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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.

Network236.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
236.136.0.0
Broadcast address
236.137.255.255
First usable
236.136.0.1
Last usable
236.137.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EC880000 · Integer 3968335872 to 3968466943
Reverse DNS zones
136.236.in-addr.arpa
137.236.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101100.10001000.00000000.00000000236.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11101100.10001000.00000000.00000000236.136.0.0
Broadcast11101100.10001001.11111111.11111111236.137.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

236.136.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1236.136.0.0/25236.136.0.1 to 236.136.0.126236.136.0.127126
2236.136.0.128/25236.136.0.129 to 236.136.0.254236.136.0.255126
3236.136.1.0/25236.136.1.1 to 236.136.1.126236.136.1.127126
4236.136.1.128/25236.136.1.129 to 236.136.1.254236.136.1.255126
5236.136.2.0/25236.136.2.1 to 236.136.2.126236.136.2.127126
6236.136.2.128/25236.136.2.129 to 236.136.2.254236.136.2.255126
7236.136.3.0/25236.136.3.1 to 236.136.3.126236.136.3.127126
8236.136.3.128/25236.136.3.129 to 236.136.3.254236.136.3.255126
9236.136.4.0/25236.136.4.1 to 236.136.4.126236.136.4.127126
10236.136.4.128/25236.136.4.129 to 236.136.4.254236.136.4.255126
11236.136.5.0/25236.136.5.1 to 236.136.5.126236.136.5.127126
12236.136.5.128/25236.136.5.129 to 236.136.5.254236.136.5.255126
13236.136.6.0/25236.136.6.1 to 236.136.6.126236.136.6.127126
14236.136.6.128/25236.136.6.129 to 236.136.6.254236.136.6.255126
15236.136.7.0/25236.136.7.1 to 236.136.7.126236.136.7.127126
16236.136.7.128/25236.136.7.129 to 236.136.7.254236.136.7.255126
17236.136.8.0/25236.136.8.1 to 236.136.8.126236.136.8.127126
18236.136.8.128/25236.136.8.129 to 236.136.8.254236.136.8.255126
19236.136.9.0/25236.136.9.1 to 236.136.9.126236.136.9.127126
20236.136.9.128/25236.136.9.129 to 236.136.9.254236.136.9.255126
21236.136.10.0/25236.136.10.1 to 236.136.10.126236.136.10.127126
22236.136.10.128/25236.136.10.129 to 236.136.10.254236.136.10.255126
23236.136.11.0/25236.136.11.1 to 236.136.11.126236.136.11.127126
24236.136.11.128/25236.136.11.129 to 236.136.11.254236.136.11.255126
25236.136.12.0/25236.136.12.1 to 236.136.12.126236.136.12.127126
26236.136.12.128/25236.136.12.129 to 236.136.12.254236.136.12.255126
27236.136.13.0/25236.136.13.1 to 236.136.13.126236.136.13.127126
28236.136.13.128/25236.136.13.129 to 236.136.13.254236.136.13.255126
29236.136.14.0/25236.136.14.1 to 236.136.14.126236.136.14.127126
30236.136.14.128/25236.136.14.129 to 236.136.14.254236.136.14.255126
31236.136.15.0/25236.136.15.1 to 236.136.15.126236.136.15.127126
32236.136.15.128/25236.136.15.129 to 236.136.15.254236.136.15.255126
33236.136.16.0/25236.136.16.1 to 236.136.16.126236.136.16.127126
34236.136.16.128/25236.136.16.129 to 236.136.16.254236.136.16.255126
35236.136.17.0/25236.136.17.1 to 236.136.17.126236.136.17.127126
36236.136.17.128/25236.136.17.129 to 236.136.17.254236.136.17.255126
37236.136.18.0/25236.136.18.1 to 236.136.18.126236.136.18.127126
38236.136.18.128/25236.136.18.129 to 236.136.18.254236.136.18.255126
39236.136.19.0/25236.136.19.1 to 236.136.19.126236.136.19.127126
40236.136.19.128/25236.136.19.129 to 236.136.19.254236.136.19.255126
41236.136.20.0/25236.136.20.1 to 236.136.20.126236.136.20.127126
42236.136.20.128/25236.136.20.129 to 236.136.20.254236.136.20.255126
43236.136.21.0/25236.136.21.1 to 236.136.21.126236.136.21.127126
44236.136.21.128/25236.136.21.129 to 236.136.21.254236.136.21.255126
45236.136.22.0/25236.136.22.1 to 236.136.22.126236.136.22.127126
46236.136.22.128/25236.136.22.129 to 236.136.22.254236.136.22.255126
47236.136.23.0/25236.136.23.1 to 236.136.23.126236.136.23.127126
48236.136.23.128/25236.136.23.129 to 236.136.23.254236.136.23.255126
49236.136.24.0/25236.136.24.1 to 236.136.24.126236.136.24.127126
50236.136.24.128/25236.136.24.129 to 236.136.24.254236.136.24.255126
51236.136.25.0/25236.136.25.1 to 236.136.25.126236.136.25.127126
52236.136.25.128/25236.136.25.129 to 236.136.25.254236.136.25.255126
53236.136.26.0/25236.136.26.1 to 236.136.26.126236.136.26.127126
54236.136.26.128/25236.136.26.129 to 236.136.26.254236.136.26.255126
55236.136.27.0/25236.136.27.1 to 236.136.27.126236.136.27.127126
56236.136.27.128/25236.136.27.129 to 236.136.27.254236.136.27.255126
57236.136.28.0/25236.136.28.1 to 236.136.28.126236.136.28.127126
58236.136.28.128/25236.136.28.129 to 236.136.28.254236.136.28.255126
59236.136.29.0/25236.136.29.1 to 236.136.29.126236.136.29.127126
60236.136.29.128/25236.136.29.129 to 236.136.29.254236.136.29.255126
61236.136.30.0/25236.136.30.1 to 236.136.30.126236.136.30.127126
62236.136.30.128/25236.136.30.129 to 236.136.30.254236.136.30.255126
63236.136.31.0/25236.136.31.1 to 236.136.31.126236.136.31.127126
64236.136.31.128/25236.136.31.129 to 236.136.31.254236.136.31.255126
65236.136.32.0/25236.136.32.1 to 236.136.32.126236.136.32.127126
66236.136.32.128/25236.136.32.129 to 236.136.32.254236.136.32.255126
67236.136.33.0/25236.136.33.1 to 236.136.33.126236.136.33.127126
68236.136.33.128/25236.136.33.129 to 236.136.33.254236.136.33.255126
69236.136.34.0/25236.136.34.1 to 236.136.34.126236.136.34.127126
70236.136.34.128/25236.136.34.129 to 236.136.34.254236.136.34.255126
71236.136.35.0/25236.136.35.1 to 236.136.35.126236.136.35.127126
72236.136.35.128/25236.136.35.129 to 236.136.35.254236.136.35.255126
73236.136.36.0/25236.136.36.1 to 236.136.36.126236.136.36.127126
74236.136.36.128/25236.136.36.129 to 236.136.36.254236.136.36.255126
75236.136.37.0/25236.136.37.1 to 236.136.37.126236.136.37.127126
76236.136.37.128/25236.136.37.129 to 236.136.37.254236.136.37.255126
77236.136.38.0/25236.136.38.1 to 236.136.38.126236.136.38.127126
78236.136.38.128/25236.136.38.129 to 236.136.38.254236.136.38.255126
79236.136.39.0/25236.136.39.1 to 236.136.39.126236.136.39.127126
80236.136.39.128/25236.136.39.129 to 236.136.39.254236.136.39.255126
81236.136.40.0/25236.136.40.1 to 236.136.40.126236.136.40.127126
82236.136.40.128/25236.136.40.129 to 236.136.40.254236.136.40.255126
83236.136.41.0/25236.136.41.1 to 236.136.41.126236.136.41.127126
84236.136.41.128/25236.136.41.129 to 236.136.41.254236.136.41.255126
85236.136.42.0/25236.136.42.1 to 236.136.42.126236.136.42.127126
86236.136.42.128/25236.136.42.129 to 236.136.42.254236.136.42.255126
87236.136.43.0/25236.136.43.1 to 236.136.43.126236.136.43.127126
88236.136.43.128/25236.136.43.129 to 236.136.43.254236.136.43.255126
89236.136.44.0/25236.136.44.1 to 236.136.44.126236.136.44.127126
90236.136.44.128/25236.136.44.129 to 236.136.44.254236.136.44.255126
91236.136.45.0/25236.136.45.1 to 236.136.45.126236.136.45.127126
92236.136.45.128/25236.136.45.129 to 236.136.45.254236.136.45.255126
93236.136.46.0/25236.136.46.1 to 236.136.46.126236.136.46.127126
94236.136.46.128/25236.136.46.129 to 236.136.46.254236.136.46.255126
95236.136.47.0/25236.136.47.1 to 236.136.47.126236.136.47.127126
96236.136.47.128/25236.136.47.129 to 236.136.47.254236.136.47.255126
97236.136.48.0/25236.136.48.1 to 236.136.48.126236.136.48.127126
98236.136.48.128/25236.136.48.129 to 236.136.48.254236.136.48.255126
99236.136.49.0/25236.136.49.1 to 236.136.49.126236.136.49.127126
100236.136.49.128/25236.136.49.129 to 236.136.49.254236.136.49.255126
101236.136.50.0/25236.136.50.1 to 236.136.50.126236.136.50.127126
102236.136.50.128/25236.136.50.129 to 236.136.50.254236.136.50.255126
103236.136.51.0/25236.136.51.1 to 236.136.51.126236.136.51.127126
104236.136.51.128/25236.136.51.129 to 236.136.51.254236.136.51.255126
105236.136.52.0/25236.136.52.1 to 236.136.52.126236.136.52.127126
106236.136.52.128/25236.136.52.129 to 236.136.52.254236.136.52.255126
107236.136.53.0/25236.136.53.1 to 236.136.53.126236.136.53.127126
108236.136.53.128/25236.136.53.129 to 236.136.53.254236.136.53.255126
109236.136.54.0/25236.136.54.1 to 236.136.54.126236.136.54.127126
110236.136.54.128/25236.136.54.129 to 236.136.54.254236.136.54.255126
111236.136.55.0/25236.136.55.1 to 236.136.55.126236.136.55.127126
112236.136.55.128/25236.136.55.129 to 236.136.55.254236.136.55.255126
113236.136.56.0/25236.136.56.1 to 236.136.56.126236.136.56.127126
114236.136.56.128/25236.136.56.129 to 236.136.56.254236.136.56.255126
115236.136.57.0/25236.136.57.1 to 236.136.57.126236.136.57.127126
116236.136.57.128/25236.136.57.129 to 236.136.57.254236.136.57.255126
117236.136.58.0/25236.136.58.1 to 236.136.58.126236.136.58.127126
118236.136.58.128/25236.136.58.129 to 236.136.58.254236.136.58.255126
119236.136.59.0/25236.136.59.1 to 236.136.59.126236.136.59.127126
120236.136.59.128/25236.136.59.129 to 236.136.59.254236.136.59.255126
121236.136.60.0/25236.136.60.1 to 236.136.60.126236.136.60.127126
122236.136.60.128/25236.136.60.129 to 236.136.60.254236.136.60.255126
123236.136.61.0/25236.136.61.1 to 236.136.61.126236.136.61.127126
124236.136.61.128/25236.136.61.129 to 236.136.61.254236.136.61.255126
125236.136.62.0/25236.136.62.1 to 236.136.62.126236.136.62.127126
126236.136.62.128/25236.136.62.129 to 236.136.62.254236.136.62.255126
127236.136.63.0/25236.136.63.1 to 236.136.63.126236.136.63.127126
128236.136.63.128/25236.136.63.129 to 236.136.63.254236.136.63.255126
129236.136.64.0/25236.136.64.1 to 236.136.64.126236.136.64.127126
130236.136.64.128/25236.136.64.129 to 236.136.64.254236.136.64.255126
131236.136.65.0/25236.136.65.1 to 236.136.65.126236.136.65.127126
132236.136.65.128/25236.136.65.129 to 236.136.65.254236.136.65.255126
133236.136.66.0/25236.136.66.1 to 236.136.66.126236.136.66.127126
134236.136.66.128/25236.136.66.129 to 236.136.66.254236.136.66.255126
135236.136.67.0/25236.136.67.1 to 236.136.67.126236.136.67.127126
136236.136.67.128/25236.136.67.129 to 236.136.67.254236.136.67.255126
137236.136.68.0/25236.136.68.1 to 236.136.68.126236.136.68.127126
138236.136.68.128/25236.136.68.129 to 236.136.68.254236.136.68.255126
139236.136.69.0/25236.136.69.1 to 236.136.69.126236.136.69.127126
140236.136.69.128/25236.136.69.129 to 236.136.69.254236.136.69.255126
141236.136.70.0/25236.136.70.1 to 236.136.70.126236.136.70.127126
142236.136.70.128/25236.136.70.129 to 236.136.70.254236.136.70.255126
143236.136.71.0/25236.136.71.1 to 236.136.71.126236.136.71.127126
144236.136.71.128/25236.136.71.129 to 236.136.71.254236.136.71.255126
145236.136.72.0/25236.136.72.1 to 236.136.72.126236.136.72.127126
146236.136.72.128/25236.136.72.129 to 236.136.72.254236.136.72.255126
147236.136.73.0/25236.136.73.1 to 236.136.73.126236.136.73.127126
148236.136.73.128/25236.136.73.129 to 236.136.73.254236.136.73.255126
149236.136.74.0/25236.136.74.1 to 236.136.74.126236.136.74.127126
150236.136.74.128/25236.136.74.129 to 236.136.74.254236.136.74.255126
151236.136.75.0/25236.136.75.1 to 236.136.75.126236.136.75.127126
152236.136.75.128/25236.136.75.129 to 236.136.75.254236.136.75.255126
153236.136.76.0/25236.136.76.1 to 236.136.76.126236.136.76.127126
154236.136.76.128/25236.136.76.129 to 236.136.76.254236.136.76.255126
155236.136.77.0/25236.136.77.1 to 236.136.77.126236.136.77.127126
156236.136.77.128/25236.136.77.129 to 236.136.77.254236.136.77.255126
157236.136.78.0/25236.136.78.1 to 236.136.78.126236.136.78.127126
158236.136.78.128/25236.136.78.129 to 236.136.78.254236.136.78.255126
159236.136.79.0/25236.136.79.1 to 236.136.79.126236.136.79.127126
160236.136.79.128/25236.136.79.129 to 236.136.79.254236.136.79.255126
161236.136.80.0/25236.136.80.1 to 236.136.80.126236.136.80.127126
162236.136.80.128/25236.136.80.129 to 236.136.80.254236.136.80.255126
163236.136.81.0/25236.136.81.1 to 236.136.81.126236.136.81.127126
164236.136.81.128/25236.136.81.129 to 236.136.81.254236.136.81.255126
165236.136.82.0/25236.136.82.1 to 236.136.82.126236.136.82.127126
166236.136.82.128/25236.136.82.129 to 236.136.82.254236.136.82.255126
167236.136.83.0/25236.136.83.1 to 236.136.83.126236.136.83.127126
168236.136.83.128/25236.136.83.129 to 236.136.83.254236.136.83.255126
169236.136.84.0/25236.136.84.1 to 236.136.84.126236.136.84.127126
170236.136.84.128/25236.136.84.129 to 236.136.84.254236.136.84.255126
171236.136.85.0/25236.136.85.1 to 236.136.85.126236.136.85.127126
172236.136.85.128/25236.136.85.129 to 236.136.85.254236.136.85.255126
173236.136.86.0/25236.136.86.1 to 236.136.86.126236.136.86.127126
174236.136.86.128/25236.136.86.129 to 236.136.86.254236.136.86.255126
175236.136.87.0/25236.136.87.1 to 236.136.87.126236.136.87.127126
176236.136.87.128/25236.136.87.129 to 236.136.87.254236.136.87.255126
177236.136.88.0/25236.136.88.1 to 236.136.88.126236.136.88.127126
178236.136.88.128/25236.136.88.129 to 236.136.88.254236.136.88.255126
179236.136.89.0/25236.136.89.1 to 236.136.89.126236.136.89.127126
180236.136.89.128/25236.136.89.129 to 236.136.89.254236.136.89.255126
181236.136.90.0/25236.136.90.1 to 236.136.90.126236.136.90.127126
182236.136.90.128/25236.136.90.129 to 236.136.90.254236.136.90.255126
183236.136.91.0/25236.136.91.1 to 236.136.91.126236.136.91.127126
184236.136.91.128/25236.136.91.129 to 236.136.91.254236.136.91.255126
185236.136.92.0/25236.136.92.1 to 236.136.92.126236.136.92.127126
186236.136.92.128/25236.136.92.129 to 236.136.92.254236.136.92.255126
187236.136.93.0/25236.136.93.1 to 236.136.93.126236.136.93.127126
188236.136.93.128/25236.136.93.129 to 236.136.93.254236.136.93.255126
189236.136.94.0/25236.136.94.1 to 236.136.94.126236.136.94.127126
190236.136.94.128/25236.136.94.129 to 236.136.94.254236.136.94.255126
191236.136.95.0/25236.136.95.1 to 236.136.95.126236.136.95.127126
192236.136.95.128/25236.136.95.129 to 236.136.95.254236.136.95.255126
193236.136.96.0/25236.136.96.1 to 236.136.96.126236.136.96.127126
194236.136.96.128/25236.136.96.129 to 236.136.96.254236.136.96.255126
195236.136.97.0/25236.136.97.1 to 236.136.97.126236.136.97.127126
196236.136.97.128/25236.136.97.129 to 236.136.97.254236.136.97.255126
197236.136.98.0/25236.136.98.1 to 236.136.98.126236.136.98.127126
198236.136.98.128/25236.136.98.129 to 236.136.98.254236.136.98.255126
199236.136.99.0/25236.136.99.1 to 236.136.99.126236.136.99.127126
200236.136.99.128/25236.136.99.129 to 236.136.99.254236.136.99.255126
201236.136.100.0/25236.136.100.1 to 236.136.100.126236.136.100.127126
202236.136.100.128/25236.136.100.129 to 236.136.100.254236.136.100.255126
203236.136.101.0/25236.136.101.1 to 236.136.101.126236.136.101.127126
204236.136.101.128/25236.136.101.129 to 236.136.101.254236.136.101.255126
205236.136.102.0/25236.136.102.1 to 236.136.102.126236.136.102.127126
206236.136.102.128/25236.136.102.129 to 236.136.102.254236.136.102.255126
207236.136.103.0/25236.136.103.1 to 236.136.103.126236.136.103.127126
208236.136.103.128/25236.136.103.129 to 236.136.103.254236.136.103.255126
209236.136.104.0/25236.136.104.1 to 236.136.104.126236.136.104.127126
210236.136.104.128/25236.136.104.129 to 236.136.104.254236.136.104.255126
211236.136.105.0/25236.136.105.1 to 236.136.105.126236.136.105.127126
212236.136.105.128/25236.136.105.129 to 236.136.105.254236.136.105.255126
213236.136.106.0/25236.136.106.1 to 236.136.106.126236.136.106.127126
214236.136.106.128/25236.136.106.129 to 236.136.106.254236.136.106.255126
215236.136.107.0/25236.136.107.1 to 236.136.107.126236.136.107.127126
216236.136.107.128/25236.136.107.129 to 236.136.107.254236.136.107.255126
217236.136.108.0/25236.136.108.1 to 236.136.108.126236.136.108.127126
218236.136.108.128/25236.136.108.129 to 236.136.108.254236.136.108.255126
219236.136.109.0/25236.136.109.1 to 236.136.109.126236.136.109.127126
220236.136.109.128/25236.136.109.129 to 236.136.109.254236.136.109.255126
221236.136.110.0/25236.136.110.1 to 236.136.110.126236.136.110.127126
222236.136.110.128/25236.136.110.129 to 236.136.110.254236.136.110.255126
223236.136.111.0/25236.136.111.1 to 236.136.111.126236.136.111.127126
224236.136.111.128/25236.136.111.129 to 236.136.111.254236.136.111.255126
225236.136.112.0/25236.136.112.1 to 236.136.112.126236.136.112.127126
226236.136.112.128/25236.136.112.129 to 236.136.112.254236.136.112.255126
227236.136.113.0/25236.136.113.1 to 236.136.113.126236.136.113.127126
228236.136.113.128/25236.136.113.129 to 236.136.113.254236.136.113.255126
229236.136.114.0/25236.136.114.1 to 236.136.114.126236.136.114.127126
230236.136.114.128/25236.136.114.129 to 236.136.114.254236.136.114.255126
231236.136.115.0/25236.136.115.1 to 236.136.115.126236.136.115.127126
232236.136.115.128/25236.136.115.129 to 236.136.115.254236.136.115.255126
233236.136.116.0/25236.136.116.1 to 236.136.116.126236.136.116.127126
234236.136.116.128/25236.136.116.129 to 236.136.116.254236.136.116.255126
235236.136.117.0/25236.136.117.1 to 236.136.117.126236.136.117.127126
236236.136.117.128/25236.136.117.129 to 236.136.117.254236.136.117.255126
237236.136.118.0/25236.136.118.1 to 236.136.118.126236.136.118.127126
238236.136.118.128/25236.136.118.129 to 236.136.118.254236.136.118.255126
239236.136.119.0/25236.136.119.1 to 236.136.119.126236.136.119.127126
240236.136.119.128/25236.136.119.129 to 236.136.119.254236.136.119.255126
241236.136.120.0/25236.136.120.1 to 236.136.120.126236.136.120.127126
242236.136.120.128/25236.136.120.129 to 236.136.120.254236.136.120.255126
243236.136.121.0/25236.136.121.1 to 236.136.121.126236.136.121.127126
244236.136.121.128/25236.136.121.129 to 236.136.121.254236.136.121.255126
245236.136.122.0/25236.136.122.1 to 236.136.122.126236.136.122.127126
246236.136.122.128/25236.136.122.129 to 236.136.122.254236.136.122.255126
247236.136.123.0/25236.136.123.1 to 236.136.123.126236.136.123.127126
248236.136.123.128/25236.136.123.129 to 236.136.123.254236.136.123.255126
249236.136.124.0/25236.136.124.1 to 236.136.124.126236.136.124.127126
250236.136.124.128/25236.136.124.129 to 236.136.124.254236.136.124.255126
251236.136.125.0/25236.136.125.1 to 236.136.125.126236.136.125.127126
252236.136.125.128/25236.136.125.129 to 236.136.125.254236.136.125.255126
253236.136.126.0/25236.136.126.1 to 236.136.126.126236.136.126.127126
254236.136.126.128/25236.136.126.129 to 236.136.126.254236.136.126.255126
255236.136.127.0/25236.136.127.1 to 236.136.127.126236.136.127.127126
256236.136.127.128/25236.136.127.129 to 236.136.127.254236.136.127.255126

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.