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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.

Network220.22.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
220.22.0.0
Broadcast address
220.22.127.255
First usable
220.22.0.1
Last usable
220.22.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
C (default /24)
As numbers
Hex DC160000 · Integer 3692429312 to 3692462079
Reverse DNS zones
0.22.220.in-addr.arpa
1.22.220.in-addr.arpa
2.22.220.in-addr.arpa
3.22.220.in-addr.arpa
4.22.220.in-addr.arpa
5.22.220.in-addr.arpa
6.22.220.in-addr.arpa
7.22.220.in-addr.arpa
8.22.220.in-addr.arpa
9.22.220.in-addr.arpa
10.22.220.in-addr.arpa
11.22.220.in-addr.arpa
12.22.220.in-addr.arpa
13.22.220.in-addr.arpa
14.22.220.in-addr.arpa
15.22.220.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011100.00010110.00000000.00000000220.22.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11011100.00010110.00000000.00000000220.22.0.0
Broadcast11011100.00010110.01111111.11111111220.22.127.255
Split into smaller subnets/29
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

220.22.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1220.22.0.0/29220.22.0.1 to 220.22.0.6220.22.0.76
2220.22.0.8/29220.22.0.9 to 220.22.0.14220.22.0.156
3220.22.0.16/29220.22.0.17 to 220.22.0.22220.22.0.236
4220.22.0.24/29220.22.0.25 to 220.22.0.30220.22.0.316
5220.22.0.32/29220.22.0.33 to 220.22.0.38220.22.0.396
6220.22.0.40/29220.22.0.41 to 220.22.0.46220.22.0.476
7220.22.0.48/29220.22.0.49 to 220.22.0.54220.22.0.556
8220.22.0.56/29220.22.0.57 to 220.22.0.62220.22.0.636
9220.22.0.64/29220.22.0.65 to 220.22.0.70220.22.0.716
10220.22.0.72/29220.22.0.73 to 220.22.0.78220.22.0.796
11220.22.0.80/29220.22.0.81 to 220.22.0.86220.22.0.876
12220.22.0.88/29220.22.0.89 to 220.22.0.94220.22.0.956
13220.22.0.96/29220.22.0.97 to 220.22.0.102220.22.0.1036
14220.22.0.104/29220.22.0.105 to 220.22.0.110220.22.0.1116
15220.22.0.112/29220.22.0.113 to 220.22.0.118220.22.0.1196
16220.22.0.120/29220.22.0.121 to 220.22.0.126220.22.0.1276
17220.22.0.128/29220.22.0.129 to 220.22.0.134220.22.0.1356
18220.22.0.136/29220.22.0.137 to 220.22.0.142220.22.0.1436
19220.22.0.144/29220.22.0.145 to 220.22.0.150220.22.0.1516
20220.22.0.152/29220.22.0.153 to 220.22.0.158220.22.0.1596
21220.22.0.160/29220.22.0.161 to 220.22.0.166220.22.0.1676
22220.22.0.168/29220.22.0.169 to 220.22.0.174220.22.0.1756
23220.22.0.176/29220.22.0.177 to 220.22.0.182220.22.0.1836
24220.22.0.184/29220.22.0.185 to 220.22.0.190220.22.0.1916
25220.22.0.192/29220.22.0.193 to 220.22.0.198220.22.0.1996
26220.22.0.200/29220.22.0.201 to 220.22.0.206220.22.0.2076
27220.22.0.208/29220.22.0.209 to 220.22.0.214220.22.0.2156
28220.22.0.216/29220.22.0.217 to 220.22.0.222220.22.0.2236
29220.22.0.224/29220.22.0.225 to 220.22.0.230220.22.0.2316
30220.22.0.232/29220.22.0.233 to 220.22.0.238220.22.0.2396
31220.22.0.240/29220.22.0.241 to 220.22.0.246220.22.0.2476
32220.22.0.248/29220.22.0.249 to 220.22.0.254220.22.0.2556
33220.22.1.0/29220.22.1.1 to 220.22.1.6220.22.1.76
34220.22.1.8/29220.22.1.9 to 220.22.1.14220.22.1.156
35220.22.1.16/29220.22.1.17 to 220.22.1.22220.22.1.236
36220.22.1.24/29220.22.1.25 to 220.22.1.30220.22.1.316
37220.22.1.32/29220.22.1.33 to 220.22.1.38220.22.1.396
38220.22.1.40/29220.22.1.41 to 220.22.1.46220.22.1.476
39220.22.1.48/29220.22.1.49 to 220.22.1.54220.22.1.556
40220.22.1.56/29220.22.1.57 to 220.22.1.62220.22.1.636
41220.22.1.64/29220.22.1.65 to 220.22.1.70220.22.1.716
42220.22.1.72/29220.22.1.73 to 220.22.1.78220.22.1.796
43220.22.1.80/29220.22.1.81 to 220.22.1.86220.22.1.876
44220.22.1.88/29220.22.1.89 to 220.22.1.94220.22.1.956
45220.22.1.96/29220.22.1.97 to 220.22.1.102220.22.1.1036
46220.22.1.104/29220.22.1.105 to 220.22.1.110220.22.1.1116
47220.22.1.112/29220.22.1.113 to 220.22.1.118220.22.1.1196
48220.22.1.120/29220.22.1.121 to 220.22.1.126220.22.1.1276
49220.22.1.128/29220.22.1.129 to 220.22.1.134220.22.1.1356
50220.22.1.136/29220.22.1.137 to 220.22.1.142220.22.1.1436
51220.22.1.144/29220.22.1.145 to 220.22.1.150220.22.1.1516
52220.22.1.152/29220.22.1.153 to 220.22.1.158220.22.1.1596
53220.22.1.160/29220.22.1.161 to 220.22.1.166220.22.1.1676
54220.22.1.168/29220.22.1.169 to 220.22.1.174220.22.1.1756
55220.22.1.176/29220.22.1.177 to 220.22.1.182220.22.1.1836
56220.22.1.184/29220.22.1.185 to 220.22.1.190220.22.1.1916
57220.22.1.192/29220.22.1.193 to 220.22.1.198220.22.1.1996
58220.22.1.200/29220.22.1.201 to 220.22.1.206220.22.1.2076
59220.22.1.208/29220.22.1.209 to 220.22.1.214220.22.1.2156
60220.22.1.216/29220.22.1.217 to 220.22.1.222220.22.1.2236
61220.22.1.224/29220.22.1.225 to 220.22.1.230220.22.1.2316
62220.22.1.232/29220.22.1.233 to 220.22.1.238220.22.1.2396
63220.22.1.240/29220.22.1.241 to 220.22.1.246220.22.1.2476
64220.22.1.248/29220.22.1.249 to 220.22.1.254220.22.1.2556
65220.22.2.0/29220.22.2.1 to 220.22.2.6220.22.2.76
66220.22.2.8/29220.22.2.9 to 220.22.2.14220.22.2.156
67220.22.2.16/29220.22.2.17 to 220.22.2.22220.22.2.236
68220.22.2.24/29220.22.2.25 to 220.22.2.30220.22.2.316
69220.22.2.32/29220.22.2.33 to 220.22.2.38220.22.2.396
70220.22.2.40/29220.22.2.41 to 220.22.2.46220.22.2.476
71220.22.2.48/29220.22.2.49 to 220.22.2.54220.22.2.556
72220.22.2.56/29220.22.2.57 to 220.22.2.62220.22.2.636
73220.22.2.64/29220.22.2.65 to 220.22.2.70220.22.2.716
74220.22.2.72/29220.22.2.73 to 220.22.2.78220.22.2.796
75220.22.2.80/29220.22.2.81 to 220.22.2.86220.22.2.876
76220.22.2.88/29220.22.2.89 to 220.22.2.94220.22.2.956
77220.22.2.96/29220.22.2.97 to 220.22.2.102220.22.2.1036
78220.22.2.104/29220.22.2.105 to 220.22.2.110220.22.2.1116
79220.22.2.112/29220.22.2.113 to 220.22.2.118220.22.2.1196
80220.22.2.120/29220.22.2.121 to 220.22.2.126220.22.2.1276
81220.22.2.128/29220.22.2.129 to 220.22.2.134220.22.2.1356
82220.22.2.136/29220.22.2.137 to 220.22.2.142220.22.2.1436
83220.22.2.144/29220.22.2.145 to 220.22.2.150220.22.2.1516
84220.22.2.152/29220.22.2.153 to 220.22.2.158220.22.2.1596
85220.22.2.160/29220.22.2.161 to 220.22.2.166220.22.2.1676
86220.22.2.168/29220.22.2.169 to 220.22.2.174220.22.2.1756
87220.22.2.176/29220.22.2.177 to 220.22.2.182220.22.2.1836
88220.22.2.184/29220.22.2.185 to 220.22.2.190220.22.2.1916
89220.22.2.192/29220.22.2.193 to 220.22.2.198220.22.2.1996
90220.22.2.200/29220.22.2.201 to 220.22.2.206220.22.2.2076
91220.22.2.208/29220.22.2.209 to 220.22.2.214220.22.2.2156
92220.22.2.216/29220.22.2.217 to 220.22.2.222220.22.2.2236
93220.22.2.224/29220.22.2.225 to 220.22.2.230220.22.2.2316
94220.22.2.232/29220.22.2.233 to 220.22.2.238220.22.2.2396
95220.22.2.240/29220.22.2.241 to 220.22.2.246220.22.2.2476
96220.22.2.248/29220.22.2.249 to 220.22.2.254220.22.2.2556
97220.22.3.0/29220.22.3.1 to 220.22.3.6220.22.3.76
98220.22.3.8/29220.22.3.9 to 220.22.3.14220.22.3.156
99220.22.3.16/29220.22.3.17 to 220.22.3.22220.22.3.236
100220.22.3.24/29220.22.3.25 to 220.22.3.30220.22.3.316
101220.22.3.32/29220.22.3.33 to 220.22.3.38220.22.3.396
102220.22.3.40/29220.22.3.41 to 220.22.3.46220.22.3.476
103220.22.3.48/29220.22.3.49 to 220.22.3.54220.22.3.556
104220.22.3.56/29220.22.3.57 to 220.22.3.62220.22.3.636
105220.22.3.64/29220.22.3.65 to 220.22.3.70220.22.3.716
106220.22.3.72/29220.22.3.73 to 220.22.3.78220.22.3.796
107220.22.3.80/29220.22.3.81 to 220.22.3.86220.22.3.876
108220.22.3.88/29220.22.3.89 to 220.22.3.94220.22.3.956
109220.22.3.96/29220.22.3.97 to 220.22.3.102220.22.3.1036
110220.22.3.104/29220.22.3.105 to 220.22.3.110220.22.3.1116
111220.22.3.112/29220.22.3.113 to 220.22.3.118220.22.3.1196
112220.22.3.120/29220.22.3.121 to 220.22.3.126220.22.3.1276
113220.22.3.128/29220.22.3.129 to 220.22.3.134220.22.3.1356
114220.22.3.136/29220.22.3.137 to 220.22.3.142220.22.3.1436
115220.22.3.144/29220.22.3.145 to 220.22.3.150220.22.3.1516
116220.22.3.152/29220.22.3.153 to 220.22.3.158220.22.3.1596
117220.22.3.160/29220.22.3.161 to 220.22.3.166220.22.3.1676
118220.22.3.168/29220.22.3.169 to 220.22.3.174220.22.3.1756
119220.22.3.176/29220.22.3.177 to 220.22.3.182220.22.3.1836
120220.22.3.184/29220.22.3.185 to 220.22.3.190220.22.3.1916
121220.22.3.192/29220.22.3.193 to 220.22.3.198220.22.3.1996
122220.22.3.200/29220.22.3.201 to 220.22.3.206220.22.3.2076
123220.22.3.208/29220.22.3.209 to 220.22.3.214220.22.3.2156
124220.22.3.216/29220.22.3.217 to 220.22.3.222220.22.3.2236
125220.22.3.224/29220.22.3.225 to 220.22.3.230220.22.3.2316
126220.22.3.232/29220.22.3.233 to 220.22.3.238220.22.3.2396
127220.22.3.240/29220.22.3.241 to 220.22.3.246220.22.3.2476
128220.22.3.248/29220.22.3.249 to 220.22.3.254220.22.3.2556
129220.22.4.0/29220.22.4.1 to 220.22.4.6220.22.4.76
130220.22.4.8/29220.22.4.9 to 220.22.4.14220.22.4.156
131220.22.4.16/29220.22.4.17 to 220.22.4.22220.22.4.236
132220.22.4.24/29220.22.4.25 to 220.22.4.30220.22.4.316
133220.22.4.32/29220.22.4.33 to 220.22.4.38220.22.4.396
134220.22.4.40/29220.22.4.41 to 220.22.4.46220.22.4.476
135220.22.4.48/29220.22.4.49 to 220.22.4.54220.22.4.556
136220.22.4.56/29220.22.4.57 to 220.22.4.62220.22.4.636
137220.22.4.64/29220.22.4.65 to 220.22.4.70220.22.4.716
138220.22.4.72/29220.22.4.73 to 220.22.4.78220.22.4.796
139220.22.4.80/29220.22.4.81 to 220.22.4.86220.22.4.876
140220.22.4.88/29220.22.4.89 to 220.22.4.94220.22.4.956
141220.22.4.96/29220.22.4.97 to 220.22.4.102220.22.4.1036
142220.22.4.104/29220.22.4.105 to 220.22.4.110220.22.4.1116
143220.22.4.112/29220.22.4.113 to 220.22.4.118220.22.4.1196
144220.22.4.120/29220.22.4.121 to 220.22.4.126220.22.4.1276
145220.22.4.128/29220.22.4.129 to 220.22.4.134220.22.4.1356
146220.22.4.136/29220.22.4.137 to 220.22.4.142220.22.4.1436
147220.22.4.144/29220.22.4.145 to 220.22.4.150220.22.4.1516
148220.22.4.152/29220.22.4.153 to 220.22.4.158220.22.4.1596
149220.22.4.160/29220.22.4.161 to 220.22.4.166220.22.4.1676
150220.22.4.168/29220.22.4.169 to 220.22.4.174220.22.4.1756
151220.22.4.176/29220.22.4.177 to 220.22.4.182220.22.4.1836
152220.22.4.184/29220.22.4.185 to 220.22.4.190220.22.4.1916
153220.22.4.192/29220.22.4.193 to 220.22.4.198220.22.4.1996
154220.22.4.200/29220.22.4.201 to 220.22.4.206220.22.4.2076
155220.22.4.208/29220.22.4.209 to 220.22.4.214220.22.4.2156
156220.22.4.216/29220.22.4.217 to 220.22.4.222220.22.4.2236
157220.22.4.224/29220.22.4.225 to 220.22.4.230220.22.4.2316
158220.22.4.232/29220.22.4.233 to 220.22.4.238220.22.4.2396
159220.22.4.240/29220.22.4.241 to 220.22.4.246220.22.4.2476
160220.22.4.248/29220.22.4.249 to 220.22.4.254220.22.4.2556
161220.22.5.0/29220.22.5.1 to 220.22.5.6220.22.5.76
162220.22.5.8/29220.22.5.9 to 220.22.5.14220.22.5.156
163220.22.5.16/29220.22.5.17 to 220.22.5.22220.22.5.236
164220.22.5.24/29220.22.5.25 to 220.22.5.30220.22.5.316
165220.22.5.32/29220.22.5.33 to 220.22.5.38220.22.5.396
166220.22.5.40/29220.22.5.41 to 220.22.5.46220.22.5.476
167220.22.5.48/29220.22.5.49 to 220.22.5.54220.22.5.556
168220.22.5.56/29220.22.5.57 to 220.22.5.62220.22.5.636
169220.22.5.64/29220.22.5.65 to 220.22.5.70220.22.5.716
170220.22.5.72/29220.22.5.73 to 220.22.5.78220.22.5.796
171220.22.5.80/29220.22.5.81 to 220.22.5.86220.22.5.876
172220.22.5.88/29220.22.5.89 to 220.22.5.94220.22.5.956
173220.22.5.96/29220.22.5.97 to 220.22.5.102220.22.5.1036
174220.22.5.104/29220.22.5.105 to 220.22.5.110220.22.5.1116
175220.22.5.112/29220.22.5.113 to 220.22.5.118220.22.5.1196
176220.22.5.120/29220.22.5.121 to 220.22.5.126220.22.5.1276
177220.22.5.128/29220.22.5.129 to 220.22.5.134220.22.5.1356
178220.22.5.136/29220.22.5.137 to 220.22.5.142220.22.5.1436
179220.22.5.144/29220.22.5.145 to 220.22.5.150220.22.5.1516
180220.22.5.152/29220.22.5.153 to 220.22.5.158220.22.5.1596
181220.22.5.160/29220.22.5.161 to 220.22.5.166220.22.5.1676
182220.22.5.168/29220.22.5.169 to 220.22.5.174220.22.5.1756
183220.22.5.176/29220.22.5.177 to 220.22.5.182220.22.5.1836
184220.22.5.184/29220.22.5.185 to 220.22.5.190220.22.5.1916
185220.22.5.192/29220.22.5.193 to 220.22.5.198220.22.5.1996
186220.22.5.200/29220.22.5.201 to 220.22.5.206220.22.5.2076
187220.22.5.208/29220.22.5.209 to 220.22.5.214220.22.5.2156
188220.22.5.216/29220.22.5.217 to 220.22.5.222220.22.5.2236
189220.22.5.224/29220.22.5.225 to 220.22.5.230220.22.5.2316
190220.22.5.232/29220.22.5.233 to 220.22.5.238220.22.5.2396
191220.22.5.240/29220.22.5.241 to 220.22.5.246220.22.5.2476
192220.22.5.248/29220.22.5.249 to 220.22.5.254220.22.5.2556
193220.22.6.0/29220.22.6.1 to 220.22.6.6220.22.6.76
194220.22.6.8/29220.22.6.9 to 220.22.6.14220.22.6.156
195220.22.6.16/29220.22.6.17 to 220.22.6.22220.22.6.236
196220.22.6.24/29220.22.6.25 to 220.22.6.30220.22.6.316
197220.22.6.32/29220.22.6.33 to 220.22.6.38220.22.6.396
198220.22.6.40/29220.22.6.41 to 220.22.6.46220.22.6.476
199220.22.6.48/29220.22.6.49 to 220.22.6.54220.22.6.556
200220.22.6.56/29220.22.6.57 to 220.22.6.62220.22.6.636
201220.22.6.64/29220.22.6.65 to 220.22.6.70220.22.6.716
202220.22.6.72/29220.22.6.73 to 220.22.6.78220.22.6.796
203220.22.6.80/29220.22.6.81 to 220.22.6.86220.22.6.876
204220.22.6.88/29220.22.6.89 to 220.22.6.94220.22.6.956
205220.22.6.96/29220.22.6.97 to 220.22.6.102220.22.6.1036
206220.22.6.104/29220.22.6.105 to 220.22.6.110220.22.6.1116
207220.22.6.112/29220.22.6.113 to 220.22.6.118220.22.6.1196
208220.22.6.120/29220.22.6.121 to 220.22.6.126220.22.6.1276
209220.22.6.128/29220.22.6.129 to 220.22.6.134220.22.6.1356
210220.22.6.136/29220.22.6.137 to 220.22.6.142220.22.6.1436
211220.22.6.144/29220.22.6.145 to 220.22.6.150220.22.6.1516
212220.22.6.152/29220.22.6.153 to 220.22.6.158220.22.6.1596
213220.22.6.160/29220.22.6.161 to 220.22.6.166220.22.6.1676
214220.22.6.168/29220.22.6.169 to 220.22.6.174220.22.6.1756
215220.22.6.176/29220.22.6.177 to 220.22.6.182220.22.6.1836
216220.22.6.184/29220.22.6.185 to 220.22.6.190220.22.6.1916
217220.22.6.192/29220.22.6.193 to 220.22.6.198220.22.6.1996
218220.22.6.200/29220.22.6.201 to 220.22.6.206220.22.6.2076
219220.22.6.208/29220.22.6.209 to 220.22.6.214220.22.6.2156
220220.22.6.216/29220.22.6.217 to 220.22.6.222220.22.6.2236
221220.22.6.224/29220.22.6.225 to 220.22.6.230220.22.6.2316
222220.22.6.232/29220.22.6.233 to 220.22.6.238220.22.6.2396
223220.22.6.240/29220.22.6.241 to 220.22.6.246220.22.6.2476
224220.22.6.248/29220.22.6.249 to 220.22.6.254220.22.6.2556
225220.22.7.0/29220.22.7.1 to 220.22.7.6220.22.7.76
226220.22.7.8/29220.22.7.9 to 220.22.7.14220.22.7.156
227220.22.7.16/29220.22.7.17 to 220.22.7.22220.22.7.236
228220.22.7.24/29220.22.7.25 to 220.22.7.30220.22.7.316
229220.22.7.32/29220.22.7.33 to 220.22.7.38220.22.7.396
230220.22.7.40/29220.22.7.41 to 220.22.7.46220.22.7.476
231220.22.7.48/29220.22.7.49 to 220.22.7.54220.22.7.556
232220.22.7.56/29220.22.7.57 to 220.22.7.62220.22.7.636
233220.22.7.64/29220.22.7.65 to 220.22.7.70220.22.7.716
234220.22.7.72/29220.22.7.73 to 220.22.7.78220.22.7.796
235220.22.7.80/29220.22.7.81 to 220.22.7.86220.22.7.876
236220.22.7.88/29220.22.7.89 to 220.22.7.94220.22.7.956
237220.22.7.96/29220.22.7.97 to 220.22.7.102220.22.7.1036
238220.22.7.104/29220.22.7.105 to 220.22.7.110220.22.7.1116
239220.22.7.112/29220.22.7.113 to 220.22.7.118220.22.7.1196
240220.22.7.120/29220.22.7.121 to 220.22.7.126220.22.7.1276
241220.22.7.128/29220.22.7.129 to 220.22.7.134220.22.7.1356
242220.22.7.136/29220.22.7.137 to 220.22.7.142220.22.7.1436
243220.22.7.144/29220.22.7.145 to 220.22.7.150220.22.7.1516
244220.22.7.152/29220.22.7.153 to 220.22.7.158220.22.7.1596
245220.22.7.160/29220.22.7.161 to 220.22.7.166220.22.7.1676
246220.22.7.168/29220.22.7.169 to 220.22.7.174220.22.7.1756
247220.22.7.176/29220.22.7.177 to 220.22.7.182220.22.7.1836
248220.22.7.184/29220.22.7.185 to 220.22.7.190220.22.7.1916
249220.22.7.192/29220.22.7.193 to 220.22.7.198220.22.7.1996
250220.22.7.200/29220.22.7.201 to 220.22.7.206220.22.7.2076
251220.22.7.208/29220.22.7.209 to 220.22.7.214220.22.7.2156
252220.22.7.216/29220.22.7.217 to 220.22.7.222220.22.7.2236
253220.22.7.224/29220.22.7.225 to 220.22.7.230220.22.7.2316
254220.22.7.232/29220.22.7.233 to 220.22.7.238220.22.7.2396
255220.22.7.240/29220.22.7.241 to 220.22.7.246220.22.7.2476
256220.22.7.248/29220.22.7.249 to 220.22.7.254220.22.7.2556

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.