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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.

Network236.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
236.0.0.0
Broadcast address
236.255.255.255
First usable
236.0.0.1
Last usable
236.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EC000000 · Integer 3959422976 to 3976200191
Reverse DNS zone
236.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101100..00000000.00000000.00000000236.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11101100..00000000.00000000.00000000236.0.0.0
Broadcast11101100..11111111.11111111.11111111236.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

236.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1236.0.0.0/18236.0.0.1 to 236.0.63.254236.0.63.25516,382
2236.0.64.0/18236.0.64.1 to 236.0.127.254236.0.127.25516,382
3236.0.128.0/18236.0.128.1 to 236.0.191.254236.0.191.25516,382
4236.0.192.0/18236.0.192.1 to 236.0.255.254236.0.255.25516,382
5236.1.0.0/18236.1.0.1 to 236.1.63.254236.1.63.25516,382
6236.1.64.0/18236.1.64.1 to 236.1.127.254236.1.127.25516,382
7236.1.128.0/18236.1.128.1 to 236.1.191.254236.1.191.25516,382
8236.1.192.0/18236.1.192.1 to 236.1.255.254236.1.255.25516,382
9236.2.0.0/18236.2.0.1 to 236.2.63.254236.2.63.25516,382
10236.2.64.0/18236.2.64.1 to 236.2.127.254236.2.127.25516,382
11236.2.128.0/18236.2.128.1 to 236.2.191.254236.2.191.25516,382
12236.2.192.0/18236.2.192.1 to 236.2.255.254236.2.255.25516,382
13236.3.0.0/18236.3.0.1 to 236.3.63.254236.3.63.25516,382
14236.3.64.0/18236.3.64.1 to 236.3.127.254236.3.127.25516,382
15236.3.128.0/18236.3.128.1 to 236.3.191.254236.3.191.25516,382
16236.3.192.0/18236.3.192.1 to 236.3.255.254236.3.255.25516,382
17236.4.0.0/18236.4.0.1 to 236.4.63.254236.4.63.25516,382
18236.4.64.0/18236.4.64.1 to 236.4.127.254236.4.127.25516,382
19236.4.128.0/18236.4.128.1 to 236.4.191.254236.4.191.25516,382
20236.4.192.0/18236.4.192.1 to 236.4.255.254236.4.255.25516,382
21236.5.0.0/18236.5.0.1 to 236.5.63.254236.5.63.25516,382
22236.5.64.0/18236.5.64.1 to 236.5.127.254236.5.127.25516,382
23236.5.128.0/18236.5.128.1 to 236.5.191.254236.5.191.25516,382
24236.5.192.0/18236.5.192.1 to 236.5.255.254236.5.255.25516,382
25236.6.0.0/18236.6.0.1 to 236.6.63.254236.6.63.25516,382
26236.6.64.0/18236.6.64.1 to 236.6.127.254236.6.127.25516,382
27236.6.128.0/18236.6.128.1 to 236.6.191.254236.6.191.25516,382
28236.6.192.0/18236.6.192.1 to 236.6.255.254236.6.255.25516,382
29236.7.0.0/18236.7.0.1 to 236.7.63.254236.7.63.25516,382
30236.7.64.0/18236.7.64.1 to 236.7.127.254236.7.127.25516,382
31236.7.128.0/18236.7.128.1 to 236.7.191.254236.7.191.25516,382
32236.7.192.0/18236.7.192.1 to 236.7.255.254236.7.255.25516,382
33236.8.0.0/18236.8.0.1 to 236.8.63.254236.8.63.25516,382
34236.8.64.0/18236.8.64.1 to 236.8.127.254236.8.127.25516,382
35236.8.128.0/18236.8.128.1 to 236.8.191.254236.8.191.25516,382
36236.8.192.0/18236.8.192.1 to 236.8.255.254236.8.255.25516,382
37236.9.0.0/18236.9.0.1 to 236.9.63.254236.9.63.25516,382
38236.9.64.0/18236.9.64.1 to 236.9.127.254236.9.127.25516,382
39236.9.128.0/18236.9.128.1 to 236.9.191.254236.9.191.25516,382
40236.9.192.0/18236.9.192.1 to 236.9.255.254236.9.255.25516,382
41236.10.0.0/18236.10.0.1 to 236.10.63.254236.10.63.25516,382
42236.10.64.0/18236.10.64.1 to 236.10.127.254236.10.127.25516,382
43236.10.128.0/18236.10.128.1 to 236.10.191.254236.10.191.25516,382
44236.10.192.0/18236.10.192.1 to 236.10.255.254236.10.255.25516,382
45236.11.0.0/18236.11.0.1 to 236.11.63.254236.11.63.25516,382
46236.11.64.0/18236.11.64.1 to 236.11.127.254236.11.127.25516,382
47236.11.128.0/18236.11.128.1 to 236.11.191.254236.11.191.25516,382
48236.11.192.0/18236.11.192.1 to 236.11.255.254236.11.255.25516,382
49236.12.0.0/18236.12.0.1 to 236.12.63.254236.12.63.25516,382
50236.12.64.0/18236.12.64.1 to 236.12.127.254236.12.127.25516,382
51236.12.128.0/18236.12.128.1 to 236.12.191.254236.12.191.25516,382
52236.12.192.0/18236.12.192.1 to 236.12.255.254236.12.255.25516,382
53236.13.0.0/18236.13.0.1 to 236.13.63.254236.13.63.25516,382
54236.13.64.0/18236.13.64.1 to 236.13.127.254236.13.127.25516,382
55236.13.128.0/18236.13.128.1 to 236.13.191.254236.13.191.25516,382
56236.13.192.0/18236.13.192.1 to 236.13.255.254236.13.255.25516,382
57236.14.0.0/18236.14.0.1 to 236.14.63.254236.14.63.25516,382
58236.14.64.0/18236.14.64.1 to 236.14.127.254236.14.127.25516,382
59236.14.128.0/18236.14.128.1 to 236.14.191.254236.14.191.25516,382
60236.14.192.0/18236.14.192.1 to 236.14.255.254236.14.255.25516,382
61236.15.0.0/18236.15.0.1 to 236.15.63.254236.15.63.25516,382
62236.15.64.0/18236.15.64.1 to 236.15.127.254236.15.127.25516,382
63236.15.128.0/18236.15.128.1 to 236.15.191.254236.15.191.25516,382
64236.15.192.0/18236.15.192.1 to 236.15.255.254236.15.255.25516,382
65236.16.0.0/18236.16.0.1 to 236.16.63.254236.16.63.25516,382
66236.16.64.0/18236.16.64.1 to 236.16.127.254236.16.127.25516,382
67236.16.128.0/18236.16.128.1 to 236.16.191.254236.16.191.25516,382
68236.16.192.0/18236.16.192.1 to 236.16.255.254236.16.255.25516,382
69236.17.0.0/18236.17.0.1 to 236.17.63.254236.17.63.25516,382
70236.17.64.0/18236.17.64.1 to 236.17.127.254236.17.127.25516,382
71236.17.128.0/18236.17.128.1 to 236.17.191.254236.17.191.25516,382
72236.17.192.0/18236.17.192.1 to 236.17.255.254236.17.255.25516,382
73236.18.0.0/18236.18.0.1 to 236.18.63.254236.18.63.25516,382
74236.18.64.0/18236.18.64.1 to 236.18.127.254236.18.127.25516,382
75236.18.128.0/18236.18.128.1 to 236.18.191.254236.18.191.25516,382
76236.18.192.0/18236.18.192.1 to 236.18.255.254236.18.255.25516,382
77236.19.0.0/18236.19.0.1 to 236.19.63.254236.19.63.25516,382
78236.19.64.0/18236.19.64.1 to 236.19.127.254236.19.127.25516,382
79236.19.128.0/18236.19.128.1 to 236.19.191.254236.19.191.25516,382
80236.19.192.0/18236.19.192.1 to 236.19.255.254236.19.255.25516,382
81236.20.0.0/18236.20.0.1 to 236.20.63.254236.20.63.25516,382
82236.20.64.0/18236.20.64.1 to 236.20.127.254236.20.127.25516,382
83236.20.128.0/18236.20.128.1 to 236.20.191.254236.20.191.25516,382
84236.20.192.0/18236.20.192.1 to 236.20.255.254236.20.255.25516,382
85236.21.0.0/18236.21.0.1 to 236.21.63.254236.21.63.25516,382
86236.21.64.0/18236.21.64.1 to 236.21.127.254236.21.127.25516,382
87236.21.128.0/18236.21.128.1 to 236.21.191.254236.21.191.25516,382
88236.21.192.0/18236.21.192.1 to 236.21.255.254236.21.255.25516,382
89236.22.0.0/18236.22.0.1 to 236.22.63.254236.22.63.25516,382
90236.22.64.0/18236.22.64.1 to 236.22.127.254236.22.127.25516,382
91236.22.128.0/18236.22.128.1 to 236.22.191.254236.22.191.25516,382
92236.22.192.0/18236.22.192.1 to 236.22.255.254236.22.255.25516,382
93236.23.0.0/18236.23.0.1 to 236.23.63.254236.23.63.25516,382
94236.23.64.0/18236.23.64.1 to 236.23.127.254236.23.127.25516,382
95236.23.128.0/18236.23.128.1 to 236.23.191.254236.23.191.25516,382
96236.23.192.0/18236.23.192.1 to 236.23.255.254236.23.255.25516,382
97236.24.0.0/18236.24.0.1 to 236.24.63.254236.24.63.25516,382
98236.24.64.0/18236.24.64.1 to 236.24.127.254236.24.127.25516,382
99236.24.128.0/18236.24.128.1 to 236.24.191.254236.24.191.25516,382
100236.24.192.0/18236.24.192.1 to 236.24.255.254236.24.255.25516,382
101236.25.0.0/18236.25.0.1 to 236.25.63.254236.25.63.25516,382
102236.25.64.0/18236.25.64.1 to 236.25.127.254236.25.127.25516,382
103236.25.128.0/18236.25.128.1 to 236.25.191.254236.25.191.25516,382
104236.25.192.0/18236.25.192.1 to 236.25.255.254236.25.255.25516,382
105236.26.0.0/18236.26.0.1 to 236.26.63.254236.26.63.25516,382
106236.26.64.0/18236.26.64.1 to 236.26.127.254236.26.127.25516,382
107236.26.128.0/18236.26.128.1 to 236.26.191.254236.26.191.25516,382
108236.26.192.0/18236.26.192.1 to 236.26.255.254236.26.255.25516,382
109236.27.0.0/18236.27.0.1 to 236.27.63.254236.27.63.25516,382
110236.27.64.0/18236.27.64.1 to 236.27.127.254236.27.127.25516,382
111236.27.128.0/18236.27.128.1 to 236.27.191.254236.27.191.25516,382
112236.27.192.0/18236.27.192.1 to 236.27.255.254236.27.255.25516,382
113236.28.0.0/18236.28.0.1 to 236.28.63.254236.28.63.25516,382
114236.28.64.0/18236.28.64.1 to 236.28.127.254236.28.127.25516,382
115236.28.128.0/18236.28.128.1 to 236.28.191.254236.28.191.25516,382
116236.28.192.0/18236.28.192.1 to 236.28.255.254236.28.255.25516,382
117236.29.0.0/18236.29.0.1 to 236.29.63.254236.29.63.25516,382
118236.29.64.0/18236.29.64.1 to 236.29.127.254236.29.127.25516,382
119236.29.128.0/18236.29.128.1 to 236.29.191.254236.29.191.25516,382
120236.29.192.0/18236.29.192.1 to 236.29.255.254236.29.255.25516,382
121236.30.0.0/18236.30.0.1 to 236.30.63.254236.30.63.25516,382
122236.30.64.0/18236.30.64.1 to 236.30.127.254236.30.127.25516,382
123236.30.128.0/18236.30.128.1 to 236.30.191.254236.30.191.25516,382
124236.30.192.0/18236.30.192.1 to 236.30.255.254236.30.255.25516,382
125236.31.0.0/18236.31.0.1 to 236.31.63.254236.31.63.25516,382
126236.31.64.0/18236.31.64.1 to 236.31.127.254236.31.127.25516,382
127236.31.128.0/18236.31.128.1 to 236.31.191.254236.31.191.25516,382
128236.31.192.0/18236.31.192.1 to 236.31.255.254236.31.255.25516,382
129236.32.0.0/18236.32.0.1 to 236.32.63.254236.32.63.25516,382
130236.32.64.0/18236.32.64.1 to 236.32.127.254236.32.127.25516,382
131236.32.128.0/18236.32.128.1 to 236.32.191.254236.32.191.25516,382
132236.32.192.0/18236.32.192.1 to 236.32.255.254236.32.255.25516,382
133236.33.0.0/18236.33.0.1 to 236.33.63.254236.33.63.25516,382
134236.33.64.0/18236.33.64.1 to 236.33.127.254236.33.127.25516,382
135236.33.128.0/18236.33.128.1 to 236.33.191.254236.33.191.25516,382
136236.33.192.0/18236.33.192.1 to 236.33.255.254236.33.255.25516,382
137236.34.0.0/18236.34.0.1 to 236.34.63.254236.34.63.25516,382
138236.34.64.0/18236.34.64.1 to 236.34.127.254236.34.127.25516,382
139236.34.128.0/18236.34.128.1 to 236.34.191.254236.34.191.25516,382
140236.34.192.0/18236.34.192.1 to 236.34.255.254236.34.255.25516,382
141236.35.0.0/18236.35.0.1 to 236.35.63.254236.35.63.25516,382
142236.35.64.0/18236.35.64.1 to 236.35.127.254236.35.127.25516,382
143236.35.128.0/18236.35.128.1 to 236.35.191.254236.35.191.25516,382
144236.35.192.0/18236.35.192.1 to 236.35.255.254236.35.255.25516,382
145236.36.0.0/18236.36.0.1 to 236.36.63.254236.36.63.25516,382
146236.36.64.0/18236.36.64.1 to 236.36.127.254236.36.127.25516,382
147236.36.128.0/18236.36.128.1 to 236.36.191.254236.36.191.25516,382
148236.36.192.0/18236.36.192.1 to 236.36.255.254236.36.255.25516,382
149236.37.0.0/18236.37.0.1 to 236.37.63.254236.37.63.25516,382
150236.37.64.0/18236.37.64.1 to 236.37.127.254236.37.127.25516,382
151236.37.128.0/18236.37.128.1 to 236.37.191.254236.37.191.25516,382
152236.37.192.0/18236.37.192.1 to 236.37.255.254236.37.255.25516,382
153236.38.0.0/18236.38.0.1 to 236.38.63.254236.38.63.25516,382
154236.38.64.0/18236.38.64.1 to 236.38.127.254236.38.127.25516,382
155236.38.128.0/18236.38.128.1 to 236.38.191.254236.38.191.25516,382
156236.38.192.0/18236.38.192.1 to 236.38.255.254236.38.255.25516,382
157236.39.0.0/18236.39.0.1 to 236.39.63.254236.39.63.25516,382
158236.39.64.0/18236.39.64.1 to 236.39.127.254236.39.127.25516,382
159236.39.128.0/18236.39.128.1 to 236.39.191.254236.39.191.25516,382
160236.39.192.0/18236.39.192.1 to 236.39.255.254236.39.255.25516,382
161236.40.0.0/18236.40.0.1 to 236.40.63.254236.40.63.25516,382
162236.40.64.0/18236.40.64.1 to 236.40.127.254236.40.127.25516,382
163236.40.128.0/18236.40.128.1 to 236.40.191.254236.40.191.25516,382
164236.40.192.0/18236.40.192.1 to 236.40.255.254236.40.255.25516,382
165236.41.0.0/18236.41.0.1 to 236.41.63.254236.41.63.25516,382
166236.41.64.0/18236.41.64.1 to 236.41.127.254236.41.127.25516,382
167236.41.128.0/18236.41.128.1 to 236.41.191.254236.41.191.25516,382
168236.41.192.0/18236.41.192.1 to 236.41.255.254236.41.255.25516,382
169236.42.0.0/18236.42.0.1 to 236.42.63.254236.42.63.25516,382
170236.42.64.0/18236.42.64.1 to 236.42.127.254236.42.127.25516,382
171236.42.128.0/18236.42.128.1 to 236.42.191.254236.42.191.25516,382
172236.42.192.0/18236.42.192.1 to 236.42.255.254236.42.255.25516,382
173236.43.0.0/18236.43.0.1 to 236.43.63.254236.43.63.25516,382
174236.43.64.0/18236.43.64.1 to 236.43.127.254236.43.127.25516,382
175236.43.128.0/18236.43.128.1 to 236.43.191.254236.43.191.25516,382
176236.43.192.0/18236.43.192.1 to 236.43.255.254236.43.255.25516,382
177236.44.0.0/18236.44.0.1 to 236.44.63.254236.44.63.25516,382
178236.44.64.0/18236.44.64.1 to 236.44.127.254236.44.127.25516,382
179236.44.128.0/18236.44.128.1 to 236.44.191.254236.44.191.25516,382
180236.44.192.0/18236.44.192.1 to 236.44.255.254236.44.255.25516,382
181236.45.0.0/18236.45.0.1 to 236.45.63.254236.45.63.25516,382
182236.45.64.0/18236.45.64.1 to 236.45.127.254236.45.127.25516,382
183236.45.128.0/18236.45.128.1 to 236.45.191.254236.45.191.25516,382
184236.45.192.0/18236.45.192.1 to 236.45.255.254236.45.255.25516,382
185236.46.0.0/18236.46.0.1 to 236.46.63.254236.46.63.25516,382
186236.46.64.0/18236.46.64.1 to 236.46.127.254236.46.127.25516,382
187236.46.128.0/18236.46.128.1 to 236.46.191.254236.46.191.25516,382
188236.46.192.0/18236.46.192.1 to 236.46.255.254236.46.255.25516,382
189236.47.0.0/18236.47.0.1 to 236.47.63.254236.47.63.25516,382
190236.47.64.0/18236.47.64.1 to 236.47.127.254236.47.127.25516,382
191236.47.128.0/18236.47.128.1 to 236.47.191.254236.47.191.25516,382
192236.47.192.0/18236.47.192.1 to 236.47.255.254236.47.255.25516,382
193236.48.0.0/18236.48.0.1 to 236.48.63.254236.48.63.25516,382
194236.48.64.0/18236.48.64.1 to 236.48.127.254236.48.127.25516,382
195236.48.128.0/18236.48.128.1 to 236.48.191.254236.48.191.25516,382
196236.48.192.0/18236.48.192.1 to 236.48.255.254236.48.255.25516,382
197236.49.0.0/18236.49.0.1 to 236.49.63.254236.49.63.25516,382
198236.49.64.0/18236.49.64.1 to 236.49.127.254236.49.127.25516,382
199236.49.128.0/18236.49.128.1 to 236.49.191.254236.49.191.25516,382
200236.49.192.0/18236.49.192.1 to 236.49.255.254236.49.255.25516,382
201236.50.0.0/18236.50.0.1 to 236.50.63.254236.50.63.25516,382
202236.50.64.0/18236.50.64.1 to 236.50.127.254236.50.127.25516,382
203236.50.128.0/18236.50.128.1 to 236.50.191.254236.50.191.25516,382
204236.50.192.0/18236.50.192.1 to 236.50.255.254236.50.255.25516,382
205236.51.0.0/18236.51.0.1 to 236.51.63.254236.51.63.25516,382
206236.51.64.0/18236.51.64.1 to 236.51.127.254236.51.127.25516,382
207236.51.128.0/18236.51.128.1 to 236.51.191.254236.51.191.25516,382
208236.51.192.0/18236.51.192.1 to 236.51.255.254236.51.255.25516,382
209236.52.0.0/18236.52.0.1 to 236.52.63.254236.52.63.25516,382
210236.52.64.0/18236.52.64.1 to 236.52.127.254236.52.127.25516,382
211236.52.128.0/18236.52.128.1 to 236.52.191.254236.52.191.25516,382
212236.52.192.0/18236.52.192.1 to 236.52.255.254236.52.255.25516,382
213236.53.0.0/18236.53.0.1 to 236.53.63.254236.53.63.25516,382
214236.53.64.0/18236.53.64.1 to 236.53.127.254236.53.127.25516,382
215236.53.128.0/18236.53.128.1 to 236.53.191.254236.53.191.25516,382
216236.53.192.0/18236.53.192.1 to 236.53.255.254236.53.255.25516,382
217236.54.0.0/18236.54.0.1 to 236.54.63.254236.54.63.25516,382
218236.54.64.0/18236.54.64.1 to 236.54.127.254236.54.127.25516,382
219236.54.128.0/18236.54.128.1 to 236.54.191.254236.54.191.25516,382
220236.54.192.0/18236.54.192.1 to 236.54.255.254236.54.255.25516,382
221236.55.0.0/18236.55.0.1 to 236.55.63.254236.55.63.25516,382
222236.55.64.0/18236.55.64.1 to 236.55.127.254236.55.127.25516,382
223236.55.128.0/18236.55.128.1 to 236.55.191.254236.55.191.25516,382
224236.55.192.0/18236.55.192.1 to 236.55.255.254236.55.255.25516,382
225236.56.0.0/18236.56.0.1 to 236.56.63.254236.56.63.25516,382
226236.56.64.0/18236.56.64.1 to 236.56.127.254236.56.127.25516,382
227236.56.128.0/18236.56.128.1 to 236.56.191.254236.56.191.25516,382
228236.56.192.0/18236.56.192.1 to 236.56.255.254236.56.255.25516,382
229236.57.0.0/18236.57.0.1 to 236.57.63.254236.57.63.25516,382
230236.57.64.0/18236.57.64.1 to 236.57.127.254236.57.127.25516,382
231236.57.128.0/18236.57.128.1 to 236.57.191.254236.57.191.25516,382
232236.57.192.0/18236.57.192.1 to 236.57.255.254236.57.255.25516,382
233236.58.0.0/18236.58.0.1 to 236.58.63.254236.58.63.25516,382
234236.58.64.0/18236.58.64.1 to 236.58.127.254236.58.127.25516,382
235236.58.128.0/18236.58.128.1 to 236.58.191.254236.58.191.25516,382
236236.58.192.0/18236.58.192.1 to 236.58.255.254236.58.255.25516,382
237236.59.0.0/18236.59.0.1 to 236.59.63.254236.59.63.25516,382
238236.59.64.0/18236.59.64.1 to 236.59.127.254236.59.127.25516,382
239236.59.128.0/18236.59.128.1 to 236.59.191.254236.59.191.25516,382
240236.59.192.0/18236.59.192.1 to 236.59.255.254236.59.255.25516,382
241236.60.0.0/18236.60.0.1 to 236.60.63.254236.60.63.25516,382
242236.60.64.0/18236.60.64.1 to 236.60.127.254236.60.127.25516,382
243236.60.128.0/18236.60.128.1 to 236.60.191.254236.60.191.25516,382
244236.60.192.0/18236.60.192.1 to 236.60.255.254236.60.255.25516,382
245236.61.0.0/18236.61.0.1 to 236.61.63.254236.61.63.25516,382
246236.61.64.0/18236.61.64.1 to 236.61.127.254236.61.127.25516,382
247236.61.128.0/18236.61.128.1 to 236.61.191.254236.61.191.25516,382
248236.61.192.0/18236.61.192.1 to 236.61.255.254236.61.255.25516,382
249236.62.0.0/18236.62.0.1 to 236.62.63.254236.62.63.25516,382
250236.62.64.0/18236.62.64.1 to 236.62.127.254236.62.127.25516,382
251236.62.128.0/18236.62.128.1 to 236.62.191.254236.62.191.25516,382
252236.62.192.0/18236.62.192.1 to 236.62.255.254236.62.255.25516,382
253236.63.0.0/18236.63.0.1 to 236.63.63.254236.63.63.25516,382
254236.63.64.0/18236.63.64.1 to 236.63.127.254236.63.127.25516,382
255236.63.128.0/18236.63.128.1 to 236.63.191.254236.63.191.25516,382
256236.63.192.0/18236.63.192.1 to 236.63.255.254236.63.255.25516,382

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.