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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.

Network235.3.48.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
235.3.48.0
Broadcast address
235.3.63.255
First usable
235.3.48.1
Last usable
235.3.63.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EB033000 · Integer 3942854656 to 3942858751
Reverse DNS zones
48.3.235.in-addr.arpa
49.3.235.in-addr.arpa
50.3.235.in-addr.arpa
51.3.235.in-addr.arpa
52.3.235.in-addr.arpa
53.3.235.in-addr.arpa
54.3.235.in-addr.arpa
55.3.235.in-addr.arpa
56.3.235.in-addr.arpa
57.3.235.in-addr.arpa
58.3.235.in-addr.arpa
59.3.235.in-addr.arpa
60.3.235.in-addr.arpa
61.3.235.in-addr.arpa
62.3.235.in-addr.arpa
63.3.235.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101011.00000011.00110000.00000000235.3.48.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network11101011.00000011.00110000.00000000235.3.48.0
Broadcast11101011.00000011.00111111.11111111235.3.63.255
Split into smaller subnets/29
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

235.3.48.0/20 makes 512 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1235.3.48.0/29235.3.48.1 to 235.3.48.6235.3.48.76
2235.3.48.8/29235.3.48.9 to 235.3.48.14235.3.48.156
3235.3.48.16/29235.3.48.17 to 235.3.48.22235.3.48.236
4235.3.48.24/29235.3.48.25 to 235.3.48.30235.3.48.316
5235.3.48.32/29235.3.48.33 to 235.3.48.38235.3.48.396
6235.3.48.40/29235.3.48.41 to 235.3.48.46235.3.48.476
7235.3.48.48/29235.3.48.49 to 235.3.48.54235.3.48.556
8235.3.48.56/29235.3.48.57 to 235.3.48.62235.3.48.636
9235.3.48.64/29235.3.48.65 to 235.3.48.70235.3.48.716
10235.3.48.72/29235.3.48.73 to 235.3.48.78235.3.48.796
11235.3.48.80/29235.3.48.81 to 235.3.48.86235.3.48.876
12235.3.48.88/29235.3.48.89 to 235.3.48.94235.3.48.956
13235.3.48.96/29235.3.48.97 to 235.3.48.102235.3.48.1036
14235.3.48.104/29235.3.48.105 to 235.3.48.110235.3.48.1116
15235.3.48.112/29235.3.48.113 to 235.3.48.118235.3.48.1196
16235.3.48.120/29235.3.48.121 to 235.3.48.126235.3.48.1276
17235.3.48.128/29235.3.48.129 to 235.3.48.134235.3.48.1356
18235.3.48.136/29235.3.48.137 to 235.3.48.142235.3.48.1436
19235.3.48.144/29235.3.48.145 to 235.3.48.150235.3.48.1516
20235.3.48.152/29235.3.48.153 to 235.3.48.158235.3.48.1596
21235.3.48.160/29235.3.48.161 to 235.3.48.166235.3.48.1676
22235.3.48.168/29235.3.48.169 to 235.3.48.174235.3.48.1756
23235.3.48.176/29235.3.48.177 to 235.3.48.182235.3.48.1836
24235.3.48.184/29235.3.48.185 to 235.3.48.190235.3.48.1916
25235.3.48.192/29235.3.48.193 to 235.3.48.198235.3.48.1996
26235.3.48.200/29235.3.48.201 to 235.3.48.206235.3.48.2076
27235.3.48.208/29235.3.48.209 to 235.3.48.214235.3.48.2156
28235.3.48.216/29235.3.48.217 to 235.3.48.222235.3.48.2236
29235.3.48.224/29235.3.48.225 to 235.3.48.230235.3.48.2316
30235.3.48.232/29235.3.48.233 to 235.3.48.238235.3.48.2396
31235.3.48.240/29235.3.48.241 to 235.3.48.246235.3.48.2476
32235.3.48.248/29235.3.48.249 to 235.3.48.254235.3.48.2556
33235.3.49.0/29235.3.49.1 to 235.3.49.6235.3.49.76
34235.3.49.8/29235.3.49.9 to 235.3.49.14235.3.49.156
35235.3.49.16/29235.3.49.17 to 235.3.49.22235.3.49.236
36235.3.49.24/29235.3.49.25 to 235.3.49.30235.3.49.316
37235.3.49.32/29235.3.49.33 to 235.3.49.38235.3.49.396
38235.3.49.40/29235.3.49.41 to 235.3.49.46235.3.49.476
39235.3.49.48/29235.3.49.49 to 235.3.49.54235.3.49.556
40235.3.49.56/29235.3.49.57 to 235.3.49.62235.3.49.636
41235.3.49.64/29235.3.49.65 to 235.3.49.70235.3.49.716
42235.3.49.72/29235.3.49.73 to 235.3.49.78235.3.49.796
43235.3.49.80/29235.3.49.81 to 235.3.49.86235.3.49.876
44235.3.49.88/29235.3.49.89 to 235.3.49.94235.3.49.956
45235.3.49.96/29235.3.49.97 to 235.3.49.102235.3.49.1036
46235.3.49.104/29235.3.49.105 to 235.3.49.110235.3.49.1116
47235.3.49.112/29235.3.49.113 to 235.3.49.118235.3.49.1196
48235.3.49.120/29235.3.49.121 to 235.3.49.126235.3.49.1276
49235.3.49.128/29235.3.49.129 to 235.3.49.134235.3.49.1356
50235.3.49.136/29235.3.49.137 to 235.3.49.142235.3.49.1436
51235.3.49.144/29235.3.49.145 to 235.3.49.150235.3.49.1516
52235.3.49.152/29235.3.49.153 to 235.3.49.158235.3.49.1596
53235.3.49.160/29235.3.49.161 to 235.3.49.166235.3.49.1676
54235.3.49.168/29235.3.49.169 to 235.3.49.174235.3.49.1756
55235.3.49.176/29235.3.49.177 to 235.3.49.182235.3.49.1836
56235.3.49.184/29235.3.49.185 to 235.3.49.190235.3.49.1916
57235.3.49.192/29235.3.49.193 to 235.3.49.198235.3.49.1996
58235.3.49.200/29235.3.49.201 to 235.3.49.206235.3.49.2076
59235.3.49.208/29235.3.49.209 to 235.3.49.214235.3.49.2156
60235.3.49.216/29235.3.49.217 to 235.3.49.222235.3.49.2236
61235.3.49.224/29235.3.49.225 to 235.3.49.230235.3.49.2316
62235.3.49.232/29235.3.49.233 to 235.3.49.238235.3.49.2396
63235.3.49.240/29235.3.49.241 to 235.3.49.246235.3.49.2476
64235.3.49.248/29235.3.49.249 to 235.3.49.254235.3.49.2556
65235.3.50.0/29235.3.50.1 to 235.3.50.6235.3.50.76
66235.3.50.8/29235.3.50.9 to 235.3.50.14235.3.50.156
67235.3.50.16/29235.3.50.17 to 235.3.50.22235.3.50.236
68235.3.50.24/29235.3.50.25 to 235.3.50.30235.3.50.316
69235.3.50.32/29235.3.50.33 to 235.3.50.38235.3.50.396
70235.3.50.40/29235.3.50.41 to 235.3.50.46235.3.50.476
71235.3.50.48/29235.3.50.49 to 235.3.50.54235.3.50.556
72235.3.50.56/29235.3.50.57 to 235.3.50.62235.3.50.636
73235.3.50.64/29235.3.50.65 to 235.3.50.70235.3.50.716
74235.3.50.72/29235.3.50.73 to 235.3.50.78235.3.50.796
75235.3.50.80/29235.3.50.81 to 235.3.50.86235.3.50.876
76235.3.50.88/29235.3.50.89 to 235.3.50.94235.3.50.956
77235.3.50.96/29235.3.50.97 to 235.3.50.102235.3.50.1036
78235.3.50.104/29235.3.50.105 to 235.3.50.110235.3.50.1116
79235.3.50.112/29235.3.50.113 to 235.3.50.118235.3.50.1196
80235.3.50.120/29235.3.50.121 to 235.3.50.126235.3.50.1276
81235.3.50.128/29235.3.50.129 to 235.3.50.134235.3.50.1356
82235.3.50.136/29235.3.50.137 to 235.3.50.142235.3.50.1436
83235.3.50.144/29235.3.50.145 to 235.3.50.150235.3.50.1516
84235.3.50.152/29235.3.50.153 to 235.3.50.158235.3.50.1596
85235.3.50.160/29235.3.50.161 to 235.3.50.166235.3.50.1676
86235.3.50.168/29235.3.50.169 to 235.3.50.174235.3.50.1756
87235.3.50.176/29235.3.50.177 to 235.3.50.182235.3.50.1836
88235.3.50.184/29235.3.50.185 to 235.3.50.190235.3.50.1916
89235.3.50.192/29235.3.50.193 to 235.3.50.198235.3.50.1996
90235.3.50.200/29235.3.50.201 to 235.3.50.206235.3.50.2076
91235.3.50.208/29235.3.50.209 to 235.3.50.214235.3.50.2156
92235.3.50.216/29235.3.50.217 to 235.3.50.222235.3.50.2236
93235.3.50.224/29235.3.50.225 to 235.3.50.230235.3.50.2316
94235.3.50.232/29235.3.50.233 to 235.3.50.238235.3.50.2396
95235.3.50.240/29235.3.50.241 to 235.3.50.246235.3.50.2476
96235.3.50.248/29235.3.50.249 to 235.3.50.254235.3.50.2556
97235.3.51.0/29235.3.51.1 to 235.3.51.6235.3.51.76
98235.3.51.8/29235.3.51.9 to 235.3.51.14235.3.51.156
99235.3.51.16/29235.3.51.17 to 235.3.51.22235.3.51.236
100235.3.51.24/29235.3.51.25 to 235.3.51.30235.3.51.316
101235.3.51.32/29235.3.51.33 to 235.3.51.38235.3.51.396
102235.3.51.40/29235.3.51.41 to 235.3.51.46235.3.51.476
103235.3.51.48/29235.3.51.49 to 235.3.51.54235.3.51.556
104235.3.51.56/29235.3.51.57 to 235.3.51.62235.3.51.636
105235.3.51.64/29235.3.51.65 to 235.3.51.70235.3.51.716
106235.3.51.72/29235.3.51.73 to 235.3.51.78235.3.51.796
107235.3.51.80/29235.3.51.81 to 235.3.51.86235.3.51.876
108235.3.51.88/29235.3.51.89 to 235.3.51.94235.3.51.956
109235.3.51.96/29235.3.51.97 to 235.3.51.102235.3.51.1036
110235.3.51.104/29235.3.51.105 to 235.3.51.110235.3.51.1116
111235.3.51.112/29235.3.51.113 to 235.3.51.118235.3.51.1196
112235.3.51.120/29235.3.51.121 to 235.3.51.126235.3.51.1276
113235.3.51.128/29235.3.51.129 to 235.3.51.134235.3.51.1356
114235.3.51.136/29235.3.51.137 to 235.3.51.142235.3.51.1436
115235.3.51.144/29235.3.51.145 to 235.3.51.150235.3.51.1516
116235.3.51.152/29235.3.51.153 to 235.3.51.158235.3.51.1596
117235.3.51.160/29235.3.51.161 to 235.3.51.166235.3.51.1676
118235.3.51.168/29235.3.51.169 to 235.3.51.174235.3.51.1756
119235.3.51.176/29235.3.51.177 to 235.3.51.182235.3.51.1836
120235.3.51.184/29235.3.51.185 to 235.3.51.190235.3.51.1916
121235.3.51.192/29235.3.51.193 to 235.3.51.198235.3.51.1996
122235.3.51.200/29235.3.51.201 to 235.3.51.206235.3.51.2076
123235.3.51.208/29235.3.51.209 to 235.3.51.214235.3.51.2156
124235.3.51.216/29235.3.51.217 to 235.3.51.222235.3.51.2236
125235.3.51.224/29235.3.51.225 to 235.3.51.230235.3.51.2316
126235.3.51.232/29235.3.51.233 to 235.3.51.238235.3.51.2396
127235.3.51.240/29235.3.51.241 to 235.3.51.246235.3.51.2476
128235.3.51.248/29235.3.51.249 to 235.3.51.254235.3.51.2556
129235.3.52.0/29235.3.52.1 to 235.3.52.6235.3.52.76
130235.3.52.8/29235.3.52.9 to 235.3.52.14235.3.52.156
131235.3.52.16/29235.3.52.17 to 235.3.52.22235.3.52.236
132235.3.52.24/29235.3.52.25 to 235.3.52.30235.3.52.316
133235.3.52.32/29235.3.52.33 to 235.3.52.38235.3.52.396
134235.3.52.40/29235.3.52.41 to 235.3.52.46235.3.52.476
135235.3.52.48/29235.3.52.49 to 235.3.52.54235.3.52.556
136235.3.52.56/29235.3.52.57 to 235.3.52.62235.3.52.636
137235.3.52.64/29235.3.52.65 to 235.3.52.70235.3.52.716
138235.3.52.72/29235.3.52.73 to 235.3.52.78235.3.52.796
139235.3.52.80/29235.3.52.81 to 235.3.52.86235.3.52.876
140235.3.52.88/29235.3.52.89 to 235.3.52.94235.3.52.956
141235.3.52.96/29235.3.52.97 to 235.3.52.102235.3.52.1036
142235.3.52.104/29235.3.52.105 to 235.3.52.110235.3.52.1116
143235.3.52.112/29235.3.52.113 to 235.3.52.118235.3.52.1196
144235.3.52.120/29235.3.52.121 to 235.3.52.126235.3.52.1276
145235.3.52.128/29235.3.52.129 to 235.3.52.134235.3.52.1356
146235.3.52.136/29235.3.52.137 to 235.3.52.142235.3.52.1436
147235.3.52.144/29235.3.52.145 to 235.3.52.150235.3.52.1516
148235.3.52.152/29235.3.52.153 to 235.3.52.158235.3.52.1596
149235.3.52.160/29235.3.52.161 to 235.3.52.166235.3.52.1676
150235.3.52.168/29235.3.52.169 to 235.3.52.174235.3.52.1756
151235.3.52.176/29235.3.52.177 to 235.3.52.182235.3.52.1836
152235.3.52.184/29235.3.52.185 to 235.3.52.190235.3.52.1916
153235.3.52.192/29235.3.52.193 to 235.3.52.198235.3.52.1996
154235.3.52.200/29235.3.52.201 to 235.3.52.206235.3.52.2076
155235.3.52.208/29235.3.52.209 to 235.3.52.214235.3.52.2156
156235.3.52.216/29235.3.52.217 to 235.3.52.222235.3.52.2236
157235.3.52.224/29235.3.52.225 to 235.3.52.230235.3.52.2316
158235.3.52.232/29235.3.52.233 to 235.3.52.238235.3.52.2396
159235.3.52.240/29235.3.52.241 to 235.3.52.246235.3.52.2476
160235.3.52.248/29235.3.52.249 to 235.3.52.254235.3.52.2556
161235.3.53.0/29235.3.53.1 to 235.3.53.6235.3.53.76
162235.3.53.8/29235.3.53.9 to 235.3.53.14235.3.53.156
163235.3.53.16/29235.3.53.17 to 235.3.53.22235.3.53.236
164235.3.53.24/29235.3.53.25 to 235.3.53.30235.3.53.316
165235.3.53.32/29235.3.53.33 to 235.3.53.38235.3.53.396
166235.3.53.40/29235.3.53.41 to 235.3.53.46235.3.53.476
167235.3.53.48/29235.3.53.49 to 235.3.53.54235.3.53.556
168235.3.53.56/29235.3.53.57 to 235.3.53.62235.3.53.636
169235.3.53.64/29235.3.53.65 to 235.3.53.70235.3.53.716
170235.3.53.72/29235.3.53.73 to 235.3.53.78235.3.53.796
171235.3.53.80/29235.3.53.81 to 235.3.53.86235.3.53.876
172235.3.53.88/29235.3.53.89 to 235.3.53.94235.3.53.956
173235.3.53.96/29235.3.53.97 to 235.3.53.102235.3.53.1036
174235.3.53.104/29235.3.53.105 to 235.3.53.110235.3.53.1116
175235.3.53.112/29235.3.53.113 to 235.3.53.118235.3.53.1196
176235.3.53.120/29235.3.53.121 to 235.3.53.126235.3.53.1276
177235.3.53.128/29235.3.53.129 to 235.3.53.134235.3.53.1356
178235.3.53.136/29235.3.53.137 to 235.3.53.142235.3.53.1436
179235.3.53.144/29235.3.53.145 to 235.3.53.150235.3.53.1516
180235.3.53.152/29235.3.53.153 to 235.3.53.158235.3.53.1596
181235.3.53.160/29235.3.53.161 to 235.3.53.166235.3.53.1676
182235.3.53.168/29235.3.53.169 to 235.3.53.174235.3.53.1756
183235.3.53.176/29235.3.53.177 to 235.3.53.182235.3.53.1836
184235.3.53.184/29235.3.53.185 to 235.3.53.190235.3.53.1916
185235.3.53.192/29235.3.53.193 to 235.3.53.198235.3.53.1996
186235.3.53.200/29235.3.53.201 to 235.3.53.206235.3.53.2076
187235.3.53.208/29235.3.53.209 to 235.3.53.214235.3.53.2156
188235.3.53.216/29235.3.53.217 to 235.3.53.222235.3.53.2236
189235.3.53.224/29235.3.53.225 to 235.3.53.230235.3.53.2316
190235.3.53.232/29235.3.53.233 to 235.3.53.238235.3.53.2396
191235.3.53.240/29235.3.53.241 to 235.3.53.246235.3.53.2476
192235.3.53.248/29235.3.53.249 to 235.3.53.254235.3.53.2556
193235.3.54.0/29235.3.54.1 to 235.3.54.6235.3.54.76
194235.3.54.8/29235.3.54.9 to 235.3.54.14235.3.54.156
195235.3.54.16/29235.3.54.17 to 235.3.54.22235.3.54.236
196235.3.54.24/29235.3.54.25 to 235.3.54.30235.3.54.316
197235.3.54.32/29235.3.54.33 to 235.3.54.38235.3.54.396
198235.3.54.40/29235.3.54.41 to 235.3.54.46235.3.54.476
199235.3.54.48/29235.3.54.49 to 235.3.54.54235.3.54.556
200235.3.54.56/29235.3.54.57 to 235.3.54.62235.3.54.636
201235.3.54.64/29235.3.54.65 to 235.3.54.70235.3.54.716
202235.3.54.72/29235.3.54.73 to 235.3.54.78235.3.54.796
203235.3.54.80/29235.3.54.81 to 235.3.54.86235.3.54.876
204235.3.54.88/29235.3.54.89 to 235.3.54.94235.3.54.956
205235.3.54.96/29235.3.54.97 to 235.3.54.102235.3.54.1036
206235.3.54.104/29235.3.54.105 to 235.3.54.110235.3.54.1116
207235.3.54.112/29235.3.54.113 to 235.3.54.118235.3.54.1196
208235.3.54.120/29235.3.54.121 to 235.3.54.126235.3.54.1276
209235.3.54.128/29235.3.54.129 to 235.3.54.134235.3.54.1356
210235.3.54.136/29235.3.54.137 to 235.3.54.142235.3.54.1436
211235.3.54.144/29235.3.54.145 to 235.3.54.150235.3.54.1516
212235.3.54.152/29235.3.54.153 to 235.3.54.158235.3.54.1596
213235.3.54.160/29235.3.54.161 to 235.3.54.166235.3.54.1676
214235.3.54.168/29235.3.54.169 to 235.3.54.174235.3.54.1756
215235.3.54.176/29235.3.54.177 to 235.3.54.182235.3.54.1836
216235.3.54.184/29235.3.54.185 to 235.3.54.190235.3.54.1916
217235.3.54.192/29235.3.54.193 to 235.3.54.198235.3.54.1996
218235.3.54.200/29235.3.54.201 to 235.3.54.206235.3.54.2076
219235.3.54.208/29235.3.54.209 to 235.3.54.214235.3.54.2156
220235.3.54.216/29235.3.54.217 to 235.3.54.222235.3.54.2236
221235.3.54.224/29235.3.54.225 to 235.3.54.230235.3.54.2316
222235.3.54.232/29235.3.54.233 to 235.3.54.238235.3.54.2396
223235.3.54.240/29235.3.54.241 to 235.3.54.246235.3.54.2476
224235.3.54.248/29235.3.54.249 to 235.3.54.254235.3.54.2556
225235.3.55.0/29235.3.55.1 to 235.3.55.6235.3.55.76
226235.3.55.8/29235.3.55.9 to 235.3.55.14235.3.55.156
227235.3.55.16/29235.3.55.17 to 235.3.55.22235.3.55.236
228235.3.55.24/29235.3.55.25 to 235.3.55.30235.3.55.316
229235.3.55.32/29235.3.55.33 to 235.3.55.38235.3.55.396
230235.3.55.40/29235.3.55.41 to 235.3.55.46235.3.55.476
231235.3.55.48/29235.3.55.49 to 235.3.55.54235.3.55.556
232235.3.55.56/29235.3.55.57 to 235.3.55.62235.3.55.636
233235.3.55.64/29235.3.55.65 to 235.3.55.70235.3.55.716
234235.3.55.72/29235.3.55.73 to 235.3.55.78235.3.55.796
235235.3.55.80/29235.3.55.81 to 235.3.55.86235.3.55.876
236235.3.55.88/29235.3.55.89 to 235.3.55.94235.3.55.956
237235.3.55.96/29235.3.55.97 to 235.3.55.102235.3.55.1036
238235.3.55.104/29235.3.55.105 to 235.3.55.110235.3.55.1116
239235.3.55.112/29235.3.55.113 to 235.3.55.118235.3.55.1196
240235.3.55.120/29235.3.55.121 to 235.3.55.126235.3.55.1276
241235.3.55.128/29235.3.55.129 to 235.3.55.134235.3.55.1356
242235.3.55.136/29235.3.55.137 to 235.3.55.142235.3.55.1436
243235.3.55.144/29235.3.55.145 to 235.3.55.150235.3.55.1516
244235.3.55.152/29235.3.55.153 to 235.3.55.158235.3.55.1596
245235.3.55.160/29235.3.55.161 to 235.3.55.166235.3.55.1676
246235.3.55.168/29235.3.55.169 to 235.3.55.174235.3.55.1756
247235.3.55.176/29235.3.55.177 to 235.3.55.182235.3.55.1836
248235.3.55.184/29235.3.55.185 to 235.3.55.190235.3.55.1916
249235.3.55.192/29235.3.55.193 to 235.3.55.198235.3.55.1996
250235.3.55.200/29235.3.55.201 to 235.3.55.206235.3.55.2076
251235.3.55.208/29235.3.55.209 to 235.3.55.214235.3.55.2156
252235.3.55.216/29235.3.55.217 to 235.3.55.222235.3.55.2236
253235.3.55.224/29235.3.55.225 to 235.3.55.230235.3.55.2316
254235.3.55.232/29235.3.55.233 to 235.3.55.238235.3.55.2396
255235.3.55.240/29235.3.55.241 to 235.3.55.246235.3.55.2476
256235.3.55.248/29235.3.55.249 to 235.3.55.254235.3.55.2556

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.