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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.

Network104.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
104.0.0.0
Broadcast address
104.127.255.255
First usable
104.0.0.1
Last usable
104.127.255.254
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
Public public
Old class
A (default /8)
As numbers
Hex 68000000 · Integer 1744830464 to 1753219071
Reverse DNS zones
0.104.in-addr.arpa
1.104.in-addr.arpa
2.104.in-addr.arpa
3.104.in-addr.arpa
4.104.in-addr.arpa
5.104.in-addr.arpa
6.104.in-addr.arpa
7.104.in-addr.arpa
8.104.in-addr.arpa
9.104.in-addr.arpa
10.104.in-addr.arpa
11.104.in-addr.arpa
12.104.in-addr.arpa
13.104.in-addr.arpa
14.104.in-addr.arpa
15.104.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
Address01101000.00000000.00000000.00000000104.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101000.00000000.00000000.00000000104.0.0.0
Broadcast01101000.01111111.11111111.11111111104.127.255.255
Split into smaller subnets/18
/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)

104.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1104.0.0.0/18104.0.0.1 to 104.0.63.254104.0.63.25516,382
2104.0.64.0/18104.0.64.1 to 104.0.127.254104.0.127.25516,382
3104.0.128.0/18104.0.128.1 to 104.0.191.254104.0.191.25516,382
4104.0.192.0/18104.0.192.1 to 104.0.255.254104.0.255.25516,382
5104.1.0.0/18104.1.0.1 to 104.1.63.254104.1.63.25516,382
6104.1.64.0/18104.1.64.1 to 104.1.127.254104.1.127.25516,382
7104.1.128.0/18104.1.128.1 to 104.1.191.254104.1.191.25516,382
8104.1.192.0/18104.1.192.1 to 104.1.255.254104.1.255.25516,382
9104.2.0.0/18104.2.0.1 to 104.2.63.254104.2.63.25516,382
10104.2.64.0/18104.2.64.1 to 104.2.127.254104.2.127.25516,382
11104.2.128.0/18104.2.128.1 to 104.2.191.254104.2.191.25516,382
12104.2.192.0/18104.2.192.1 to 104.2.255.254104.2.255.25516,382
13104.3.0.0/18104.3.0.1 to 104.3.63.254104.3.63.25516,382
14104.3.64.0/18104.3.64.1 to 104.3.127.254104.3.127.25516,382
15104.3.128.0/18104.3.128.1 to 104.3.191.254104.3.191.25516,382
16104.3.192.0/18104.3.192.1 to 104.3.255.254104.3.255.25516,382
17104.4.0.0/18104.4.0.1 to 104.4.63.254104.4.63.25516,382
18104.4.64.0/18104.4.64.1 to 104.4.127.254104.4.127.25516,382
19104.4.128.0/18104.4.128.1 to 104.4.191.254104.4.191.25516,382
20104.4.192.0/18104.4.192.1 to 104.4.255.254104.4.255.25516,382
21104.5.0.0/18104.5.0.1 to 104.5.63.254104.5.63.25516,382
22104.5.64.0/18104.5.64.1 to 104.5.127.254104.5.127.25516,382
23104.5.128.0/18104.5.128.1 to 104.5.191.254104.5.191.25516,382
24104.5.192.0/18104.5.192.1 to 104.5.255.254104.5.255.25516,382
25104.6.0.0/18104.6.0.1 to 104.6.63.254104.6.63.25516,382
26104.6.64.0/18104.6.64.1 to 104.6.127.254104.6.127.25516,382
27104.6.128.0/18104.6.128.1 to 104.6.191.254104.6.191.25516,382
28104.6.192.0/18104.6.192.1 to 104.6.255.254104.6.255.25516,382
29104.7.0.0/18104.7.0.1 to 104.7.63.254104.7.63.25516,382
30104.7.64.0/18104.7.64.1 to 104.7.127.254104.7.127.25516,382
31104.7.128.0/18104.7.128.1 to 104.7.191.254104.7.191.25516,382
32104.7.192.0/18104.7.192.1 to 104.7.255.254104.7.255.25516,382
33104.8.0.0/18104.8.0.1 to 104.8.63.254104.8.63.25516,382
34104.8.64.0/18104.8.64.1 to 104.8.127.254104.8.127.25516,382
35104.8.128.0/18104.8.128.1 to 104.8.191.254104.8.191.25516,382
36104.8.192.0/18104.8.192.1 to 104.8.255.254104.8.255.25516,382
37104.9.0.0/18104.9.0.1 to 104.9.63.254104.9.63.25516,382
38104.9.64.0/18104.9.64.1 to 104.9.127.254104.9.127.25516,382
39104.9.128.0/18104.9.128.1 to 104.9.191.254104.9.191.25516,382
40104.9.192.0/18104.9.192.1 to 104.9.255.254104.9.255.25516,382
41104.10.0.0/18104.10.0.1 to 104.10.63.254104.10.63.25516,382
42104.10.64.0/18104.10.64.1 to 104.10.127.254104.10.127.25516,382
43104.10.128.0/18104.10.128.1 to 104.10.191.254104.10.191.25516,382
44104.10.192.0/18104.10.192.1 to 104.10.255.254104.10.255.25516,382
45104.11.0.0/18104.11.0.1 to 104.11.63.254104.11.63.25516,382
46104.11.64.0/18104.11.64.1 to 104.11.127.254104.11.127.25516,382
47104.11.128.0/18104.11.128.1 to 104.11.191.254104.11.191.25516,382
48104.11.192.0/18104.11.192.1 to 104.11.255.254104.11.255.25516,382
49104.12.0.0/18104.12.0.1 to 104.12.63.254104.12.63.25516,382
50104.12.64.0/18104.12.64.1 to 104.12.127.254104.12.127.25516,382
51104.12.128.0/18104.12.128.1 to 104.12.191.254104.12.191.25516,382
52104.12.192.0/18104.12.192.1 to 104.12.255.254104.12.255.25516,382
53104.13.0.0/18104.13.0.1 to 104.13.63.254104.13.63.25516,382
54104.13.64.0/18104.13.64.1 to 104.13.127.254104.13.127.25516,382
55104.13.128.0/18104.13.128.1 to 104.13.191.254104.13.191.25516,382
56104.13.192.0/18104.13.192.1 to 104.13.255.254104.13.255.25516,382
57104.14.0.0/18104.14.0.1 to 104.14.63.254104.14.63.25516,382
58104.14.64.0/18104.14.64.1 to 104.14.127.254104.14.127.25516,382
59104.14.128.0/18104.14.128.1 to 104.14.191.254104.14.191.25516,382
60104.14.192.0/18104.14.192.1 to 104.14.255.254104.14.255.25516,382
61104.15.0.0/18104.15.0.1 to 104.15.63.254104.15.63.25516,382
62104.15.64.0/18104.15.64.1 to 104.15.127.254104.15.127.25516,382
63104.15.128.0/18104.15.128.1 to 104.15.191.254104.15.191.25516,382
64104.15.192.0/18104.15.192.1 to 104.15.255.254104.15.255.25516,382
65104.16.0.0/18104.16.0.1 to 104.16.63.254104.16.63.25516,382
66104.16.64.0/18104.16.64.1 to 104.16.127.254104.16.127.25516,382
67104.16.128.0/18104.16.128.1 to 104.16.191.254104.16.191.25516,382
68104.16.192.0/18104.16.192.1 to 104.16.255.254104.16.255.25516,382
69104.17.0.0/18104.17.0.1 to 104.17.63.254104.17.63.25516,382
70104.17.64.0/18104.17.64.1 to 104.17.127.254104.17.127.25516,382
71104.17.128.0/18104.17.128.1 to 104.17.191.254104.17.191.25516,382
72104.17.192.0/18104.17.192.1 to 104.17.255.254104.17.255.25516,382
73104.18.0.0/18104.18.0.1 to 104.18.63.254104.18.63.25516,382
74104.18.64.0/18104.18.64.1 to 104.18.127.254104.18.127.25516,382
75104.18.128.0/18104.18.128.1 to 104.18.191.254104.18.191.25516,382
76104.18.192.0/18104.18.192.1 to 104.18.255.254104.18.255.25516,382
77104.19.0.0/18104.19.0.1 to 104.19.63.254104.19.63.25516,382
78104.19.64.0/18104.19.64.1 to 104.19.127.254104.19.127.25516,382
79104.19.128.0/18104.19.128.1 to 104.19.191.254104.19.191.25516,382
80104.19.192.0/18104.19.192.1 to 104.19.255.254104.19.255.25516,382
81104.20.0.0/18104.20.0.1 to 104.20.63.254104.20.63.25516,382
82104.20.64.0/18104.20.64.1 to 104.20.127.254104.20.127.25516,382
83104.20.128.0/18104.20.128.1 to 104.20.191.254104.20.191.25516,382
84104.20.192.0/18104.20.192.1 to 104.20.255.254104.20.255.25516,382
85104.21.0.0/18104.21.0.1 to 104.21.63.254104.21.63.25516,382
86104.21.64.0/18104.21.64.1 to 104.21.127.254104.21.127.25516,382
87104.21.128.0/18104.21.128.1 to 104.21.191.254104.21.191.25516,382
88104.21.192.0/18104.21.192.1 to 104.21.255.254104.21.255.25516,382
89104.22.0.0/18104.22.0.1 to 104.22.63.254104.22.63.25516,382
90104.22.64.0/18104.22.64.1 to 104.22.127.254104.22.127.25516,382
91104.22.128.0/18104.22.128.1 to 104.22.191.254104.22.191.25516,382
92104.22.192.0/18104.22.192.1 to 104.22.255.254104.22.255.25516,382
93104.23.0.0/18104.23.0.1 to 104.23.63.254104.23.63.25516,382
94104.23.64.0/18104.23.64.1 to 104.23.127.254104.23.127.25516,382
95104.23.128.0/18104.23.128.1 to 104.23.191.254104.23.191.25516,382
96104.23.192.0/18104.23.192.1 to 104.23.255.254104.23.255.25516,382
97104.24.0.0/18104.24.0.1 to 104.24.63.254104.24.63.25516,382
98104.24.64.0/18104.24.64.1 to 104.24.127.254104.24.127.25516,382
99104.24.128.0/18104.24.128.1 to 104.24.191.254104.24.191.25516,382
100104.24.192.0/18104.24.192.1 to 104.24.255.254104.24.255.25516,382
101104.25.0.0/18104.25.0.1 to 104.25.63.254104.25.63.25516,382
102104.25.64.0/18104.25.64.1 to 104.25.127.254104.25.127.25516,382
103104.25.128.0/18104.25.128.1 to 104.25.191.254104.25.191.25516,382
104104.25.192.0/18104.25.192.1 to 104.25.255.254104.25.255.25516,382
105104.26.0.0/18104.26.0.1 to 104.26.63.254104.26.63.25516,382
106104.26.64.0/18104.26.64.1 to 104.26.127.254104.26.127.25516,382
107104.26.128.0/18104.26.128.1 to 104.26.191.254104.26.191.25516,382
108104.26.192.0/18104.26.192.1 to 104.26.255.254104.26.255.25516,382
109104.27.0.0/18104.27.0.1 to 104.27.63.254104.27.63.25516,382
110104.27.64.0/18104.27.64.1 to 104.27.127.254104.27.127.25516,382
111104.27.128.0/18104.27.128.1 to 104.27.191.254104.27.191.25516,382
112104.27.192.0/18104.27.192.1 to 104.27.255.254104.27.255.25516,382
113104.28.0.0/18104.28.0.1 to 104.28.63.254104.28.63.25516,382
114104.28.64.0/18104.28.64.1 to 104.28.127.254104.28.127.25516,382
115104.28.128.0/18104.28.128.1 to 104.28.191.254104.28.191.25516,382
116104.28.192.0/18104.28.192.1 to 104.28.255.254104.28.255.25516,382
117104.29.0.0/18104.29.0.1 to 104.29.63.254104.29.63.25516,382
118104.29.64.0/18104.29.64.1 to 104.29.127.254104.29.127.25516,382
119104.29.128.0/18104.29.128.1 to 104.29.191.254104.29.191.25516,382
120104.29.192.0/18104.29.192.1 to 104.29.255.254104.29.255.25516,382
121104.30.0.0/18104.30.0.1 to 104.30.63.254104.30.63.25516,382
122104.30.64.0/18104.30.64.1 to 104.30.127.254104.30.127.25516,382
123104.30.128.0/18104.30.128.1 to 104.30.191.254104.30.191.25516,382
124104.30.192.0/18104.30.192.1 to 104.30.255.254104.30.255.25516,382
125104.31.0.0/18104.31.0.1 to 104.31.63.254104.31.63.25516,382
126104.31.64.0/18104.31.64.1 to 104.31.127.254104.31.127.25516,382
127104.31.128.0/18104.31.128.1 to 104.31.191.254104.31.191.25516,382
128104.31.192.0/18104.31.192.1 to 104.31.255.254104.31.255.25516,382
129104.32.0.0/18104.32.0.1 to 104.32.63.254104.32.63.25516,382
130104.32.64.0/18104.32.64.1 to 104.32.127.254104.32.127.25516,382
131104.32.128.0/18104.32.128.1 to 104.32.191.254104.32.191.25516,382
132104.32.192.0/18104.32.192.1 to 104.32.255.254104.32.255.25516,382
133104.33.0.0/18104.33.0.1 to 104.33.63.254104.33.63.25516,382
134104.33.64.0/18104.33.64.1 to 104.33.127.254104.33.127.25516,382
135104.33.128.0/18104.33.128.1 to 104.33.191.254104.33.191.25516,382
136104.33.192.0/18104.33.192.1 to 104.33.255.254104.33.255.25516,382
137104.34.0.0/18104.34.0.1 to 104.34.63.254104.34.63.25516,382
138104.34.64.0/18104.34.64.1 to 104.34.127.254104.34.127.25516,382
139104.34.128.0/18104.34.128.1 to 104.34.191.254104.34.191.25516,382
140104.34.192.0/18104.34.192.1 to 104.34.255.254104.34.255.25516,382
141104.35.0.0/18104.35.0.1 to 104.35.63.254104.35.63.25516,382
142104.35.64.0/18104.35.64.1 to 104.35.127.254104.35.127.25516,382
143104.35.128.0/18104.35.128.1 to 104.35.191.254104.35.191.25516,382
144104.35.192.0/18104.35.192.1 to 104.35.255.254104.35.255.25516,382
145104.36.0.0/18104.36.0.1 to 104.36.63.254104.36.63.25516,382
146104.36.64.0/18104.36.64.1 to 104.36.127.254104.36.127.25516,382
147104.36.128.0/18104.36.128.1 to 104.36.191.254104.36.191.25516,382
148104.36.192.0/18104.36.192.1 to 104.36.255.254104.36.255.25516,382
149104.37.0.0/18104.37.0.1 to 104.37.63.254104.37.63.25516,382
150104.37.64.0/18104.37.64.1 to 104.37.127.254104.37.127.25516,382
151104.37.128.0/18104.37.128.1 to 104.37.191.254104.37.191.25516,382
152104.37.192.0/18104.37.192.1 to 104.37.255.254104.37.255.25516,382
153104.38.0.0/18104.38.0.1 to 104.38.63.254104.38.63.25516,382
154104.38.64.0/18104.38.64.1 to 104.38.127.254104.38.127.25516,382
155104.38.128.0/18104.38.128.1 to 104.38.191.254104.38.191.25516,382
156104.38.192.0/18104.38.192.1 to 104.38.255.254104.38.255.25516,382
157104.39.0.0/18104.39.0.1 to 104.39.63.254104.39.63.25516,382
158104.39.64.0/18104.39.64.1 to 104.39.127.254104.39.127.25516,382
159104.39.128.0/18104.39.128.1 to 104.39.191.254104.39.191.25516,382
160104.39.192.0/18104.39.192.1 to 104.39.255.254104.39.255.25516,382
161104.40.0.0/18104.40.0.1 to 104.40.63.254104.40.63.25516,382
162104.40.64.0/18104.40.64.1 to 104.40.127.254104.40.127.25516,382
163104.40.128.0/18104.40.128.1 to 104.40.191.254104.40.191.25516,382
164104.40.192.0/18104.40.192.1 to 104.40.255.254104.40.255.25516,382
165104.41.0.0/18104.41.0.1 to 104.41.63.254104.41.63.25516,382
166104.41.64.0/18104.41.64.1 to 104.41.127.254104.41.127.25516,382
167104.41.128.0/18104.41.128.1 to 104.41.191.254104.41.191.25516,382
168104.41.192.0/18104.41.192.1 to 104.41.255.254104.41.255.25516,382
169104.42.0.0/18104.42.0.1 to 104.42.63.254104.42.63.25516,382
170104.42.64.0/18104.42.64.1 to 104.42.127.254104.42.127.25516,382
171104.42.128.0/18104.42.128.1 to 104.42.191.254104.42.191.25516,382
172104.42.192.0/18104.42.192.1 to 104.42.255.254104.42.255.25516,382
173104.43.0.0/18104.43.0.1 to 104.43.63.254104.43.63.25516,382
174104.43.64.0/18104.43.64.1 to 104.43.127.254104.43.127.25516,382
175104.43.128.0/18104.43.128.1 to 104.43.191.254104.43.191.25516,382
176104.43.192.0/18104.43.192.1 to 104.43.255.254104.43.255.25516,382
177104.44.0.0/18104.44.0.1 to 104.44.63.254104.44.63.25516,382
178104.44.64.0/18104.44.64.1 to 104.44.127.254104.44.127.25516,382
179104.44.128.0/18104.44.128.1 to 104.44.191.254104.44.191.25516,382
180104.44.192.0/18104.44.192.1 to 104.44.255.254104.44.255.25516,382
181104.45.0.0/18104.45.0.1 to 104.45.63.254104.45.63.25516,382
182104.45.64.0/18104.45.64.1 to 104.45.127.254104.45.127.25516,382
183104.45.128.0/18104.45.128.1 to 104.45.191.254104.45.191.25516,382
184104.45.192.0/18104.45.192.1 to 104.45.255.254104.45.255.25516,382
185104.46.0.0/18104.46.0.1 to 104.46.63.254104.46.63.25516,382
186104.46.64.0/18104.46.64.1 to 104.46.127.254104.46.127.25516,382
187104.46.128.0/18104.46.128.1 to 104.46.191.254104.46.191.25516,382
188104.46.192.0/18104.46.192.1 to 104.46.255.254104.46.255.25516,382
189104.47.0.0/18104.47.0.1 to 104.47.63.254104.47.63.25516,382
190104.47.64.0/18104.47.64.1 to 104.47.127.254104.47.127.25516,382
191104.47.128.0/18104.47.128.1 to 104.47.191.254104.47.191.25516,382
192104.47.192.0/18104.47.192.1 to 104.47.255.254104.47.255.25516,382
193104.48.0.0/18104.48.0.1 to 104.48.63.254104.48.63.25516,382
194104.48.64.0/18104.48.64.1 to 104.48.127.254104.48.127.25516,382
195104.48.128.0/18104.48.128.1 to 104.48.191.254104.48.191.25516,382
196104.48.192.0/18104.48.192.1 to 104.48.255.254104.48.255.25516,382
197104.49.0.0/18104.49.0.1 to 104.49.63.254104.49.63.25516,382
198104.49.64.0/18104.49.64.1 to 104.49.127.254104.49.127.25516,382
199104.49.128.0/18104.49.128.1 to 104.49.191.254104.49.191.25516,382
200104.49.192.0/18104.49.192.1 to 104.49.255.254104.49.255.25516,382
201104.50.0.0/18104.50.0.1 to 104.50.63.254104.50.63.25516,382
202104.50.64.0/18104.50.64.1 to 104.50.127.254104.50.127.25516,382
203104.50.128.0/18104.50.128.1 to 104.50.191.254104.50.191.25516,382
204104.50.192.0/18104.50.192.1 to 104.50.255.254104.50.255.25516,382
205104.51.0.0/18104.51.0.1 to 104.51.63.254104.51.63.25516,382
206104.51.64.0/18104.51.64.1 to 104.51.127.254104.51.127.25516,382
207104.51.128.0/18104.51.128.1 to 104.51.191.254104.51.191.25516,382
208104.51.192.0/18104.51.192.1 to 104.51.255.254104.51.255.25516,382
209104.52.0.0/18104.52.0.1 to 104.52.63.254104.52.63.25516,382
210104.52.64.0/18104.52.64.1 to 104.52.127.254104.52.127.25516,382
211104.52.128.0/18104.52.128.1 to 104.52.191.254104.52.191.25516,382
212104.52.192.0/18104.52.192.1 to 104.52.255.254104.52.255.25516,382
213104.53.0.0/18104.53.0.1 to 104.53.63.254104.53.63.25516,382
214104.53.64.0/18104.53.64.1 to 104.53.127.254104.53.127.25516,382
215104.53.128.0/18104.53.128.1 to 104.53.191.254104.53.191.25516,382
216104.53.192.0/18104.53.192.1 to 104.53.255.254104.53.255.25516,382
217104.54.0.0/18104.54.0.1 to 104.54.63.254104.54.63.25516,382
218104.54.64.0/18104.54.64.1 to 104.54.127.254104.54.127.25516,382
219104.54.128.0/18104.54.128.1 to 104.54.191.254104.54.191.25516,382
220104.54.192.0/18104.54.192.1 to 104.54.255.254104.54.255.25516,382
221104.55.0.0/18104.55.0.1 to 104.55.63.254104.55.63.25516,382
222104.55.64.0/18104.55.64.1 to 104.55.127.254104.55.127.25516,382
223104.55.128.0/18104.55.128.1 to 104.55.191.254104.55.191.25516,382
224104.55.192.0/18104.55.192.1 to 104.55.255.254104.55.255.25516,382
225104.56.0.0/18104.56.0.1 to 104.56.63.254104.56.63.25516,382
226104.56.64.0/18104.56.64.1 to 104.56.127.254104.56.127.25516,382
227104.56.128.0/18104.56.128.1 to 104.56.191.254104.56.191.25516,382
228104.56.192.0/18104.56.192.1 to 104.56.255.254104.56.255.25516,382
229104.57.0.0/18104.57.0.1 to 104.57.63.254104.57.63.25516,382
230104.57.64.0/18104.57.64.1 to 104.57.127.254104.57.127.25516,382
231104.57.128.0/18104.57.128.1 to 104.57.191.254104.57.191.25516,382
232104.57.192.0/18104.57.192.1 to 104.57.255.254104.57.255.25516,382
233104.58.0.0/18104.58.0.1 to 104.58.63.254104.58.63.25516,382
234104.58.64.0/18104.58.64.1 to 104.58.127.254104.58.127.25516,382
235104.58.128.0/18104.58.128.1 to 104.58.191.254104.58.191.25516,382
236104.58.192.0/18104.58.192.1 to 104.58.255.254104.58.255.25516,382
237104.59.0.0/18104.59.0.1 to 104.59.63.254104.59.63.25516,382
238104.59.64.0/18104.59.64.1 to 104.59.127.254104.59.127.25516,382
239104.59.128.0/18104.59.128.1 to 104.59.191.254104.59.191.25516,382
240104.59.192.0/18104.59.192.1 to 104.59.255.254104.59.255.25516,382
241104.60.0.0/18104.60.0.1 to 104.60.63.254104.60.63.25516,382
242104.60.64.0/18104.60.64.1 to 104.60.127.254104.60.127.25516,382
243104.60.128.0/18104.60.128.1 to 104.60.191.254104.60.191.25516,382
244104.60.192.0/18104.60.192.1 to 104.60.255.254104.60.255.25516,382
245104.61.0.0/18104.61.0.1 to 104.61.63.254104.61.63.25516,382
246104.61.64.0/18104.61.64.1 to 104.61.127.254104.61.127.25516,382
247104.61.128.0/18104.61.128.1 to 104.61.191.254104.61.191.25516,382
248104.61.192.0/18104.61.192.1 to 104.61.255.254104.61.255.25516,382
249104.62.0.0/18104.62.0.1 to 104.62.63.254104.62.63.25516,382
250104.62.64.0/18104.62.64.1 to 104.62.127.254104.62.127.25516,382
251104.62.128.0/18104.62.128.1 to 104.62.191.254104.62.191.25516,382
252104.62.192.0/18104.62.192.1 to 104.62.255.254104.62.255.25516,382
253104.63.0.0/18104.63.0.1 to 104.63.63.254104.63.63.25516,382
254104.63.64.0/18104.63.64.1 to 104.63.127.254104.63.127.25516,382
255104.63.128.0/18104.63.128.1 to 104.63.191.254104.63.191.25516,382
256104.63.192.0/18104.63.192.1 to 104.63.255.254104.63.255.25516,382

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.