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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.

Network183.45.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
183.45.0.0
Broadcast address
183.45.127.255
First usable
183.45.0.1
Last usable
183.45.127.254
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
B (default /16)
As numbers
Hex B72D0000 · Integer 3073179648 to 3073212415
Reverse DNS zones
0.45.183.in-addr.arpa
1.45.183.in-addr.arpa
2.45.183.in-addr.arpa
3.45.183.in-addr.arpa
4.45.183.in-addr.arpa
5.45.183.in-addr.arpa
6.45.183.in-addr.arpa
7.45.183.in-addr.arpa
8.45.183.in-addr.arpa
9.45.183.in-addr.arpa
10.45.183.in-addr.arpa
11.45.183.in-addr.arpa
12.45.183.in-addr.arpa
13.45.183.in-addr.arpa
14.45.183.in-addr.arpa
15.45.183.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
Address10110111.00101101.00000000.00000000183.45.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10110111.00101101.00000000.00000000183.45.0.0
Broadcast10110111.00101101.01111111.11111111183.45.127.255
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)

183.45.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.45.0.0/29183.45.0.1 to 183.45.0.6183.45.0.76
2183.45.0.8/29183.45.0.9 to 183.45.0.14183.45.0.156
3183.45.0.16/29183.45.0.17 to 183.45.0.22183.45.0.236
4183.45.0.24/29183.45.0.25 to 183.45.0.30183.45.0.316
5183.45.0.32/29183.45.0.33 to 183.45.0.38183.45.0.396
6183.45.0.40/29183.45.0.41 to 183.45.0.46183.45.0.476
7183.45.0.48/29183.45.0.49 to 183.45.0.54183.45.0.556
8183.45.0.56/29183.45.0.57 to 183.45.0.62183.45.0.636
9183.45.0.64/29183.45.0.65 to 183.45.0.70183.45.0.716
10183.45.0.72/29183.45.0.73 to 183.45.0.78183.45.0.796
11183.45.0.80/29183.45.0.81 to 183.45.0.86183.45.0.876
12183.45.0.88/29183.45.0.89 to 183.45.0.94183.45.0.956
13183.45.0.96/29183.45.0.97 to 183.45.0.102183.45.0.1036
14183.45.0.104/29183.45.0.105 to 183.45.0.110183.45.0.1116
15183.45.0.112/29183.45.0.113 to 183.45.0.118183.45.0.1196
16183.45.0.120/29183.45.0.121 to 183.45.0.126183.45.0.1276
17183.45.0.128/29183.45.0.129 to 183.45.0.134183.45.0.1356
18183.45.0.136/29183.45.0.137 to 183.45.0.142183.45.0.1436
19183.45.0.144/29183.45.0.145 to 183.45.0.150183.45.0.1516
20183.45.0.152/29183.45.0.153 to 183.45.0.158183.45.0.1596
21183.45.0.160/29183.45.0.161 to 183.45.0.166183.45.0.1676
22183.45.0.168/29183.45.0.169 to 183.45.0.174183.45.0.1756
23183.45.0.176/29183.45.0.177 to 183.45.0.182183.45.0.1836
24183.45.0.184/29183.45.0.185 to 183.45.0.190183.45.0.1916
25183.45.0.192/29183.45.0.193 to 183.45.0.198183.45.0.1996
26183.45.0.200/29183.45.0.201 to 183.45.0.206183.45.0.2076
27183.45.0.208/29183.45.0.209 to 183.45.0.214183.45.0.2156
28183.45.0.216/29183.45.0.217 to 183.45.0.222183.45.0.2236
29183.45.0.224/29183.45.0.225 to 183.45.0.230183.45.0.2316
30183.45.0.232/29183.45.0.233 to 183.45.0.238183.45.0.2396
31183.45.0.240/29183.45.0.241 to 183.45.0.246183.45.0.2476
32183.45.0.248/29183.45.0.249 to 183.45.0.254183.45.0.2556
33183.45.1.0/29183.45.1.1 to 183.45.1.6183.45.1.76
34183.45.1.8/29183.45.1.9 to 183.45.1.14183.45.1.156
35183.45.1.16/29183.45.1.17 to 183.45.1.22183.45.1.236
36183.45.1.24/29183.45.1.25 to 183.45.1.30183.45.1.316
37183.45.1.32/29183.45.1.33 to 183.45.1.38183.45.1.396
38183.45.1.40/29183.45.1.41 to 183.45.1.46183.45.1.476
39183.45.1.48/29183.45.1.49 to 183.45.1.54183.45.1.556
40183.45.1.56/29183.45.1.57 to 183.45.1.62183.45.1.636
41183.45.1.64/29183.45.1.65 to 183.45.1.70183.45.1.716
42183.45.1.72/29183.45.1.73 to 183.45.1.78183.45.1.796
43183.45.1.80/29183.45.1.81 to 183.45.1.86183.45.1.876
44183.45.1.88/29183.45.1.89 to 183.45.1.94183.45.1.956
45183.45.1.96/29183.45.1.97 to 183.45.1.102183.45.1.1036
46183.45.1.104/29183.45.1.105 to 183.45.1.110183.45.1.1116
47183.45.1.112/29183.45.1.113 to 183.45.1.118183.45.1.1196
48183.45.1.120/29183.45.1.121 to 183.45.1.126183.45.1.1276
49183.45.1.128/29183.45.1.129 to 183.45.1.134183.45.1.1356
50183.45.1.136/29183.45.1.137 to 183.45.1.142183.45.1.1436
51183.45.1.144/29183.45.1.145 to 183.45.1.150183.45.1.1516
52183.45.1.152/29183.45.1.153 to 183.45.1.158183.45.1.1596
53183.45.1.160/29183.45.1.161 to 183.45.1.166183.45.1.1676
54183.45.1.168/29183.45.1.169 to 183.45.1.174183.45.1.1756
55183.45.1.176/29183.45.1.177 to 183.45.1.182183.45.1.1836
56183.45.1.184/29183.45.1.185 to 183.45.1.190183.45.1.1916
57183.45.1.192/29183.45.1.193 to 183.45.1.198183.45.1.1996
58183.45.1.200/29183.45.1.201 to 183.45.1.206183.45.1.2076
59183.45.1.208/29183.45.1.209 to 183.45.1.214183.45.1.2156
60183.45.1.216/29183.45.1.217 to 183.45.1.222183.45.1.2236
61183.45.1.224/29183.45.1.225 to 183.45.1.230183.45.1.2316
62183.45.1.232/29183.45.1.233 to 183.45.1.238183.45.1.2396
63183.45.1.240/29183.45.1.241 to 183.45.1.246183.45.1.2476
64183.45.1.248/29183.45.1.249 to 183.45.1.254183.45.1.2556
65183.45.2.0/29183.45.2.1 to 183.45.2.6183.45.2.76
66183.45.2.8/29183.45.2.9 to 183.45.2.14183.45.2.156
67183.45.2.16/29183.45.2.17 to 183.45.2.22183.45.2.236
68183.45.2.24/29183.45.2.25 to 183.45.2.30183.45.2.316
69183.45.2.32/29183.45.2.33 to 183.45.2.38183.45.2.396
70183.45.2.40/29183.45.2.41 to 183.45.2.46183.45.2.476
71183.45.2.48/29183.45.2.49 to 183.45.2.54183.45.2.556
72183.45.2.56/29183.45.2.57 to 183.45.2.62183.45.2.636
73183.45.2.64/29183.45.2.65 to 183.45.2.70183.45.2.716
74183.45.2.72/29183.45.2.73 to 183.45.2.78183.45.2.796
75183.45.2.80/29183.45.2.81 to 183.45.2.86183.45.2.876
76183.45.2.88/29183.45.2.89 to 183.45.2.94183.45.2.956
77183.45.2.96/29183.45.2.97 to 183.45.2.102183.45.2.1036
78183.45.2.104/29183.45.2.105 to 183.45.2.110183.45.2.1116
79183.45.2.112/29183.45.2.113 to 183.45.2.118183.45.2.1196
80183.45.2.120/29183.45.2.121 to 183.45.2.126183.45.2.1276
81183.45.2.128/29183.45.2.129 to 183.45.2.134183.45.2.1356
82183.45.2.136/29183.45.2.137 to 183.45.2.142183.45.2.1436
83183.45.2.144/29183.45.2.145 to 183.45.2.150183.45.2.1516
84183.45.2.152/29183.45.2.153 to 183.45.2.158183.45.2.1596
85183.45.2.160/29183.45.2.161 to 183.45.2.166183.45.2.1676
86183.45.2.168/29183.45.2.169 to 183.45.2.174183.45.2.1756
87183.45.2.176/29183.45.2.177 to 183.45.2.182183.45.2.1836
88183.45.2.184/29183.45.2.185 to 183.45.2.190183.45.2.1916
89183.45.2.192/29183.45.2.193 to 183.45.2.198183.45.2.1996
90183.45.2.200/29183.45.2.201 to 183.45.2.206183.45.2.2076
91183.45.2.208/29183.45.2.209 to 183.45.2.214183.45.2.2156
92183.45.2.216/29183.45.2.217 to 183.45.2.222183.45.2.2236
93183.45.2.224/29183.45.2.225 to 183.45.2.230183.45.2.2316
94183.45.2.232/29183.45.2.233 to 183.45.2.238183.45.2.2396
95183.45.2.240/29183.45.2.241 to 183.45.2.246183.45.2.2476
96183.45.2.248/29183.45.2.249 to 183.45.2.254183.45.2.2556
97183.45.3.0/29183.45.3.1 to 183.45.3.6183.45.3.76
98183.45.3.8/29183.45.3.9 to 183.45.3.14183.45.3.156
99183.45.3.16/29183.45.3.17 to 183.45.3.22183.45.3.236
100183.45.3.24/29183.45.3.25 to 183.45.3.30183.45.3.316
101183.45.3.32/29183.45.3.33 to 183.45.3.38183.45.3.396
102183.45.3.40/29183.45.3.41 to 183.45.3.46183.45.3.476
103183.45.3.48/29183.45.3.49 to 183.45.3.54183.45.3.556
104183.45.3.56/29183.45.3.57 to 183.45.3.62183.45.3.636
105183.45.3.64/29183.45.3.65 to 183.45.3.70183.45.3.716
106183.45.3.72/29183.45.3.73 to 183.45.3.78183.45.3.796
107183.45.3.80/29183.45.3.81 to 183.45.3.86183.45.3.876
108183.45.3.88/29183.45.3.89 to 183.45.3.94183.45.3.956
109183.45.3.96/29183.45.3.97 to 183.45.3.102183.45.3.1036
110183.45.3.104/29183.45.3.105 to 183.45.3.110183.45.3.1116
111183.45.3.112/29183.45.3.113 to 183.45.3.118183.45.3.1196
112183.45.3.120/29183.45.3.121 to 183.45.3.126183.45.3.1276
113183.45.3.128/29183.45.3.129 to 183.45.3.134183.45.3.1356
114183.45.3.136/29183.45.3.137 to 183.45.3.142183.45.3.1436
115183.45.3.144/29183.45.3.145 to 183.45.3.150183.45.3.1516
116183.45.3.152/29183.45.3.153 to 183.45.3.158183.45.3.1596
117183.45.3.160/29183.45.3.161 to 183.45.3.166183.45.3.1676
118183.45.3.168/29183.45.3.169 to 183.45.3.174183.45.3.1756
119183.45.3.176/29183.45.3.177 to 183.45.3.182183.45.3.1836
120183.45.3.184/29183.45.3.185 to 183.45.3.190183.45.3.1916
121183.45.3.192/29183.45.3.193 to 183.45.3.198183.45.3.1996
122183.45.3.200/29183.45.3.201 to 183.45.3.206183.45.3.2076
123183.45.3.208/29183.45.3.209 to 183.45.3.214183.45.3.2156
124183.45.3.216/29183.45.3.217 to 183.45.3.222183.45.3.2236
125183.45.3.224/29183.45.3.225 to 183.45.3.230183.45.3.2316
126183.45.3.232/29183.45.3.233 to 183.45.3.238183.45.3.2396
127183.45.3.240/29183.45.3.241 to 183.45.3.246183.45.3.2476
128183.45.3.248/29183.45.3.249 to 183.45.3.254183.45.3.2556
129183.45.4.0/29183.45.4.1 to 183.45.4.6183.45.4.76
130183.45.4.8/29183.45.4.9 to 183.45.4.14183.45.4.156
131183.45.4.16/29183.45.4.17 to 183.45.4.22183.45.4.236
132183.45.4.24/29183.45.4.25 to 183.45.4.30183.45.4.316
133183.45.4.32/29183.45.4.33 to 183.45.4.38183.45.4.396
134183.45.4.40/29183.45.4.41 to 183.45.4.46183.45.4.476
135183.45.4.48/29183.45.4.49 to 183.45.4.54183.45.4.556
136183.45.4.56/29183.45.4.57 to 183.45.4.62183.45.4.636
137183.45.4.64/29183.45.4.65 to 183.45.4.70183.45.4.716
138183.45.4.72/29183.45.4.73 to 183.45.4.78183.45.4.796
139183.45.4.80/29183.45.4.81 to 183.45.4.86183.45.4.876
140183.45.4.88/29183.45.4.89 to 183.45.4.94183.45.4.956
141183.45.4.96/29183.45.4.97 to 183.45.4.102183.45.4.1036
142183.45.4.104/29183.45.4.105 to 183.45.4.110183.45.4.1116
143183.45.4.112/29183.45.4.113 to 183.45.4.118183.45.4.1196
144183.45.4.120/29183.45.4.121 to 183.45.4.126183.45.4.1276
145183.45.4.128/29183.45.4.129 to 183.45.4.134183.45.4.1356
146183.45.4.136/29183.45.4.137 to 183.45.4.142183.45.4.1436
147183.45.4.144/29183.45.4.145 to 183.45.4.150183.45.4.1516
148183.45.4.152/29183.45.4.153 to 183.45.4.158183.45.4.1596
149183.45.4.160/29183.45.4.161 to 183.45.4.166183.45.4.1676
150183.45.4.168/29183.45.4.169 to 183.45.4.174183.45.4.1756
151183.45.4.176/29183.45.4.177 to 183.45.4.182183.45.4.1836
152183.45.4.184/29183.45.4.185 to 183.45.4.190183.45.4.1916
153183.45.4.192/29183.45.4.193 to 183.45.4.198183.45.4.1996
154183.45.4.200/29183.45.4.201 to 183.45.4.206183.45.4.2076
155183.45.4.208/29183.45.4.209 to 183.45.4.214183.45.4.2156
156183.45.4.216/29183.45.4.217 to 183.45.4.222183.45.4.2236
157183.45.4.224/29183.45.4.225 to 183.45.4.230183.45.4.2316
158183.45.4.232/29183.45.4.233 to 183.45.4.238183.45.4.2396
159183.45.4.240/29183.45.4.241 to 183.45.4.246183.45.4.2476
160183.45.4.248/29183.45.4.249 to 183.45.4.254183.45.4.2556
161183.45.5.0/29183.45.5.1 to 183.45.5.6183.45.5.76
162183.45.5.8/29183.45.5.9 to 183.45.5.14183.45.5.156
163183.45.5.16/29183.45.5.17 to 183.45.5.22183.45.5.236
164183.45.5.24/29183.45.5.25 to 183.45.5.30183.45.5.316
165183.45.5.32/29183.45.5.33 to 183.45.5.38183.45.5.396
166183.45.5.40/29183.45.5.41 to 183.45.5.46183.45.5.476
167183.45.5.48/29183.45.5.49 to 183.45.5.54183.45.5.556
168183.45.5.56/29183.45.5.57 to 183.45.5.62183.45.5.636
169183.45.5.64/29183.45.5.65 to 183.45.5.70183.45.5.716
170183.45.5.72/29183.45.5.73 to 183.45.5.78183.45.5.796
171183.45.5.80/29183.45.5.81 to 183.45.5.86183.45.5.876
172183.45.5.88/29183.45.5.89 to 183.45.5.94183.45.5.956
173183.45.5.96/29183.45.5.97 to 183.45.5.102183.45.5.1036
174183.45.5.104/29183.45.5.105 to 183.45.5.110183.45.5.1116
175183.45.5.112/29183.45.5.113 to 183.45.5.118183.45.5.1196
176183.45.5.120/29183.45.5.121 to 183.45.5.126183.45.5.1276
177183.45.5.128/29183.45.5.129 to 183.45.5.134183.45.5.1356
178183.45.5.136/29183.45.5.137 to 183.45.5.142183.45.5.1436
179183.45.5.144/29183.45.5.145 to 183.45.5.150183.45.5.1516
180183.45.5.152/29183.45.5.153 to 183.45.5.158183.45.5.1596
181183.45.5.160/29183.45.5.161 to 183.45.5.166183.45.5.1676
182183.45.5.168/29183.45.5.169 to 183.45.5.174183.45.5.1756
183183.45.5.176/29183.45.5.177 to 183.45.5.182183.45.5.1836
184183.45.5.184/29183.45.5.185 to 183.45.5.190183.45.5.1916
185183.45.5.192/29183.45.5.193 to 183.45.5.198183.45.5.1996
186183.45.5.200/29183.45.5.201 to 183.45.5.206183.45.5.2076
187183.45.5.208/29183.45.5.209 to 183.45.5.214183.45.5.2156
188183.45.5.216/29183.45.5.217 to 183.45.5.222183.45.5.2236
189183.45.5.224/29183.45.5.225 to 183.45.5.230183.45.5.2316
190183.45.5.232/29183.45.5.233 to 183.45.5.238183.45.5.2396
191183.45.5.240/29183.45.5.241 to 183.45.5.246183.45.5.2476
192183.45.5.248/29183.45.5.249 to 183.45.5.254183.45.5.2556
193183.45.6.0/29183.45.6.1 to 183.45.6.6183.45.6.76
194183.45.6.8/29183.45.6.9 to 183.45.6.14183.45.6.156
195183.45.6.16/29183.45.6.17 to 183.45.6.22183.45.6.236
196183.45.6.24/29183.45.6.25 to 183.45.6.30183.45.6.316
197183.45.6.32/29183.45.6.33 to 183.45.6.38183.45.6.396
198183.45.6.40/29183.45.6.41 to 183.45.6.46183.45.6.476
199183.45.6.48/29183.45.6.49 to 183.45.6.54183.45.6.556
200183.45.6.56/29183.45.6.57 to 183.45.6.62183.45.6.636
201183.45.6.64/29183.45.6.65 to 183.45.6.70183.45.6.716
202183.45.6.72/29183.45.6.73 to 183.45.6.78183.45.6.796
203183.45.6.80/29183.45.6.81 to 183.45.6.86183.45.6.876
204183.45.6.88/29183.45.6.89 to 183.45.6.94183.45.6.956
205183.45.6.96/29183.45.6.97 to 183.45.6.102183.45.6.1036
206183.45.6.104/29183.45.6.105 to 183.45.6.110183.45.6.1116
207183.45.6.112/29183.45.6.113 to 183.45.6.118183.45.6.1196
208183.45.6.120/29183.45.6.121 to 183.45.6.126183.45.6.1276
209183.45.6.128/29183.45.6.129 to 183.45.6.134183.45.6.1356
210183.45.6.136/29183.45.6.137 to 183.45.6.142183.45.6.1436
211183.45.6.144/29183.45.6.145 to 183.45.6.150183.45.6.1516
212183.45.6.152/29183.45.6.153 to 183.45.6.158183.45.6.1596
213183.45.6.160/29183.45.6.161 to 183.45.6.166183.45.6.1676
214183.45.6.168/29183.45.6.169 to 183.45.6.174183.45.6.1756
215183.45.6.176/29183.45.6.177 to 183.45.6.182183.45.6.1836
216183.45.6.184/29183.45.6.185 to 183.45.6.190183.45.6.1916
217183.45.6.192/29183.45.6.193 to 183.45.6.198183.45.6.1996
218183.45.6.200/29183.45.6.201 to 183.45.6.206183.45.6.2076
219183.45.6.208/29183.45.6.209 to 183.45.6.214183.45.6.2156
220183.45.6.216/29183.45.6.217 to 183.45.6.222183.45.6.2236
221183.45.6.224/29183.45.6.225 to 183.45.6.230183.45.6.2316
222183.45.6.232/29183.45.6.233 to 183.45.6.238183.45.6.2396
223183.45.6.240/29183.45.6.241 to 183.45.6.246183.45.6.2476
224183.45.6.248/29183.45.6.249 to 183.45.6.254183.45.6.2556
225183.45.7.0/29183.45.7.1 to 183.45.7.6183.45.7.76
226183.45.7.8/29183.45.7.9 to 183.45.7.14183.45.7.156
227183.45.7.16/29183.45.7.17 to 183.45.7.22183.45.7.236
228183.45.7.24/29183.45.7.25 to 183.45.7.30183.45.7.316
229183.45.7.32/29183.45.7.33 to 183.45.7.38183.45.7.396
230183.45.7.40/29183.45.7.41 to 183.45.7.46183.45.7.476
231183.45.7.48/29183.45.7.49 to 183.45.7.54183.45.7.556
232183.45.7.56/29183.45.7.57 to 183.45.7.62183.45.7.636
233183.45.7.64/29183.45.7.65 to 183.45.7.70183.45.7.716
234183.45.7.72/29183.45.7.73 to 183.45.7.78183.45.7.796
235183.45.7.80/29183.45.7.81 to 183.45.7.86183.45.7.876
236183.45.7.88/29183.45.7.89 to 183.45.7.94183.45.7.956
237183.45.7.96/29183.45.7.97 to 183.45.7.102183.45.7.1036
238183.45.7.104/29183.45.7.105 to 183.45.7.110183.45.7.1116
239183.45.7.112/29183.45.7.113 to 183.45.7.118183.45.7.1196
240183.45.7.120/29183.45.7.121 to 183.45.7.126183.45.7.1276
241183.45.7.128/29183.45.7.129 to 183.45.7.134183.45.7.1356
242183.45.7.136/29183.45.7.137 to 183.45.7.142183.45.7.1436
243183.45.7.144/29183.45.7.145 to 183.45.7.150183.45.7.1516
244183.45.7.152/29183.45.7.153 to 183.45.7.158183.45.7.1596
245183.45.7.160/29183.45.7.161 to 183.45.7.166183.45.7.1676
246183.45.7.168/29183.45.7.169 to 183.45.7.174183.45.7.1756
247183.45.7.176/29183.45.7.177 to 183.45.7.182183.45.7.1836
248183.45.7.184/29183.45.7.185 to 183.45.7.190183.45.7.1916
249183.45.7.192/29183.45.7.193 to 183.45.7.198183.45.7.1996
250183.45.7.200/29183.45.7.201 to 183.45.7.206183.45.7.2076
251183.45.7.208/29183.45.7.209 to 183.45.7.214183.45.7.2156
252183.45.7.216/29183.45.7.217 to 183.45.7.222183.45.7.2236
253183.45.7.224/29183.45.7.225 to 183.45.7.230183.45.7.2316
254183.45.7.232/29183.45.7.233 to 183.45.7.238183.45.7.2396
255183.45.7.240/29183.45.7.241 to 183.45.7.246183.45.7.2476
256183.45.7.248/29183.45.7.249 to 183.45.7.254183.45.7.2556

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.