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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.

Network213.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
213.0.0.0
Broadcast address
213.255.255.255
First usable
213.0.0.1
Last usable
213.255.255.254
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 D5000000 · Integer 3573547008 to 3590324223
Reverse DNS zone
213.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010101..00000000.00000000.00000000213.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11010101..00000000.00000000.00000000213.0.0.0
Broadcast11010101..11111111.11111111.11111111213.255.255.255
Split into smaller subnets/19
/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)

213.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1213.0.0.0/19213.0.0.1 to 213.0.31.254213.0.31.2558,190
2213.0.32.0/19213.0.32.1 to 213.0.63.254213.0.63.2558,190
3213.0.64.0/19213.0.64.1 to 213.0.95.254213.0.95.2558,190
4213.0.96.0/19213.0.96.1 to 213.0.127.254213.0.127.2558,190
5213.0.128.0/19213.0.128.1 to 213.0.159.254213.0.159.2558,190
6213.0.160.0/19213.0.160.1 to 213.0.191.254213.0.191.2558,190
7213.0.192.0/19213.0.192.1 to 213.0.223.254213.0.223.2558,190
8213.0.224.0/19213.0.224.1 to 213.0.255.254213.0.255.2558,190
9213.1.0.0/19213.1.0.1 to 213.1.31.254213.1.31.2558,190
10213.1.32.0/19213.1.32.1 to 213.1.63.254213.1.63.2558,190
11213.1.64.0/19213.1.64.1 to 213.1.95.254213.1.95.2558,190
12213.1.96.0/19213.1.96.1 to 213.1.127.254213.1.127.2558,190
13213.1.128.0/19213.1.128.1 to 213.1.159.254213.1.159.2558,190
14213.1.160.0/19213.1.160.1 to 213.1.191.254213.1.191.2558,190
15213.1.192.0/19213.1.192.1 to 213.1.223.254213.1.223.2558,190
16213.1.224.0/19213.1.224.1 to 213.1.255.254213.1.255.2558,190
17213.2.0.0/19213.2.0.1 to 213.2.31.254213.2.31.2558,190
18213.2.32.0/19213.2.32.1 to 213.2.63.254213.2.63.2558,190
19213.2.64.0/19213.2.64.1 to 213.2.95.254213.2.95.2558,190
20213.2.96.0/19213.2.96.1 to 213.2.127.254213.2.127.2558,190
21213.2.128.0/19213.2.128.1 to 213.2.159.254213.2.159.2558,190
22213.2.160.0/19213.2.160.1 to 213.2.191.254213.2.191.2558,190
23213.2.192.0/19213.2.192.1 to 213.2.223.254213.2.223.2558,190
24213.2.224.0/19213.2.224.1 to 213.2.255.254213.2.255.2558,190
25213.3.0.0/19213.3.0.1 to 213.3.31.254213.3.31.2558,190
26213.3.32.0/19213.3.32.1 to 213.3.63.254213.3.63.2558,190
27213.3.64.0/19213.3.64.1 to 213.3.95.254213.3.95.2558,190
28213.3.96.0/19213.3.96.1 to 213.3.127.254213.3.127.2558,190
29213.3.128.0/19213.3.128.1 to 213.3.159.254213.3.159.2558,190
30213.3.160.0/19213.3.160.1 to 213.3.191.254213.3.191.2558,190
31213.3.192.0/19213.3.192.1 to 213.3.223.254213.3.223.2558,190
32213.3.224.0/19213.3.224.1 to 213.3.255.254213.3.255.2558,190
33213.4.0.0/19213.4.0.1 to 213.4.31.254213.4.31.2558,190
34213.4.32.0/19213.4.32.1 to 213.4.63.254213.4.63.2558,190
35213.4.64.0/19213.4.64.1 to 213.4.95.254213.4.95.2558,190
36213.4.96.0/19213.4.96.1 to 213.4.127.254213.4.127.2558,190
37213.4.128.0/19213.4.128.1 to 213.4.159.254213.4.159.2558,190
38213.4.160.0/19213.4.160.1 to 213.4.191.254213.4.191.2558,190
39213.4.192.0/19213.4.192.1 to 213.4.223.254213.4.223.2558,190
40213.4.224.0/19213.4.224.1 to 213.4.255.254213.4.255.2558,190
41213.5.0.0/19213.5.0.1 to 213.5.31.254213.5.31.2558,190
42213.5.32.0/19213.5.32.1 to 213.5.63.254213.5.63.2558,190
43213.5.64.0/19213.5.64.1 to 213.5.95.254213.5.95.2558,190
44213.5.96.0/19213.5.96.1 to 213.5.127.254213.5.127.2558,190
45213.5.128.0/19213.5.128.1 to 213.5.159.254213.5.159.2558,190
46213.5.160.0/19213.5.160.1 to 213.5.191.254213.5.191.2558,190
47213.5.192.0/19213.5.192.1 to 213.5.223.254213.5.223.2558,190
48213.5.224.0/19213.5.224.1 to 213.5.255.254213.5.255.2558,190
49213.6.0.0/19213.6.0.1 to 213.6.31.254213.6.31.2558,190
50213.6.32.0/19213.6.32.1 to 213.6.63.254213.6.63.2558,190
51213.6.64.0/19213.6.64.1 to 213.6.95.254213.6.95.2558,190
52213.6.96.0/19213.6.96.1 to 213.6.127.254213.6.127.2558,190
53213.6.128.0/19213.6.128.1 to 213.6.159.254213.6.159.2558,190
54213.6.160.0/19213.6.160.1 to 213.6.191.254213.6.191.2558,190
55213.6.192.0/19213.6.192.1 to 213.6.223.254213.6.223.2558,190
56213.6.224.0/19213.6.224.1 to 213.6.255.254213.6.255.2558,190
57213.7.0.0/19213.7.0.1 to 213.7.31.254213.7.31.2558,190
58213.7.32.0/19213.7.32.1 to 213.7.63.254213.7.63.2558,190
59213.7.64.0/19213.7.64.1 to 213.7.95.254213.7.95.2558,190
60213.7.96.0/19213.7.96.1 to 213.7.127.254213.7.127.2558,190
61213.7.128.0/19213.7.128.1 to 213.7.159.254213.7.159.2558,190
62213.7.160.0/19213.7.160.1 to 213.7.191.254213.7.191.2558,190
63213.7.192.0/19213.7.192.1 to 213.7.223.254213.7.223.2558,190
64213.7.224.0/19213.7.224.1 to 213.7.255.254213.7.255.2558,190
65213.8.0.0/19213.8.0.1 to 213.8.31.254213.8.31.2558,190
66213.8.32.0/19213.8.32.1 to 213.8.63.254213.8.63.2558,190
67213.8.64.0/19213.8.64.1 to 213.8.95.254213.8.95.2558,190
68213.8.96.0/19213.8.96.1 to 213.8.127.254213.8.127.2558,190
69213.8.128.0/19213.8.128.1 to 213.8.159.254213.8.159.2558,190
70213.8.160.0/19213.8.160.1 to 213.8.191.254213.8.191.2558,190
71213.8.192.0/19213.8.192.1 to 213.8.223.254213.8.223.2558,190
72213.8.224.0/19213.8.224.1 to 213.8.255.254213.8.255.2558,190
73213.9.0.0/19213.9.0.1 to 213.9.31.254213.9.31.2558,190
74213.9.32.0/19213.9.32.1 to 213.9.63.254213.9.63.2558,190
75213.9.64.0/19213.9.64.1 to 213.9.95.254213.9.95.2558,190
76213.9.96.0/19213.9.96.1 to 213.9.127.254213.9.127.2558,190
77213.9.128.0/19213.9.128.1 to 213.9.159.254213.9.159.2558,190
78213.9.160.0/19213.9.160.1 to 213.9.191.254213.9.191.2558,190
79213.9.192.0/19213.9.192.1 to 213.9.223.254213.9.223.2558,190
80213.9.224.0/19213.9.224.1 to 213.9.255.254213.9.255.2558,190
81213.10.0.0/19213.10.0.1 to 213.10.31.254213.10.31.2558,190
82213.10.32.0/19213.10.32.1 to 213.10.63.254213.10.63.2558,190
83213.10.64.0/19213.10.64.1 to 213.10.95.254213.10.95.2558,190
84213.10.96.0/19213.10.96.1 to 213.10.127.254213.10.127.2558,190
85213.10.128.0/19213.10.128.1 to 213.10.159.254213.10.159.2558,190
86213.10.160.0/19213.10.160.1 to 213.10.191.254213.10.191.2558,190
87213.10.192.0/19213.10.192.1 to 213.10.223.254213.10.223.2558,190
88213.10.224.0/19213.10.224.1 to 213.10.255.254213.10.255.2558,190
89213.11.0.0/19213.11.0.1 to 213.11.31.254213.11.31.2558,190
90213.11.32.0/19213.11.32.1 to 213.11.63.254213.11.63.2558,190
91213.11.64.0/19213.11.64.1 to 213.11.95.254213.11.95.2558,190
92213.11.96.0/19213.11.96.1 to 213.11.127.254213.11.127.2558,190
93213.11.128.0/19213.11.128.1 to 213.11.159.254213.11.159.2558,190
94213.11.160.0/19213.11.160.1 to 213.11.191.254213.11.191.2558,190
95213.11.192.0/19213.11.192.1 to 213.11.223.254213.11.223.2558,190
96213.11.224.0/19213.11.224.1 to 213.11.255.254213.11.255.2558,190
97213.12.0.0/19213.12.0.1 to 213.12.31.254213.12.31.2558,190
98213.12.32.0/19213.12.32.1 to 213.12.63.254213.12.63.2558,190
99213.12.64.0/19213.12.64.1 to 213.12.95.254213.12.95.2558,190
100213.12.96.0/19213.12.96.1 to 213.12.127.254213.12.127.2558,190
101213.12.128.0/19213.12.128.1 to 213.12.159.254213.12.159.2558,190
102213.12.160.0/19213.12.160.1 to 213.12.191.254213.12.191.2558,190
103213.12.192.0/19213.12.192.1 to 213.12.223.254213.12.223.2558,190
104213.12.224.0/19213.12.224.1 to 213.12.255.254213.12.255.2558,190
105213.13.0.0/19213.13.0.1 to 213.13.31.254213.13.31.2558,190
106213.13.32.0/19213.13.32.1 to 213.13.63.254213.13.63.2558,190
107213.13.64.0/19213.13.64.1 to 213.13.95.254213.13.95.2558,190
108213.13.96.0/19213.13.96.1 to 213.13.127.254213.13.127.2558,190
109213.13.128.0/19213.13.128.1 to 213.13.159.254213.13.159.2558,190
110213.13.160.0/19213.13.160.1 to 213.13.191.254213.13.191.2558,190
111213.13.192.0/19213.13.192.1 to 213.13.223.254213.13.223.2558,190
112213.13.224.0/19213.13.224.1 to 213.13.255.254213.13.255.2558,190
113213.14.0.0/19213.14.0.1 to 213.14.31.254213.14.31.2558,190
114213.14.32.0/19213.14.32.1 to 213.14.63.254213.14.63.2558,190
115213.14.64.0/19213.14.64.1 to 213.14.95.254213.14.95.2558,190
116213.14.96.0/19213.14.96.1 to 213.14.127.254213.14.127.2558,190
117213.14.128.0/19213.14.128.1 to 213.14.159.254213.14.159.2558,190
118213.14.160.0/19213.14.160.1 to 213.14.191.254213.14.191.2558,190
119213.14.192.0/19213.14.192.1 to 213.14.223.254213.14.223.2558,190
120213.14.224.0/19213.14.224.1 to 213.14.255.254213.14.255.2558,190
121213.15.0.0/19213.15.0.1 to 213.15.31.254213.15.31.2558,190
122213.15.32.0/19213.15.32.1 to 213.15.63.254213.15.63.2558,190
123213.15.64.0/19213.15.64.1 to 213.15.95.254213.15.95.2558,190
124213.15.96.0/19213.15.96.1 to 213.15.127.254213.15.127.2558,190
125213.15.128.0/19213.15.128.1 to 213.15.159.254213.15.159.2558,190
126213.15.160.0/19213.15.160.1 to 213.15.191.254213.15.191.2558,190
127213.15.192.0/19213.15.192.1 to 213.15.223.254213.15.223.2558,190
128213.15.224.0/19213.15.224.1 to 213.15.255.254213.15.255.2558,190
129213.16.0.0/19213.16.0.1 to 213.16.31.254213.16.31.2558,190
130213.16.32.0/19213.16.32.1 to 213.16.63.254213.16.63.2558,190
131213.16.64.0/19213.16.64.1 to 213.16.95.254213.16.95.2558,190
132213.16.96.0/19213.16.96.1 to 213.16.127.254213.16.127.2558,190
133213.16.128.0/19213.16.128.1 to 213.16.159.254213.16.159.2558,190
134213.16.160.0/19213.16.160.1 to 213.16.191.254213.16.191.2558,190
135213.16.192.0/19213.16.192.1 to 213.16.223.254213.16.223.2558,190
136213.16.224.0/19213.16.224.1 to 213.16.255.254213.16.255.2558,190
137213.17.0.0/19213.17.0.1 to 213.17.31.254213.17.31.2558,190
138213.17.32.0/19213.17.32.1 to 213.17.63.254213.17.63.2558,190
139213.17.64.0/19213.17.64.1 to 213.17.95.254213.17.95.2558,190
140213.17.96.0/19213.17.96.1 to 213.17.127.254213.17.127.2558,190
141213.17.128.0/19213.17.128.1 to 213.17.159.254213.17.159.2558,190
142213.17.160.0/19213.17.160.1 to 213.17.191.254213.17.191.2558,190
143213.17.192.0/19213.17.192.1 to 213.17.223.254213.17.223.2558,190
144213.17.224.0/19213.17.224.1 to 213.17.255.254213.17.255.2558,190
145213.18.0.0/19213.18.0.1 to 213.18.31.254213.18.31.2558,190
146213.18.32.0/19213.18.32.1 to 213.18.63.254213.18.63.2558,190
147213.18.64.0/19213.18.64.1 to 213.18.95.254213.18.95.2558,190
148213.18.96.0/19213.18.96.1 to 213.18.127.254213.18.127.2558,190
149213.18.128.0/19213.18.128.1 to 213.18.159.254213.18.159.2558,190
150213.18.160.0/19213.18.160.1 to 213.18.191.254213.18.191.2558,190
151213.18.192.0/19213.18.192.1 to 213.18.223.254213.18.223.2558,190
152213.18.224.0/19213.18.224.1 to 213.18.255.254213.18.255.2558,190
153213.19.0.0/19213.19.0.1 to 213.19.31.254213.19.31.2558,190
154213.19.32.0/19213.19.32.1 to 213.19.63.254213.19.63.2558,190
155213.19.64.0/19213.19.64.1 to 213.19.95.254213.19.95.2558,190
156213.19.96.0/19213.19.96.1 to 213.19.127.254213.19.127.2558,190
157213.19.128.0/19213.19.128.1 to 213.19.159.254213.19.159.2558,190
158213.19.160.0/19213.19.160.1 to 213.19.191.254213.19.191.2558,190
159213.19.192.0/19213.19.192.1 to 213.19.223.254213.19.223.2558,190
160213.19.224.0/19213.19.224.1 to 213.19.255.254213.19.255.2558,190
161213.20.0.0/19213.20.0.1 to 213.20.31.254213.20.31.2558,190
162213.20.32.0/19213.20.32.1 to 213.20.63.254213.20.63.2558,190
163213.20.64.0/19213.20.64.1 to 213.20.95.254213.20.95.2558,190
164213.20.96.0/19213.20.96.1 to 213.20.127.254213.20.127.2558,190
165213.20.128.0/19213.20.128.1 to 213.20.159.254213.20.159.2558,190
166213.20.160.0/19213.20.160.1 to 213.20.191.254213.20.191.2558,190
167213.20.192.0/19213.20.192.1 to 213.20.223.254213.20.223.2558,190
168213.20.224.0/19213.20.224.1 to 213.20.255.254213.20.255.2558,190
169213.21.0.0/19213.21.0.1 to 213.21.31.254213.21.31.2558,190
170213.21.32.0/19213.21.32.1 to 213.21.63.254213.21.63.2558,190
171213.21.64.0/19213.21.64.1 to 213.21.95.254213.21.95.2558,190
172213.21.96.0/19213.21.96.1 to 213.21.127.254213.21.127.2558,190
173213.21.128.0/19213.21.128.1 to 213.21.159.254213.21.159.2558,190
174213.21.160.0/19213.21.160.1 to 213.21.191.254213.21.191.2558,190
175213.21.192.0/19213.21.192.1 to 213.21.223.254213.21.223.2558,190
176213.21.224.0/19213.21.224.1 to 213.21.255.254213.21.255.2558,190
177213.22.0.0/19213.22.0.1 to 213.22.31.254213.22.31.2558,190
178213.22.32.0/19213.22.32.1 to 213.22.63.254213.22.63.2558,190
179213.22.64.0/19213.22.64.1 to 213.22.95.254213.22.95.2558,190
180213.22.96.0/19213.22.96.1 to 213.22.127.254213.22.127.2558,190
181213.22.128.0/19213.22.128.1 to 213.22.159.254213.22.159.2558,190
182213.22.160.0/19213.22.160.1 to 213.22.191.254213.22.191.2558,190
183213.22.192.0/19213.22.192.1 to 213.22.223.254213.22.223.2558,190
184213.22.224.0/19213.22.224.1 to 213.22.255.254213.22.255.2558,190
185213.23.0.0/19213.23.0.1 to 213.23.31.254213.23.31.2558,190
186213.23.32.0/19213.23.32.1 to 213.23.63.254213.23.63.2558,190
187213.23.64.0/19213.23.64.1 to 213.23.95.254213.23.95.2558,190
188213.23.96.0/19213.23.96.1 to 213.23.127.254213.23.127.2558,190
189213.23.128.0/19213.23.128.1 to 213.23.159.254213.23.159.2558,190
190213.23.160.0/19213.23.160.1 to 213.23.191.254213.23.191.2558,190
191213.23.192.0/19213.23.192.1 to 213.23.223.254213.23.223.2558,190
192213.23.224.0/19213.23.224.1 to 213.23.255.254213.23.255.2558,190
193213.24.0.0/19213.24.0.1 to 213.24.31.254213.24.31.2558,190
194213.24.32.0/19213.24.32.1 to 213.24.63.254213.24.63.2558,190
195213.24.64.0/19213.24.64.1 to 213.24.95.254213.24.95.2558,190
196213.24.96.0/19213.24.96.1 to 213.24.127.254213.24.127.2558,190
197213.24.128.0/19213.24.128.1 to 213.24.159.254213.24.159.2558,190
198213.24.160.0/19213.24.160.1 to 213.24.191.254213.24.191.2558,190
199213.24.192.0/19213.24.192.1 to 213.24.223.254213.24.223.2558,190
200213.24.224.0/19213.24.224.1 to 213.24.255.254213.24.255.2558,190
201213.25.0.0/19213.25.0.1 to 213.25.31.254213.25.31.2558,190
202213.25.32.0/19213.25.32.1 to 213.25.63.254213.25.63.2558,190
203213.25.64.0/19213.25.64.1 to 213.25.95.254213.25.95.2558,190
204213.25.96.0/19213.25.96.1 to 213.25.127.254213.25.127.2558,190
205213.25.128.0/19213.25.128.1 to 213.25.159.254213.25.159.2558,190
206213.25.160.0/19213.25.160.1 to 213.25.191.254213.25.191.2558,190
207213.25.192.0/19213.25.192.1 to 213.25.223.254213.25.223.2558,190
208213.25.224.0/19213.25.224.1 to 213.25.255.254213.25.255.2558,190
209213.26.0.0/19213.26.0.1 to 213.26.31.254213.26.31.2558,190
210213.26.32.0/19213.26.32.1 to 213.26.63.254213.26.63.2558,190
211213.26.64.0/19213.26.64.1 to 213.26.95.254213.26.95.2558,190
212213.26.96.0/19213.26.96.1 to 213.26.127.254213.26.127.2558,190
213213.26.128.0/19213.26.128.1 to 213.26.159.254213.26.159.2558,190
214213.26.160.0/19213.26.160.1 to 213.26.191.254213.26.191.2558,190
215213.26.192.0/19213.26.192.1 to 213.26.223.254213.26.223.2558,190
216213.26.224.0/19213.26.224.1 to 213.26.255.254213.26.255.2558,190
217213.27.0.0/19213.27.0.1 to 213.27.31.254213.27.31.2558,190
218213.27.32.0/19213.27.32.1 to 213.27.63.254213.27.63.2558,190
219213.27.64.0/19213.27.64.1 to 213.27.95.254213.27.95.2558,190
220213.27.96.0/19213.27.96.1 to 213.27.127.254213.27.127.2558,190
221213.27.128.0/19213.27.128.1 to 213.27.159.254213.27.159.2558,190
222213.27.160.0/19213.27.160.1 to 213.27.191.254213.27.191.2558,190
223213.27.192.0/19213.27.192.1 to 213.27.223.254213.27.223.2558,190
224213.27.224.0/19213.27.224.1 to 213.27.255.254213.27.255.2558,190
225213.28.0.0/19213.28.0.1 to 213.28.31.254213.28.31.2558,190
226213.28.32.0/19213.28.32.1 to 213.28.63.254213.28.63.2558,190
227213.28.64.0/19213.28.64.1 to 213.28.95.254213.28.95.2558,190
228213.28.96.0/19213.28.96.1 to 213.28.127.254213.28.127.2558,190
229213.28.128.0/19213.28.128.1 to 213.28.159.254213.28.159.2558,190
230213.28.160.0/19213.28.160.1 to 213.28.191.254213.28.191.2558,190
231213.28.192.0/19213.28.192.1 to 213.28.223.254213.28.223.2558,190
232213.28.224.0/19213.28.224.1 to 213.28.255.254213.28.255.2558,190
233213.29.0.0/19213.29.0.1 to 213.29.31.254213.29.31.2558,190
234213.29.32.0/19213.29.32.1 to 213.29.63.254213.29.63.2558,190
235213.29.64.0/19213.29.64.1 to 213.29.95.254213.29.95.2558,190
236213.29.96.0/19213.29.96.1 to 213.29.127.254213.29.127.2558,190
237213.29.128.0/19213.29.128.1 to 213.29.159.254213.29.159.2558,190
238213.29.160.0/19213.29.160.1 to 213.29.191.254213.29.191.2558,190
239213.29.192.0/19213.29.192.1 to 213.29.223.254213.29.223.2558,190
240213.29.224.0/19213.29.224.1 to 213.29.255.254213.29.255.2558,190
241213.30.0.0/19213.30.0.1 to 213.30.31.254213.30.31.2558,190
242213.30.32.0/19213.30.32.1 to 213.30.63.254213.30.63.2558,190
243213.30.64.0/19213.30.64.1 to 213.30.95.254213.30.95.2558,190
244213.30.96.0/19213.30.96.1 to 213.30.127.254213.30.127.2558,190
245213.30.128.0/19213.30.128.1 to 213.30.159.254213.30.159.2558,190
246213.30.160.0/19213.30.160.1 to 213.30.191.254213.30.191.2558,190
247213.30.192.0/19213.30.192.1 to 213.30.223.254213.30.223.2558,190
248213.30.224.0/19213.30.224.1 to 213.30.255.254213.30.255.2558,190
249213.31.0.0/19213.31.0.1 to 213.31.31.254213.31.31.2558,190
250213.31.32.0/19213.31.32.1 to 213.31.63.254213.31.63.2558,190
251213.31.64.0/19213.31.64.1 to 213.31.95.254213.31.95.2558,190
252213.31.96.0/19213.31.96.1 to 213.31.127.254213.31.127.2558,190
253213.31.128.0/19213.31.128.1 to 213.31.159.254213.31.159.2558,190
254213.31.160.0/19213.31.160.1 to 213.31.191.254213.31.191.2558,190
255213.31.192.0/19213.31.192.1 to 213.31.223.254213.31.223.2558,190
256213.31.224.0/19213.31.224.1 to 213.31.255.254213.31.255.2558,190

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.