.192.213.255254
215222.192.214.0/24222.192.214.1 to 222.192.214.254222.192.214.255254
216222.192.215.0/24222.192.215.1 to 222.192.215.254222.192.215.255254
217222.192.216.0/24222.192.216.1 to 222.192.216.254222.192.216.255254
218222.192.217.0/24222.192.217.1 to 222.192.217.254222.192.217.255254
219222.192.218.0/24222.192.218.1 to 222.192.218.254222.192.218.255254
220222.192.219.0/24222.192.219.1 to 222.192.219.254222.192.219.255254
221222.192.220.0/24222.192.220.1 to 222.192.220.254222.192.220.255254
222222.192.221.0/24222.192.221.1 to 222.192.221.254222.192.221.255254
223222.192.222.0/24222.192.222.1 to 222.192.222.254222.192.222.255254
224222.192.223.0/24222.192.223.1 to 222.192.223.254222.192.223.255254
225222.192.224.0/24222.192.224.1 to 222.192.224.254222.192.224.255254
226222.192.225.0/24222.192.225.1 to 222.192.225.254222.192.225.255254
227222.192.226.0/24222.192.226.1 to 222.192.226.254222.192.226.255254
228222.192.227.0/24222.192.227.1 to 222.192.227.254222.192.227.255254
229222.192.228.0/24222.192.228.1 to 222.192.228.254222.192.228.255254
230222.192.229.0/24222.192.229.1 to 222.192.229.254222.192.229.255254
231222.192.230.0/24222.192.230.1 to 222.192.230.254222.192.230.255254
232222.192.231.0/24222.192.231.1 to 222.192.231.254222.192.231.255254
233222.192.232.0/24222.192.232.1 to 222.192.232.254222.192.232.255254
234222.192.233.0/24222.192.233.1 to 222.192.233.254222.192.233.255254
235222.192.234.0/24222.192.234.1 to 222.192.234.254222.192.234.255254
236222.192.235.0/24222.192.235.1 to 222.192.235.254222.192.235.255254
237222.192.236.0/24222.192.236.1 to 222.192.236.254222.192.236.255254
238222.192.237.0/24222.192.237.1 to 222.192.237.254222.192.237.255254
239222.192.238.0/24222.192.238.1 to 222.192.238.254222.192.238.255254
240222.192.239.0/24222.192.239.1 to 222.192.239.254222.192.239.255254
241222.192.240.0/24222.192.240.1 to 222.192.240.254222.192.240.255254
242222.192.241.0/24222.192.241.1 to 222.192.241.254222.192.241.255254
243222.192.242.0/24222.192.242.1 to 222.192.242.254222.192.242.255254
244222.192.243.0/24222.192.243.1 to 222.192.243.254222.192.243.255254
245222.192.244.0/24222.192.244.1 to 222.192.244.254222.192.244.255254
246222.192.245.0/24222.192.245.1 to 222.192.245.254222.192.245.255254
247222.192.246.0/24222.192.246.1 to 222.192.246.254222.192.246.255254
248222.192.247.0/24222.192.247.1 to 222.192.247.254222.192.247.255254
249222.192.248.0/24222.192.248.1 to 222.192.248.254222.192.248.255254
250222.192.249.0/24222.192.249.1 to 222.192.249.254222.192.249.255254
251222.192.250.0/24222.192.250.1 to 222.192.250.254222.192.250.255254
252222.192.251.0/24222.192.251.1 to 222.192.251.254222.192.251.255254
253222.192.252.0/24222.192.252.1 to 222.192.252.254222.192.252.255254
254222.192.253.0/24222.192.253.1 to 222.192.253.254222.192.253.255254
255222.192.254.0/24222.192.254.1 to 222.192.254.254222.192.254.255254
256222.192.255.0/24222.192.255.1 to 222.192.255.254222.192.255.255254

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.