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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/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)

246.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1246.0.0.0/15246.0.0.1 to 246.1.255.254246.1.255.255131,070
2246.2.0.0/15246.2.0.1 to 246.3.255.254246.3.255.255131,070
3246.4.0.0/15246.4.0.1 to 246.5.255.254246.5.255.255131,070
4246.6.0.0/15246.6.0.1 to 246.7.255.254246.7.255.255131,070
5246.8.0.0/15246.8.0.1 to 246.9.255.254246.9.255.255131,070
6246.10.0.0/15246.10.0.1 to 246.11.255.254246.11.255.255131,070
7246.12.0.0/15246.12.0.1 to 246.13.255.254246.13.255.255131,070
8246.14.0.0/15246.14.0.1 to 246.15.255.254246.15.255.255131,070
9246.16.0.0/15246.16.0.1 to 246.17.255.254246.17.255.255131,070
10246.18.0.0/15246.18.0.1 to 246.19.255.254246.19.255.255131,070
11246.20.0.0/15246.20.0.1 to 246.21.255.254246.21.255.255131,070
12246.22.0.0/15246.22.0.1 to 246.23.255.254246.23.255.255131,070
13246.24.0.0/15246.24.0.1 to 246.25.255.254246.25.255.255131,070
14246.26.0.0/15246.26.0.1 to 246.27.255.254246.27.255.255131,070
15246.28.0.0/15246.28.0.1 to 246.29.255.254246.29.255.255131,070
16246.30.0.0/15246.30.0.1 to 246.31.255.254246.31.255.255131,070
17246.32.0.0/15246.32.0.1 to 246.33.255.254246.33.255.255131,070
18246.34.0.0/15246.34.0.1 to 246.35.255.254246.35.255.255131,070
19246.36.0.0/15246.36.0.1 to 246.37.255.254246.37.255.255131,070
20246.38.0.0/15246.38.0.1 to 246.39.255.254246.39.255.255131,070
21246.40.0.0/15246.40.0.1 to 246.41.255.254246.41.255.255131,070
22246.42.0.0/15246.42.0.1 to 246.43.255.254246.43.255.255131,070
23246.44.0.0/15246.44.0.1 to 246.45.255.254246.45.255.255131,070
24246.46.0.0/15246.46.0.1 to 246.47.255.254246.47.255.255131,070
25246.48.0.0/15246.48.0.1 to 246.49.255.254246.49.255.255131,070
26246.50.0.0/15246.50.0.1 to 246.51.255.254246.51.255.255131,070
27246.52.0.0/15246.52.0.1 to 246.53.255.254246.53.255.255131,070
28246.54.0.0/15246.54.0.1 to 246.55.255.254246.55.255.255131,070
29246.56.0.0/15246.56.0.1 to 246.57.255.254246.57.255.255131,070
30246.58.0.0/15246.58.0.1 to 246.59.255.254246.59.255.255131,070
31246.60.0.0/15246.60.0.1 to 246.61.255.254246.61.255.255131,070
32246.62.0.0/15246.62.0.1 to 246.63.255.254246.63.255.255131,070
33246.64.0.0/15246.64.0.1 to 246.65.255.254246.65.255.255131,070
34246.66.0.0/15246.66.0.1 to 246.67.255.254246.67.255.255131,070
35246.68.0.0/15246.68.0.1 to 246.69.255.254246.69.255.255131,070
36246.70.0.0/15246.70.0.1 to 246.71.255.254246.71.255.255131,070
37246.72.0.0/15246.72.0.1 to 246.73.255.254246.73.255.255131,070
38246.74.0.0/15246.74.0.1 to 246.75.255.254246.75.255.255131,070
39246.76.0.0/15246.76.0.1 to 246.77.255.254246.77.255.255131,070
40246.78.0.0/15246.78.0.1 to 246.79.255.254246.79.255.255131,070
41246.80.0.0/15246.80.0.1 to 246.81.255.254246.81.255.255131,070
42246.82.0.0/15246.82.0.1 to 246.83.255.254246.83.255.255131,070
43246.84.0.0/15246.84.0.1 to 246.85.255.254246.85.255.255131,070
44246.86.0.0/15246.86.0.1 to 246.87.255.254246.87.255.255131,070
45246.88.0.0/15246.88.0.1 to 246.89.255.254246.89.255.255131,070
46246.90.0.0/15246.90.0.1 to 246.91.255.254246.91.255.255131,070
47246.92.0.0/15246.92.0.1 to 246.93.255.254246.93.255.255131,070
48246.94.0.0/15246.94.0.1 to 246.95.255.254246.95.255.255131,070
49246.96.0.0/15246.96.0.1 to 246.97.255.254246.97.255.255131,070
50246.98.0.0/15246.98.0.1 to 246.99.255.254246.99.255.255131,070
51246.100.0.0/15246.100.0.1 to 246.101.255.254246.101.255.255131,070
52246.102.0.0/15246.102.0.1 to 246.103.255.254246.103.255.255131,070
53246.104.0.0/15246.104.0.1 to 246.105.255.254246.105.255.255131,070
54246.106.0.0/15246.106.0.1 to 246.107.255.254246.107.255.255131,070
55246.108.0.0/15246.108.0.1 to 246.109.255.254246.109.255.255131,070
56246.110.0.0/15246.110.0.1 to 246.111.255.254246.111.255.255131,070
57246.112.0.0/15246.112.0.1 to 246.113.255.254246.113.255.255131,070
58246.114.0.0/15246.114.0.1 to 246.115.255.254246.115.255.255131,070
59246.116.0.0/15246.116.0.1 to 246.117.255.254246.117.255.255131,070
60246.118.0.0/15246.118.0.1 to 246.119.255.254246.119.255.255131,070
61246.120.0.0/15246.120.0.1 to 246.121.255.254246.121.255.255131,070
62246.122.0.0/15246.122.0.1 to 246.123.255.254246.123.255.255131,070
63246.124.0.0/15246.124.0.1 to 246.125.255.254246.125.255.255131,070
64246.126.0.0/15246.126.0.1 to 246.127.255.254246.127.255.255131,070
65246.128.0.0/15246.128.0.1 to 246.129.255.254246.129.255.255131,070
66246.130.0.0/15246.130.0.1 to 246.131.255.254246.131.255.255131,070
67246.132.0.0/15246.132.0.1 to 246.133.255.254246.133.255.255131,070
68246.134.0.0/15246.134.0.1 to 246.135.255.254246.135.255.255131,070
69246.136.0.0/15246.136.0.1 to 246.137.255.254246.137.255.255131,070
70246.138.0.0/15246.138.0.1 to 246.139.255.254246.139.255.255131,070
71246.140.0.0/15246.140.0.1 to 246.141.255.254246.141.255.255131,070
72246.142.0.0/15246.142.0.1 to 246.143.255.254246.143.255.255131,070
73246.144.0.0/15246.144.0.1 to 246.145.255.254246.145.255.255131,070
74246.146.0.0/15246.146.0.1 to 246.147.255.254246.147.255.255131,070
75246.148.0.0/15246.148.0.1 to 246.149.255.254246.149.255.255131,070
76246.150.0.0/15246.150.0.1 to 246.151.255.254246.151.255.255131,070
77246.152.0.0/15246.152.0.1 to 246.153.255.254246.153.255.255131,070
78246.154.0.0/15246.154.0.1 to 246.155.255.254246.155.255.255131,070
79246.156.0.0/15246.156.0.1 to 246.157.255.254246.157.255.255131,070
80246.158.0.0/15246.158.0.1 to 246.159.255.254246.159.255.255131,070
81246.160.0.0/15246.160.0.1 to 246.161.255.254246.161.255.255131,070
82246.162.0.0/15246.162.0.1 to 246.163.255.254246.163.255.255131,070
83246.164.0.0/15246.164.0.1 to 246.165.255.254246.165.255.255131,070
84246.166.0.0/15246.166.0.1 to 246.167.255.254246.167.255.255131,070
85246.168.0.0/15246.168.0.1 to 246.169.255.254246.169.255.255131,070
86246.170.0.0/15246.170.0.1 to 246.171.255.254246.171.255.255131,070
87246.172.0.0/15246.172.0.1 to 246.173.255.254246.173.255.255131,070
88246.174.0.0/15246.174.0.1 to 246.175.255.254246.175.255.255131,070
89246.176.0.0/15246.176.0.1 to 246.177.255.254246.177.255.255131,070
90246.178.0.0/15246.178.0.1 to 246.179.255.254246.179.255.255131,070
91246.180.0.0/15246.180.0.1 to 246.181.255.254246.181.255.255131,070
92246.182.0.0/15246.182.0.1 to 246.183.255.254246.183.255.255131,070
93246.184.0.0/15246.184.0.1 to 246.185.255.254246.185.255.255131,070
94246.186.0.0/15246.186.0.1 to 246.187.255.254246.187.255.255131,070
95246.188.0.0/15246.188.0.1 to 246.189.255.254246.189.255.255131,070
96246.190.0.0/15246.190.0.1 to 246.191.255.254246.191.255.255131,070
97246.192.0.0/15246.192.0.1 to 246.193.255.254246.193.255.255131,070
98246.194.0.0/15246.194.0.1 to 246.195.255.254246.195.255.255131,070
99246.196.0.0/15246.196.0.1 to 246.197.255.254246.197.255.255131,070
100246.198.0.0/15246.198.0.1 to 246.199.255.254246.199.255.255131,070
101246.200.0.0/15246.200.0.1 to 246.201.255.254246.201.255.255131,070
102246.202.0.0/15246.202.0.1 to 246.203.255.254246.203.255.255131,070
103246.204.0.0/15246.204.0.1 to 246.205.255.254246.205.255.255131,070
104246.206.0.0/15246.206.0.1 to 246.207.255.254246.207.255.255131,070
105246.208.0.0/15246.208.0.1 to 246.209.255.254246.209.255.255131,070
106246.210.0.0/15246.210.0.1 to 246.211.255.254246.211.255.255131,070
107246.212.0.0/15246.212.0.1 to 246.213.255.254246.213.255.255131,070
108246.214.0.0/15246.214.0.1 to 246.215.255.254246.215.255.255131,070
109246.216.0.0/15246.216.0.1 to 246.217.255.254246.217.255.255131,070
110246.218.0.0/15246.218.0.1 to 246.219.255.254246.219.255.255131,070
111246.220.0.0/15246.220.0.1 to 246.221.255.254246.221.255.255131,070
112246.222.0.0/15246.222.0.1 to 246.223.255.254246.223.255.255131,070
113246.224.0.0/15246.224.0.1 to 246.225.255.254246.225.255.255131,070
114246.226.0.0/15246.226.0.1 to 246.227.255.254246.227.255.255131,070
115246.228.0.0/15246.228.0.1 to 246.229.255.254246.229.255.255131,070
116246.230.0.0/15246.230.0.1 to 246.231.255.254246.231.255.255131,070
117246.232.0.0/15246.232.0.1 to 246.233.255.254246.233.255.255131,070
118246.234.0.0/15246.234.0.1 to 246.235.255.254246.235.255.255131,070
119246.236.0.0/15246.236.0.1 to 246.237.255.254246.237.255.255131,070
120246.238.0.0/15246.238.0.1 to 246.239.255.254246.239.255.255131,070
121246.240.0.0/15246.240.0.1 to 246.241.255.254246.241.255.255131,070
122246.242.0.0/15246.242.0.1 to 246.243.255.254246.243.255.255131,070
123246.244.0.0/15246.244.0.1 to 246.245.255.254246.245.255.255131,070
124246.246.0.0/15246.246.0.1 to 246.247.255.254246.247.255.255131,070
125246.248.0.0/15246.248.0.1 to 246.249.255.254246.249.255.255131,070
126246.250.0.0/15246.250.0.1 to 246.251.255.254246.251.255.255131,070
127246.252.0.0/15246.252.0.1 to 246.253.255.254246.253.255.255131,070
128246.254.0.0/15246.254.0.1 to 246.255.255.254246.255.255.255131,070
129247.0.0.0/15247.0.0.1 to 247.1.255.254247.1.255.255131,070
130247.2.0.0/15247.2.0.1 to 247.3.255.254247.3.255.255131,070
131247.4.0.0/15247.4.0.1 to 247.5.255.254247.5.255.255131,070
132247.6.0.0/15247.6.0.1 to 247.7.255.254247.7.255.255131,070
133247.8.0.0/15247.8.0.1 to 247.9.255.254247.9.255.255131,070
134247.10.0.0/15247.10.0.1 to 247.11.255.254247.11.255.255131,070
135247.12.0.0/15247.12.0.1 to 247.13.255.254247.13.255.255131,070
136247.14.0.0/15247.14.0.1 to 247.15.255.254247.15.255.255131,070
137247.16.0.0/15247.16.0.1 to 247.17.255.254247.17.255.255131,070
138247.18.0.0/15247.18.0.1 to 247.19.255.254247.19.255.255131,070
139247.20.0.0/15247.20.0.1 to 247.21.255.254247.21.255.255131,070
140247.22.0.0/15247.22.0.1 to 247.23.255.254247.23.255.255131,070
141247.24.0.0/15247.24.0.1 to 247.25.255.254247.25.255.255131,070
142247.26.0.0/15247.26.0.1 to 247.27.255.254247.27.255.255131,070
143247.28.0.0/15247.28.0.1 to 247.29.255.254247.29.255.255131,070
144247.30.0.0/15247.30.0.1 to 247.31.255.254247.31.255.255131,070
145247.32.0.0/15247.32.0.1 to 247.33.255.254247.33.255.255131,070
146247.34.0.0/15247.34.0.1 to 247.35.255.254247.35.255.255131,070
147247.36.0.0/15247.36.0.1 to 247.37.255.254247.37.255.255131,070
148247.38.0.0/15247.38.0.1 to 247.39.255.254247.39.255.255131,070
149247.40.0.0/15247.40.0.1 to 247.41.255.254247.41.255.255131,070
150247.42.0.0/15247.42.0.1 to 247.43.255.254247.43.255.255131,070
151247.44.0.0/15247.44.0.1 to 247.45.255.254247.45.255.255131,070
152247.46.0.0/15247.46.0.1 to 247.47.255.254247.47.255.255131,070
153247.48.0.0/15247.48.0.1 to 247.49.255.254247.49.255.255131,070
154247.50.0.0/15247.50.0.1 to 247.51.255.254247.51.255.255131,070
155247.52.0.0/15247.52.0.1 to 247.53.255.254247.53.255.255131,070
156247.54.0.0/15247.54.0.1 to 247.55.255.254247.55.255.255131,070
157247.56.0.0/15247.56.0.1 to 247.57.255.254247.57.255.255131,070
158247.58.0.0/15247.58.0.1 to 247.59.255.254247.59.255.255131,070
159247.60.0.0/15247.60.0.1 to 247.61.255.254247.61.255.255131,070
160247.62.0.0/15247.62.0.1 to 247.63.255.254247.63.255.255131,070
161247.64.0.0/15247.64.0.1 to 247.65.255.254247.65.255.255131,070
162247.66.0.0/15247.66.0.1 to 247.67.255.254247.67.255.255131,070
163247.68.0.0/15247.68.0.1 to 247.69.255.254247.69.255.255131,070
164247.70.0.0/15247.70.0.1 to 247.71.255.254247.71.255.255131,070
165247.72.0.0/15247.72.0.1 to 247.73.255.254247.73.255.255131,070
166247.74.0.0/15247.74.0.1 to 247.75.255.254247.75.255.255131,070
167247.76.0.0/15247.76.0.1 to 247.77.255.254247.77.255.255131,070
168247.78.0.0/15247.78.0.1 to 247.79.255.254247.79.255.255131,070
169247.80.0.0/15247.80.0.1 to 247.81.255.254247.81.255.255131,070
170247.82.0.0/15247.82.0.1 to 247.83.255.254247.83.255.255131,070
171247.84.0.0/15247.84.0.1 to 247.85.255.254247.85.255.255131,070
172247.86.0.0/15247.86.0.1 to 247.87.255.254247.87.255.255131,070
173247.88.0.0/15247.88.0.1 to 247.89.255.254247.89.255.255131,070
174247.90.0.0/15247.90.0.1 to 247.91.255.254247.91.255.255131,070
175247.92.0.0/15247.92.0.1 to 247.93.255.254247.93.255.255131,070
176247.94.0.0/15247.94.0.1 to 247.95.255.254247.95.255.255131,070
177247.96.0.0/15247.96.0.1 to 247.97.255.254247.97.255.255131,070
178247.98.0.0/15247.98.0.1 to 247.99.255.254247.99.255.255131,070
179247.100.0.0/15247.100.0.1 to 247.101.255.254247.101.255.255131,070
180247.102.0.0/15247.102.0.1 to 247.103.255.254247.103.255.255131,070
181247.104.0.0/15247.104.0.1 to 247.105.255.254247.105.255.255131,070
182247.106.0.0/15247.106.0.1 to 247.107.255.254247.107.255.255131,070
183247.108.0.0/15247.108.0.1 to 247.109.255.254247.109.255.255131,070
184247.110.0.0/15247.110.0.1 to 247.111.255.254247.111.255.255131,070
185247.112.0.0/15247.112.0.1 to 247.113.255.254247.113.255.255131,070
186247.114.0.0/15247.114.0.1 to 247.115.255.254247.115.255.255131,070
187247.116.0.0/15247.116.0.1 to 247.117.255.254247.117.255.255131,070
188247.118.0.0/15247.118.0.1 to 247.119.255.254247.119.255.255131,070
189247.120.0.0/15247.120.0.1 to 247.121.255.254247.121.255.255131,070
190247.122.0.0/15247.122.0.1 to 247.123.255.254247.123.255.255131,070
191247.124.0.0/15247.124.0.1 to 247.125.255.254247.125.255.255131,070
192247.126.0.0/15247.126.0.1 to 247.127.255.254247.127.255.255131,070
193247.128.0.0/15247.128.0.1 to 247.129.255.254247.129.255.255131,070
194247.130.0.0/15247.130.0.1 to 247.131.255.254247.131.255.255131,070
195247.132.0.0/15247.132.0.1 to 247.133.255.254247.133.255.255131,070
196247.134.0.0/15247.134.0.1 to 247.135.255.254247.135.255.255131,070
197247.136.0.0/15247.136.0.1 to 247.137.255.254247.137.255.255131,070
198247.138.0.0/15247.138.0.1 to 247.139.255.254247.139.255.255131,070
199247.140.0.0/15247.140.0.1 to 247.141.255.254247.141.255.255131,070
200247.142.0.0/15247.142.0.1 to 247.143.255.254247.143.255.255131,070
201247.144.0.0/15247.144.0.1 to 247.145.255.254247.145.255.255131,070
202247.146.0.0/15247.146.0.1 to 247.147.255.254247.147.255.255131,070
203247.148.0.0/15247.148.0.1 to 247.149.255.254247.149.255.255131,070
204247.150.0.0/15247.150.0.1 to 247.151.255.254247.151.255.255131,070
205247.152.0.0/15247.152.0.1 to 247.153.255.254247.153.255.255131,070
206247.154.0.0/15247.154.0.1 to 247.155.255.254247.155.255.255131,070
207247.156.0.0/15247.156.0.1 to 247.157.255.254247.157.255.255131,070
208247.158.0.0/15247.158.0.1 to 247.159.255.254247.159.255.255131,070
209247.160.0.0/15247.160.0.1 to 247.161.255.254247.161.255.255131,070
210247.162.0.0/15247.162.0.1 to 247.163.255.254247.163.255.255131,070
211247.164.0.0/15247.164.0.1 to 247.165.255.254247.165.255.255131,070
212247.166.0.0/15247.166.0.1 to 247.167.255.254247.167.255.255131,070
213247.168.0.0/15247.168.0.1 to 247.169.255.254247.169.255.255131,070
214247.170.0.0/15247.170.0.1 to 247.171.255.254247.171.255.255131,070
215247.172.0.0/15247.172.0.1 to 247.173.255.254247.173.255.255131,070
216247.174.0.0/15247.174.0.1 to 247.175.255.254247.175.255.255131,070
217247.176.0.0/15247.176.0.1 to 247.177.255.254247.177.255.255131,070
218247.178.0.0/15247.178.0.1 to 247.179.255.254247.179.255.255131,070
219247.180.0.0/15247.180.0.1 to 247.181.255.254247.181.255.255131,070
220247.182.0.0/15247.182.0.1 to 247.183.255.254247.183.255.255131,070
221247.184.0.0/15247.184.0.1 to 247.185.255.254247.185.255.255131,070
222247.186.0.0/15247.186.0.1 to 247.187.255.254247.187.255.255131,070
223247.188.0.0/15247.188.0.1 to 247.189.255.254247.189.255.255131,070
224247.190.0.0/15247.190.0.1 to 247.191.255.254247.191.255.255131,070
225247.192.0.0/15247.192.0.1 to 247.193.255.254247.193.255.255131,070
226247.194.0.0/15247.194.0.1 to 247.195.255.254247.195.255.255131,070
227247.196.0.0/15247.196.0.1 to 247.197.255.254247.197.255.255131,070
228247.198.0.0/15247.198.0.1 to 247.199.255.254247.199.255.255131,070
229247.200.0.0/15247.200.0.1 to 247.201.255.254247.201.255.255131,070
230247.202.0.0/15247.202.0.1 to 247.203.255.254247.203.255.255131,070
231247.204.0.0/15247.204.0.1 to 247.205.255.254247.205.255.255131,070
232247.206.0.0/15247.206.0.1 to 247.207.255.254247.207.255.255131,070
233247.208.0.0/15247.208.0.1 to 247.209.255.254247.209.255.255131,070
234247.210.0.0/15247.210.0.1 to 247.211.255.254247.211.255.255131,070
235247.212.0.0/15247.212.0.1 to 247.213.255.254247.213.255.255131,070
236247.214.0.0/15247.214.0.1 to 247.215.255.254247.215.255.255131,070
237247.216.0.0/15247.216.0.1 to 247.217.255.254247.217.255.255131,070
238247.218.0.0/15247.218.0.1 to 247.219.255.254247.219.255.255131,070
239247.220.0.0/15247.220.0.1 to 247.221.255.254247.221.255.255131,070
240247.222.0.0/15247.222.0.1 to 247.223.255.254247.223.255.255131,070
241247.224.0.0/15247.224.0.1 to 247.225.255.254247.225.255.255131,070
242247.226.0.0/15247.226.0.1 to 247.227.255.254247.227.255.255131,070
243247.228.0.0/15247.228.0.1 to 247.229.255.254247.229.255.255131,070
244247.230.0.0/15247.230.0.1 to 247.231.255.254247.231.255.255131,070
245247.232.0.0/15247.232.0.1 to 247.233.255.254247.233.255.255131,070
246247.234.0.0/15247.234.0.1 to 247.235.255.254247.235.255.255131,070
247247.236.0.0/15247.236.0.1 to 247.237.255.254247.237.255.255131,070
248247.238.0.0/15247.238.0.1 to 247.239.255.254247.239.255.255131,070
249247.240.0.0/15247.240.0.1 to 247.241.255.254247.241.255.255131,070
250247.242.0.0/15247.242.0.1 to 247.243.255.254247.243.255.255131,070
251247.244.0.0/15247.244.0.1 to 247.245.255.254247.245.255.255131,070
252247.246.0.0/15247.246.0.1 to 247.247.255.254247.247.255.255131,070
253247.248.0.0/15247.248.0.1 to 247.249.255.254247.249.255.255131,070
254247.250.0.0/15247.250.0.1 to 247.251.255.254247.251.255.255131,070
255247.252.0.0/15247.252.0.1 to 247.253.255.254247.253.255.255131,070
256247.254.0.0/15247.254.0.1 to 247.255.255.254247.255.255.255131,070

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.