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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.

Network244.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
244.0.0.0
Broadcast address
244.7.255.255
First usable
244.0.0.1
Last usable
244.7.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F4000000 · Integer 4093640704 to 4094164991
Reverse DNS zones
0.244.in-addr.arpa
1.244.in-addr.arpa
2.244.in-addr.arpa
3.244.in-addr.arpa
4.244.in-addr.arpa
5.244.in-addr.arpa
6.244.in-addr.arpa
7.244.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110100.00000000.00000000.00000000244.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11110100.00000000.00000000.00000000244.0.0.0
Broadcast11110100.00000111.11111111.11111111244.7.255.255
Split into smaller subnets/21
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

244.0.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1244.0.0.0/21244.0.0.1 to 244.0.7.254244.0.7.2552,046
2244.0.8.0/21244.0.8.1 to 244.0.15.254244.0.15.2552,046
3244.0.16.0/21244.0.16.1 to 244.0.23.254244.0.23.2552,046
4244.0.24.0/21244.0.24.1 to 244.0.31.254244.0.31.2552,046
5244.0.32.0/21244.0.32.1 to 244.0.39.254244.0.39.2552,046
6244.0.40.0/21244.0.40.1 to 244.0.47.254244.0.47.2552,046
7244.0.48.0/21244.0.48.1 to 244.0.55.254244.0.55.2552,046
8244.0.56.0/21244.0.56.1 to 244.0.63.254244.0.63.2552,046
9244.0.64.0/21244.0.64.1 to 244.0.71.254244.0.71.2552,046
10244.0.72.0/21244.0.72.1 to 244.0.79.254244.0.79.2552,046
11244.0.80.0/21244.0.80.1 to 244.0.87.254244.0.87.2552,046
12244.0.88.0/21244.0.88.1 to 244.0.95.254244.0.95.2552,046
13244.0.96.0/21244.0.96.1 to 244.0.103.254244.0.103.2552,046
14244.0.104.0/21244.0.104.1 to 244.0.111.254244.0.111.2552,046
15244.0.112.0/21244.0.112.1 to 244.0.119.254244.0.119.2552,046
16244.0.120.0/21244.0.120.1 to 244.0.127.254244.0.127.2552,046
17244.0.128.0/21244.0.128.1 to 244.0.135.254244.0.135.2552,046
18244.0.136.0/21244.0.136.1 to 244.0.143.254244.0.143.2552,046
19244.0.144.0/21244.0.144.1 to 244.0.151.254244.0.151.2552,046
20244.0.152.0/21244.0.152.1 to 244.0.159.254244.0.159.2552,046
21244.0.160.0/21244.0.160.1 to 244.0.167.254244.0.167.2552,046
22244.0.168.0/21244.0.168.1 to 244.0.175.254244.0.175.2552,046
23244.0.176.0/21244.0.176.1 to 244.0.183.254244.0.183.2552,046
24244.0.184.0/21244.0.184.1 to 244.0.191.254244.0.191.2552,046
25244.0.192.0/21244.0.192.1 to 244.0.199.254244.0.199.2552,046
26244.0.200.0/21244.0.200.1 to 244.0.207.254244.0.207.2552,046
27244.0.208.0/21244.0.208.1 to 244.0.215.254244.0.215.2552,046
28244.0.216.0/21244.0.216.1 to 244.0.223.254244.0.223.2552,046
29244.0.224.0/21244.0.224.1 to 244.0.231.254244.0.231.2552,046
30244.0.232.0/21244.0.232.1 to 244.0.239.254244.0.239.2552,046
31244.0.240.0/21244.0.240.1 to 244.0.247.254244.0.247.2552,046
32244.0.248.0/21244.0.248.1 to 244.0.255.254244.0.255.2552,046
33244.1.0.0/21244.1.0.1 to 244.1.7.254244.1.7.2552,046
34244.1.8.0/21244.1.8.1 to 244.1.15.254244.1.15.2552,046
35244.1.16.0/21244.1.16.1 to 244.1.23.254244.1.23.2552,046
36244.1.24.0/21244.1.24.1 to 244.1.31.254244.1.31.2552,046
37244.1.32.0/21244.1.32.1 to 244.1.39.254244.1.39.2552,046
38244.1.40.0/21244.1.40.1 to 244.1.47.254244.1.47.2552,046
39244.1.48.0/21244.1.48.1 to 244.1.55.254244.1.55.2552,046
40244.1.56.0/21244.1.56.1 to 244.1.63.254244.1.63.2552,046
41244.1.64.0/21244.1.64.1 to 244.1.71.254244.1.71.2552,046
42244.1.72.0/21244.1.72.1 to 244.1.79.254244.1.79.2552,046
43244.1.80.0/21244.1.80.1 to 244.1.87.254244.1.87.2552,046
44244.1.88.0/21244.1.88.1 to 244.1.95.254244.1.95.2552,046
45244.1.96.0/21244.1.96.1 to 244.1.103.254244.1.103.2552,046
46244.1.104.0/21244.1.104.1 to 244.1.111.254244.1.111.2552,046
47244.1.112.0/21244.1.112.1 to 244.1.119.254244.1.119.2552,046
48244.1.120.0/21244.1.120.1 to 244.1.127.254244.1.127.2552,046
49244.1.128.0/21244.1.128.1 to 244.1.135.254244.1.135.2552,046
50244.1.136.0/21244.1.136.1 to 244.1.143.254244.1.143.2552,046
51244.1.144.0/21244.1.144.1 to 244.1.151.254244.1.151.2552,046
52244.1.152.0/21244.1.152.1 to 244.1.159.254244.1.159.2552,046
53244.1.160.0/21244.1.160.1 to 244.1.167.254244.1.167.2552,046
54244.1.168.0/21244.1.168.1 to 244.1.175.254244.1.175.2552,046
55244.1.176.0/21244.1.176.1 to 244.1.183.254244.1.183.2552,046
56244.1.184.0/21244.1.184.1 to 244.1.191.254244.1.191.2552,046
57244.1.192.0/21244.1.192.1 to 244.1.199.254244.1.199.2552,046
58244.1.200.0/21244.1.200.1 to 244.1.207.254244.1.207.2552,046
59244.1.208.0/21244.1.208.1 to 244.1.215.254244.1.215.2552,046
60244.1.216.0/21244.1.216.1 to 244.1.223.254244.1.223.2552,046
61244.1.224.0/21244.1.224.1 to 244.1.231.254244.1.231.2552,046
62244.1.232.0/21244.1.232.1 to 244.1.239.254244.1.239.2552,046
63244.1.240.0/21244.1.240.1 to 244.1.247.254244.1.247.2552,046
64244.1.248.0/21244.1.248.1 to 244.1.255.254244.1.255.2552,046
65244.2.0.0/21244.2.0.1 to 244.2.7.254244.2.7.2552,046
66244.2.8.0/21244.2.8.1 to 244.2.15.254244.2.15.2552,046
67244.2.16.0/21244.2.16.1 to 244.2.23.254244.2.23.2552,046
68244.2.24.0/21244.2.24.1 to 244.2.31.254244.2.31.2552,046
69244.2.32.0/21244.2.32.1 to 244.2.39.254244.2.39.2552,046
70244.2.40.0/21244.2.40.1 to 244.2.47.254244.2.47.2552,046
71244.2.48.0/21244.2.48.1 to 244.2.55.254244.2.55.2552,046
72244.2.56.0/21244.2.56.1 to 244.2.63.254244.2.63.2552,046
73244.2.64.0/21244.2.64.1 to 244.2.71.254244.2.71.2552,046
74244.2.72.0/21244.2.72.1 to 244.2.79.254244.2.79.2552,046
75244.2.80.0/21244.2.80.1 to 244.2.87.254244.2.87.2552,046
76244.2.88.0/21244.2.88.1 to 244.2.95.254244.2.95.2552,046
77244.2.96.0/21244.2.96.1 to 244.2.103.254244.2.103.2552,046
78244.2.104.0/21244.2.104.1 to 244.2.111.254244.2.111.2552,046
79244.2.112.0/21244.2.112.1 to 244.2.119.254244.2.119.2552,046
80244.2.120.0/21244.2.120.1 to 244.2.127.254244.2.127.2552,046
81244.2.128.0/21244.2.128.1 to 244.2.135.254244.2.135.2552,046
82244.2.136.0/21244.2.136.1 to 244.2.143.254244.2.143.2552,046
83244.2.144.0/21244.2.144.1 to 244.2.151.254244.2.151.2552,046
84244.2.152.0/21244.2.152.1 to 244.2.159.254244.2.159.2552,046
85244.2.160.0/21244.2.160.1 to 244.2.167.254244.2.167.2552,046
86244.2.168.0/21244.2.168.1 to 244.2.175.254244.2.175.2552,046
87244.2.176.0/21244.2.176.1 to 244.2.183.254244.2.183.2552,046
88244.2.184.0/21244.2.184.1 to 244.2.191.254244.2.191.2552,046
89244.2.192.0/21244.2.192.1 to 244.2.199.254244.2.199.2552,046
90244.2.200.0/21244.2.200.1 to 244.2.207.254244.2.207.2552,046
91244.2.208.0/21244.2.208.1 to 244.2.215.254244.2.215.2552,046
92244.2.216.0/21244.2.216.1 to 244.2.223.254244.2.223.2552,046
93244.2.224.0/21244.2.224.1 to 244.2.231.254244.2.231.2552,046
94244.2.232.0/21244.2.232.1 to 244.2.239.254244.2.239.2552,046
95244.2.240.0/21244.2.240.1 to 244.2.247.254244.2.247.2552,046
96244.2.248.0/21244.2.248.1 to 244.2.255.254244.2.255.2552,046
97244.3.0.0/21244.3.0.1 to 244.3.7.254244.3.7.2552,046
98244.3.8.0/21244.3.8.1 to 244.3.15.254244.3.15.2552,046
99244.3.16.0/21244.3.16.1 to 244.3.23.254244.3.23.2552,046
100244.3.24.0/21244.3.24.1 to 244.3.31.254244.3.31.2552,046
101244.3.32.0/21244.3.32.1 to 244.3.39.254244.3.39.2552,046
102244.3.40.0/21244.3.40.1 to 244.3.47.254244.3.47.2552,046
103244.3.48.0/21244.3.48.1 to 244.3.55.254244.3.55.2552,046
104244.3.56.0/21244.3.56.1 to 244.3.63.254244.3.63.2552,046
105244.3.64.0/21244.3.64.1 to 244.3.71.254244.3.71.2552,046
106244.3.72.0/21244.3.72.1 to 244.3.79.254244.3.79.2552,046
107244.3.80.0/21244.3.80.1 to 244.3.87.254244.3.87.2552,046
108244.3.88.0/21244.3.88.1 to 244.3.95.254244.3.95.2552,046
109244.3.96.0/21244.3.96.1 to 244.3.103.254244.3.103.2552,046
110244.3.104.0/21244.3.104.1 to 244.3.111.254244.3.111.2552,046
111244.3.112.0/21244.3.112.1 to 244.3.119.254244.3.119.2552,046
112244.3.120.0/21244.3.120.1 to 244.3.127.254244.3.127.2552,046
113244.3.128.0/21244.3.128.1 to 244.3.135.254244.3.135.2552,046
114244.3.136.0/21244.3.136.1 to 244.3.143.254244.3.143.2552,046
115244.3.144.0/21244.3.144.1 to 244.3.151.254244.3.151.2552,046
116244.3.152.0/21244.3.152.1 to 244.3.159.254244.3.159.2552,046
117244.3.160.0/21244.3.160.1 to 244.3.167.254244.3.167.2552,046
118244.3.168.0/21244.3.168.1 to 244.3.175.254244.3.175.2552,046
119244.3.176.0/21244.3.176.1 to 244.3.183.254244.3.183.2552,046
120244.3.184.0/21244.3.184.1 to 244.3.191.254244.3.191.2552,046
121244.3.192.0/21244.3.192.1 to 244.3.199.254244.3.199.2552,046
122244.3.200.0/21244.3.200.1 to 244.3.207.254244.3.207.2552,046
123244.3.208.0/21244.3.208.1 to 244.3.215.254244.3.215.2552,046
124244.3.216.0/21244.3.216.1 to 244.3.223.254244.3.223.2552,046
125244.3.224.0/21244.3.224.1 to 244.3.231.254244.3.231.2552,046
126244.3.232.0/21244.3.232.1 to 244.3.239.254244.3.239.2552,046
127244.3.240.0/21244.3.240.1 to 244.3.247.254244.3.247.2552,046
128244.3.248.0/21244.3.248.1 to 244.3.255.254244.3.255.2552,046
129244.4.0.0/21244.4.0.1 to 244.4.7.254244.4.7.2552,046
130244.4.8.0/21244.4.8.1 to 244.4.15.254244.4.15.2552,046
131244.4.16.0/21244.4.16.1 to 244.4.23.254244.4.23.2552,046
132244.4.24.0/21244.4.24.1 to 244.4.31.254244.4.31.2552,046
133244.4.32.0/21244.4.32.1 to 244.4.39.254244.4.39.2552,046
134244.4.40.0/21244.4.40.1 to 244.4.47.254244.4.47.2552,046
135244.4.48.0/21244.4.48.1 to 244.4.55.254244.4.55.2552,046
136244.4.56.0/21244.4.56.1 to 244.4.63.254244.4.63.2552,046
137244.4.64.0/21244.4.64.1 to 244.4.71.254244.4.71.2552,046
138244.4.72.0/21244.4.72.1 to 244.4.79.254244.4.79.2552,046
139244.4.80.0/21244.4.80.1 to 244.4.87.254244.4.87.2552,046
140244.4.88.0/21244.4.88.1 to 244.4.95.254244.4.95.2552,046
141244.4.96.0/21244.4.96.1 to 244.4.103.254244.4.103.2552,046
142244.4.104.0/21244.4.104.1 to 244.4.111.254244.4.111.2552,046
143244.4.112.0/21244.4.112.1 to 244.4.119.254244.4.119.2552,046
144244.4.120.0/21244.4.120.1 to 244.4.127.254244.4.127.2552,046
145244.4.128.0/21244.4.128.1 to 244.4.135.254244.4.135.2552,046
146244.4.136.0/21244.4.136.1 to 244.4.143.254244.4.143.2552,046
147244.4.144.0/21244.4.144.1 to 244.4.151.254244.4.151.2552,046
148244.4.152.0/21244.4.152.1 to 244.4.159.254244.4.159.2552,046
149244.4.160.0/21244.4.160.1 to 244.4.167.254244.4.167.2552,046
150244.4.168.0/21244.4.168.1 to 244.4.175.254244.4.175.2552,046
151244.4.176.0/21244.4.176.1 to 244.4.183.254244.4.183.2552,046
152244.4.184.0/21244.4.184.1 to 244.4.191.254244.4.191.2552,046
153244.4.192.0/21244.4.192.1 to 244.4.199.254244.4.199.2552,046
154244.4.200.0/21244.4.200.1 to 244.4.207.254244.4.207.2552,046
155244.4.208.0/21244.4.208.1 to 244.4.215.254244.4.215.2552,046
156244.4.216.0/21244.4.216.1 to 244.4.223.254244.4.223.2552,046
157244.4.224.0/21244.4.224.1 to 244.4.231.254244.4.231.2552,046
158244.4.232.0/21244.4.232.1 to 244.4.239.254244.4.239.2552,046
159244.4.240.0/21244.4.240.1 to 244.4.247.254244.4.247.2552,046
160244.4.248.0/21244.4.248.1 to 244.4.255.254244.4.255.2552,046
161244.5.0.0/21244.5.0.1 to 244.5.7.254244.5.7.2552,046
162244.5.8.0/21244.5.8.1 to 244.5.15.254244.5.15.2552,046
163244.5.16.0/21244.5.16.1 to 244.5.23.254244.5.23.2552,046
164244.5.24.0/21244.5.24.1 to 244.5.31.254244.5.31.2552,046
165244.5.32.0/21244.5.32.1 to 244.5.39.254244.5.39.2552,046
166244.5.40.0/21244.5.40.1 to 244.5.47.254244.5.47.2552,046
167244.5.48.0/21244.5.48.1 to 244.5.55.254244.5.55.2552,046
168244.5.56.0/21244.5.56.1 to 244.5.63.254244.5.63.2552,046
169244.5.64.0/21244.5.64.1 to 244.5.71.254244.5.71.2552,046
170244.5.72.0/21244.5.72.1 to 244.5.79.254244.5.79.2552,046
171244.5.80.0/21244.5.80.1 to 244.5.87.254244.5.87.2552,046
172244.5.88.0/21244.5.88.1 to 244.5.95.254244.5.95.2552,046
173244.5.96.0/21244.5.96.1 to 244.5.103.254244.5.103.2552,046
174244.5.104.0/21244.5.104.1 to 244.5.111.254244.5.111.2552,046
175244.5.112.0/21244.5.112.1 to 244.5.119.254244.5.119.2552,046
176244.5.120.0/21244.5.120.1 to 244.5.127.254244.5.127.2552,046
177244.5.128.0/21244.5.128.1 to 244.5.135.254244.5.135.2552,046
178244.5.136.0/21244.5.136.1 to 244.5.143.254244.5.143.2552,046
179244.5.144.0/21244.5.144.1 to 244.5.151.254244.5.151.2552,046
180244.5.152.0/21244.5.152.1 to 244.5.159.254244.5.159.2552,046
181244.5.160.0/21244.5.160.1 to 244.5.167.254244.5.167.2552,046
182244.5.168.0/21244.5.168.1 to 244.5.175.254244.5.175.2552,046
183244.5.176.0/21244.5.176.1 to 244.5.183.254244.5.183.2552,046
184244.5.184.0/21244.5.184.1 to 244.5.191.254244.5.191.2552,046
185244.5.192.0/21244.5.192.1 to 244.5.199.254244.5.199.2552,046
186244.5.200.0/21244.5.200.1 to 244.5.207.254244.5.207.2552,046
187244.5.208.0/21244.5.208.1 to 244.5.215.254244.5.215.2552,046
188244.5.216.0/21244.5.216.1 to 244.5.223.254244.5.223.2552,046
189244.5.224.0/21244.5.224.1 to 244.5.231.254244.5.231.2552,046
190244.5.232.0/21244.5.232.1 to 244.5.239.254244.5.239.2552,046
191244.5.240.0/21244.5.240.1 to 244.5.247.254244.5.247.2552,046
192244.5.248.0/21244.5.248.1 to 244.5.255.254244.5.255.2552,046
193244.6.0.0/21244.6.0.1 to 244.6.7.254244.6.7.2552,046
194244.6.8.0/21244.6.8.1 to 244.6.15.254244.6.15.2552,046
195244.6.16.0/21244.6.16.1 to 244.6.23.254244.6.23.2552,046
196244.6.24.0/21244.6.24.1 to 244.6.31.254244.6.31.2552,046
197244.6.32.0/21244.6.32.1 to 244.6.39.254244.6.39.2552,046
198244.6.40.0/21244.6.40.1 to 244.6.47.254244.6.47.2552,046
199244.6.48.0/21244.6.48.1 to 244.6.55.254244.6.55.2552,046
200244.6.56.0/21244.6.56.1 to 244.6.63.254244.6.63.2552,046
201244.6.64.0/21244.6.64.1 to 244.6.71.254244.6.71.2552,046
202244.6.72.0/21244.6.72.1 to 244.6.79.254244.6.79.2552,046
203244.6.80.0/21244.6.80.1 to 244.6.87.254244.6.87.2552,046
204244.6.88.0/21244.6.88.1 to 244.6.95.254244.6.95.2552,046
205244.6.96.0/21244.6.96.1 to 244.6.103.254244.6.103.2552,046
206244.6.104.0/21244.6.104.1 to 244.6.111.254244.6.111.2552,046
207244.6.112.0/21244.6.112.1 to 244.6.119.254244.6.119.2552,046
208244.6.120.0/21244.6.120.1 to 244.6.127.254244.6.127.2552,046
209244.6.128.0/21244.6.128.1 to 244.6.135.254244.6.135.2552,046
210244.6.136.0/21244.6.136.1 to 244.6.143.254244.6.143.2552,046
211244.6.144.0/21244.6.144.1 to 244.6.151.254244.6.151.2552,046
212244.6.152.0/21244.6.152.1 to 244.6.159.254244.6.159.2552,046
213244.6.160.0/21244.6.160.1 to 244.6.167.254244.6.167.2552,046
214244.6.168.0/21244.6.168.1 to 244.6.175.254244.6.175.2552,046
215244.6.176.0/21244.6.176.1 to 244.6.183.254244.6.183.2552,046
216244.6.184.0/21244.6.184.1 to 244.6.191.254244.6.191.2552,046
217244.6.192.0/21244.6.192.1 to 244.6.199.254244.6.199.2552,046
218244.6.200.0/21244.6.200.1 to 244.6.207.254244.6.207.2552,046
219244.6.208.0/21244.6.208.1 to 244.6.215.254244.6.215.2552,046
220244.6.216.0/21244.6.216.1 to 244.6.223.254244.6.223.2552,046
221244.6.224.0/21244.6.224.1 to 244.6.231.254244.6.231.2552,046
222244.6.232.0/21244.6.232.1 to 244.6.239.254244.6.239.2552,046
223244.6.240.0/21244.6.240.1 to 244.6.247.254244.6.247.2552,046
224244.6.248.0/21244.6.248.1 to 244.6.255.254244.6.255.2552,046
225244.7.0.0/21244.7.0.1 to 244.7.7.254244.7.7.2552,046
226244.7.8.0/21244.7.8.1 to 244.7.15.254244.7.15.2552,046
227244.7.16.0/21244.7.16.1 to 244.7.23.254244.7.23.2552,046
228244.7.24.0/21244.7.24.1 to 244.7.31.254244.7.31.2552,046
229244.7.32.0/21244.7.32.1 to 244.7.39.254244.7.39.2552,046
230244.7.40.0/21244.7.40.1 to 244.7.47.254244.7.47.2552,046
231244.7.48.0/21244.7.48.1 to 244.7.55.254244.7.55.2552,046
232244.7.56.0/21244.7.56.1 to 244.7.63.254244.7.63.2552,046
233244.7.64.0/21244.7.64.1 to 244.7.71.254244.7.71.2552,046
234244.7.72.0/21244.7.72.1 to 244.7.79.254244.7.79.2552,046
235244.7.80.0/21244.7.80.1 to 244.7.87.254244.7.87.2552,046
236244.7.88.0/21244.7.88.1 to 244.7.95.254244.7.95.2552,046
237244.7.96.0/21244.7.96.1 to 244.7.103.254244.7.103.2552,046
238244.7.104.0/21244.7.104.1 to 244.7.111.254244.7.111.2552,046
239244.7.112.0/21244.7.112.1 to 244.7.119.254244.7.119.2552,046
240244.7.120.0/21244.7.120.1 to 244.7.127.254244.7.127.2552,046
241244.7.128.0/21244.7.128.1 to 244.7.135.254244.7.135.2552,046
242244.7.136.0/21244.7.136.1 to 244.7.143.254244.7.143.2552,046
243244.7.144.0/21244.7.144.1 to 244.7.151.254244.7.151.2552,046
244244.7.152.0/21244.7.152.1 to 244.7.159.254244.7.159.2552,046
245244.7.160.0/21244.7.160.1 to 244.7.167.254244.7.167.2552,046
246244.7.168.0/21244.7.168.1 to 244.7.175.254244.7.175.2552,046
247244.7.176.0/21244.7.176.1 to 244.7.183.254244.7.183.2552,046
248244.7.184.0/21244.7.184.1 to 244.7.191.254244.7.191.2552,046
249244.7.192.0/21244.7.192.1 to 244.7.199.254244.7.199.2552,046
250244.7.200.0/21244.7.200.1 to 244.7.207.254244.7.207.2552,046
251244.7.208.0/21244.7.208.1 to 244.7.215.254244.7.215.2552,046
252244.7.216.0/21244.7.216.1 to 244.7.223.254244.7.223.2552,046
253244.7.224.0/21244.7.224.1 to 244.7.231.254244.7.231.2552,046
254244.7.232.0/21244.7.232.1 to 244.7.239.254244.7.239.2552,046
255244.7.240.0/21244.7.240.1 to 244.7.247.254244.7.247.2552,046
256244.7.248.0/21244.7.248.1 to 244.7.255.254244.7.255.2552,046

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.