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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.

Network213.3.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
213.3.64.0
Broadcast address
213.3.95.255
First usable
213.3.64.1
Last usable
213.3.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
C (default /24)
As numbers
Hex D5034000 · Integer 3573760000 to 3573768191
Reverse DNS zones
64.3.213.in-addr.arpa
65.3.213.in-addr.arpa
66.3.213.in-addr.arpa
67.3.213.in-addr.arpa
68.3.213.in-addr.arpa
69.3.213.in-addr.arpa
70.3.213.in-addr.arpa
71.3.213.in-addr.arpa
72.3.213.in-addr.arpa
73.3.213.in-addr.arpa
74.3.213.in-addr.arpa
75.3.213.in-addr.arpa
76.3.213.in-addr.arpa
77.3.213.in-addr.arpa
78.3.213.in-addr.arpa
79.3.213.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010101.00000011.01000000.00000000213.3.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11010101.00000011.01000000.00000000213.3.64.0
Broadcast11010101.00000011.01011111.11111111213.3.95.255
Split into smaller subnets/29
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

213.3.64.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1213.3.64.0/29213.3.64.1 to 213.3.64.6213.3.64.76
2213.3.64.8/29213.3.64.9 to 213.3.64.14213.3.64.156
3213.3.64.16/29213.3.64.17 to 213.3.64.22213.3.64.236
4213.3.64.24/29213.3.64.25 to 213.3.64.30213.3.64.316
5213.3.64.32/29213.3.64.33 to 213.3.64.38213.3.64.396
6213.3.64.40/29213.3.64.41 to 213.3.64.46213.3.64.476
7213.3.64.48/29213.3.64.49 to 213.3.64.54213.3.64.556
8213.3.64.56/29213.3.64.57 to 213.3.64.62213.3.64.636
9213.3.64.64/29213.3.64.65 to 213.3.64.70213.3.64.716
10213.3.64.72/29213.3.64.73 to 213.3.64.78213.3.64.796
11213.3.64.80/29213.3.64.81 to 213.3.64.86213.3.64.876
12213.3.64.88/29213.3.64.89 to 213.3.64.94213.3.64.956
13213.3.64.96/29213.3.64.97 to 213.3.64.102213.3.64.1036
14213.3.64.104/29213.3.64.105 to 213.3.64.110213.3.64.1116
15213.3.64.112/29213.3.64.113 to 213.3.64.118213.3.64.1196
16213.3.64.120/29213.3.64.121 to 213.3.64.126213.3.64.1276
17213.3.64.128/29213.3.64.129 to 213.3.64.134213.3.64.1356
18213.3.64.136/29213.3.64.137 to 213.3.64.142213.3.64.1436
19213.3.64.144/29213.3.64.145 to 213.3.64.150213.3.64.1516
20213.3.64.152/29213.3.64.153 to 213.3.64.158213.3.64.1596
21213.3.64.160/29213.3.64.161 to 213.3.64.166213.3.64.1676
22213.3.64.168/29213.3.64.169 to 213.3.64.174213.3.64.1756
23213.3.64.176/29213.3.64.177 to 213.3.64.182213.3.64.1836
24213.3.64.184/29213.3.64.185 to 213.3.64.190213.3.64.1916
25213.3.64.192/29213.3.64.193 to 213.3.64.198213.3.64.1996
26213.3.64.200/29213.3.64.201 to 213.3.64.206213.3.64.2076
27213.3.64.208/29213.3.64.209 to 213.3.64.214213.3.64.2156
28213.3.64.216/29213.3.64.217 to 213.3.64.222213.3.64.2236
29213.3.64.224/29213.3.64.225 to 213.3.64.230213.3.64.2316
30213.3.64.232/29213.3.64.233 to 213.3.64.238213.3.64.2396
31213.3.64.240/29213.3.64.241 to 213.3.64.246213.3.64.2476
32213.3.64.248/29213.3.64.249 to 213.3.64.254213.3.64.2556
33213.3.65.0/29213.3.65.1 to 213.3.65.6213.3.65.76
34213.3.65.8/29213.3.65.9 to 213.3.65.14213.3.65.156
35213.3.65.16/29213.3.65.17 to 213.3.65.22213.3.65.236
36213.3.65.24/29213.3.65.25 to 213.3.65.30213.3.65.316
37213.3.65.32/29213.3.65.33 to 213.3.65.38213.3.65.396
38213.3.65.40/29213.3.65.41 to 213.3.65.46213.3.65.476
39213.3.65.48/29213.3.65.49 to 213.3.65.54213.3.65.556
40213.3.65.56/29213.3.65.57 to 213.3.65.62213.3.65.636
41213.3.65.64/29213.3.65.65 to 213.3.65.70213.3.65.716
42213.3.65.72/29213.3.65.73 to 213.3.65.78213.3.65.796
43213.3.65.80/29213.3.65.81 to 213.3.65.86213.3.65.876
44213.3.65.88/29213.3.65.89 to 213.3.65.94213.3.65.956
45213.3.65.96/29213.3.65.97 to 213.3.65.102213.3.65.1036
46213.3.65.104/29213.3.65.105 to 213.3.65.110213.3.65.1116
47213.3.65.112/29213.3.65.113 to 213.3.65.118213.3.65.1196
48213.3.65.120/29213.3.65.121 to 213.3.65.126213.3.65.1276
49213.3.65.128/29213.3.65.129 to 213.3.65.134213.3.65.1356
50213.3.65.136/29213.3.65.137 to 213.3.65.142213.3.65.1436
51213.3.65.144/29213.3.65.145 to 213.3.65.150213.3.65.1516
52213.3.65.152/29213.3.65.153 to 213.3.65.158213.3.65.1596
53213.3.65.160/29213.3.65.161 to 213.3.65.166213.3.65.1676
54213.3.65.168/29213.3.65.169 to 213.3.65.174213.3.65.1756
55213.3.65.176/29213.3.65.177 to 213.3.65.182213.3.65.1836
56213.3.65.184/29213.3.65.185 to 213.3.65.190213.3.65.1916
57213.3.65.192/29213.3.65.193 to 213.3.65.198213.3.65.1996
58213.3.65.200/29213.3.65.201 to 213.3.65.206213.3.65.2076
59213.3.65.208/29213.3.65.209 to 213.3.65.214213.3.65.2156
60213.3.65.216/29213.3.65.217 to 213.3.65.222213.3.65.2236
61213.3.65.224/29213.3.65.225 to 213.3.65.230213.3.65.2316
62213.3.65.232/29213.3.65.233 to 213.3.65.238213.3.65.2396
63213.3.65.240/29213.3.65.241 to 213.3.65.246213.3.65.2476
64213.3.65.248/29213.3.65.249 to 213.3.65.254213.3.65.2556
65213.3.66.0/29213.3.66.1 to 213.3.66.6213.3.66.76
66213.3.66.8/29213.3.66.9 to 213.3.66.14213.3.66.156
67213.3.66.16/29213.3.66.17 to 213.3.66.22213.3.66.236
68213.3.66.24/29213.3.66.25 to 213.3.66.30213.3.66.316
69213.3.66.32/29213.3.66.33 to 213.3.66.38213.3.66.396
70213.3.66.40/29213.3.66.41 to 213.3.66.46213.3.66.476
71213.3.66.48/29213.3.66.49 to 213.3.66.54213.3.66.556
72213.3.66.56/29213.3.66.57 to 213.3.66.62213.3.66.636
73213.3.66.64/29213.3.66.65 to 213.3.66.70213.3.66.716
74213.3.66.72/29213.3.66.73 to 213.3.66.78213.3.66.796
75213.3.66.80/29213.3.66.81 to 213.3.66.86213.3.66.876
76213.3.66.88/29213.3.66.89 to 213.3.66.94213.3.66.956
77213.3.66.96/29213.3.66.97 to 213.3.66.102213.3.66.1036
78213.3.66.104/29213.3.66.105 to 213.3.66.110213.3.66.1116
79213.3.66.112/29213.3.66.113 to 213.3.66.118213.3.66.1196
80213.3.66.120/29213.3.66.121 to 213.3.66.126213.3.66.1276
81213.3.66.128/29213.3.66.129 to 213.3.66.134213.3.66.1356
82213.3.66.136/29213.3.66.137 to 213.3.66.142213.3.66.1436
83213.3.66.144/29213.3.66.145 to 213.3.66.150213.3.66.1516
84213.3.66.152/29213.3.66.153 to 213.3.66.158213.3.66.1596
85213.3.66.160/29213.3.66.161 to 213.3.66.166213.3.66.1676
86213.3.66.168/29213.3.66.169 to 213.3.66.174213.3.66.1756
87213.3.66.176/29213.3.66.177 to 213.3.66.182213.3.66.1836
88213.3.66.184/29213.3.66.185 to 213.3.66.190213.3.66.1916
89213.3.66.192/29213.3.66.193 to 213.3.66.198213.3.66.1996
90213.3.66.200/29213.3.66.201 to 213.3.66.206213.3.66.2076
91213.3.66.208/29213.3.66.209 to 213.3.66.214213.3.66.2156
92213.3.66.216/29213.3.66.217 to 213.3.66.222213.3.66.2236
93213.3.66.224/29213.3.66.225 to 213.3.66.230213.3.66.2316
94213.3.66.232/29213.3.66.233 to 213.3.66.238213.3.66.2396
95213.3.66.240/29213.3.66.241 to 213.3.66.246213.3.66.2476
96213.3.66.248/29213.3.66.249 to 213.3.66.254213.3.66.2556
97213.3.67.0/29213.3.67.1 to 213.3.67.6213.3.67.76
98213.3.67.8/29213.3.67.9 to 213.3.67.14213.3.67.156
99213.3.67.16/29213.3.67.17 to 213.3.67.22213.3.67.236
100213.3.67.24/29213.3.67.25 to 213.3.67.30213.3.67.316
101213.3.67.32/29213.3.67.33 to 213.3.67.38213.3.67.396
102213.3.67.40/29213.3.67.41 to 213.3.67.46213.3.67.476
103213.3.67.48/29213.3.67.49 to 213.3.67.54213.3.67.556
104213.3.67.56/29213.3.67.57 to 213.3.67.62213.3.67.636
105213.3.67.64/29213.3.67.65 to 213.3.67.70213.3.67.716
106213.3.67.72/29213.3.67.73 to 213.3.67.78213.3.67.796
107213.3.67.80/29213.3.67.81 to 213.3.67.86213.3.67.876
108213.3.67.88/29213.3.67.89 to 213.3.67.94213.3.67.956
109213.3.67.96/29213.3.67.97 to 213.3.67.102213.3.67.1036
110213.3.67.104/29213.3.67.105 to 213.3.67.110213.3.67.1116
111213.3.67.112/29213.3.67.113 to 213.3.67.118213.3.67.1196
112213.3.67.120/29213.3.67.121 to 213.3.67.126213.3.67.1276
113213.3.67.128/29213.3.67.129 to 213.3.67.134213.3.67.1356
114213.3.67.136/29213.3.67.137 to 213.3.67.142213.3.67.1436
115213.3.67.144/29213.3.67.145 to 213.3.67.150213.3.67.1516
116213.3.67.152/29213.3.67.153 to 213.3.67.158213.3.67.1596
117213.3.67.160/29213.3.67.161 to 213.3.67.166213.3.67.1676
118213.3.67.168/29213.3.67.169 to 213.3.67.174213.3.67.1756
119213.3.67.176/29213.3.67.177 to 213.3.67.182213.3.67.1836
120213.3.67.184/29213.3.67.185 to 213.3.67.190213.3.67.1916
121213.3.67.192/29213.3.67.193 to 213.3.67.198213.3.67.1996
122213.3.67.200/29213.3.67.201 to 213.3.67.206213.3.67.2076
123213.3.67.208/29213.3.67.209 to 213.3.67.214213.3.67.2156
124213.3.67.216/29213.3.67.217 to 213.3.67.222213.3.67.2236
125213.3.67.224/29213.3.67.225 to 213.3.67.230213.3.67.2316
126213.3.67.232/29213.3.67.233 to 213.3.67.238213.3.67.2396
127213.3.67.240/29213.3.67.241 to 213.3.67.246213.3.67.2476
128213.3.67.248/29213.3.67.249 to 213.3.67.254213.3.67.2556
129213.3.68.0/29213.3.68.1 to 213.3.68.6213.3.68.76
130213.3.68.8/29213.3.68.9 to 213.3.68.14213.3.68.156
131213.3.68.16/29213.3.68.17 to 213.3.68.22213.3.68.236
132213.3.68.24/29213.3.68.25 to 213.3.68.30213.3.68.316
133213.3.68.32/29213.3.68.33 to 213.3.68.38213.3.68.396
134213.3.68.40/29213.3.68.41 to 213.3.68.46213.3.68.476
135213.3.68.48/29213.3.68.49 to 213.3.68.54213.3.68.556
136213.3.68.56/29213.3.68.57 to 213.3.68.62213.3.68.636
137213.3.68.64/29213.3.68.65 to 213.3.68.70213.3.68.716
138213.3.68.72/29213.3.68.73 to 213.3.68.78213.3.68.796
139213.3.68.80/29213.3.68.81 to 213.3.68.86213.3.68.876
140213.3.68.88/29213.3.68.89 to 213.3.68.94213.3.68.956
141213.3.68.96/29213.3.68.97 to 213.3.68.102213.3.68.1036
142213.3.68.104/29213.3.68.105 to 213.3.68.110213.3.68.1116
143213.3.68.112/29213.3.68.113 to 213.3.68.118213.3.68.1196
144213.3.68.120/29213.3.68.121 to 213.3.68.126213.3.68.1276
145213.3.68.128/29213.3.68.129 to 213.3.68.134213.3.68.1356
146213.3.68.136/29213.3.68.137 to 213.3.68.142213.3.68.1436
147213.3.68.144/29213.3.68.145 to 213.3.68.150213.3.68.1516
148213.3.68.152/29213.3.68.153 to 213.3.68.158213.3.68.1596
149213.3.68.160/29213.3.68.161 to 213.3.68.166213.3.68.1676
150213.3.68.168/29213.3.68.169 to 213.3.68.174213.3.68.1756
151213.3.68.176/29213.3.68.177 to 213.3.68.182213.3.68.1836
152213.3.68.184/29213.3.68.185 to 213.3.68.190213.3.68.1916
153213.3.68.192/29213.3.68.193 to 213.3.68.198213.3.68.1996
154213.3.68.200/29213.3.68.201 to 213.3.68.206213.3.68.2076
155213.3.68.208/29213.3.68.209 to 213.3.68.214213.3.68.2156
156213.3.68.216/29213.3.68.217 to 213.3.68.222213.3.68.2236
157213.3.68.224/29213.3.68.225 to 213.3.68.230213.3.68.2316
158213.3.68.232/29213.3.68.233 to 213.3.68.238213.3.68.2396
159213.3.68.240/29213.3.68.241 to 213.3.68.246213.3.68.2476
160213.3.68.248/29213.3.68.249 to 213.3.68.254213.3.68.2556
161213.3.69.0/29213.3.69.1 to 213.3.69.6213.3.69.76
162213.3.69.8/29213.3.69.9 to 213.3.69.14213.3.69.156
163213.3.69.16/29213.3.69.17 to 213.3.69.22213.3.69.236
164213.3.69.24/29213.3.69.25 to 213.3.69.30213.3.69.316
165213.3.69.32/29213.3.69.33 to 213.3.69.38213.3.69.396
166213.3.69.40/29213.3.69.41 to 213.3.69.46213.3.69.476
167213.3.69.48/29213.3.69.49 to 213.3.69.54213.3.69.556
168213.3.69.56/29213.3.69.57 to 213.3.69.62213.3.69.636
169213.3.69.64/29213.3.69.65 to 213.3.69.70213.3.69.716
170213.3.69.72/29213.3.69.73 to 213.3.69.78213.3.69.796
171213.3.69.80/29213.3.69.81 to 213.3.69.86213.3.69.876
172213.3.69.88/29213.3.69.89 to 213.3.69.94213.3.69.956
173213.3.69.96/29213.3.69.97 to 213.3.69.102213.3.69.1036
174213.3.69.104/29213.3.69.105 to 213.3.69.110213.3.69.1116
175213.3.69.112/29213.3.69.113 to 213.3.69.118213.3.69.1196
176213.3.69.120/29213.3.69.121 to 213.3.69.126213.3.69.1276
177213.3.69.128/29213.3.69.129 to 213.3.69.134213.3.69.1356
178213.3.69.136/29213.3.69.137 to 213.3.69.142213.3.69.1436
179213.3.69.144/29213.3.69.145 to 213.3.69.150213.3.69.1516
180213.3.69.152/29213.3.69.153 to 213.3.69.158213.3.69.1596
181213.3.69.160/29213.3.69.161 to 213.3.69.166213.3.69.1676
182213.3.69.168/29213.3.69.169 to 213.3.69.174213.3.69.1756
183213.3.69.176/29213.3.69.177 to 213.3.69.182213.3.69.1836
184213.3.69.184/29213.3.69.185 to 213.3.69.190213.3.69.1916
185213.3.69.192/29213.3.69.193 to 213.3.69.198213.3.69.1996
186213.3.69.200/29213.3.69.201 to 213.3.69.206213.3.69.2076
187213.3.69.208/29213.3.69.209 to 213.3.69.214213.3.69.2156
188213.3.69.216/29213.3.69.217 to 213.3.69.222213.3.69.2236
189213.3.69.224/29213.3.69.225 to 213.3.69.230213.3.69.2316
190213.3.69.232/29213.3.69.233 to 213.3.69.238213.3.69.2396
191213.3.69.240/29213.3.69.241 to 213.3.69.246213.3.69.2476
192213.3.69.248/29213.3.69.249 to 213.3.69.254213.3.69.2556
193213.3.70.0/29213.3.70.1 to 213.3.70.6213.3.70.76
194213.3.70.8/29213.3.70.9 to 213.3.70.14213.3.70.156
195213.3.70.16/29213.3.70.17 to 213.3.70.22213.3.70.236
196213.3.70.24/29213.3.70.25 to 213.3.70.30213.3.70.316
197213.3.70.32/29213.3.70.33 to 213.3.70.38213.3.70.396
198213.3.70.40/29213.3.70.41 to 213.3.70.46213.3.70.476
199213.3.70.48/29213.3.70.49 to 213.3.70.54213.3.70.556
200213.3.70.56/29213.3.70.57 to 213.3.70.62213.3.70.636
201213.3.70.64/29213.3.70.65 to 213.3.70.70213.3.70.716
202213.3.70.72/29213.3.70.73 to 213.3.70.78213.3.70.796
203213.3.70.80/29213.3.70.81 to 213.3.70.86213.3.70.876
204213.3.70.88/29213.3.70.89 to 213.3.70.94213.3.70.956
205213.3.70.96/29213.3.70.97 to 213.3.70.102213.3.70.1036
206213.3.70.104/29213.3.70.105 to 213.3.70.110213.3.70.1116
207213.3.70.112/29213.3.70.113 to 213.3.70.118213.3.70.1196
208213.3.70.120/29213.3.70.121 to 213.3.70.126213.3.70.1276
209213.3.70.128/29213.3.70.129 to 213.3.70.134213.3.70.1356
210213.3.70.136/29213.3.70.137 to 213.3.70.142213.3.70.1436
211213.3.70.144/29213.3.70.145 to 213.3.70.150213.3.70.1516
212213.3.70.152/29213.3.70.153 to 213.3.70.158213.3.70.1596
213213.3.70.160/29213.3.70.161 to 213.3.70.166213.3.70.1676
214213.3.70.168/29213.3.70.169 to 213.3.70.174213.3.70.1756
215213.3.70.176/29213.3.70.177 to 213.3.70.182213.3.70.1836
216213.3.70.184/29213.3.70.185 to 213.3.70.190213.3.70.1916
217213.3.70.192/29213.3.70.193 to 213.3.70.198213.3.70.1996
218213.3.70.200/29213.3.70.201 to 213.3.70.206213.3.70.2076
219213.3.70.208/29213.3.70.209 to 213.3.70.214213.3.70.2156
220213.3.70.216/29213.3.70.217 to 213.3.70.222213.3.70.2236
221213.3.70.224/29213.3.70.225 to 213.3.70.230213.3.70.2316
222213.3.70.232/29213.3.70.233 to 213.3.70.238213.3.70.2396
223213.3.70.240/29213.3.70.241 to 213.3.70.246213.3.70.2476
224213.3.70.248/29213.3.70.249 to 213.3.70.254213.3.70.2556
225213.3.71.0/29213.3.71.1 to 213.3.71.6213.3.71.76
226213.3.71.8/29213.3.71.9 to 213.3.71.14213.3.71.156
227213.3.71.16/29213.3.71.17 to 213.3.71.22213.3.71.236
228213.3.71.24/29213.3.71.25 to 213.3.71.30213.3.71.316
229213.3.71.32/29213.3.71.33 to 213.3.71.38213.3.71.396
230213.3.71.40/29213.3.71.41 to 213.3.71.46213.3.71.476
231213.3.71.48/29213.3.71.49 to 213.3.71.54213.3.71.556
232213.3.71.56/29213.3.71.57 to 213.3.71.62213.3.71.636
233213.3.71.64/29213.3.71.65 to 213.3.71.70213.3.71.716
234213.3.71.72/29213.3.71.73 to 213.3.71.78213.3.71.796
235213.3.71.80/29213.3.71.81 to 213.3.71.86213.3.71.876
236213.3.71.88/29213.3.71.89 to 213.3.71.94213.3.71.956
237213.3.71.96/29213.3.71.97 to 213.3.71.102213.3.71.1036
238213.3.71.104/29213.3.71.105 to 213.3.71.110213.3.71.1116
239213.3.71.112/29213.3.71.113 to 213.3.71.118213.3.71.1196
240213.3.71.120/29213.3.71.121 to 213.3.71.126213.3.71.1276
241213.3.71.128/29213.3.71.129 to 213.3.71.134213.3.71.1356
242213.3.71.136/29213.3.71.137 to 213.3.71.142213.3.71.1436
243213.3.71.144/29213.3.71.145 to 213.3.71.150213.3.71.1516
244213.3.71.152/29213.3.71.153 to 213.3.71.158213.3.71.1596
245213.3.71.160/29213.3.71.161 to 213.3.71.166213.3.71.1676
246213.3.71.168/29213.3.71.169 to 213.3.71.174213.3.71.1756
247213.3.71.176/29213.3.71.177 to 213.3.71.182213.3.71.1836
248213.3.71.184/29213.3.71.185 to 213.3.71.190213.3.71.1916
249213.3.71.192/29213.3.71.193 to 213.3.71.198213.3.71.1996
250213.3.71.200/29213.3.71.201 to 213.3.71.206213.3.71.2076
251213.3.71.208/29213.3.71.209 to 213.3.71.214213.3.71.2156
252213.3.71.216/29213.3.71.217 to 213.3.71.222213.3.71.2236
253213.3.71.224/29213.3.71.225 to 213.3.71.230213.3.71.2316
254213.3.71.232/29213.3.71.233 to 213.3.71.238213.3.71.2396
255213.3.71.240/29213.3.71.241 to 213.3.71.246213.3.71.2476
256213.3.71.248/29213.3.71.249 to 213.3.71.254213.3.71.2556

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.