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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.

Network211.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
211.0.0.0
Broadcast address
211.255.255.255
First usable
211.0.0.1
Last usable
211.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex D3000000 · Integer 3539992576 to 3556769791
Reverse DNS zone
211.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010011..00000000.00000000.00000000211.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11010011..00000000.00000000.00000000211.0.0.0
Broadcast11010011..11111111.11111111.11111111211.255.255.255
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

211.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1211.0.0.0/20211.0.0.1 to 211.0.15.254211.0.15.2554,094
2211.0.16.0/20211.0.16.1 to 211.0.31.254211.0.31.2554,094
3211.0.32.0/20211.0.32.1 to 211.0.47.254211.0.47.2554,094
4211.0.48.0/20211.0.48.1 to 211.0.63.254211.0.63.2554,094
5211.0.64.0/20211.0.64.1 to 211.0.79.254211.0.79.2554,094
6211.0.80.0/20211.0.80.1 to 211.0.95.254211.0.95.2554,094
7211.0.96.0/20211.0.96.1 to 211.0.111.254211.0.111.2554,094
8211.0.112.0/20211.0.112.1 to 211.0.127.254211.0.127.2554,094
9211.0.128.0/20211.0.128.1 to 211.0.143.254211.0.143.2554,094
10211.0.144.0/20211.0.144.1 to 211.0.159.254211.0.159.2554,094
11211.0.160.0/20211.0.160.1 to 211.0.175.254211.0.175.2554,094
12211.0.176.0/20211.0.176.1 to 211.0.191.254211.0.191.2554,094
13211.0.192.0/20211.0.192.1 to 211.0.207.254211.0.207.2554,094
14211.0.208.0/20211.0.208.1 to 211.0.223.254211.0.223.2554,094
15211.0.224.0/20211.0.224.1 to 211.0.239.254211.0.239.2554,094
16211.0.240.0/20211.0.240.1 to 211.0.255.254211.0.255.2554,094
17211.1.0.0/20211.1.0.1 to 211.1.15.254211.1.15.2554,094
18211.1.16.0/20211.1.16.1 to 211.1.31.254211.1.31.2554,094
19211.1.32.0/20211.1.32.1 to 211.1.47.254211.1.47.2554,094
20211.1.48.0/20211.1.48.1 to 211.1.63.254211.1.63.2554,094
21211.1.64.0/20211.1.64.1 to 211.1.79.254211.1.79.2554,094
22211.1.80.0/20211.1.80.1 to 211.1.95.254211.1.95.2554,094
23211.1.96.0/20211.1.96.1 to 211.1.111.254211.1.111.2554,094
24211.1.112.0/20211.1.112.1 to 211.1.127.254211.1.127.2554,094
25211.1.128.0/20211.1.128.1 to 211.1.143.254211.1.143.2554,094
26211.1.144.0/20211.1.144.1 to 211.1.159.254211.1.159.2554,094
27211.1.160.0/20211.1.160.1 to 211.1.175.254211.1.175.2554,094
28211.1.176.0/20211.1.176.1 to 211.1.191.254211.1.191.2554,094
29211.1.192.0/20211.1.192.1 to 211.1.207.254211.1.207.2554,094
30211.1.208.0/20211.1.208.1 to 211.1.223.254211.1.223.2554,094
31211.1.224.0/20211.1.224.1 to 211.1.239.254211.1.239.2554,094
32211.1.240.0/20211.1.240.1 to 211.1.255.254211.1.255.2554,094
33211.2.0.0/20211.2.0.1 to 211.2.15.254211.2.15.2554,094
34211.2.16.0/20211.2.16.1 to 211.2.31.254211.2.31.2554,094
35211.2.32.0/20211.2.32.1 to 211.2.47.254211.2.47.2554,094
36211.2.48.0/20211.2.48.1 to 211.2.63.254211.2.63.2554,094
37211.2.64.0/20211.2.64.1 to 211.2.79.254211.2.79.2554,094
38211.2.80.0/20211.2.80.1 to 211.2.95.254211.2.95.2554,094
39211.2.96.0/20211.2.96.1 to 211.2.111.254211.2.111.2554,094
40211.2.112.0/20211.2.112.1 to 211.2.127.254211.2.127.2554,094
41211.2.128.0/20211.2.128.1 to 211.2.143.254211.2.143.2554,094
42211.2.144.0/20211.2.144.1 to 211.2.159.254211.2.159.2554,094
43211.2.160.0/20211.2.160.1 to 211.2.175.254211.2.175.2554,094
44211.2.176.0/20211.2.176.1 to 211.2.191.254211.2.191.2554,094
45211.2.192.0/20211.2.192.1 to 211.2.207.254211.2.207.2554,094
46211.2.208.0/20211.2.208.1 to 211.2.223.254211.2.223.2554,094
47211.2.224.0/20211.2.224.1 to 211.2.239.254211.2.239.2554,094
48211.2.240.0/20211.2.240.1 to 211.2.255.254211.2.255.2554,094
49211.3.0.0/20211.3.0.1 to 211.3.15.254211.3.15.2554,094
50211.3.16.0/20211.3.16.1 to 211.3.31.254211.3.31.2554,094
51211.3.32.0/20211.3.32.1 to 211.3.47.254211.3.47.2554,094
52211.3.48.0/20211.3.48.1 to 211.3.63.254211.3.63.2554,094
53211.3.64.0/20211.3.64.1 to 211.3.79.254211.3.79.2554,094
54211.3.80.0/20211.3.80.1 to 211.3.95.254211.3.95.2554,094
55211.3.96.0/20211.3.96.1 to 211.3.111.254211.3.111.2554,094
56211.3.112.0/20211.3.112.1 to 211.3.127.254211.3.127.2554,094
57211.3.128.0/20211.3.128.1 to 211.3.143.254211.3.143.2554,094
58211.3.144.0/20211.3.144.1 to 211.3.159.254211.3.159.2554,094
59211.3.160.0/20211.3.160.1 to 211.3.175.254211.3.175.2554,094
60211.3.176.0/20211.3.176.1 to 211.3.191.254211.3.191.2554,094
61211.3.192.0/20211.3.192.1 to 211.3.207.254211.3.207.2554,094
62211.3.208.0/20211.3.208.1 to 211.3.223.254211.3.223.2554,094
63211.3.224.0/20211.3.224.1 to 211.3.239.254211.3.239.2554,094
64211.3.240.0/20211.3.240.1 to 211.3.255.254211.3.255.2554,094
65211.4.0.0/20211.4.0.1 to 211.4.15.254211.4.15.2554,094
66211.4.16.0/20211.4.16.1 to 211.4.31.254211.4.31.2554,094
67211.4.32.0/20211.4.32.1 to 211.4.47.254211.4.47.2554,094
68211.4.48.0/20211.4.48.1 to 211.4.63.254211.4.63.2554,094
69211.4.64.0/20211.4.64.1 to 211.4.79.254211.4.79.2554,094
70211.4.80.0/20211.4.80.1 to 211.4.95.254211.4.95.2554,094
71211.4.96.0/20211.4.96.1 to 211.4.111.254211.4.111.2554,094
72211.4.112.0/20211.4.112.1 to 211.4.127.254211.4.127.2554,094
73211.4.128.0/20211.4.128.1 to 211.4.143.254211.4.143.2554,094
74211.4.144.0/20211.4.144.1 to 211.4.159.254211.4.159.2554,094
75211.4.160.0/20211.4.160.1 to 211.4.175.254211.4.175.2554,094
76211.4.176.0/20211.4.176.1 to 211.4.191.254211.4.191.2554,094
77211.4.192.0/20211.4.192.1 to 211.4.207.254211.4.207.2554,094
78211.4.208.0/20211.4.208.1 to 211.4.223.254211.4.223.2554,094
79211.4.224.0/20211.4.224.1 to 211.4.239.254211.4.239.2554,094
80211.4.240.0/20211.4.240.1 to 211.4.255.254211.4.255.2554,094
81211.5.0.0/20211.5.0.1 to 211.5.15.254211.5.15.2554,094
82211.5.16.0/20211.5.16.1 to 211.5.31.254211.5.31.2554,094
83211.5.32.0/20211.5.32.1 to 211.5.47.254211.5.47.2554,094
84211.5.48.0/20211.5.48.1 to 211.5.63.254211.5.63.2554,094
85211.5.64.0/20211.5.64.1 to 211.5.79.254211.5.79.2554,094
86211.5.80.0/20211.5.80.1 to 211.5.95.254211.5.95.2554,094
87211.5.96.0/20211.5.96.1 to 211.5.111.254211.5.111.2554,094
88211.5.112.0/20211.5.112.1 to 211.5.127.254211.5.127.2554,094
89211.5.128.0/20211.5.128.1 to 211.5.143.254211.5.143.2554,094
90211.5.144.0/20211.5.144.1 to 211.5.159.254211.5.159.2554,094
91211.5.160.0/20211.5.160.1 to 211.5.175.254211.5.175.2554,094
92211.5.176.0/20211.5.176.1 to 211.5.191.254211.5.191.2554,094
93211.5.192.0/20211.5.192.1 to 211.5.207.254211.5.207.2554,094
94211.5.208.0/20211.5.208.1 to 211.5.223.254211.5.223.2554,094
95211.5.224.0/20211.5.224.1 to 211.5.239.254211.5.239.2554,094
96211.5.240.0/20211.5.240.1 to 211.5.255.254211.5.255.2554,094
97211.6.0.0/20211.6.0.1 to 211.6.15.254211.6.15.2554,094
98211.6.16.0/20211.6.16.1 to 211.6.31.254211.6.31.2554,094
99211.6.32.0/20211.6.32.1 to 211.6.47.254211.6.47.2554,094
100211.6.48.0/20211.6.48.1 to 211.6.63.254211.6.63.2554,094
101211.6.64.0/20211.6.64.1 to 211.6.79.254211.6.79.2554,094
102211.6.80.0/20211.6.80.1 to 211.6.95.254211.6.95.2554,094
103211.6.96.0/20211.6.96.1 to 211.6.111.254211.6.111.2554,094
104211.6.112.0/20211.6.112.1 to 211.6.127.254211.6.127.2554,094
105211.6.128.0/20211.6.128.1 to 211.6.143.254211.6.143.2554,094
106211.6.144.0/20211.6.144.1 to 211.6.159.254211.6.159.2554,094
107211.6.160.0/20211.6.160.1 to 211.6.175.254211.6.175.2554,094
108211.6.176.0/20211.6.176.1 to 211.6.191.254211.6.191.2554,094
109211.6.192.0/20211.6.192.1 to 211.6.207.254211.6.207.2554,094
110211.6.208.0/20211.6.208.1 to 211.6.223.254211.6.223.2554,094
111211.6.224.0/20211.6.224.1 to 211.6.239.254211.6.239.2554,094
112211.6.240.0/20211.6.240.1 to 211.6.255.254211.6.255.2554,094
113211.7.0.0/20211.7.0.1 to 211.7.15.254211.7.15.2554,094
114211.7.16.0/20211.7.16.1 to 211.7.31.254211.7.31.2554,094
115211.7.32.0/20211.7.32.1 to 211.7.47.254211.7.47.2554,094
116211.7.48.0/20211.7.48.1 to 211.7.63.254211.7.63.2554,094
117211.7.64.0/20211.7.64.1 to 211.7.79.254211.7.79.2554,094
118211.7.80.0/20211.7.80.1 to 211.7.95.254211.7.95.2554,094
119211.7.96.0/20211.7.96.1 to 211.7.111.254211.7.111.2554,094
120211.7.112.0/20211.7.112.1 to 211.7.127.254211.7.127.2554,094
121211.7.128.0/20211.7.128.1 to 211.7.143.254211.7.143.2554,094
122211.7.144.0/20211.7.144.1 to 211.7.159.254211.7.159.2554,094
123211.7.160.0/20211.7.160.1 to 211.7.175.254211.7.175.2554,094
124211.7.176.0/20211.7.176.1 to 211.7.191.254211.7.191.2554,094
125211.7.192.0/20211.7.192.1 to 211.7.207.254211.7.207.2554,094
126211.7.208.0/20211.7.208.1 to 211.7.223.254211.7.223.2554,094
127211.7.224.0/20211.7.224.1 to 211.7.239.254211.7.239.2554,094
128211.7.240.0/20211.7.240.1 to 211.7.255.254211.7.255.2554,094
129211.8.0.0/20211.8.0.1 to 211.8.15.254211.8.15.2554,094
130211.8.16.0/20211.8.16.1 to 211.8.31.254211.8.31.2554,094
131211.8.32.0/20211.8.32.1 to 211.8.47.254211.8.47.2554,094
132211.8.48.0/20211.8.48.1 to 211.8.63.254211.8.63.2554,094
133211.8.64.0/20211.8.64.1 to 211.8.79.254211.8.79.2554,094
134211.8.80.0/20211.8.80.1 to 211.8.95.254211.8.95.2554,094
135211.8.96.0/20211.8.96.1 to 211.8.111.254211.8.111.2554,094
136211.8.112.0/20211.8.112.1 to 211.8.127.254211.8.127.2554,094
137211.8.128.0/20211.8.128.1 to 211.8.143.254211.8.143.2554,094
138211.8.144.0/20211.8.144.1 to 211.8.159.254211.8.159.2554,094
139211.8.160.0/20211.8.160.1 to 211.8.175.254211.8.175.2554,094
140211.8.176.0/20211.8.176.1 to 211.8.191.254211.8.191.2554,094
141211.8.192.0/20211.8.192.1 to 211.8.207.254211.8.207.2554,094
142211.8.208.0/20211.8.208.1 to 211.8.223.254211.8.223.2554,094
143211.8.224.0/20211.8.224.1 to 211.8.239.254211.8.239.2554,094
144211.8.240.0/20211.8.240.1 to 211.8.255.254211.8.255.2554,094
145211.9.0.0/20211.9.0.1 to 211.9.15.254211.9.15.2554,094
146211.9.16.0/20211.9.16.1 to 211.9.31.254211.9.31.2554,094
147211.9.32.0/20211.9.32.1 to 211.9.47.254211.9.47.2554,094
148211.9.48.0/20211.9.48.1 to 211.9.63.254211.9.63.2554,094
149211.9.64.0/20211.9.64.1 to 211.9.79.254211.9.79.2554,094
150211.9.80.0/20211.9.80.1 to 211.9.95.254211.9.95.2554,094
151211.9.96.0/20211.9.96.1 to 211.9.111.254211.9.111.2554,094
152211.9.112.0/20211.9.112.1 to 211.9.127.254211.9.127.2554,094
153211.9.128.0/20211.9.128.1 to 211.9.143.254211.9.143.2554,094
154211.9.144.0/20211.9.144.1 to 211.9.159.254211.9.159.2554,094
155211.9.160.0/20211.9.160.1 to 211.9.175.254211.9.175.2554,094
156211.9.176.0/20211.9.176.1 to 211.9.191.254211.9.191.2554,094
157211.9.192.0/20211.9.192.1 to 211.9.207.254211.9.207.2554,094
158211.9.208.0/20211.9.208.1 to 211.9.223.254211.9.223.2554,094
159211.9.224.0/20211.9.224.1 to 211.9.239.254211.9.239.2554,094
160211.9.240.0/20211.9.240.1 to 211.9.255.254211.9.255.2554,094
161211.10.0.0/20211.10.0.1 to 211.10.15.254211.10.15.2554,094
162211.10.16.0/20211.10.16.1 to 211.10.31.254211.10.31.2554,094
163211.10.32.0/20211.10.32.1 to 211.10.47.254211.10.47.2554,094
164211.10.48.0/20211.10.48.1 to 211.10.63.254211.10.63.2554,094
165211.10.64.0/20211.10.64.1 to 211.10.79.254211.10.79.2554,094
166211.10.80.0/20211.10.80.1 to 211.10.95.254211.10.95.2554,094
167211.10.96.0/20211.10.96.1 to 211.10.111.254211.10.111.2554,094
168211.10.112.0/20211.10.112.1 to 211.10.127.254211.10.127.2554,094
169211.10.128.0/20211.10.128.1 to 211.10.143.254211.10.143.2554,094
170211.10.144.0/20211.10.144.1 to 211.10.159.254211.10.159.2554,094
171211.10.160.0/20211.10.160.1 to 211.10.175.254211.10.175.2554,094
172211.10.176.0/20211.10.176.1 to 211.10.191.254211.10.191.2554,094
173211.10.192.0/20211.10.192.1 to 211.10.207.254211.10.207.2554,094
174211.10.208.0/20211.10.208.1 to 211.10.223.254211.10.223.2554,094
175211.10.224.0/20211.10.224.1 to 211.10.239.254211.10.239.2554,094
176211.10.240.0/20211.10.240.1 to 211.10.255.254211.10.255.2554,094
177211.11.0.0/20211.11.0.1 to 211.11.15.254211.11.15.2554,094
178211.11.16.0/20211.11.16.1 to 211.11.31.254211.11.31.2554,094
179211.11.32.0/20211.11.32.1 to 211.11.47.254211.11.47.2554,094
180211.11.48.0/20211.11.48.1 to 211.11.63.254211.11.63.2554,094
181211.11.64.0/20211.11.64.1 to 211.11.79.254211.11.79.2554,094
182211.11.80.0/20211.11.80.1 to 211.11.95.254211.11.95.2554,094
183211.11.96.0/20211.11.96.1 to 211.11.111.254211.11.111.2554,094
184211.11.112.0/20211.11.112.1 to 211.11.127.254211.11.127.2554,094
185211.11.128.0/20211.11.128.1 to 211.11.143.254211.11.143.2554,094
186211.11.144.0/20211.11.144.1 to 211.11.159.254211.11.159.2554,094
187211.11.160.0/20211.11.160.1 to 211.11.175.254211.11.175.2554,094
188211.11.176.0/20211.11.176.1 to 211.11.191.254211.11.191.2554,094
189211.11.192.0/20211.11.192.1 to 211.11.207.254211.11.207.2554,094
190211.11.208.0/20211.11.208.1 to 211.11.223.254211.11.223.2554,094
191211.11.224.0/20211.11.224.1 to 211.11.239.254211.11.239.2554,094
192211.11.240.0/20211.11.240.1 to 211.11.255.254211.11.255.2554,094
193211.12.0.0/20211.12.0.1 to 211.12.15.254211.12.15.2554,094
194211.12.16.0/20211.12.16.1 to 211.12.31.254211.12.31.2554,094
195211.12.32.0/20211.12.32.1 to 211.12.47.254211.12.47.2554,094
196211.12.48.0/20211.12.48.1 to 211.12.63.254211.12.63.2554,094
197211.12.64.0/20211.12.64.1 to 211.12.79.254211.12.79.2554,094
198211.12.80.0/20211.12.80.1 to 211.12.95.254211.12.95.2554,094
199211.12.96.0/20211.12.96.1 to 211.12.111.254211.12.111.2554,094
200211.12.112.0/20211.12.112.1 to 211.12.127.254211.12.127.2554,094
201211.12.128.0/20211.12.128.1 to 211.12.143.254211.12.143.2554,094
202211.12.144.0/20211.12.144.1 to 211.12.159.254211.12.159.2554,094
203211.12.160.0/20211.12.160.1 to 211.12.175.254211.12.175.2554,094
204211.12.176.0/20211.12.176.1 to 211.12.191.254211.12.191.2554,094
205211.12.192.0/20211.12.192.1 to 211.12.207.254211.12.207.2554,094
206211.12.208.0/20211.12.208.1 to 211.12.223.254211.12.223.2554,094
207211.12.224.0/20211.12.224.1 to 211.12.239.254211.12.239.2554,094
208211.12.240.0/20211.12.240.1 to 211.12.255.254211.12.255.2554,094
209211.13.0.0/20211.13.0.1 to 211.13.15.254211.13.15.2554,094
210211.13.16.0/20211.13.16.1 to 211.13.31.254211.13.31.2554,094
211211.13.32.0/20211.13.32.1 to 211.13.47.254211.13.47.2554,094
212211.13.48.0/20211.13.48.1 to 211.13.63.254211.13.63.2554,094
213211.13.64.0/20211.13.64.1 to 211.13.79.254211.13.79.2554,094
214211.13.80.0/20211.13.80.1 to 211.13.95.254211.13.95.2554,094
215211.13.96.0/20211.13.96.1 to 211.13.111.254211.13.111.2554,094
216211.13.112.0/20211.13.112.1 to 211.13.127.254211.13.127.2554,094
217211.13.128.0/20211.13.128.1 to 211.13.143.254211.13.143.2554,094
218211.13.144.0/20211.13.144.1 to 211.13.159.254211.13.159.2554,094
219211.13.160.0/20211.13.160.1 to 211.13.175.254211.13.175.2554,094
220211.13.176.0/20211.13.176.1 to 211.13.191.254211.13.191.2554,094
221211.13.192.0/20211.13.192.1 to 211.13.207.254211.13.207.2554,094
222211.13.208.0/20211.13.208.1 to 211.13.223.254211.13.223.2554,094
223211.13.224.0/20211.13.224.1 to 211.13.239.254211.13.239.2554,094
224211.13.240.0/20211.13.240.1 to 211.13.255.254211.13.255.2554,094
225211.14.0.0/20211.14.0.1 to 211.14.15.254211.14.15.2554,094
226211.14.16.0/20211.14.16.1 to 211.14.31.254211.14.31.2554,094
227211.14.32.0/20211.14.32.1 to 211.14.47.254211.14.47.2554,094
228211.14.48.0/20211.14.48.1 to 211.14.63.254211.14.63.2554,094
229211.14.64.0/20211.14.64.1 to 211.14.79.254211.14.79.2554,094
230211.14.80.0/20211.14.80.1 to 211.14.95.254211.14.95.2554,094
231211.14.96.0/20211.14.96.1 to 211.14.111.254211.14.111.2554,094
232211.14.112.0/20211.14.112.1 to 211.14.127.254211.14.127.2554,094
233211.14.128.0/20211.14.128.1 to 211.14.143.254211.14.143.2554,094
234211.14.144.0/20211.14.144.1 to 211.14.159.254211.14.159.2554,094
235211.14.160.0/20211.14.160.1 to 211.14.175.254211.14.175.2554,094
236211.14.176.0/20211.14.176.1 to 211.14.191.254211.14.191.2554,094
237211.14.192.0/20211.14.192.1 to 211.14.207.254211.14.207.2554,094
238211.14.208.0/20211.14.208.1 to 211.14.223.254211.14.223.2554,094
239211.14.224.0/20211.14.224.1 to 211.14.239.254211.14.239.2554,094
240211.14.240.0/20211.14.240.1 to 211.14.255.254211.14.255.2554,094
241211.15.0.0/20211.15.0.1 to 211.15.15.254211.15.15.2554,094
242211.15.16.0/20211.15.16.1 to 211.15.31.254211.15.31.2554,094
243211.15.32.0/20211.15.32.1 to 211.15.47.254211.15.47.2554,094
244211.15.48.0/20211.15.48.1 to 211.15.63.254211.15.63.2554,094
245211.15.64.0/20211.15.64.1 to 211.15.79.254211.15.79.2554,094
246211.15.80.0/20211.15.80.1 to 211.15.95.254211.15.95.2554,094
247211.15.96.0/20211.15.96.1 to 211.15.111.254211.15.111.2554,094
248211.15.112.0/20211.15.112.1 to 211.15.127.254211.15.127.2554,094
249211.15.128.0/20211.15.128.1 to 211.15.143.254211.15.143.2554,094
250211.15.144.0/20211.15.144.1 to 211.15.159.254211.15.159.2554,094
251211.15.160.0/20211.15.160.1 to 211.15.175.254211.15.175.2554,094
252211.15.176.0/20211.15.176.1 to 211.15.191.254211.15.191.2554,094
253211.15.192.0/20211.15.192.1 to 211.15.207.254211.15.207.2554,094
254211.15.208.0/20211.15.208.1 to 211.15.223.254211.15.223.2554,094
255211.15.224.0/20211.15.224.1 to 211.15.239.254211.15.239.2554,094
256211.15.240.0/20211.15.240.1 to 211.15.255.254211.15.255.2554,094

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.