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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.

Network168.201.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
168.201.0.0
Broadcast address
168.201.255.255
First usable
168.201.0.1
Last usable
168.201.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
B (default /16)
As numbers
Hex A8C90000 · Integer 2831745024 to 2831810559
Reverse DNS zone
201.168.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101000.11001001..00000000.00000000168.201.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network10101000.11001001..00000000.00000000168.201.0.0
Broadcast10101000.11001001..11111111.11111111168.201.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

168.201.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1168.201.0.0/24168.201.0.1 to 168.201.0.254168.201.0.255254
2168.201.1.0/24168.201.1.1 to 168.201.1.254168.201.1.255254
3168.201.2.0/24168.201.2.1 to 168.201.2.254168.201.2.255254
4168.201.3.0/24168.201.3.1 to 168.201.3.254168.201.3.255254
5168.201.4.0/24168.201.4.1 to 168.201.4.254168.201.4.255254
6168.201.5.0/24168.201.5.1 to 168.201.5.254168.201.5.255254
7168.201.6.0/24168.201.6.1 to 168.201.6.254168.201.6.255254
8168.201.7.0/24168.201.7.1 to 168.201.7.254168.201.7.255254
9168.201.8.0/24168.201.8.1 to 168.201.8.254168.201.8.255254
10168.201.9.0/24168.201.9.1 to 168.201.9.254168.201.9.255254
11168.201.10.0/24168.201.10.1 to 168.201.10.254168.201.10.255254
12168.201.11.0/24168.201.11.1 to 168.201.11.254168.201.11.255254
13168.201.12.0/24168.201.12.1 to 168.201.12.254168.201.12.255254
14168.201.13.0/24168.201.13.1 to 168.201.13.254168.201.13.255254
15168.201.14.0/24168.201.14.1 to 168.201.14.254168.201.14.255254
16168.201.15.0/24168.201.15.1 to 168.201.15.254168.201.15.255254
17168.201.16.0/24168.201.16.1 to 168.201.16.254168.201.16.255254
18168.201.17.0/24168.201.17.1 to 168.201.17.254168.201.17.255254
19168.201.18.0/24168.201.18.1 to 168.201.18.254168.201.18.255254
20168.201.19.0/24168.201.19.1 to 168.201.19.254168.201.19.255254
21168.201.20.0/24168.201.20.1 to 168.201.20.254168.201.20.255254
22168.201.21.0/24168.201.21.1 to 168.201.21.254168.201.21.255254
23168.201.22.0/24168.201.22.1 to 168.201.22.254168.201.22.255254
24168.201.23.0/24168.201.23.1 to 168.201.23.254168.201.23.255254
25168.201.24.0/24168.201.24.1 to 168.201.24.254168.201.24.255254
26168.201.25.0/24168.201.25.1 to 168.201.25.254168.201.25.255254
27168.201.26.0/24168.201.26.1 to 168.201.26.254168.201.26.255254
28168.201.27.0/24168.201.27.1 to 168.201.27.254168.201.27.255254
29168.201.28.0/24168.201.28.1 to 168.201.28.254168.201.28.255254
30168.201.29.0/24168.201.29.1 to 168.201.29.254168.201.29.255254
31168.201.30.0/24168.201.30.1 to 168.201.30.254168.201.30.255254
32168.201.31.0/24168.201.31.1 to 168.201.31.254168.201.31.255254
33168.201.32.0/24168.201.32.1 to 168.201.32.254168.201.32.255254
34168.201.33.0/24168.201.33.1 to 168.201.33.254168.201.33.255254
35168.201.34.0/24168.201.34.1 to 168.201.34.254168.201.34.255254
36168.201.35.0/24168.201.35.1 to 168.201.35.254168.201.35.255254
37168.201.36.0/24168.201.36.1 to 168.201.36.254168.201.36.255254
38168.201.37.0/24168.201.37.1 to 168.201.37.254168.201.37.255254
39168.201.38.0/24168.201.38.1 to 168.201.38.254168.201.38.255254
40168.201.39.0/24168.201.39.1 to 168.201.39.254168.201.39.255254
41168.201.40.0/24168.201.40.1 to 168.201.40.254168.201.40.255254
42168.201.41.0/24168.201.41.1 to 168.201.41.254168.201.41.255254
43168.201.42.0/24168.201.42.1 to 168.201.42.254168.201.42.255254
44168.201.43.0/24168.201.43.1 to 168.201.43.254168.201.43.255254
45168.201.44.0/24168.201.44.1 to 168.201.44.254168.201.44.255254
46168.201.45.0/24168.201.45.1 to 168.201.45.254168.201.45.255254
47168.201.46.0/24168.201.46.1 to 168.201.46.254168.201.46.255254
48168.201.47.0/24168.201.47.1 to 168.201.47.254168.201.47.255254
49168.201.48.0/24168.201.48.1 to 168.201.48.254168.201.48.255254
50168.201.49.0/24168.201.49.1 to 168.201.49.254168.201.49.255254
51168.201.50.0/24168.201.50.1 to 168.201.50.254168.201.50.255254
52168.201.51.0/24168.201.51.1 to 168.201.51.254168.201.51.255254
53168.201.52.0/24168.201.52.1 to 168.201.52.254168.201.52.255254
54168.201.53.0/24168.201.53.1 to 168.201.53.254168.201.53.255254
55168.201.54.0/24168.201.54.1 to 168.201.54.254168.201.54.255254
56168.201.55.0/24168.201.55.1 to 168.201.55.254168.201.55.255254
57168.201.56.0/24168.201.56.1 to 168.201.56.254168.201.56.255254
58168.201.57.0/24168.201.57.1 to 168.201.57.254168.201.57.255254
59168.201.58.0/24168.201.58.1 to 168.201.58.254168.201.58.255254
60168.201.59.0/24168.201.59.1 to 168.201.59.254168.201.59.255254
61168.201.60.0/24168.201.60.1 to 168.201.60.254168.201.60.255254
62168.201.61.0/24168.201.61.1 to 168.201.61.254168.201.61.255254
63168.201.62.0/24168.201.62.1 to 168.201.62.254168.201.62.255254
64168.201.63.0/24168.201.63.1 to 168.201.63.254168.201.63.255254
65168.201.64.0/24168.201.64.1 to 168.201.64.254168.201.64.255254
66168.201.65.0/24168.201.65.1 to 168.201.65.254168.201.65.255254
67168.201.66.0/24168.201.66.1 to 168.201.66.254168.201.66.255254
68168.201.67.0/24168.201.67.1 to 168.201.67.254168.201.67.255254
69168.201.68.0/24168.201.68.1 to 168.201.68.254168.201.68.255254
70168.201.69.0/24168.201.69.1 to 168.201.69.254168.201.69.255254
71168.201.70.0/24168.201.70.1 to 168.201.70.254168.201.70.255254
72168.201.71.0/24168.201.71.1 to 168.201.71.254168.201.71.255254
73168.201.72.0/24168.201.72.1 to 168.201.72.254168.201.72.255254
74168.201.73.0/24168.201.73.1 to 168.201.73.254168.201.73.255254
75168.201.74.0/24168.201.74.1 to 168.201.74.254168.201.74.255254
76168.201.75.0/24168.201.75.1 to 168.201.75.254168.201.75.255254
77168.201.76.0/24168.201.76.1 to 168.201.76.254168.201.76.255254
78168.201.77.0/24168.201.77.1 to 168.201.77.254168.201.77.255254
79168.201.78.0/24168.201.78.1 to 168.201.78.254168.201.78.255254
80168.201.79.0/24168.201.79.1 to 168.201.79.254168.201.79.255254
81168.201.80.0/24168.201.80.1 to 168.201.80.254168.201.80.255254
82168.201.81.0/24168.201.81.1 to 168.201.81.254168.201.81.255254
83168.201.82.0/24168.201.82.1 to 168.201.82.254168.201.82.255254
84168.201.83.0/24168.201.83.1 to 168.201.83.254168.201.83.255254
85168.201.84.0/24168.201.84.1 to 168.201.84.254168.201.84.255254
86168.201.85.0/24168.201.85.1 to 168.201.85.254168.201.85.255254
87168.201.86.0/24168.201.86.1 to 168.201.86.254168.201.86.255254
88168.201.87.0/24168.201.87.1 to 168.201.87.254168.201.87.255254
89168.201.88.0/24168.201.88.1 to 168.201.88.254168.201.88.255254
90168.201.89.0/24168.201.89.1 to 168.201.89.254168.201.89.255254
91168.201.90.0/24168.201.90.1 to 168.201.90.254168.201.90.255254
92168.201.91.0/24168.201.91.1 to 168.201.91.254168.201.91.255254
93168.201.92.0/24168.201.92.1 to 168.201.92.254168.201.92.255254
94168.201.93.0/24168.201.93.1 to 168.201.93.254168.201.93.255254
95168.201.94.0/24168.201.94.1 to 168.201.94.254168.201.94.255254
96168.201.95.0/24168.201.95.1 to 168.201.95.254168.201.95.255254
97168.201.96.0/24168.201.96.1 to 168.201.96.254168.201.96.255254
98168.201.97.0/24168.201.97.1 to 168.201.97.254168.201.97.255254
99168.201.98.0/24168.201.98.1 to 168.201.98.254168.201.98.255254
100168.201.99.0/24168.201.99.1 to 168.201.99.254168.201.99.255254
101168.201.100.0/24168.201.100.1 to 168.201.100.254168.201.100.255254
102168.201.101.0/24168.201.101.1 to 168.201.101.254168.201.101.255254
103168.201.102.0/24168.201.102.1 to 168.201.102.254168.201.102.255254
104168.201.103.0/24168.201.103.1 to 168.201.103.254168.201.103.255254
105168.201.104.0/24168.201.104.1 to 168.201.104.254168.201.104.255254
106168.201.105.0/24168.201.105.1 to 168.201.105.254168.201.105.255254
107168.201.106.0/24168.201.106.1 to 168.201.106.254168.201.106.255254
108168.201.107.0/24168.201.107.1 to 168.201.107.254168.201.107.255254
109168.201.108.0/24168.201.108.1 to 168.201.108.254168.201.108.255254
110168.201.109.0/24168.201.109.1 to 168.201.109.254168.201.109.255254
111168.201.110.0/24168.201.110.1 to 168.201.110.254168.201.110.255254
112168.201.111.0/24168.201.111.1 to 168.201.111.254168.201.111.255254
113168.201.112.0/24168.201.112.1 to 168.201.112.254168.201.112.255254
114168.201.113.0/24168.201.113.1 to 168.201.113.254168.201.113.255254
115168.201.114.0/24168.201.114.1 to 168.201.114.254168.201.114.255254
116168.201.115.0/24168.201.115.1 to 168.201.115.254168.201.115.255254
117168.201.116.0/24168.201.116.1 to 168.201.116.254168.201.116.255254
118168.201.117.0/24168.201.117.1 to 168.201.117.254168.201.117.255254
119168.201.118.0/24168.201.118.1 to 168.201.118.254168.201.118.255254
120168.201.119.0/24168.201.119.1 to 168.201.119.254168.201.119.255254
121168.201.120.0/24168.201.120.1 to 168.201.120.254168.201.120.255254
122168.201.121.0/24168.201.121.1 to 168.201.121.254168.201.121.255254
123168.201.122.0/24168.201.122.1 to 168.201.122.254168.201.122.255254
124168.201.123.0/24168.201.123.1 to 168.201.123.254168.201.123.255254
125168.201.124.0/24168.201.124.1 to 168.201.124.254168.201.124.255254
126168.201.125.0/24168.201.125.1 to 168.201.125.254168.201.125.255254
127168.201.126.0/24168.201.126.1 to 168.201.126.254168.201.126.255254
128168.201.127.0/24168.201.127.1 to 168.201.127.254168.201.127.255254
129168.201.128.0/24168.201.128.1 to 168.201.128.254168.201.128.255254
130168.201.129.0/24168.201.129.1 to 168.201.129.254168.201.129.255254
131168.201.130.0/24168.201.130.1 to 168.201.130.254168.201.130.255254
132168.201.131.0/24168.201.131.1 to 168.201.131.254168.201.131.255254
133168.201.132.0/24168.201.132.1 to 168.201.132.254168.201.132.255254
134168.201.133.0/24168.201.133.1 to 168.201.133.254168.201.133.255254
135168.201.134.0/24168.201.134.1 to 168.201.134.254168.201.134.255254
136168.201.135.0/24168.201.135.1 to 168.201.135.254168.201.135.255254
137168.201.136.0/24168.201.136.1 to 168.201.136.254168.201.136.255254
138168.201.137.0/24168.201.137.1 to 168.201.137.254168.201.137.255254
139168.201.138.0/24168.201.138.1 to 168.201.138.254168.201.138.255254
140168.201.139.0/24168.201.139.1 to 168.201.139.254168.201.139.255254
141168.201.140.0/24168.201.140.1 to 168.201.140.254168.201.140.255254
142168.201.141.0/24168.201.141.1 to 168.201.141.254168.201.141.255254
143168.201.142.0/24168.201.142.1 to 168.201.142.254168.201.142.255254
144168.201.143.0/24168.201.143.1 to 168.201.143.254168.201.143.255254
145168.201.144.0/24168.201.144.1 to 168.201.144.254168.201.144.255254
146168.201.145.0/24168.201.145.1 to 168.201.145.254168.201.145.255254
147168.201.146.0/24168.201.146.1 to 168.201.146.254168.201.146.255254
148168.201.147.0/24168.201.147.1 to 168.201.147.254168.201.147.255254
149168.201.148.0/24168.201.148.1 to 168.201.148.254168.201.148.255254
150168.201.149.0/24168.201.149.1 to 168.201.149.254168.201.149.255254
151168.201.150.0/24168.201.150.1 to 168.201.150.254168.201.150.255254
152168.201.151.0/24168.201.151.1 to 168.201.151.254168.201.151.255254
153168.201.152.0/24168.201.152.1 to 168.201.152.254168.201.152.255254
154168.201.153.0/24168.201.153.1 to 168.201.153.254168.201.153.255254
155168.201.154.0/24168.201.154.1 to 168.201.154.254168.201.154.255254
156168.201.155.0/24168.201.155.1 to 168.201.155.254168.201.155.255254
157168.201.156.0/24168.201.156.1 to 168.201.156.254168.201.156.255254
158168.201.157.0/24168.201.157.1 to 168.201.157.254168.201.157.255254
159168.201.158.0/24168.201.158.1 to 168.201.158.254168.201.158.255254
160168.201.159.0/24168.201.159.1 to 168.201.159.254168.201.159.255254
161168.201.160.0/24168.201.160.1 to 168.201.160.254168.201.160.255254
162168.201.161.0/24168.201.161.1 to 168.201.161.254168.201.161.255254
163168.201.162.0/24168.201.162.1 to 168.201.162.254168.201.162.255254
164168.201.163.0/24168.201.163.1 to 168.201.163.254168.201.163.255254
165168.201.164.0/24168.201.164.1 to 168.201.164.254168.201.164.255254
166168.201.165.0/24168.201.165.1 to 168.201.165.254168.201.165.255254
167168.201.166.0/24168.201.166.1 to 168.201.166.254168.201.166.255254
168168.201.167.0/24168.201.167.1 to 168.201.167.254168.201.167.255254
169168.201.168.0/24168.201.168.1 to 168.201.168.254168.201.168.255254
170168.201.169.0/24168.201.169.1 to 168.201.169.254168.201.169.255254
171168.201.170.0/24168.201.170.1 to 168.201.170.254168.201.170.255254
172168.201.171.0/24168.201.171.1 to 168.201.171.254168.201.171.255254
173168.201.172.0/24168.201.172.1 to 168.201.172.254168.201.172.255254
174168.201.173.0/24168.201.173.1 to 168.201.173.254168.201.173.255254
175168.201.174.0/24168.201.174.1 to 168.201.174.254168.201.174.255254
176168.201.175.0/24168.201.175.1 to 168.201.175.254168.201.175.255254
177168.201.176.0/24168.201.176.1 to 168.201.176.254168.201.176.255254
178168.201.177.0/24168.201.177.1 to 168.201.177.254168.201.177.255254
179168.201.178.0/24168.201.178.1 to 168.201.178.254168.201.178.255254
180168.201.179.0/24168.201.179.1 to 168.201.179.254168.201.179.255254
181168.201.180.0/24168.201.180.1 to 168.201.180.254168.201.180.255254
182168.201.181.0/24168.201.181.1 to 168.201.181.254168.201.181.255254
183168.201.182.0/24168.201.182.1 to 168.201.182.254168.201.182.255254
184168.201.183.0/24168.201.183.1 to 168.201.183.254168.201.183.255254
185168.201.184.0/24168.201.184.1 to 168.201.184.254168.201.184.255254
186168.201.185.0/24168.201.185.1 to 168.201.185.254168.201.185.255254
187168.201.186.0/24168.201.186.1 to 168.201.186.254168.201.186.255254
188168.201.187.0/24168.201.187.1 to 168.201.187.254168.201.187.255254
189168.201.188.0/24168.201.188.1 to 168.201.188.254168.201.188.255254
190168.201.189.0/24168.201.189.1 to 168.201.189.254168.201.189.255254
191168.201.190.0/24168.201.190.1 to 168.201.190.254168.201.190.255254
192168.201.191.0/24168.201.191.1 to 168.201.191.254168.201.191.255254
193168.201.192.0/24168.201.192.1 to 168.201.192.254168.201.192.255254
194168.201.193.0/24168.201.193.1 to 168.201.193.254168.201.193.255254
195168.201.194.0/24168.201.194.1 to 168.201.194.254168.201.194.255254
196168.201.195.0/24168.201.195.1 to 168.201.195.254168.201.195.255254
197168.201.196.0/24168.201.196.1 to 168.201.196.254168.201.196.255254
198168.201.197.0/24168.201.197.1 to 168.201.197.254168.201.197.255254
199168.201.198.0/24168.201.198.1 to 168.201.198.254168.201.198.255254
200168.201.199.0/24168.201.199.1 to 168.201.199.254168.201.199.255254
201168.201.200.0/24168.201.200.1 to 168.201.200.254168.201.200.255254
202168.201.201.0/24168.201.201.1 to 168.201.201.254168.201.201.255254
203168.201.202.0/24168.201.202.1 to 168.201.202.254168.201.202.255254
204168.201.203.0/24168.201.203.1 to 168.201.203.254168.201.203.255254
205168.201.204.0/24168.201.204.1 to 168.201.204.254168.201.204.255254
206168.201.205.0/24168.201.205.1 to 168.201.205.254168.201.205.255254
207168.201.206.0/24168.201.206.1 to 168.201.206.254168.201.206.255254
208168.201.207.0/24168.201.207.1 to 168.201.207.254168.201.207.255254
209168.201.208.0/24168.201.208.1 to 168.201.208.254168.201.208.255254
210168.201.209.0/24168.201.209.1 to 168.201.209.254168.201.209.255254
211168.201.210.0/24168.201.210.1 to 168.201.210.254168.201.210.255254
212168.201.211.0/24168.201.211.1 to 168.201.211.254168.201.211.255254
213168.201.212.0/24168.201.212.1 to 168.201.212.254168.201.212.255254
214168.201.213.0/24168.201.213.1 to 168.201.213.254168.201.213.255254
215168.201.214.0/24168.201.214.1 to 168.201.214.254168.201.214.255254
216168.201.215.0/24168.201.215.1 to 168.201.215.254168.201.215.255254
217168.201.216.0/24168.201.216.1 to 168.201.216.254168.201.216.255254
218168.201.217.0/24168.201.217.1 to 168.201.217.254168.201.217.255254
219168.201.218.0/24168.201.218.1 to 168.201.218.254168.201.218.255254
220168.201.219.0/24168.201.219.1 to 168.201.219.254168.201.219.255254
221168.201.220.0/24168.201.220.1 to 168.201.220.254168.201.220.255254
222168.201.221.0/24168.201.221.1 to 168.201.221.254168.201.221.255254
223168.201.222.0/24168.201.222.1 to 168.201.222.254168.201.222.255254
224168.201.223.0/24168.201.223.1 to 168.201.223.254168.201.223.255254
225168.201.224.0/24168.201.224.1 to 168.201.224.254168.201.224.255254
226168.201.225.0/24168.201.225.1 to 168.201.225.254168.201.225.255254
227168.201.226.0/24168.201.226.1 to 168.201.226.254168.201.226.255254
228168.201.227.0/24168.201.227.1 to 168.201.227.254168.201.227.255254
229168.201.228.0/24168.201.228.1 to 168.201.228.254168.201.228.255254
230168.201.229.0/24168.201.229.1 to 168.201.229.254168.201.229.255254
231168.201.230.0/24168.201.230.1 to 168.201.230.254168.201.230.255254
232168.201.231.0/24168.201.231.1 to 168.201.231.254168.201.231.255254
233168.201.232.0/24168.201.232.1 to 168.201.232.254168.201.232.255254
234168.201.233.0/24168.201.233.1 to 168.201.233.254168.201.233.255254
235168.201.234.0/24168.201.234.1 to 168.201.234.254168.201.234.255254
236168.201.235.0/24168.201.235.1 to 168.201.235.254168.201.235.255254
237168.201.236.0/24168.201.236.1 to 168.201.236.254168.201.236.255254
238168.201.237.0/24168.201.237.1 to 168.201.237.254168.201.237.255254
239168.201.238.0/24168.201.238.1 to 168.201.238.254168.201.238.255254
240168.201.239.0/24168.201.239.1 to 168.201.239.254168.201.239.255254
241168.201.240.0/24168.201.240.1 to 168.201.240.254168.201.240.255254
242168.201.241.0/24168.201.241.1 to 168.201.241.254168.201.241.255254
243168.201.242.0/24168.201.242.1 to 168.201.242.254168.201.242.255254
244168.201.243.0/24168.201.243.1 to 168.201.243.254168.201.243.255254
245168.201.244.0/24168.201.244.1 to 168.201.244.254168.201.244.255254
246168.201.245.0/24168.201.245.1 to 168.201.245.254168.201.245.255254
247168.201.246.0/24168.201.246.1 to 168.201.246.254168.201.246.255254
248168.201.247.0/24168.201.247.1 to 168.201.247.254168.201.247.255254
249168.201.248.0/24168.201.248.1 to 168.201.248.254168.201.248.255254
250168.201.249.0/24168.201.249.1 to 168.201.249.254168.201.249.255254
251168.201.250.0/24168.201.250.1 to 168.201.250.254168.201.250.255254
252168.201.251.0/24168.201.251.1 to 168.201.251.254168.201.251.255254
253168.201.252.0/24168.201.252.1 to 168.201.252.254168.201.252.255254
254168.201.253.0/24168.201.253.1 to 168.201.253.254168.201.253.255254
255168.201.254.0/24168.201.254.1 to 168.201.254.254168.201.254.255254
256168.201.255.0/24168.201.255.1 to 168.201.255.254168.201.255.255254

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.