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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.

Network236.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
236.0.0.0
Broadcast address
236.127.255.255
First usable
236.0.0.1
Last usable
236.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
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 3967811583
Reverse DNS zones
0.236.in-addr.arpa
1.236.in-addr.arpa
2.236.in-addr.arpa
3.236.in-addr.arpa
4.236.in-addr.arpa
5.236.in-addr.arpa
6.236.in-addr.arpa
7.236.in-addr.arpa
8.236.in-addr.arpa
9.236.in-addr.arpa
10.236.in-addr.arpa
11.236.in-addr.arpa
12.236.in-addr.arpa
13.236.in-addr.arpa
14.236.in-addr.arpa
15.236.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101100.00000000.00000000.00000000236.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11101100.00000000.00000000.00000000236.0.0.0
Broadcast11101100.01111111.11111111.11111111236.127.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

236.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1236.0.0.0/17236.0.0.1 to 236.0.127.254236.0.127.25532,766
2236.0.128.0/17236.0.128.1 to 236.0.255.254236.0.255.25532,766
3236.1.0.0/17236.1.0.1 to 236.1.127.254236.1.127.25532,766
4236.1.128.0/17236.1.128.1 to 236.1.255.254236.1.255.25532,766
5236.2.0.0/17236.2.0.1 to 236.2.127.254236.2.127.25532,766
6236.2.128.0/17236.2.128.1 to 236.2.255.254236.2.255.25532,766
7236.3.0.0/17236.3.0.1 to 236.3.127.254236.3.127.25532,766
8236.3.128.0/17236.3.128.1 to 236.3.255.254236.3.255.25532,766
9236.4.0.0/17236.4.0.1 to 236.4.127.254236.4.127.25532,766
10236.4.128.0/17236.4.128.1 to 236.4.255.254236.4.255.25532,766
11236.5.0.0/17236.5.0.1 to 236.5.127.254236.5.127.25532,766
12236.5.128.0/17236.5.128.1 to 236.5.255.254236.5.255.25532,766
13236.6.0.0/17236.6.0.1 to 236.6.127.254236.6.127.25532,766
14236.6.128.0/17236.6.128.1 to 236.6.255.254236.6.255.25532,766
15236.7.0.0/17236.7.0.1 to 236.7.127.254236.7.127.25532,766
16236.7.128.0/17236.7.128.1 to 236.7.255.254236.7.255.25532,766
17236.8.0.0/17236.8.0.1 to 236.8.127.254236.8.127.25532,766
18236.8.128.0/17236.8.128.1 to 236.8.255.254236.8.255.25532,766
19236.9.0.0/17236.9.0.1 to 236.9.127.254236.9.127.25532,766
20236.9.128.0/17236.9.128.1 to 236.9.255.254236.9.255.25532,766
21236.10.0.0/17236.10.0.1 to 236.10.127.254236.10.127.25532,766
22236.10.128.0/17236.10.128.1 to 236.10.255.254236.10.255.25532,766
23236.11.0.0/17236.11.0.1 to 236.11.127.254236.11.127.25532,766
24236.11.128.0/17236.11.128.1 to 236.11.255.254236.11.255.25532,766
25236.12.0.0/17236.12.0.1 to 236.12.127.254236.12.127.25532,766
26236.12.128.0/17236.12.128.1 to 236.12.255.254236.12.255.25532,766
27236.13.0.0/17236.13.0.1 to 236.13.127.254236.13.127.25532,766
28236.13.128.0/17236.13.128.1 to 236.13.255.254236.13.255.25532,766
29236.14.0.0/17236.14.0.1 to 236.14.127.254236.14.127.25532,766
30236.14.128.0/17236.14.128.1 to 236.14.255.254236.14.255.25532,766
31236.15.0.0/17236.15.0.1 to 236.15.127.254236.15.127.25532,766
32236.15.128.0/17236.15.128.1 to 236.15.255.254236.15.255.25532,766
33236.16.0.0/17236.16.0.1 to 236.16.127.254236.16.127.25532,766
34236.16.128.0/17236.16.128.1 to 236.16.255.254236.16.255.25532,766
35236.17.0.0/17236.17.0.1 to 236.17.127.254236.17.127.25532,766
36236.17.128.0/17236.17.128.1 to 236.17.255.254236.17.255.25532,766
37236.18.0.0/17236.18.0.1 to 236.18.127.254236.18.127.25532,766
38236.18.128.0/17236.18.128.1 to 236.18.255.254236.18.255.25532,766
39236.19.0.0/17236.19.0.1 to 236.19.127.254236.19.127.25532,766
40236.19.128.0/17236.19.128.1 to 236.19.255.254236.19.255.25532,766
41236.20.0.0/17236.20.0.1 to 236.20.127.254236.20.127.25532,766
42236.20.128.0/17236.20.128.1 to 236.20.255.254236.20.255.25532,766
43236.21.0.0/17236.21.0.1 to 236.21.127.254236.21.127.25532,766
44236.21.128.0/17236.21.128.1 to 236.21.255.254236.21.255.25532,766
45236.22.0.0/17236.22.0.1 to 236.22.127.254236.22.127.25532,766
46236.22.128.0/17236.22.128.1 to 236.22.255.254236.22.255.25532,766
47236.23.0.0/17236.23.0.1 to 236.23.127.254236.23.127.25532,766
48236.23.128.0/17236.23.128.1 to 236.23.255.254236.23.255.25532,766
49236.24.0.0/17236.24.0.1 to 236.24.127.254236.24.127.25532,766
50236.24.128.0/17236.24.128.1 to 236.24.255.254236.24.255.25532,766
51236.25.0.0/17236.25.0.1 to 236.25.127.254236.25.127.25532,766
52236.25.128.0/17236.25.128.1 to 236.25.255.254236.25.255.25532,766
53236.26.0.0/17236.26.0.1 to 236.26.127.254236.26.127.25532,766
54236.26.128.0/17236.26.128.1 to 236.26.255.254236.26.255.25532,766
55236.27.0.0/17236.27.0.1 to 236.27.127.254236.27.127.25532,766
56236.27.128.0/17236.27.128.1 to 236.27.255.254236.27.255.25532,766
57236.28.0.0/17236.28.0.1 to 236.28.127.254236.28.127.25532,766
58236.28.128.0/17236.28.128.1 to 236.28.255.254236.28.255.25532,766
59236.29.0.0/17236.29.0.1 to 236.29.127.254236.29.127.25532,766
60236.29.128.0/17236.29.128.1 to 236.29.255.254236.29.255.25532,766
61236.30.0.0/17236.30.0.1 to 236.30.127.254236.30.127.25532,766
62236.30.128.0/17236.30.128.1 to 236.30.255.254236.30.255.25532,766
63236.31.0.0/17236.31.0.1 to 236.31.127.254236.31.127.25532,766
64236.31.128.0/17236.31.128.1 to 236.31.255.254236.31.255.25532,766
65236.32.0.0/17236.32.0.1 to 236.32.127.254236.32.127.25532,766
66236.32.128.0/17236.32.128.1 to 236.32.255.254236.32.255.25532,766
67236.33.0.0/17236.33.0.1 to 236.33.127.254236.33.127.25532,766
68236.33.128.0/17236.33.128.1 to 236.33.255.254236.33.255.25532,766
69236.34.0.0/17236.34.0.1 to 236.34.127.254236.34.127.25532,766
70236.34.128.0/17236.34.128.1 to 236.34.255.254236.34.255.25532,766
71236.35.0.0/17236.35.0.1 to 236.35.127.254236.35.127.25532,766
72236.35.128.0/17236.35.128.1 to 236.35.255.254236.35.255.25532,766
73236.36.0.0/17236.36.0.1 to 236.36.127.254236.36.127.25532,766
74236.36.128.0/17236.36.128.1 to 236.36.255.254236.36.255.25532,766
75236.37.0.0/17236.37.0.1 to 236.37.127.254236.37.127.25532,766
76236.37.128.0/17236.37.128.1 to 236.37.255.254236.37.255.25532,766
77236.38.0.0/17236.38.0.1 to 236.38.127.254236.38.127.25532,766
78236.38.128.0/17236.38.128.1 to 236.38.255.254236.38.255.25532,766
79236.39.0.0/17236.39.0.1 to 236.39.127.254236.39.127.25532,766
80236.39.128.0/17236.39.128.1 to 236.39.255.254236.39.255.25532,766
81236.40.0.0/17236.40.0.1 to 236.40.127.254236.40.127.25532,766
82236.40.128.0/17236.40.128.1 to 236.40.255.254236.40.255.25532,766
83236.41.0.0/17236.41.0.1 to 236.41.127.254236.41.127.25532,766
84236.41.128.0/17236.41.128.1 to 236.41.255.254236.41.255.25532,766
85236.42.0.0/17236.42.0.1 to 236.42.127.254236.42.127.25532,766
86236.42.128.0/17236.42.128.1 to 236.42.255.254236.42.255.25532,766
87236.43.0.0/17236.43.0.1 to 236.43.127.254236.43.127.25532,766
88236.43.128.0/17236.43.128.1 to 236.43.255.254236.43.255.25532,766
89236.44.0.0/17236.44.0.1 to 236.44.127.254236.44.127.25532,766
90236.44.128.0/17236.44.128.1 to 236.44.255.254236.44.255.25532,766
91236.45.0.0/17236.45.0.1 to 236.45.127.254236.45.127.25532,766
92236.45.128.0/17236.45.128.1 to 236.45.255.254236.45.255.25532,766
93236.46.0.0/17236.46.0.1 to 236.46.127.254236.46.127.25532,766
94236.46.128.0/17236.46.128.1 to 236.46.255.254236.46.255.25532,766
95236.47.0.0/17236.47.0.1 to 236.47.127.254236.47.127.25532,766
96236.47.128.0/17236.47.128.1 to 236.47.255.254236.47.255.25532,766
97236.48.0.0/17236.48.0.1 to 236.48.127.254236.48.127.25532,766
98236.48.128.0/17236.48.128.1 to 236.48.255.254236.48.255.25532,766
99236.49.0.0/17236.49.0.1 to 236.49.127.254236.49.127.25532,766
100236.49.128.0/17236.49.128.1 to 236.49.255.254236.49.255.25532,766
101236.50.0.0/17236.50.0.1 to 236.50.127.254236.50.127.25532,766
102236.50.128.0/17236.50.128.1 to 236.50.255.254236.50.255.25532,766
103236.51.0.0/17236.51.0.1 to 236.51.127.254236.51.127.25532,766
104236.51.128.0/17236.51.128.1 to 236.51.255.254236.51.255.25532,766
105236.52.0.0/17236.52.0.1 to 236.52.127.254236.52.127.25532,766
106236.52.128.0/17236.52.128.1 to 236.52.255.254236.52.255.25532,766
107236.53.0.0/17236.53.0.1 to 236.53.127.254236.53.127.25532,766
108236.53.128.0/17236.53.128.1 to 236.53.255.254236.53.255.25532,766
109236.54.0.0/17236.54.0.1 to 236.54.127.254236.54.127.25532,766
110236.54.128.0/17236.54.128.1 to 236.54.255.254236.54.255.25532,766
111236.55.0.0/17236.55.0.1 to 236.55.127.254236.55.127.25532,766
112236.55.128.0/17236.55.128.1 to 236.55.255.254236.55.255.25532,766
113236.56.0.0/17236.56.0.1 to 236.56.127.254236.56.127.25532,766
114236.56.128.0/17236.56.128.1 to 236.56.255.254236.56.255.25532,766
115236.57.0.0/17236.57.0.1 to 236.57.127.254236.57.127.25532,766
116236.57.128.0/17236.57.128.1 to 236.57.255.254236.57.255.25532,766
117236.58.0.0/17236.58.0.1 to 236.58.127.254236.58.127.25532,766
118236.58.128.0/17236.58.128.1 to 236.58.255.254236.58.255.25532,766
119236.59.0.0/17236.59.0.1 to 236.59.127.254236.59.127.25532,766
120236.59.128.0/17236.59.128.1 to 236.59.255.254236.59.255.25532,766
121236.60.0.0/17236.60.0.1 to 236.60.127.254236.60.127.25532,766
122236.60.128.0/17236.60.128.1 to 236.60.255.254236.60.255.25532,766
123236.61.0.0/17236.61.0.1 to 236.61.127.254236.61.127.25532,766
124236.61.128.0/17236.61.128.1 to 236.61.255.254236.61.255.25532,766
125236.62.0.0/17236.62.0.1 to 236.62.127.254236.62.127.25532,766
126236.62.128.0/17236.62.128.1 to 236.62.255.254236.62.255.25532,766
127236.63.0.0/17236.63.0.1 to 236.63.127.254236.63.127.25532,766
128236.63.128.0/17236.63.128.1 to 236.63.255.254236.63.255.25532,766
129236.64.0.0/17236.64.0.1 to 236.64.127.254236.64.127.25532,766
130236.64.128.0/17236.64.128.1 to 236.64.255.254236.64.255.25532,766
131236.65.0.0/17236.65.0.1 to 236.65.127.254236.65.127.25532,766
132236.65.128.0/17236.65.128.1 to 236.65.255.254236.65.255.25532,766
133236.66.0.0/17236.66.0.1 to 236.66.127.254236.66.127.25532,766
134236.66.128.0/17236.66.128.1 to 236.66.255.254236.66.255.25532,766
135236.67.0.0/17236.67.0.1 to 236.67.127.254236.67.127.25532,766
136236.67.128.0/17236.67.128.1 to 236.67.255.254236.67.255.25532,766
137236.68.0.0/17236.68.0.1 to 236.68.127.254236.68.127.25532,766
138236.68.128.0/17236.68.128.1 to 236.68.255.254236.68.255.25532,766
139236.69.0.0/17236.69.0.1 to 236.69.127.254236.69.127.25532,766
140236.69.128.0/17236.69.128.1 to 236.69.255.254236.69.255.25532,766
141236.70.0.0/17236.70.0.1 to 236.70.127.254236.70.127.25532,766
142236.70.128.0/17236.70.128.1 to 236.70.255.254236.70.255.25532,766
143236.71.0.0/17236.71.0.1 to 236.71.127.254236.71.127.25532,766
144236.71.128.0/17236.71.128.1 to 236.71.255.254236.71.255.25532,766
145236.72.0.0/17236.72.0.1 to 236.72.127.254236.72.127.25532,766
146236.72.128.0/17236.72.128.1 to 236.72.255.254236.72.255.25532,766
147236.73.0.0/17236.73.0.1 to 236.73.127.254236.73.127.25532,766
148236.73.128.0/17236.73.128.1 to 236.73.255.254236.73.255.25532,766
149236.74.0.0/17236.74.0.1 to 236.74.127.254236.74.127.25532,766
150236.74.128.0/17236.74.128.1 to 236.74.255.254236.74.255.25532,766
151236.75.0.0/17236.75.0.1 to 236.75.127.254236.75.127.25532,766
152236.75.128.0/17236.75.128.1 to 236.75.255.254236.75.255.25532,766
153236.76.0.0/17236.76.0.1 to 236.76.127.254236.76.127.25532,766
154236.76.128.0/17236.76.128.1 to 236.76.255.254236.76.255.25532,766
155236.77.0.0/17236.77.0.1 to 236.77.127.254236.77.127.25532,766
156236.77.128.0/17236.77.128.1 to 236.77.255.254236.77.255.25532,766
157236.78.0.0/17236.78.0.1 to 236.78.127.254236.78.127.25532,766
158236.78.128.0/17236.78.128.1 to 236.78.255.254236.78.255.25532,766
159236.79.0.0/17236.79.0.1 to 236.79.127.254236.79.127.25532,766
160236.79.128.0/17236.79.128.1 to 236.79.255.254236.79.255.25532,766
161236.80.0.0/17236.80.0.1 to 236.80.127.254236.80.127.25532,766
162236.80.128.0/17236.80.128.1 to 236.80.255.254236.80.255.25532,766
163236.81.0.0/17236.81.0.1 to 236.81.127.254236.81.127.25532,766
164236.81.128.0/17236.81.128.1 to 236.81.255.254236.81.255.25532,766
165236.82.0.0/17236.82.0.1 to 236.82.127.254236.82.127.25532,766
166236.82.128.0/17236.82.128.1 to 236.82.255.254236.82.255.25532,766
167236.83.0.0/17236.83.0.1 to 236.83.127.254236.83.127.25532,766
168236.83.128.0/17236.83.128.1 to 236.83.255.254236.83.255.25532,766
169236.84.0.0/17236.84.0.1 to 236.84.127.254236.84.127.25532,766
170236.84.128.0/17236.84.128.1 to 236.84.255.254236.84.255.25532,766
171236.85.0.0/17236.85.0.1 to 236.85.127.254236.85.127.25532,766
172236.85.128.0/17236.85.128.1 to 236.85.255.254236.85.255.25532,766
173236.86.0.0/17236.86.0.1 to 236.86.127.254236.86.127.25532,766
174236.86.128.0/17236.86.128.1 to 236.86.255.254236.86.255.25532,766
175236.87.0.0/17236.87.0.1 to 236.87.127.254236.87.127.25532,766
176236.87.128.0/17236.87.128.1 to 236.87.255.254236.87.255.25532,766
177236.88.0.0/17236.88.0.1 to 236.88.127.254236.88.127.25532,766
178236.88.128.0/17236.88.128.1 to 236.88.255.254236.88.255.25532,766
179236.89.0.0/17236.89.0.1 to 236.89.127.254236.89.127.25532,766
180236.89.128.0/17236.89.128.1 to 236.89.255.254236.89.255.25532,766
181236.90.0.0/17236.90.0.1 to 236.90.127.254236.90.127.25532,766
182236.90.128.0/17236.90.128.1 to 236.90.255.254236.90.255.25532,766
183236.91.0.0/17236.91.0.1 to 236.91.127.254236.91.127.25532,766
184236.91.128.0/17236.91.128.1 to 236.91.255.254236.91.255.25532,766
185236.92.0.0/17236.92.0.1 to 236.92.127.254236.92.127.25532,766
186236.92.128.0/17236.92.128.1 to 236.92.255.254236.92.255.25532,766
187236.93.0.0/17236.93.0.1 to 236.93.127.254236.93.127.25532,766
188236.93.128.0/17236.93.128.1 to 236.93.255.254236.93.255.25532,766
189236.94.0.0/17236.94.0.1 to 236.94.127.254236.94.127.25532,766
190236.94.128.0/17236.94.128.1 to 236.94.255.254236.94.255.25532,766
191236.95.0.0/17236.95.0.1 to 236.95.127.254236.95.127.25532,766
192236.95.128.0/17236.95.128.1 to 236.95.255.254236.95.255.25532,766
193236.96.0.0/17236.96.0.1 to 236.96.127.254236.96.127.25532,766
194236.96.128.0/17236.96.128.1 to 236.96.255.254236.96.255.25532,766
195236.97.0.0/17236.97.0.1 to 236.97.127.254236.97.127.25532,766
196236.97.128.0/17236.97.128.1 to 236.97.255.254236.97.255.25532,766
197236.98.0.0/17236.98.0.1 to 236.98.127.254236.98.127.25532,766
198236.98.128.0/17236.98.128.1 to 236.98.255.254236.98.255.25532,766
199236.99.0.0/17236.99.0.1 to 236.99.127.254236.99.127.25532,766
200236.99.128.0/17236.99.128.1 to 236.99.255.254236.99.255.25532,766
201236.100.0.0/17236.100.0.1 to 236.100.127.254236.100.127.25532,766
202236.100.128.0/17236.100.128.1 to 236.100.255.254236.100.255.25532,766
203236.101.0.0/17236.101.0.1 to 236.101.127.254236.101.127.25532,766
204236.101.128.0/17236.101.128.1 to 236.101.255.254236.101.255.25532,766
205236.102.0.0/17236.102.0.1 to 236.102.127.254236.102.127.25532,766
206236.102.128.0/17236.102.128.1 to 236.102.255.254236.102.255.25532,766
207236.103.0.0/17236.103.0.1 to 236.103.127.254236.103.127.25532,766
208236.103.128.0/17236.103.128.1 to 236.103.255.254236.103.255.25532,766
209236.104.0.0/17236.104.0.1 to 236.104.127.254236.104.127.25532,766
210236.104.128.0/17236.104.128.1 to 236.104.255.254236.104.255.25532,766
211236.105.0.0/17236.105.0.1 to 236.105.127.254236.105.127.25532,766
212236.105.128.0/17236.105.128.1 to 236.105.255.254236.105.255.25532,766
213236.106.0.0/17236.106.0.1 to 236.106.127.254236.106.127.25532,766
214236.106.128.0/17236.106.128.1 to 236.106.255.254236.106.255.25532,766
215236.107.0.0/17236.107.0.1 to 236.107.127.254236.107.127.25532,766
216236.107.128.0/17236.107.128.1 to 236.107.255.254236.107.255.25532,766
217236.108.0.0/17236.108.0.1 to 236.108.127.254236.108.127.25532,766
218236.108.128.0/17236.108.128.1 to 236.108.255.254236.108.255.25532,766
219236.109.0.0/17236.109.0.1 to 236.109.127.254236.109.127.25532,766
220236.109.128.0/17236.109.128.1 to 236.109.255.254236.109.255.25532,766
221236.110.0.0/17236.110.0.1 to 236.110.127.254236.110.127.25532,766
222236.110.128.0/17236.110.128.1 to 236.110.255.254236.110.255.25532,766
223236.111.0.0/17236.111.0.1 to 236.111.127.254236.111.127.25532,766
224236.111.128.0/17236.111.128.1 to 236.111.255.254236.111.255.25532,766
225236.112.0.0/17236.112.0.1 to 236.112.127.254236.112.127.25532,766
226236.112.128.0/17236.112.128.1 to 236.112.255.254236.112.255.25532,766
227236.113.0.0/17236.113.0.1 to 236.113.127.254236.113.127.25532,766
228236.113.128.0/17236.113.128.1 to 236.113.255.254236.113.255.25532,766
229236.114.0.0/17236.114.0.1 to 236.114.127.254236.114.127.25532,766
230236.114.128.0/17236.114.128.1 to 236.114.255.254236.114.255.25532,766
231236.115.0.0/17236.115.0.1 to 236.115.127.254236.115.127.25532,766
232236.115.128.0/17236.115.128.1 to 236.115.255.254236.115.255.25532,766
233236.116.0.0/17236.116.0.1 to 236.116.127.254236.116.127.25532,766
234236.116.128.0/17236.116.128.1 to 236.116.255.254236.116.255.25532,766
235236.117.0.0/17236.117.0.1 to 236.117.127.254236.117.127.25532,766
236236.117.128.0/17236.117.128.1 to 236.117.255.254236.117.255.25532,766
237236.118.0.0/17236.118.0.1 to 236.118.127.254236.118.127.25532,766
238236.118.128.0/17236.118.128.1 to 236.118.255.254236.118.255.25532,766
239236.119.0.0/17236.119.0.1 to 236.119.127.254236.119.127.25532,766
240236.119.128.0/17236.119.128.1 to 236.119.255.254236.119.255.25532,766
241236.120.0.0/17236.120.0.1 to 236.120.127.254236.120.127.25532,766
242236.120.128.0/17236.120.128.1 to 236.120.255.254236.120.255.25532,766
243236.121.0.0/17236.121.0.1 to 236.121.127.254236.121.127.25532,766
244236.121.128.0/17236.121.128.1 to 236.121.255.254236.121.255.25532,766
245236.122.0.0/17236.122.0.1 to 236.122.127.254236.122.127.25532,766
246236.122.128.0/17236.122.128.1 to 236.122.255.254236.122.255.25532,766
247236.123.0.0/17236.123.0.1 to 236.123.127.254236.123.127.25532,766
248236.123.128.0/17236.123.128.1 to 236.123.255.254236.123.255.25532,766
249236.124.0.0/17236.124.0.1 to 236.124.127.254236.124.127.25532,766
250236.124.128.0/17236.124.128.1 to 236.124.255.254236.124.255.25532,766
251236.125.0.0/17236.125.0.1 to 236.125.127.254236.125.127.25532,766
252236.125.128.0/17236.125.128.1 to 236.125.255.254236.125.255.25532,766
253236.126.0.0/17236.126.0.1 to 236.126.127.254236.126.127.25532,766
254236.126.128.0/17236.126.128.1 to 236.126.255.254236.126.255.25532,766
255236.127.0.0/17236.127.0.1 to 236.127.127.254236.127.127.25532,766
256236.127.128.0/17236.127.128.1 to 236.127.255.254236.127.255.25532,766

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.