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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.

Network202.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
202.0.0.0
Broadcast address
203.255.255.255
First usable
202.0.0.1
Last usable
203.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
C (default /24)
As numbers
Hex CA000000 · Integer 3388997632 to 3422552063
Reverse DNS zones
202.in-addr.arpa
203.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001010.00000000.00000000.00000000202.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11001010.00000000.00000000.00000000202.0.0.0
Broadcast11001011.11111111.11111111.11111111203.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

202.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1202.0.0.0/15202.0.0.1 to 202.1.255.254202.1.255.255131,070
2202.2.0.0/15202.2.0.1 to 202.3.255.254202.3.255.255131,070
3202.4.0.0/15202.4.0.1 to 202.5.255.254202.5.255.255131,070
4202.6.0.0/15202.6.0.1 to 202.7.255.254202.7.255.255131,070
5202.8.0.0/15202.8.0.1 to 202.9.255.254202.9.255.255131,070
6202.10.0.0/15202.10.0.1 to 202.11.255.254202.11.255.255131,070
7202.12.0.0/15202.12.0.1 to 202.13.255.254202.13.255.255131,070
8202.14.0.0/15202.14.0.1 to 202.15.255.254202.15.255.255131,070
9202.16.0.0/15202.16.0.1 to 202.17.255.254202.17.255.255131,070
10202.18.0.0/15202.18.0.1 to 202.19.255.254202.19.255.255131,070
11202.20.0.0/15202.20.0.1 to 202.21.255.254202.21.255.255131,070
12202.22.0.0/15202.22.0.1 to 202.23.255.254202.23.255.255131,070
13202.24.0.0/15202.24.0.1 to 202.25.255.254202.25.255.255131,070
14202.26.0.0/15202.26.0.1 to 202.27.255.254202.27.255.255131,070
15202.28.0.0/15202.28.0.1 to 202.29.255.254202.29.255.255131,070
16202.30.0.0/15202.30.0.1 to 202.31.255.254202.31.255.255131,070
17202.32.0.0/15202.32.0.1 to 202.33.255.254202.33.255.255131,070
18202.34.0.0/15202.34.0.1 to 202.35.255.254202.35.255.255131,070
19202.36.0.0/15202.36.0.1 to 202.37.255.254202.37.255.255131,070
20202.38.0.0/15202.38.0.1 to 202.39.255.254202.39.255.255131,070
21202.40.0.0/15202.40.0.1 to 202.41.255.254202.41.255.255131,070
22202.42.0.0/15202.42.0.1 to 202.43.255.254202.43.255.255131,070
23202.44.0.0/15202.44.0.1 to 202.45.255.254202.45.255.255131,070
24202.46.0.0/15202.46.0.1 to 202.47.255.254202.47.255.255131,070
25202.48.0.0/15202.48.0.1 to 202.49.255.254202.49.255.255131,070
26202.50.0.0/15202.50.0.1 to 202.51.255.254202.51.255.255131,070
27202.52.0.0/15202.52.0.1 to 202.53.255.254202.53.255.255131,070
28202.54.0.0/15202.54.0.1 to 202.55.255.254202.55.255.255131,070
29202.56.0.0/15202.56.0.1 to 202.57.255.254202.57.255.255131,070
30202.58.0.0/15202.58.0.1 to 202.59.255.254202.59.255.255131,070
31202.60.0.0/15202.60.0.1 to 202.61.255.254202.61.255.255131,070
32202.62.0.0/15202.62.0.1 to 202.63.255.254202.63.255.255131,070
33202.64.0.0/15202.64.0.1 to 202.65.255.254202.65.255.255131,070
34202.66.0.0/15202.66.0.1 to 202.67.255.254202.67.255.255131,070
35202.68.0.0/15202.68.0.1 to 202.69.255.254202.69.255.255131,070
36202.70.0.0/15202.70.0.1 to 202.71.255.254202.71.255.255131,070
37202.72.0.0/15202.72.0.1 to 202.73.255.254202.73.255.255131,070
38202.74.0.0/15202.74.0.1 to 202.75.255.254202.75.255.255131,070
39202.76.0.0/15202.76.0.1 to 202.77.255.254202.77.255.255131,070
40202.78.0.0/15202.78.0.1 to 202.79.255.254202.79.255.255131,070
41202.80.0.0/15202.80.0.1 to 202.81.255.254202.81.255.255131,070
42202.82.0.0/15202.82.0.1 to 202.83.255.254202.83.255.255131,070
43202.84.0.0/15202.84.0.1 to 202.85.255.254202.85.255.255131,070
44202.86.0.0/15202.86.0.1 to 202.87.255.254202.87.255.255131,070
45202.88.0.0/15202.88.0.1 to 202.89.255.254202.89.255.255131,070
46202.90.0.0/15202.90.0.1 to 202.91.255.254202.91.255.255131,070
47202.92.0.0/15202.92.0.1 to 202.93.255.254202.93.255.255131,070
48202.94.0.0/15202.94.0.1 to 202.95.255.254202.95.255.255131,070
49202.96.0.0/15202.96.0.1 to 202.97.255.254202.97.255.255131,070
50202.98.0.0/15202.98.0.1 to 202.99.255.254202.99.255.255131,070
51202.100.0.0/15202.100.0.1 to 202.101.255.254202.101.255.255131,070
52202.102.0.0/15202.102.0.1 to 202.103.255.254202.103.255.255131,070
53202.104.0.0/15202.104.0.1 to 202.105.255.254202.105.255.255131,070
54202.106.0.0/15202.106.0.1 to 202.107.255.254202.107.255.255131,070
55202.108.0.0/15202.108.0.1 to 202.109.255.254202.109.255.255131,070
56202.110.0.0/15202.110.0.1 to 202.111.255.254202.111.255.255131,070
57202.112.0.0/15202.112.0.1 to 202.113.255.254202.113.255.255131,070
58202.114.0.0/15202.114.0.1 to 202.115.255.254202.115.255.255131,070
59202.116.0.0/15202.116.0.1 to 202.117.255.254202.117.255.255131,070
60202.118.0.0/15202.118.0.1 to 202.119.255.254202.119.255.255131,070
61202.120.0.0/15202.120.0.1 to 202.121.255.254202.121.255.255131,070
62202.122.0.0/15202.122.0.1 to 202.123.255.254202.123.255.255131,070
63202.124.0.0/15202.124.0.1 to 202.125.255.254202.125.255.255131,070
64202.126.0.0/15202.126.0.1 to 202.127.255.254202.127.255.255131,070
65202.128.0.0/15202.128.0.1 to 202.129.255.254202.129.255.255131,070
66202.130.0.0/15202.130.0.1 to 202.131.255.254202.131.255.255131,070
67202.132.0.0/15202.132.0.1 to 202.133.255.254202.133.255.255131,070
68202.134.0.0/15202.134.0.1 to 202.135.255.254202.135.255.255131,070
69202.136.0.0/15202.136.0.1 to 202.137.255.254202.137.255.255131,070
70202.138.0.0/15202.138.0.1 to 202.139.255.254202.139.255.255131,070
71202.140.0.0/15202.140.0.1 to 202.141.255.254202.141.255.255131,070
72202.142.0.0/15202.142.0.1 to 202.143.255.254202.143.255.255131,070
73202.144.0.0/15202.144.0.1 to 202.145.255.254202.145.255.255131,070
74202.146.0.0/15202.146.0.1 to 202.147.255.254202.147.255.255131,070
75202.148.0.0/15202.148.0.1 to 202.149.255.254202.149.255.255131,070
76202.150.0.0/15202.150.0.1 to 202.151.255.254202.151.255.255131,070
77202.152.0.0/15202.152.0.1 to 202.153.255.254202.153.255.255131,070
78202.154.0.0/15202.154.0.1 to 202.155.255.254202.155.255.255131,070
79202.156.0.0/15202.156.0.1 to 202.157.255.254202.157.255.255131,070
80202.158.0.0/15202.158.0.1 to 202.159.255.254202.159.255.255131,070
81202.160.0.0/15202.160.0.1 to 202.161.255.254202.161.255.255131,070
82202.162.0.0/15202.162.0.1 to 202.163.255.254202.163.255.255131,070
83202.164.0.0/15202.164.0.1 to 202.165.255.254202.165.255.255131,070
84202.166.0.0/15202.166.0.1 to 202.167.255.254202.167.255.255131,070
85202.168.0.0/15202.168.0.1 to 202.169.255.254202.169.255.255131,070
86202.170.0.0/15202.170.0.1 to 202.171.255.254202.171.255.255131,070
87202.172.0.0/15202.172.0.1 to 202.173.255.254202.173.255.255131,070
88202.174.0.0/15202.174.0.1 to 202.175.255.254202.175.255.255131,070
89202.176.0.0/15202.176.0.1 to 202.177.255.254202.177.255.255131,070
90202.178.0.0/15202.178.0.1 to 202.179.255.254202.179.255.255131,070
91202.180.0.0/15202.180.0.1 to 202.181.255.254202.181.255.255131,070
92202.182.0.0/15202.182.0.1 to 202.183.255.254202.183.255.255131,070
93202.184.0.0/15202.184.0.1 to 202.185.255.254202.185.255.255131,070
94202.186.0.0/15202.186.0.1 to 202.187.255.254202.187.255.255131,070
95202.188.0.0/15202.188.0.1 to 202.189.255.254202.189.255.255131,070
96202.190.0.0/15202.190.0.1 to 202.191.255.254202.191.255.255131,070
97202.192.0.0/15202.192.0.1 to 202.193.255.254202.193.255.255131,070
98202.194.0.0/15202.194.0.1 to 202.195.255.254202.195.255.255131,070
99202.196.0.0/15202.196.0.1 to 202.197.255.254202.197.255.255131,070
100202.198.0.0/15202.198.0.1 to 202.199.255.254202.199.255.255131,070
101202.200.0.0/15202.200.0.1 to 202.201.255.254202.201.255.255131,070
102202.202.0.0/15202.202.0.1 to 202.203.255.254202.203.255.255131,070
103202.204.0.0/15202.204.0.1 to 202.205.255.254202.205.255.255131,070
104202.206.0.0/15202.206.0.1 to 202.207.255.254202.207.255.255131,070
105202.208.0.0/15202.208.0.1 to 202.209.255.254202.209.255.255131,070
106202.210.0.0/15202.210.0.1 to 202.211.255.254202.211.255.255131,070
107202.212.0.0/15202.212.0.1 to 202.213.255.254202.213.255.255131,070
108202.214.0.0/15202.214.0.1 to 202.215.255.254202.215.255.255131,070
109202.216.0.0/15202.216.0.1 to 202.217.255.254202.217.255.255131,070
110202.218.0.0/15202.218.0.1 to 202.219.255.254202.219.255.255131,070
111202.220.0.0/15202.220.0.1 to 202.221.255.254202.221.255.255131,070
112202.222.0.0/15202.222.0.1 to 202.223.255.254202.223.255.255131,070
113202.224.0.0/15202.224.0.1 to 202.225.255.254202.225.255.255131,070
114202.226.0.0/15202.226.0.1 to 202.227.255.254202.227.255.255131,070
115202.228.0.0/15202.228.0.1 to 202.229.255.254202.229.255.255131,070
116202.230.0.0/15202.230.0.1 to 202.231.255.254202.231.255.255131,070
117202.232.0.0/15202.232.0.1 to 202.233.255.254202.233.255.255131,070
118202.234.0.0/15202.234.0.1 to 202.235.255.254202.235.255.255131,070
119202.236.0.0/15202.236.0.1 to 202.237.255.254202.237.255.255131,070
120202.238.0.0/15202.238.0.1 to 202.239.255.254202.239.255.255131,070
121202.240.0.0/15202.240.0.1 to 202.241.255.254202.241.255.255131,070
122202.242.0.0/15202.242.0.1 to 202.243.255.254202.243.255.255131,070
123202.244.0.0/15202.244.0.1 to 202.245.255.254202.245.255.255131,070
124202.246.0.0/15202.246.0.1 to 202.247.255.254202.247.255.255131,070
125202.248.0.0/15202.248.0.1 to 202.249.255.254202.249.255.255131,070
126202.250.0.0/15202.250.0.1 to 202.251.255.254202.251.255.255131,070
127202.252.0.0/15202.252.0.1 to 202.253.255.254202.253.255.255131,070
128202.254.0.0/15202.254.0.1 to 202.255.255.254202.255.255.255131,070
129203.0.0.0/15203.0.0.1 to 203.1.255.254203.1.255.255131,070
130203.2.0.0/15203.2.0.1 to 203.3.255.254203.3.255.255131,070
131203.4.0.0/15203.4.0.1 to 203.5.255.254203.5.255.255131,070
132203.6.0.0/15203.6.0.1 to 203.7.255.254203.7.255.255131,070
133203.8.0.0/15203.8.0.1 to 203.9.255.254203.9.255.255131,070
134203.10.0.0/15203.10.0.1 to 203.11.255.254203.11.255.255131,070
135203.12.0.0/15203.12.0.1 to 203.13.255.254203.13.255.255131,070
136203.14.0.0/15203.14.0.1 to 203.15.255.254203.15.255.255131,070
137203.16.0.0/15203.16.0.1 to 203.17.255.254203.17.255.255131,070
138203.18.0.0/15203.18.0.1 to 203.19.255.254203.19.255.255131,070
139203.20.0.0/15203.20.0.1 to 203.21.255.254203.21.255.255131,070
140203.22.0.0/15203.22.0.1 to 203.23.255.254203.23.255.255131,070
141203.24.0.0/15203.24.0.1 to 203.25.255.254203.25.255.255131,070
142203.26.0.0/15203.26.0.1 to 203.27.255.254203.27.255.255131,070
143203.28.0.0/15203.28.0.1 to 203.29.255.254203.29.255.255131,070
144203.30.0.0/15203.30.0.1 to 203.31.255.254203.31.255.255131,070
145203.32.0.0/15203.32.0.1 to 203.33.255.254203.33.255.255131,070
146203.34.0.0/15203.34.0.1 to 203.35.255.254203.35.255.255131,070
147203.36.0.0/15203.36.0.1 to 203.37.255.254203.37.255.255131,070
148203.38.0.0/15203.38.0.1 to 203.39.255.254203.39.255.255131,070
149203.40.0.0/15203.40.0.1 to 203.41.255.254203.41.255.255131,070
150203.42.0.0/15203.42.0.1 to 203.43.255.254203.43.255.255131,070
151203.44.0.0/15203.44.0.1 to 203.45.255.254203.45.255.255131,070
152203.46.0.0/15203.46.0.1 to 203.47.255.254203.47.255.255131,070
153203.48.0.0/15203.48.0.1 to 203.49.255.254203.49.255.255131,070
154203.50.0.0/15203.50.0.1 to 203.51.255.254203.51.255.255131,070
155203.52.0.0/15203.52.0.1 to 203.53.255.254203.53.255.255131,070
156203.54.0.0/15203.54.0.1 to 203.55.255.254203.55.255.255131,070
157203.56.0.0/15203.56.0.1 to 203.57.255.254203.57.255.255131,070
158203.58.0.0/15203.58.0.1 to 203.59.255.254203.59.255.255131,070
159203.60.0.0/15203.60.0.1 to 203.61.255.254203.61.255.255131,070
160203.62.0.0/15203.62.0.1 to 203.63.255.254203.63.255.255131,070
161203.64.0.0/15203.64.0.1 to 203.65.255.254203.65.255.255131,070
162203.66.0.0/15203.66.0.1 to 203.67.255.254203.67.255.255131,070
163203.68.0.0/15203.68.0.1 to 203.69.255.254203.69.255.255131,070
164203.70.0.0/15203.70.0.1 to 203.71.255.254203.71.255.255131,070
165203.72.0.0/15203.72.0.1 to 203.73.255.254203.73.255.255131,070
166203.74.0.0/15203.74.0.1 to 203.75.255.254203.75.255.255131,070
167203.76.0.0/15203.76.0.1 to 203.77.255.254203.77.255.255131,070
168203.78.0.0/15203.78.0.1 to 203.79.255.254203.79.255.255131,070
169203.80.0.0/15203.80.0.1 to 203.81.255.254203.81.255.255131,070
170203.82.0.0/15203.82.0.1 to 203.83.255.254203.83.255.255131,070
171203.84.0.0/15203.84.0.1 to 203.85.255.254203.85.255.255131,070
172203.86.0.0/15203.86.0.1 to 203.87.255.254203.87.255.255131,070
173203.88.0.0/15203.88.0.1 to 203.89.255.254203.89.255.255131,070
174203.90.0.0/15203.90.0.1 to 203.91.255.254203.91.255.255131,070
175203.92.0.0/15203.92.0.1 to 203.93.255.254203.93.255.255131,070
176203.94.0.0/15203.94.0.1 to 203.95.255.254203.95.255.255131,070
177203.96.0.0/15203.96.0.1 to 203.97.255.254203.97.255.255131,070
178203.98.0.0/15203.98.0.1 to 203.99.255.254203.99.255.255131,070
179203.100.0.0/15203.100.0.1 to 203.101.255.254203.101.255.255131,070
180203.102.0.0/15203.102.0.1 to 203.103.255.254203.103.255.255131,070
181203.104.0.0/15203.104.0.1 to 203.105.255.254203.105.255.255131,070
182203.106.0.0/15203.106.0.1 to 203.107.255.254203.107.255.255131,070
183203.108.0.0/15203.108.0.1 to 203.109.255.254203.109.255.255131,070
184203.110.0.0/15203.110.0.1 to 203.111.255.254203.111.255.255131,070
185203.112.0.0/15203.112.0.1 to 203.113.255.254203.113.255.255131,070
186203.114.0.0/15203.114.0.1 to 203.115.255.254203.115.255.255131,070
187203.116.0.0/15203.116.0.1 to 203.117.255.254203.117.255.255131,070
188203.118.0.0/15203.118.0.1 to 203.119.255.254203.119.255.255131,070
189203.120.0.0/15203.120.0.1 to 203.121.255.254203.121.255.255131,070
190203.122.0.0/15203.122.0.1 to 203.123.255.254203.123.255.255131,070
191203.124.0.0/15203.124.0.1 to 203.125.255.254203.125.255.255131,070
192203.126.0.0/15203.126.0.1 to 203.127.255.254203.127.255.255131,070
193203.128.0.0/15203.128.0.1 to 203.129.255.254203.129.255.255131,070
194203.130.0.0/15203.130.0.1 to 203.131.255.254203.131.255.255131,070
195203.132.0.0/15203.132.0.1 to 203.133.255.254203.133.255.255131,070
196203.134.0.0/15203.134.0.1 to 203.135.255.254203.135.255.255131,070
197203.136.0.0/15203.136.0.1 to 203.137.255.254203.137.255.255131,070
198203.138.0.0/15203.138.0.1 to 203.139.255.254203.139.255.255131,070
199203.140.0.0/15203.140.0.1 to 203.141.255.254203.141.255.255131,070
200203.142.0.0/15203.142.0.1 to 203.143.255.254203.143.255.255131,070
201203.144.0.0/15203.144.0.1 to 203.145.255.254203.145.255.255131,070
202203.146.0.0/15203.146.0.1 to 203.147.255.254203.147.255.255131,070
203203.148.0.0/15203.148.0.1 to 203.149.255.254203.149.255.255131,070
204203.150.0.0/15203.150.0.1 to 203.151.255.254203.151.255.255131,070
205203.152.0.0/15203.152.0.1 to 203.153.255.254203.153.255.255131,070
206203.154.0.0/15203.154.0.1 to 203.155.255.254203.155.255.255131,070
207203.156.0.0/15203.156.0.1 to 203.157.255.254203.157.255.255131,070
208203.158.0.0/15203.158.0.1 to 203.159.255.254203.159.255.255131,070
209203.160.0.0/15203.160.0.1 to 203.161.255.254203.161.255.255131,070
210203.162.0.0/15203.162.0.1 to 203.163.255.254203.163.255.255131,070
211203.164.0.0/15203.164.0.1 to 203.165.255.254203.165.255.255131,070
212203.166.0.0/15203.166.0.1 to 203.167.255.254203.167.255.255131,070
213203.168.0.0/15203.168.0.1 to 203.169.255.254203.169.255.255131,070
214203.170.0.0/15203.170.0.1 to 203.171.255.254203.171.255.255131,070
215203.172.0.0/15203.172.0.1 to 203.173.255.254203.173.255.255131,070
216203.174.0.0/15203.174.0.1 to 203.175.255.254203.175.255.255131,070
217203.176.0.0/15203.176.0.1 to 203.177.255.254203.177.255.255131,070
218203.178.0.0/15203.178.0.1 to 203.179.255.254203.179.255.255131,070
219203.180.0.0/15203.180.0.1 to 203.181.255.254203.181.255.255131,070
220203.182.0.0/15203.182.0.1 to 203.183.255.254203.183.255.255131,070
221203.184.0.0/15203.184.0.1 to 203.185.255.254203.185.255.255131,070
222203.186.0.0/15203.186.0.1 to 203.187.255.254203.187.255.255131,070
223203.188.0.0/15203.188.0.1 to 203.189.255.254203.189.255.255131,070
224203.190.0.0/15203.190.0.1 to 203.191.255.254203.191.255.255131,070
225203.192.0.0/15203.192.0.1 to 203.193.255.254203.193.255.255131,070
226203.194.0.0/15203.194.0.1 to 203.195.255.254203.195.255.255131,070
227203.196.0.0/15203.196.0.1 to 203.197.255.254203.197.255.255131,070
228203.198.0.0/15203.198.0.1 to 203.199.255.254203.199.255.255131,070
229203.200.0.0/15203.200.0.1 to 203.201.255.254203.201.255.255131,070
230203.202.0.0/15203.202.0.1 to 203.203.255.254203.203.255.255131,070
231203.204.0.0/15203.204.0.1 to 203.205.255.254203.205.255.255131,070
232203.206.0.0/15203.206.0.1 to 203.207.255.254203.207.255.255131,070
233203.208.0.0/15203.208.0.1 to 203.209.255.254203.209.255.255131,070
234203.210.0.0/15203.210.0.1 to 203.211.255.254203.211.255.255131,070
235203.212.0.0/15203.212.0.1 to 203.213.255.254203.213.255.255131,070
236203.214.0.0/15203.214.0.1 to 203.215.255.254203.215.255.255131,070
237203.216.0.0/15203.216.0.1 to 203.217.255.254203.217.255.255131,070
238203.218.0.0/15203.218.0.1 to 203.219.255.254203.219.255.255131,070
239203.220.0.0/15203.220.0.1 to 203.221.255.254203.221.255.255131,070
240203.222.0.0/15203.222.0.1 to 203.223.255.254203.223.255.255131,070
241203.224.0.0/15203.224.0.1 to 203.225.255.254203.225.255.255131,070
242203.226.0.0/15203.226.0.1 to 203.227.255.254203.227.255.255131,070
243203.228.0.0/15203.228.0.1 to 203.229.255.254203.229.255.255131,070
244203.230.0.0/15203.230.0.1 to 203.231.255.254203.231.255.255131,070
245203.232.0.0/15203.232.0.1 to 203.233.255.254203.233.255.255131,070
246203.234.0.0/15203.234.0.1 to 203.235.255.254203.235.255.255131,070
247203.236.0.0/15203.236.0.1 to 203.237.255.254203.237.255.255131,070
248203.238.0.0/15203.238.0.1 to 203.239.255.254203.239.255.255131,070
249203.240.0.0/15203.240.0.1 to 203.241.255.254203.241.255.255131,070
250203.242.0.0/15203.242.0.1 to 203.243.255.254203.243.255.255131,070
251203.244.0.0/15203.244.0.1 to 203.245.255.254203.245.255.255131,070
252203.246.0.0/15203.246.0.1 to 203.247.255.254203.247.255.255131,070
253203.248.0.0/15203.248.0.1 to 203.249.255.254203.249.255.255131,070
254203.250.0.0/15203.250.0.1 to 203.251.255.254203.251.255.255131,070
255203.252.0.0/15203.252.0.1 to 203.253.255.254203.253.255.255131,070
256203.254.0.0/15203.254.0.1 to 203.255.255.254203.255.255.255131,070

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.