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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.

Network236.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
236.64.0.0
Broadcast address
236.127.255.255
First usable
236.64.0.1
Last usable
236.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EC400000 · Integer 3963617280 to 3967811583
Reverse DNS zones
64.236.in-addr.arpa
65.236.in-addr.arpa
66.236.in-addr.arpa
67.236.in-addr.arpa
68.236.in-addr.arpa
69.236.in-addr.arpa
70.236.in-addr.arpa
71.236.in-addr.arpa
72.236.in-addr.arpa
73.236.in-addr.arpa
74.236.in-addr.arpa
75.236.in-addr.arpa
76.236.in-addr.arpa
77.236.in-addr.arpa
78.236.in-addr.arpa
79.236.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101100.01000000.00000000.00000000236.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11101100.01000000.00000000.00000000236.64.0.0
Broadcast11101100.01111111.11111111.11111111236.127.255.255
Split into smaller subnets/20
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

236.64.0.0/10 makes 1,024 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1236.64.0.0/20236.64.0.1 to 236.64.15.254236.64.15.2554,094
2236.64.16.0/20236.64.16.1 to 236.64.31.254236.64.31.2554,094
3236.64.32.0/20236.64.32.1 to 236.64.47.254236.64.47.2554,094
4236.64.48.0/20236.64.48.1 to 236.64.63.254236.64.63.2554,094
5236.64.64.0/20236.64.64.1 to 236.64.79.254236.64.79.2554,094
6236.64.80.0/20236.64.80.1 to 236.64.95.254236.64.95.2554,094
7236.64.96.0/20236.64.96.1 to 236.64.111.254236.64.111.2554,094
8236.64.112.0/20236.64.112.1 to 236.64.127.254236.64.127.2554,094
9236.64.128.0/20236.64.128.1 to 236.64.143.254236.64.143.2554,094
10236.64.144.0/20236.64.144.1 to 236.64.159.254236.64.159.2554,094
11236.64.160.0/20236.64.160.1 to 236.64.175.254236.64.175.2554,094
12236.64.176.0/20236.64.176.1 to 236.64.191.254236.64.191.2554,094
13236.64.192.0/20236.64.192.1 to 236.64.207.254236.64.207.2554,094
14236.64.208.0/20236.64.208.1 to 236.64.223.254236.64.223.2554,094
15236.64.224.0/20236.64.224.1 to 236.64.239.254236.64.239.2554,094
16236.64.240.0/20236.64.240.1 to 236.64.255.254236.64.255.2554,094
17236.65.0.0/20236.65.0.1 to 236.65.15.254236.65.15.2554,094
18236.65.16.0/20236.65.16.1 to 236.65.31.254236.65.31.2554,094
19236.65.32.0/20236.65.32.1 to 236.65.47.254236.65.47.2554,094
20236.65.48.0/20236.65.48.1 to 236.65.63.254236.65.63.2554,094
21236.65.64.0/20236.65.64.1 to 236.65.79.254236.65.79.2554,094
22236.65.80.0/20236.65.80.1 to 236.65.95.254236.65.95.2554,094
23236.65.96.0/20236.65.96.1 to 236.65.111.254236.65.111.2554,094
24236.65.112.0/20236.65.112.1 to 236.65.127.254236.65.127.2554,094
25236.65.128.0/20236.65.128.1 to 236.65.143.254236.65.143.2554,094
26236.65.144.0/20236.65.144.1 to 236.65.159.254236.65.159.2554,094
27236.65.160.0/20236.65.160.1 to 236.65.175.254236.65.175.2554,094
28236.65.176.0/20236.65.176.1 to 236.65.191.254236.65.191.2554,094
29236.65.192.0/20236.65.192.1 to 236.65.207.254236.65.207.2554,094
30236.65.208.0/20236.65.208.1 to 236.65.223.254236.65.223.2554,094
31236.65.224.0/20236.65.224.1 to 236.65.239.254236.65.239.2554,094
32236.65.240.0/20236.65.240.1 to 236.65.255.254236.65.255.2554,094
33236.66.0.0/20236.66.0.1 to 236.66.15.254236.66.15.2554,094
34236.66.16.0/20236.66.16.1 to 236.66.31.254236.66.31.2554,094
35236.66.32.0/20236.66.32.1 to 236.66.47.254236.66.47.2554,094
36236.66.48.0/20236.66.48.1 to 236.66.63.254236.66.63.2554,094
37236.66.64.0/20236.66.64.1 to 236.66.79.254236.66.79.2554,094
38236.66.80.0/20236.66.80.1 to 236.66.95.254236.66.95.2554,094
39236.66.96.0/20236.66.96.1 to 236.66.111.254236.66.111.2554,094
40236.66.112.0/20236.66.112.1 to 236.66.127.254236.66.127.2554,094
41236.66.128.0/20236.66.128.1 to 236.66.143.254236.66.143.2554,094
42236.66.144.0/20236.66.144.1 to 236.66.159.254236.66.159.2554,094
43236.66.160.0/20236.66.160.1 to 236.66.175.254236.66.175.2554,094
44236.66.176.0/20236.66.176.1 to 236.66.191.254236.66.191.2554,094
45236.66.192.0/20236.66.192.1 to 236.66.207.254236.66.207.2554,094
46236.66.208.0/20236.66.208.1 to 236.66.223.254236.66.223.2554,094
47236.66.224.0/20236.66.224.1 to 236.66.239.254236.66.239.2554,094
48236.66.240.0/20236.66.240.1 to 236.66.255.254236.66.255.2554,094
49236.67.0.0/20236.67.0.1 to 236.67.15.254236.67.15.2554,094
50236.67.16.0/20236.67.16.1 to 236.67.31.254236.67.31.2554,094
51236.67.32.0/20236.67.32.1 to 236.67.47.254236.67.47.2554,094
52236.67.48.0/20236.67.48.1 to 236.67.63.254236.67.63.2554,094
53236.67.64.0/20236.67.64.1 to 236.67.79.254236.67.79.2554,094
54236.67.80.0/20236.67.80.1 to 236.67.95.254236.67.95.2554,094
55236.67.96.0/20236.67.96.1 to 236.67.111.254236.67.111.2554,094
56236.67.112.0/20236.67.112.1 to 236.67.127.254236.67.127.2554,094
57236.67.128.0/20236.67.128.1 to 236.67.143.254236.67.143.2554,094
58236.67.144.0/20236.67.144.1 to 236.67.159.254236.67.159.2554,094
59236.67.160.0/20236.67.160.1 to 236.67.175.254236.67.175.2554,094
60236.67.176.0/20236.67.176.1 to 236.67.191.254236.67.191.2554,094
61236.67.192.0/20236.67.192.1 to 236.67.207.254236.67.207.2554,094
62236.67.208.0/20236.67.208.1 to 236.67.223.254236.67.223.2554,094
63236.67.224.0/20236.67.224.1 to 236.67.239.254236.67.239.2554,094
64236.67.240.0/20236.67.240.1 to 236.67.255.254236.67.255.2554,094
65236.68.0.0/20236.68.0.1 to 236.68.15.254236.68.15.2554,094
66236.68.16.0/20236.68.16.1 to 236.68.31.254236.68.31.2554,094
67236.68.32.0/20236.68.32.1 to 236.68.47.254236.68.47.2554,094
68236.68.48.0/20236.68.48.1 to 236.68.63.254236.68.63.2554,094
69236.68.64.0/20236.68.64.1 to 236.68.79.254236.68.79.2554,094
70236.68.80.0/20236.68.80.1 to 236.68.95.254236.68.95.2554,094
71236.68.96.0/20236.68.96.1 to 236.68.111.254236.68.111.2554,094
72236.68.112.0/20236.68.112.1 to 236.68.127.254236.68.127.2554,094
73236.68.128.0/20236.68.128.1 to 236.68.143.254236.68.143.2554,094
74236.68.144.0/20236.68.144.1 to 236.68.159.254236.68.159.2554,094
75236.68.160.0/20236.68.160.1 to 236.68.175.254236.68.175.2554,094
76236.68.176.0/20236.68.176.1 to 236.68.191.254236.68.191.2554,094
77236.68.192.0/20236.68.192.1 to 236.68.207.254236.68.207.2554,094
78236.68.208.0/20236.68.208.1 to 236.68.223.254236.68.223.2554,094
79236.68.224.0/20236.68.224.1 to 236.68.239.254236.68.239.2554,094
80236.68.240.0/20236.68.240.1 to 236.68.255.254236.68.255.2554,094
81236.69.0.0/20236.69.0.1 to 236.69.15.254236.69.15.2554,094
82236.69.16.0/20236.69.16.1 to 236.69.31.254236.69.31.2554,094
83236.69.32.0/20236.69.32.1 to 236.69.47.254236.69.47.2554,094
84236.69.48.0/20236.69.48.1 to 236.69.63.254236.69.63.2554,094
85236.69.64.0/20236.69.64.1 to 236.69.79.254236.69.79.2554,094
86236.69.80.0/20236.69.80.1 to 236.69.95.254236.69.95.2554,094
87236.69.96.0/20236.69.96.1 to 236.69.111.254236.69.111.2554,094
88236.69.112.0/20236.69.112.1 to 236.69.127.254236.69.127.2554,094
89236.69.128.0/20236.69.128.1 to 236.69.143.254236.69.143.2554,094
90236.69.144.0/20236.69.144.1 to 236.69.159.254236.69.159.2554,094
91236.69.160.0/20236.69.160.1 to 236.69.175.254236.69.175.2554,094
92236.69.176.0/20236.69.176.1 to 236.69.191.254236.69.191.2554,094
93236.69.192.0/20236.69.192.1 to 236.69.207.254236.69.207.2554,094
94236.69.208.0/20236.69.208.1 to 236.69.223.254236.69.223.2554,094
95236.69.224.0/20236.69.224.1 to 236.69.239.254236.69.239.2554,094
96236.69.240.0/20236.69.240.1 to 236.69.255.254236.69.255.2554,094
97236.70.0.0/20236.70.0.1 to 236.70.15.254236.70.15.2554,094
98236.70.16.0/20236.70.16.1 to 236.70.31.254236.70.31.2554,094
99236.70.32.0/20236.70.32.1 to 236.70.47.254236.70.47.2554,094
100236.70.48.0/20236.70.48.1 to 236.70.63.254236.70.63.2554,094
101236.70.64.0/20236.70.64.1 to 236.70.79.254236.70.79.2554,094
102236.70.80.0/20236.70.80.1 to 236.70.95.254236.70.95.2554,094
103236.70.96.0/20236.70.96.1 to 236.70.111.254236.70.111.2554,094
104236.70.112.0/20236.70.112.1 to 236.70.127.254236.70.127.2554,094
105236.70.128.0/20236.70.128.1 to 236.70.143.254236.70.143.2554,094
106236.70.144.0/20236.70.144.1 to 236.70.159.254236.70.159.2554,094
107236.70.160.0/20236.70.160.1 to 236.70.175.254236.70.175.2554,094
108236.70.176.0/20236.70.176.1 to 236.70.191.254236.70.191.2554,094
109236.70.192.0/20236.70.192.1 to 236.70.207.254236.70.207.2554,094
110236.70.208.0/20236.70.208.1 to 236.70.223.254236.70.223.2554,094
111236.70.224.0/20236.70.224.1 to 236.70.239.254236.70.239.2554,094
112236.70.240.0/20236.70.240.1 to 236.70.255.254236.70.255.2554,094
113236.71.0.0/20236.71.0.1 to 236.71.15.254236.71.15.2554,094
114236.71.16.0/20236.71.16.1 to 236.71.31.254236.71.31.2554,094
115236.71.32.0/20236.71.32.1 to 236.71.47.254236.71.47.2554,094
116236.71.48.0/20236.71.48.1 to 236.71.63.254236.71.63.2554,094
117236.71.64.0/20236.71.64.1 to 236.71.79.254236.71.79.2554,094
118236.71.80.0/20236.71.80.1 to 236.71.95.254236.71.95.2554,094
119236.71.96.0/20236.71.96.1 to 236.71.111.254236.71.111.2554,094
120236.71.112.0/20236.71.112.1 to 236.71.127.254236.71.127.2554,094
121236.71.128.0/20236.71.128.1 to 236.71.143.254236.71.143.2554,094
122236.71.144.0/20236.71.144.1 to 236.71.159.254236.71.159.2554,094
123236.71.160.0/20236.71.160.1 to 236.71.175.254236.71.175.2554,094
124236.71.176.0/20236.71.176.1 to 236.71.191.254236.71.191.2554,094
125236.71.192.0/20236.71.192.1 to 236.71.207.254236.71.207.2554,094
126236.71.208.0/20236.71.208.1 to 236.71.223.254236.71.223.2554,094
127236.71.224.0/20236.71.224.1 to 236.71.239.254236.71.239.2554,094
128236.71.240.0/20236.71.240.1 to 236.71.255.254236.71.255.2554,094
129236.72.0.0/20236.72.0.1 to 236.72.15.254236.72.15.2554,094
130236.72.16.0/20236.72.16.1 to 236.72.31.254236.72.31.2554,094
131236.72.32.0/20236.72.32.1 to 236.72.47.254236.72.47.2554,094
132236.72.48.0/20236.72.48.1 to 236.72.63.254236.72.63.2554,094
133236.72.64.0/20236.72.64.1 to 236.72.79.254236.72.79.2554,094
134236.72.80.0/20236.72.80.1 to 236.72.95.254236.72.95.2554,094
135236.72.96.0/20236.72.96.1 to 236.72.111.254236.72.111.2554,094
136236.72.112.0/20236.72.112.1 to 236.72.127.254236.72.127.2554,094
137236.72.128.0/20236.72.128.1 to 236.72.143.254236.72.143.2554,094
138236.72.144.0/20236.72.144.1 to 236.72.159.254236.72.159.2554,094
139236.72.160.0/20236.72.160.1 to 236.72.175.254236.72.175.2554,094
140236.72.176.0/20236.72.176.1 to 236.72.191.254236.72.191.2554,094
141236.72.192.0/20236.72.192.1 to 236.72.207.254236.72.207.2554,094
142236.72.208.0/20236.72.208.1 to 236.72.223.254236.72.223.2554,094
143236.72.224.0/20236.72.224.1 to 236.72.239.254236.72.239.2554,094
144236.72.240.0/20236.72.240.1 to 236.72.255.254236.72.255.2554,094
145236.73.0.0/20236.73.0.1 to 236.73.15.254236.73.15.2554,094
146236.73.16.0/20236.73.16.1 to 236.73.31.254236.73.31.2554,094
147236.73.32.0/20236.73.32.1 to 236.73.47.254236.73.47.2554,094
148236.73.48.0/20236.73.48.1 to 236.73.63.254236.73.63.2554,094
149236.73.64.0/20236.73.64.1 to 236.73.79.254236.73.79.2554,094
150236.73.80.0/20236.73.80.1 to 236.73.95.254236.73.95.2554,094
151236.73.96.0/20236.73.96.1 to 236.73.111.254236.73.111.2554,094
152236.73.112.0/20236.73.112.1 to 236.73.127.254236.73.127.2554,094
153236.73.128.0/20236.73.128.1 to 236.73.143.254236.73.143.2554,094
154236.73.144.0/20236.73.144.1 to 236.73.159.254236.73.159.2554,094
155236.73.160.0/20236.73.160.1 to 236.73.175.254236.73.175.2554,094
156236.73.176.0/20236.73.176.1 to 236.73.191.254236.73.191.2554,094
157236.73.192.0/20236.73.192.1 to 236.73.207.254236.73.207.2554,094
158236.73.208.0/20236.73.208.1 to 236.73.223.254236.73.223.2554,094
159236.73.224.0/20236.73.224.1 to 236.73.239.254236.73.239.2554,094
160236.73.240.0/20236.73.240.1 to 236.73.255.254236.73.255.2554,094
161236.74.0.0/20236.74.0.1 to 236.74.15.254236.74.15.2554,094
162236.74.16.0/20236.74.16.1 to 236.74.31.254236.74.31.2554,094
163236.74.32.0/20236.74.32.1 to 236.74.47.254236.74.47.2554,094
164236.74.48.0/20236.74.48.1 to 236.74.63.254236.74.63.2554,094
165236.74.64.0/20236.74.64.1 to 236.74.79.254236.74.79.2554,094
166236.74.80.0/20236.74.80.1 to 236.74.95.254236.74.95.2554,094
167236.74.96.0/20236.74.96.1 to 236.74.111.254236.74.111.2554,094
168236.74.112.0/20236.74.112.1 to 236.74.127.254236.74.127.2554,094
169236.74.128.0/20236.74.128.1 to 236.74.143.254236.74.143.2554,094
170236.74.144.0/20236.74.144.1 to 236.74.159.254236.74.159.2554,094
171236.74.160.0/20236.74.160.1 to 236.74.175.254236.74.175.2554,094
172236.74.176.0/20236.74.176.1 to 236.74.191.254236.74.191.2554,094
173236.74.192.0/20236.74.192.1 to 236.74.207.254236.74.207.2554,094
174236.74.208.0/20236.74.208.1 to 236.74.223.254236.74.223.2554,094
175236.74.224.0/20236.74.224.1 to 236.74.239.254236.74.239.2554,094
176236.74.240.0/20236.74.240.1 to 236.74.255.254236.74.255.2554,094
177236.75.0.0/20236.75.0.1 to 236.75.15.254236.75.15.2554,094
178236.75.16.0/20236.75.16.1 to 236.75.31.254236.75.31.2554,094
179236.75.32.0/20236.75.32.1 to 236.75.47.254236.75.47.2554,094
180236.75.48.0/20236.75.48.1 to 236.75.63.254236.75.63.2554,094
181236.75.64.0/20236.75.64.1 to 236.75.79.254236.75.79.2554,094
182236.75.80.0/20236.75.80.1 to 236.75.95.254236.75.95.2554,094
183236.75.96.0/20236.75.96.1 to 236.75.111.254236.75.111.2554,094
184236.75.112.0/20236.75.112.1 to 236.75.127.254236.75.127.2554,094
185236.75.128.0/20236.75.128.1 to 236.75.143.254236.75.143.2554,094
186236.75.144.0/20236.75.144.1 to 236.75.159.254236.75.159.2554,094
187236.75.160.0/20236.75.160.1 to 236.75.175.254236.75.175.2554,094
188236.75.176.0/20236.75.176.1 to 236.75.191.254236.75.191.2554,094
189236.75.192.0/20236.75.192.1 to 236.75.207.254236.75.207.2554,094
190236.75.208.0/20236.75.208.1 to 236.75.223.254236.75.223.2554,094
191236.75.224.0/20236.75.224.1 to 236.75.239.254236.75.239.2554,094
192236.75.240.0/20236.75.240.1 to 236.75.255.254236.75.255.2554,094
193236.76.0.0/20236.76.0.1 to 236.76.15.254236.76.15.2554,094
194236.76.16.0/20236.76.16.1 to 236.76.31.254236.76.31.2554,094
195236.76.32.0/20236.76.32.1 to 236.76.47.254236.76.47.2554,094
196236.76.48.0/20236.76.48.1 to 236.76.63.254236.76.63.2554,094
197236.76.64.0/20236.76.64.1 to 236.76.79.254236.76.79.2554,094
198236.76.80.0/20236.76.80.1 to 236.76.95.254236.76.95.2554,094
199236.76.96.0/20236.76.96.1 to 236.76.111.254236.76.111.2554,094
200236.76.112.0/20236.76.112.1 to 236.76.127.254236.76.127.2554,094
201236.76.128.0/20236.76.128.1 to 236.76.143.254236.76.143.2554,094
202236.76.144.0/20236.76.144.1 to 236.76.159.254236.76.159.2554,094
203236.76.160.0/20236.76.160.1 to 236.76.175.254236.76.175.2554,094
204236.76.176.0/20236.76.176.1 to 236.76.191.254236.76.191.2554,094
205236.76.192.0/20236.76.192.1 to 236.76.207.254236.76.207.2554,094
206236.76.208.0/20236.76.208.1 to 236.76.223.254236.76.223.2554,094
207236.76.224.0/20236.76.224.1 to 236.76.239.254236.76.239.2554,094
208236.76.240.0/20236.76.240.1 to 236.76.255.254236.76.255.2554,094
209236.77.0.0/20236.77.0.1 to 236.77.15.254236.77.15.2554,094
210236.77.16.0/20236.77.16.1 to 236.77.31.254236.77.31.2554,094
211236.77.32.0/20236.77.32.1 to 236.77.47.254236.77.47.2554,094
212236.77.48.0/20236.77.48.1 to 236.77.63.254236.77.63.2554,094
213236.77.64.0/20236.77.64.1 to 236.77.79.254236.77.79.2554,094
214236.77.80.0/20236.77.80.1 to 236.77.95.254236.77.95.2554,094
215236.77.96.0/20236.77.96.1 to 236.77.111.254236.77.111.2554,094
216236.77.112.0/20236.77.112.1 to 236.77.127.254236.77.127.2554,094
217236.77.128.0/20236.77.128.1 to 236.77.143.254236.77.143.2554,094
218236.77.144.0/20236.77.144.1 to 236.77.159.254236.77.159.2554,094
219236.77.160.0/20236.77.160.1 to 236.77.175.254236.77.175.2554,094
220236.77.176.0/20236.77.176.1 to 236.77.191.254236.77.191.2554,094
221236.77.192.0/20236.77.192.1 to 236.77.207.254236.77.207.2554,094
222236.77.208.0/20236.77.208.1 to 236.77.223.254236.77.223.2554,094
223236.77.224.0/20236.77.224.1 to 236.77.239.254236.77.239.2554,094
224236.77.240.0/20236.77.240.1 to 236.77.255.254236.77.255.2554,094
225236.78.0.0/20236.78.0.1 to 236.78.15.254236.78.15.2554,094
226236.78.16.0/20236.78.16.1 to 236.78.31.254236.78.31.2554,094
227236.78.32.0/20236.78.32.1 to 236.78.47.254236.78.47.2554,094
228236.78.48.0/20236.78.48.1 to 236.78.63.254236.78.63.2554,094
229236.78.64.0/20236.78.64.1 to 236.78.79.254236.78.79.2554,094
230236.78.80.0/20236.78.80.1 to 236.78.95.254236.78.95.2554,094
231236.78.96.0/20236.78.96.1 to 236.78.111.254236.78.111.2554,094
232236.78.112.0/20236.78.112.1 to 236.78.127.254236.78.127.2554,094
233236.78.128.0/20236.78.128.1 to 236.78.143.254236.78.143.2554,094
234236.78.144.0/20236.78.144.1 to 236.78.159.254236.78.159.2554,094
235236.78.160.0/20236.78.160.1 to 236.78.175.254236.78.175.2554,094
236236.78.176.0/20236.78.176.1 to 236.78.191.254236.78.191.2554,094
237236.78.192.0/20236.78.192.1 to 236.78.207.254236.78.207.2554,094
238236.78.208.0/20236.78.208.1 to 236.78.223.254236.78.223.2554,094
239236.78.224.0/20236.78.224.1 to 236.78.239.254236.78.239.2554,094
240236.78.240.0/20236.78.240.1 to 236.78.255.254236.78.255.2554,094
241236.79.0.0/20236.79.0.1 to 236.79.15.254236.79.15.2554,094
242236.79.16.0/20236.79.16.1 to 236.79.31.254236.79.31.2554,094
243236.79.32.0/20236.79.32.1 to 236.79.47.254236.79.47.2554,094
244236.79.48.0/20236.79.48.1 to 236.79.63.254236.79.63.2554,094
245236.79.64.0/20236.79.64.1 to 236.79.79.254236.79.79.2554,094
246236.79.80.0/20236.79.80.1 to 236.79.95.254236.79.95.2554,094
247236.79.96.0/20236.79.96.1 to 236.79.111.254236.79.111.2554,094
248236.79.112.0/20236.79.112.1 to 236.79.127.254236.79.127.2554,094
249236.79.128.0/20236.79.128.1 to 236.79.143.254236.79.143.2554,094
250236.79.144.0/20236.79.144.1 to 236.79.159.254236.79.159.2554,094
251236.79.160.0/20236.79.160.1 to 236.79.175.254236.79.175.2554,094
252236.79.176.0/20236.79.176.1 to 236.79.191.254236.79.191.2554,094
253236.79.192.0/20236.79.192.1 to 236.79.207.254236.79.207.2554,094
254236.79.208.0/20236.79.208.1 to 236.79.223.254236.79.223.2554,094
255236.79.224.0/20236.79.224.1 to 236.79.239.254236.79.239.2554,094
256236.79.240.0/20236.79.240.1 to 236.79.255.254236.79.255.2554,094

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.