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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.

Network246.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
246.0.0.0
Broadcast address
247.255.255.255
First usable
246.0.0.1
Last usable
247.255.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F6000000 · Integer 4127195136 to 4160749567
Reverse DNS zones
246.in-addr.arpa
247.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
Address11110110.00000000.00000000.00000000246.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11110110.00000000.00000000.00000000246.0.0.0
Broadcast11110111.11111111.11111111.11111111247.255.255.255
Split into smaller subnets/16
/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)

246.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1246.0.0.0/16246.0.0.1 to 246.0.255.254246.0.255.25565,534
2246.1.0.0/16246.1.0.1 to 246.1.255.254246.1.255.25565,534
3246.2.0.0/16246.2.0.1 to 246.2.255.254246.2.255.25565,534
4246.3.0.0/16246.3.0.1 to 246.3.255.254246.3.255.25565,534
5246.4.0.0/16246.4.0.1 to 246.4.255.254246.4.255.25565,534
6246.5.0.0/16246.5.0.1 to 246.5.255.254246.5.255.25565,534
7246.6.0.0/16246.6.0.1 to 246.6.255.254246.6.255.25565,534
8246.7.0.0/16246.7.0.1 to 246.7.255.254246.7.255.25565,534
9246.8.0.0/16246.8.0.1 to 246.8.255.254246.8.255.25565,534
10246.9.0.0/16246.9.0.1 to 246.9.255.254246.9.255.25565,534
11246.10.0.0/16246.10.0.1 to 246.10.255.254246.10.255.25565,534
12246.11.0.0/16246.11.0.1 to 246.11.255.254246.11.255.25565,534
13246.12.0.0/16246.12.0.1 to 246.12.255.254246.12.255.25565,534
14246.13.0.0/16246.13.0.1 to 246.13.255.254246.13.255.25565,534
15246.14.0.0/16246.14.0.1 to 246.14.255.254246.14.255.25565,534
16246.15.0.0/16246.15.0.1 to 246.15.255.254246.15.255.25565,534
17246.16.0.0/16246.16.0.1 to 246.16.255.254246.16.255.25565,534
18246.17.0.0/16246.17.0.1 to 246.17.255.254246.17.255.25565,534
19246.18.0.0/16246.18.0.1 to 246.18.255.254246.18.255.25565,534
20246.19.0.0/16246.19.0.1 to 246.19.255.254246.19.255.25565,534
21246.20.0.0/16246.20.0.1 to 246.20.255.254246.20.255.25565,534
22246.21.0.0/16246.21.0.1 to 246.21.255.254246.21.255.25565,534
23246.22.0.0/16246.22.0.1 to 246.22.255.254246.22.255.25565,534
24246.23.0.0/16246.23.0.1 to 246.23.255.254246.23.255.25565,534
25246.24.0.0/16246.24.0.1 to 246.24.255.254246.24.255.25565,534
26246.25.0.0/16246.25.0.1 to 246.25.255.254246.25.255.25565,534
27246.26.0.0/16246.26.0.1 to 246.26.255.254246.26.255.25565,534
28246.27.0.0/16246.27.0.1 to 246.27.255.254246.27.255.25565,534
29246.28.0.0/16246.28.0.1 to 246.28.255.254246.28.255.25565,534
30246.29.0.0/16246.29.0.1 to 246.29.255.254246.29.255.25565,534
31246.30.0.0/16246.30.0.1 to 246.30.255.254246.30.255.25565,534
32246.31.0.0/16246.31.0.1 to 246.31.255.254246.31.255.25565,534
33246.32.0.0/16246.32.0.1 to 246.32.255.254246.32.255.25565,534
34246.33.0.0/16246.33.0.1 to 246.33.255.254246.33.255.25565,534
35246.34.0.0/16246.34.0.1 to 246.34.255.254246.34.255.25565,534
36246.35.0.0/16246.35.0.1 to 246.35.255.254246.35.255.25565,534
37246.36.0.0/16246.36.0.1 to 246.36.255.254246.36.255.25565,534
38246.37.0.0/16246.37.0.1 to 246.37.255.254246.37.255.25565,534
39246.38.0.0/16246.38.0.1 to 246.38.255.254246.38.255.25565,534
40246.39.0.0/16246.39.0.1 to 246.39.255.254246.39.255.25565,534
41246.40.0.0/16246.40.0.1 to 246.40.255.254246.40.255.25565,534
42246.41.0.0/16246.41.0.1 to 246.41.255.254246.41.255.25565,534
43246.42.0.0/16246.42.0.1 to 246.42.255.254246.42.255.25565,534
44246.43.0.0/16246.43.0.1 to 246.43.255.254246.43.255.25565,534
45246.44.0.0/16246.44.0.1 to 246.44.255.254246.44.255.25565,534
46246.45.0.0/16246.45.0.1 to 246.45.255.254246.45.255.25565,534
47246.46.0.0/16246.46.0.1 to 246.46.255.254246.46.255.25565,534
48246.47.0.0/16246.47.0.1 to 246.47.255.254246.47.255.25565,534
49246.48.0.0/16246.48.0.1 to 246.48.255.254246.48.255.25565,534
50246.49.0.0/16246.49.0.1 to 246.49.255.254246.49.255.25565,534
51246.50.0.0/16246.50.0.1 to 246.50.255.254246.50.255.25565,534
52246.51.0.0/16246.51.0.1 to 246.51.255.254246.51.255.25565,534
53246.52.0.0/16246.52.0.1 to 246.52.255.254246.52.255.25565,534
54246.53.0.0/16246.53.0.1 to 246.53.255.254246.53.255.25565,534
55246.54.0.0/16246.54.0.1 to 246.54.255.254246.54.255.25565,534
56246.55.0.0/16246.55.0.1 to 246.55.255.254246.55.255.25565,534
57246.56.0.0/16246.56.0.1 to 246.56.255.254246.56.255.25565,534
58246.57.0.0/16246.57.0.1 to 246.57.255.254246.57.255.25565,534
59246.58.0.0/16246.58.0.1 to 246.58.255.254246.58.255.25565,534
60246.59.0.0/16246.59.0.1 to 246.59.255.254246.59.255.25565,534
61246.60.0.0/16246.60.0.1 to 246.60.255.254246.60.255.25565,534
62246.61.0.0/16246.61.0.1 to 246.61.255.254246.61.255.25565,534
63246.62.0.0/16246.62.0.1 to 246.62.255.254246.62.255.25565,534
64246.63.0.0/16246.63.0.1 to 246.63.255.254246.63.255.25565,534
65246.64.0.0/16246.64.0.1 to 246.64.255.254246.64.255.25565,534
66246.65.0.0/16246.65.0.1 to 246.65.255.254246.65.255.25565,534
67246.66.0.0/16246.66.0.1 to 246.66.255.254246.66.255.25565,534
68246.67.0.0/16246.67.0.1 to 246.67.255.254246.67.255.25565,534
69246.68.0.0/16246.68.0.1 to 246.68.255.254246.68.255.25565,534
70246.69.0.0/16246.69.0.1 to 246.69.255.254246.69.255.25565,534
71246.70.0.0/16246.70.0.1 to 246.70.255.254246.70.255.25565,534
72246.71.0.0/16246.71.0.1 to 246.71.255.254246.71.255.25565,534
73246.72.0.0/16246.72.0.1 to 246.72.255.254246.72.255.25565,534
74246.73.0.0/16246.73.0.1 to 246.73.255.254246.73.255.25565,534
75246.74.0.0/16246.74.0.1 to 246.74.255.254246.74.255.25565,534
76246.75.0.0/16246.75.0.1 to 246.75.255.254246.75.255.25565,534
77246.76.0.0/16246.76.0.1 to 246.76.255.254246.76.255.25565,534
78246.77.0.0/16246.77.0.1 to 246.77.255.254246.77.255.25565,534
79246.78.0.0/16246.78.0.1 to 246.78.255.254246.78.255.25565,534
80246.79.0.0/16246.79.0.1 to 246.79.255.254246.79.255.25565,534
81246.80.0.0/16246.80.0.1 to 246.80.255.254246.80.255.25565,534
82246.81.0.0/16246.81.0.1 to 246.81.255.254246.81.255.25565,534
83246.82.0.0/16246.82.0.1 to 246.82.255.254246.82.255.25565,534
84246.83.0.0/16246.83.0.1 to 246.83.255.254246.83.255.25565,534
85246.84.0.0/16246.84.0.1 to 246.84.255.254246.84.255.25565,534
86246.85.0.0/16246.85.0.1 to 246.85.255.254246.85.255.25565,534
87246.86.0.0/16246.86.0.1 to 246.86.255.254246.86.255.25565,534
88246.87.0.0/16246.87.0.1 to 246.87.255.254246.87.255.25565,534
89246.88.0.0/16246.88.0.1 to 246.88.255.254246.88.255.25565,534
90246.89.0.0/16246.89.0.1 to 246.89.255.254246.89.255.25565,534
91246.90.0.0/16246.90.0.1 to 246.90.255.254246.90.255.25565,534
92246.91.0.0/16246.91.0.1 to 246.91.255.254246.91.255.25565,534
93246.92.0.0/16246.92.0.1 to 246.92.255.254246.92.255.25565,534
94246.93.0.0/16246.93.0.1 to 246.93.255.254246.93.255.25565,534
95246.94.0.0/16246.94.0.1 to 246.94.255.254246.94.255.25565,534
96246.95.0.0/16246.95.0.1 to 246.95.255.254246.95.255.25565,534
97246.96.0.0/16246.96.0.1 to 246.96.255.254246.96.255.25565,534
98246.97.0.0/16246.97.0.1 to 246.97.255.254246.97.255.25565,534
99246.98.0.0/16246.98.0.1 to 246.98.255.254246.98.255.25565,534
100246.99.0.0/16246.99.0.1 to 246.99.255.254246.99.255.25565,534
101246.100.0.0/16246.100.0.1 to 246.100.255.254246.100.255.25565,534
102246.101.0.0/16246.101.0.1 to 246.101.255.254246.101.255.25565,534
103246.102.0.0/16246.102.0.1 to 246.102.255.254246.102.255.25565,534
104246.103.0.0/16246.103.0.1 to 246.103.255.254246.103.255.25565,534
105246.104.0.0/16246.104.0.1 to 246.104.255.254246.104.255.25565,534
106246.105.0.0/16246.105.0.1 to 246.105.255.254246.105.255.25565,534
107246.106.0.0/16246.106.0.1 to 246.106.255.254246.106.255.25565,534
108246.107.0.0/16246.107.0.1 to 246.107.255.254246.107.255.25565,534
109246.108.0.0/16246.108.0.1 to 246.108.255.254246.108.255.25565,534
110246.109.0.0/16246.109.0.1 to 246.109.255.254246.109.255.25565,534
111246.110.0.0/16246.110.0.1 to 246.110.255.254246.110.255.25565,534
112246.111.0.0/16246.111.0.1 to 246.111.255.254246.111.255.25565,534
113246.112.0.0/16246.112.0.1 to 246.112.255.254246.112.255.25565,534
114246.113.0.0/16246.113.0.1 to 246.113.255.254246.113.255.25565,534
115246.114.0.0/16246.114.0.1 to 246.114.255.254246.114.255.25565,534
116246.115.0.0/16246.115.0.1 to 246.115.255.254246.115.255.25565,534
117246.116.0.0/16246.116.0.1 to 246.116.255.254246.116.255.25565,534
118246.117.0.0/16246.117.0.1 to 246.117.255.254246.117.255.25565,534
119246.118.0.0/16246.118.0.1 to 246.118.255.254246.118.255.25565,534
120246.119.0.0/16246.119.0.1 to 246.119.255.254246.119.255.25565,534
121246.120.0.0/16246.120.0.1 to 246.120.255.254246.120.255.25565,534
122246.121.0.0/16246.121.0.1 to 246.121.255.254246.121.255.25565,534
123246.122.0.0/16246.122.0.1 to 246.122.255.254246.122.255.25565,534
124246.123.0.0/16246.123.0.1 to 246.123.255.254246.123.255.25565,534
125246.124.0.0/16246.124.0.1 to 246.124.255.254246.124.255.25565,534
126246.125.0.0/16246.125.0.1 to 246.125.255.254246.125.255.25565,534
127246.126.0.0/16246.126.0.1 to 246.126.255.254246.126.255.25565,534
128246.127.0.0/16246.127.0.1 to 246.127.255.254246.127.255.25565,534
129246.128.0.0/16246.128.0.1 to 246.128.255.254246.128.255.25565,534
130246.129.0.0/16246.129.0.1 to 246.129.255.254246.129.255.25565,534
131246.130.0.0/16246.130.0.1 to 246.130.255.254246.130.255.25565,534
132246.131.0.0/16246.131.0.1 to 246.131.255.254246.131.255.25565,534
133246.132.0.0/16246.132.0.1 to 246.132.255.254246.132.255.25565,534
134246.133.0.0/16246.133.0.1 to 246.133.255.254246.133.255.25565,534
135246.134.0.0/16246.134.0.1 to 246.134.255.254246.134.255.25565,534
136246.135.0.0/16246.135.0.1 to 246.135.255.254246.135.255.25565,534
137246.136.0.0/16246.136.0.1 to 246.136.255.254246.136.255.25565,534
138246.137.0.0/16246.137.0.1 to 246.137.255.254246.137.255.25565,534
139246.138.0.0/16246.138.0.1 to 246.138.255.254246.138.255.25565,534
140246.139.0.0/16246.139.0.1 to 246.139.255.254246.139.255.25565,534
141246.140.0.0/16246.140.0.1 to 246.140.255.254246.140.255.25565,534
142246.141.0.0/16246.141.0.1 to 246.141.255.254246.141.255.25565,534
143246.142.0.0/16246.142.0.1 to 246.142.255.254246.142.255.25565,534
144246.143.0.0/16246.143.0.1 to 246.143.255.254246.143.255.25565,534
145246.144.0.0/16246.144.0.1 to 246.144.255.254246.144.255.25565,534
146246.145.0.0/16246.145.0.1 to 246.145.255.254246.145.255.25565,534
147246.146.0.0/16246.146.0.1 to 246.146.255.254246.146.255.25565,534
148246.147.0.0/16246.147.0.1 to 246.147.255.254246.147.255.25565,534
149246.148.0.0/16246.148.0.1 to 246.148.255.254246.148.255.25565,534
150246.149.0.0/16246.149.0.1 to 246.149.255.254246.149.255.25565,534
151246.150.0.0/16246.150.0.1 to 246.150.255.254246.150.255.25565,534
152246.151.0.0/16246.151.0.1 to 246.151.255.254246.151.255.25565,534
153246.152.0.0/16246.152.0.1 to 246.152.255.254246.152.255.25565,534
154246.153.0.0/16246.153.0.1 to 246.153.255.254246.153.255.25565,534
155246.154.0.0/16246.154.0.1 to 246.154.255.254246.154.255.25565,534
156246.155.0.0/16246.155.0.1 to 246.155.255.254246.155.255.25565,534
157246.156.0.0/16246.156.0.1 to 246.156.255.254246.156.255.25565,534
158246.157.0.0/16246.157.0.1 to 246.157.255.254246.157.255.25565,534
159246.158.0.0/16246.158.0.1 to 246.158.255.254246.158.255.25565,534
160246.159.0.0/16246.159.0.1 to 246.159.255.254246.159.255.25565,534
161246.160.0.0/16246.160.0.1 to 246.160.255.254246.160.255.25565,534
162246.161.0.0/16246.161.0.1 to 246.161.255.254246.161.255.25565,534
163246.162.0.0/16246.162.0.1 to 246.162.255.254246.162.255.25565,534
164246.163.0.0/16246.163.0.1 to 246.163.255.254246.163.255.25565,534
165246.164.0.0/16246.164.0.1 to 246.164.255.254246.164.255.25565,534
166246.165.0.0/16246.165.0.1 to 246.165.255.254246.165.255.25565,534
167246.166.0.0/16246.166.0.1 to 246.166.255.254246.166.255.25565,534
168246.167.0.0/16246.167.0.1 to 246.167.255.254246.167.255.25565,534
169246.168.0.0/16246.168.0.1 to 246.168.255.254246.168.255.25565,534
170246.169.0.0/16246.169.0.1 to 246.169.255.254246.169.255.25565,534
171246.170.0.0/16246.170.0.1 to 246.170.255.254246.170.255.25565,534
172246.171.0.0/16246.171.0.1 to 246.171.255.254246.171.255.25565,534
173246.172.0.0/16246.172.0.1 to 246.172.255.254246.172.255.25565,534
174246.173.0.0/16246.173.0.1 to 246.173.255.254246.173.255.25565,534
175246.174.0.0/16246.174.0.1 to 246.174.255.254246.174.255.25565,534
176246.175.0.0/16246.175.0.1 to 246.175.255.254246.175.255.25565,534
177246.176.0.0/16246.176.0.1 to 246.176.255.254246.176.255.25565,534
178246.177.0.0/16246.177.0.1 to 246.177.255.254246.177.255.25565,534
179246.178.0.0/16246.178.0.1 to 246.178.255.254246.178.255.25565,534
180246.179.0.0/16246.179.0.1 to 246.179.255.254246.179.255.25565,534
181246.180.0.0/16246.180.0.1 to 246.180.255.254246.180.255.25565,534
182246.181.0.0/16246.181.0.1 to 246.181.255.254246.181.255.25565,534
183246.182.0.0/16246.182.0.1 to 246.182.255.254246.182.255.25565,534
184246.183.0.0/16246.183.0.1 to 246.183.255.254246.183.255.25565,534
185246.184.0.0/16246.184.0.1 to 246.184.255.254246.184.255.25565,534
186246.185.0.0/16246.185.0.1 to 246.185.255.254246.185.255.25565,534
187246.186.0.0/16246.186.0.1 to 246.186.255.254246.186.255.25565,534
188246.187.0.0/16246.187.0.1 to 246.187.255.254246.187.255.25565,534
189246.188.0.0/16246.188.0.1 to 246.188.255.254246.188.255.25565,534
190246.189.0.0/16246.189.0.1 to 246.189.255.254246.189.255.25565,534
191246.190.0.0/16246.190.0.1 to 246.190.255.254246.190.255.25565,534
192246.191.0.0/16246.191.0.1 to 246.191.255.254246.191.255.25565,534
193246.192.0.0/16246.192.0.1 to 246.192.255.254246.192.255.25565,534
194246.193.0.0/16246.193.0.1 to 246.193.255.254246.193.255.25565,534
195246.194.0.0/16246.194.0.1 to 246.194.255.254246.194.255.25565,534
196246.195.0.0/16246.195.0.1 to 246.195.255.254246.195.255.25565,534
197246.196.0.0/16246.196.0.1 to 246.196.255.254246.196.255.25565,534
198246.197.0.0/16246.197.0.1 to 246.197.255.254246.197.255.25565,534
199246.198.0.0/16246.198.0.1 to 246.198.255.254246.198.255.25565,534
200246.199.0.0/16246.199.0.1 to 246.199.255.254246.199.255.25565,534
201246.200.0.0/16246.200.0.1 to 246.200.255.254246.200.255.25565,534
202246.201.0.0/16246.201.0.1 to 246.201.255.254246.201.255.25565,534
203246.202.0.0/16246.202.0.1 to 246.202.255.254246.202.255.25565,534
204246.203.0.0/16246.203.0.1 to 246.203.255.254246.203.255.25565,534
205246.204.0.0/16246.204.0.1 to 246.204.255.254246.204.255.25565,534
206246.205.0.0/16246.205.0.1 to 246.205.255.254246.205.255.25565,534
207246.206.0.0/16246.206.0.1 to 246.206.255.254246.206.255.25565,534
208246.207.0.0/16246.207.0.1 to 246.207.255.254246.207.255.25565,534
209246.208.0.0/16246.208.0.1 to 246.208.255.254246.208.255.25565,534
210246.209.0.0/16246.209.0.1 to 246.209.255.254246.209.255.25565,534
211246.210.0.0/16246.210.0.1 to 246.210.255.254246.210.255.25565,534
212246.211.0.0/16246.211.0.1 to 246.211.255.254246.211.255.25565,534
213246.212.0.0/16246.212.0.1 to 246.212.255.254246.212.255.25565,534
214246.213.0.0/16246.213.0.1 to 246.213.255.254246.213.255.25565,534
215246.214.0.0/16246.214.0.1 to 246.214.255.254246.214.255.25565,534
216246.215.0.0/16246.215.0.1 to 246.215.255.254246.215.255.25565,534
217246.216.0.0/16246.216.0.1 to 246.216.255.254246.216.255.25565,534
218246.217.0.0/16246.217.0.1 to 246.217.255.254246.217.255.25565,534
219246.218.0.0/16246.218.0.1 to 246.218.255.254246.218.255.25565,534
220246.219.0.0/16246.219.0.1 to 246.219.255.254246.219.255.25565,534
221246.220.0.0/16246.220.0.1 to 246.220.255.254246.220.255.25565,534
222246.221.0.0/16246.221.0.1 to 246.221.255.254246.221.255.25565,534
223246.222.0.0/16246.222.0.1 to 246.222.255.254246.222.255.25565,534
224246.223.0.0/16246.223.0.1 to 246.223.255.254246.223.255.25565,534
225246.224.0.0/16246.224.0.1 to 246.224.255.254246.224.255.25565,534
226246.225.0.0/16246.225.0.1 to 246.225.255.254246.225.255.25565,534
227246.226.0.0/16246.226.0.1 to 246.226.255.254246.226.255.25565,534
228246.227.0.0/16246.227.0.1 to 246.227.255.254246.227.255.25565,534
229246.228.0.0/16246.228.0.1 to 246.228.255.254246.228.255.25565,534
230246.229.0.0/16246.229.0.1 to 246.229.255.254246.229.255.25565,534
231246.230.0.0/16246.230.0.1 to 246.230.255.254246.230.255.25565,534
232246.231.0.0/16246.231.0.1 to 246.231.255.254246.231.255.25565,534
233246.232.0.0/16246.232.0.1 to 246.232.255.254246.232.255.25565,534
234246.233.0.0/16246.233.0.1 to 246.233.255.254246.233.255.25565,534
235246.234.0.0/16246.234.0.1 to 246.234.255.254246.234.255.25565,534
236246.235.0.0/16246.235.0.1 to 246.235.255.254246.235.255.25565,534
237246.236.0.0/16246.236.0.1 to 246.236.255.254246.236.255.25565,534
238246.237.0.0/16246.237.0.1 to 246.237.255.254246.237.255.25565,534
239246.238.0.0/16246.238.0.1 to 246.238.255.254246.238.255.25565,534
240246.239.0.0/16246.239.0.1 to 246.239.255.254246.239.255.25565,534
241246.240.0.0/16246.240.0.1 to 246.240.255.254246.240.255.25565,534
242246.241.0.0/16246.241.0.1 to 246.241.255.254246.241.255.25565,534
243246.242.0.0/16246.242.0.1 to 246.242.255.254246.242.255.25565,534
244246.243.0.0/16246.243.0.1 to 246.243.255.254246.243.255.25565,534
245246.244.0.0/16246.244.0.1 to 246.244.255.254246.244.255.25565,534
246246.245.0.0/16246.245.0.1 to 246.245.255.254246.245.255.25565,534
247246.246.0.0/16246.246.0.1 to 246.246.255.254246.246.255.25565,534
248246.247.0.0/16246.247.0.1 to 246.247.255.254246.247.255.25565,534
249246.248.0.0/16246.248.0.1 to 246.248.255.254246.248.255.25565,534
250246.249.0.0/16246.249.0.1 to 246.249.255.254246.249.255.25565,534
251246.250.0.0/16246.250.0.1 to 246.250.255.254246.250.255.25565,534
252246.251.0.0/16246.251.0.1 to 246.251.255.254246.251.255.25565,534
253246.252.0.0/16246.252.0.1 to 246.252.255.254246.252.255.25565,534
254246.253.0.0/16246.253.0.1 to 246.253.255.254246.253.255.25565,534
255246.254.0.0/16246.254.0.1 to 246.254.255.254246.254.255.25565,534
256246.255.0.0/16246.255.0.1 to 246.255.255.254246.255.255.25565,534

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.