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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.

Network193.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
193.0.0.0
Broadcast address
193.127.255.255
First usable
193.0.0.1
Last usable
193.127.255.254
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
C (default /24)
As numbers
Hex C1000000 · Integer 3238002688 to 3246391295
Reverse DNS zones
0.193.in-addr.arpa
1.193.in-addr.arpa
2.193.in-addr.arpa
3.193.in-addr.arpa
4.193.in-addr.arpa
5.193.in-addr.arpa
6.193.in-addr.arpa
7.193.in-addr.arpa
8.193.in-addr.arpa
9.193.in-addr.arpa
10.193.in-addr.arpa
11.193.in-addr.arpa
12.193.in-addr.arpa
13.193.in-addr.arpa
14.193.in-addr.arpa
15.193.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
Address11000001.00000000.00000000.00000000193.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11000001.00000000.00000000.00000000193.0.0.0
Broadcast11000001.01111111.11111111.11111111193.127.255.255
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)

193.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1193.0.0.0/18193.0.0.1 to 193.0.63.254193.0.63.25516,382
2193.0.64.0/18193.0.64.1 to 193.0.127.254193.0.127.25516,382
3193.0.128.0/18193.0.128.1 to 193.0.191.254193.0.191.25516,382
4193.0.192.0/18193.0.192.1 to 193.0.255.254193.0.255.25516,382
5193.1.0.0/18193.1.0.1 to 193.1.63.254193.1.63.25516,382
6193.1.64.0/18193.1.64.1 to 193.1.127.254193.1.127.25516,382
7193.1.128.0/18193.1.128.1 to 193.1.191.254193.1.191.25516,382
8193.1.192.0/18193.1.192.1 to 193.1.255.254193.1.255.25516,382
9193.2.0.0/18193.2.0.1 to 193.2.63.254193.2.63.25516,382
10193.2.64.0/18193.2.64.1 to 193.2.127.254193.2.127.25516,382
11193.2.128.0/18193.2.128.1 to 193.2.191.254193.2.191.25516,382
12193.2.192.0/18193.2.192.1 to 193.2.255.254193.2.255.25516,382
13193.3.0.0/18193.3.0.1 to 193.3.63.254193.3.63.25516,382
14193.3.64.0/18193.3.64.1 to 193.3.127.254193.3.127.25516,382
15193.3.128.0/18193.3.128.1 to 193.3.191.254193.3.191.25516,382
16193.3.192.0/18193.3.192.1 to 193.3.255.254193.3.255.25516,382
17193.4.0.0/18193.4.0.1 to 193.4.63.254193.4.63.25516,382
18193.4.64.0/18193.4.64.1 to 193.4.127.254193.4.127.25516,382
19193.4.128.0/18193.4.128.1 to 193.4.191.254193.4.191.25516,382
20193.4.192.0/18193.4.192.1 to 193.4.255.254193.4.255.25516,382
21193.5.0.0/18193.5.0.1 to 193.5.63.254193.5.63.25516,382
22193.5.64.0/18193.5.64.1 to 193.5.127.254193.5.127.25516,382
23193.5.128.0/18193.5.128.1 to 193.5.191.254193.5.191.25516,382
24193.5.192.0/18193.5.192.1 to 193.5.255.254193.5.255.25516,382
25193.6.0.0/18193.6.0.1 to 193.6.63.254193.6.63.25516,382
26193.6.64.0/18193.6.64.1 to 193.6.127.254193.6.127.25516,382
27193.6.128.0/18193.6.128.1 to 193.6.191.254193.6.191.25516,382
28193.6.192.0/18193.6.192.1 to 193.6.255.254193.6.255.25516,382
29193.7.0.0/18193.7.0.1 to 193.7.63.254193.7.63.25516,382
30193.7.64.0/18193.7.64.1 to 193.7.127.254193.7.127.25516,382
31193.7.128.0/18193.7.128.1 to 193.7.191.254193.7.191.25516,382
32193.7.192.0/18193.7.192.1 to 193.7.255.254193.7.255.25516,382
33193.8.0.0/18193.8.0.1 to 193.8.63.254193.8.63.25516,382
34193.8.64.0/18193.8.64.1 to 193.8.127.254193.8.127.25516,382
35193.8.128.0/18193.8.128.1 to 193.8.191.254193.8.191.25516,382
36193.8.192.0/18193.8.192.1 to 193.8.255.254193.8.255.25516,382
37193.9.0.0/18193.9.0.1 to 193.9.63.254193.9.63.25516,382
38193.9.64.0/18193.9.64.1 to 193.9.127.254193.9.127.25516,382
39193.9.128.0/18193.9.128.1 to 193.9.191.254193.9.191.25516,382
40193.9.192.0/18193.9.192.1 to 193.9.255.254193.9.255.25516,382
41193.10.0.0/18193.10.0.1 to 193.10.63.254193.10.63.25516,382
42193.10.64.0/18193.10.64.1 to 193.10.127.254193.10.127.25516,382
43193.10.128.0/18193.10.128.1 to 193.10.191.254193.10.191.25516,382
44193.10.192.0/18193.10.192.1 to 193.10.255.254193.10.255.25516,382
45193.11.0.0/18193.11.0.1 to 193.11.63.254193.11.63.25516,382
46193.11.64.0/18193.11.64.1 to 193.11.127.254193.11.127.25516,382
47193.11.128.0/18193.11.128.1 to 193.11.191.254193.11.191.25516,382
48193.11.192.0/18193.11.192.1 to 193.11.255.254193.11.255.25516,382
49193.12.0.0/18193.12.0.1 to 193.12.63.254193.12.63.25516,382
50193.12.64.0/18193.12.64.1 to 193.12.127.254193.12.127.25516,382
51193.12.128.0/18193.12.128.1 to 193.12.191.254193.12.191.25516,382
52193.12.192.0/18193.12.192.1 to 193.12.255.254193.12.255.25516,382
53193.13.0.0/18193.13.0.1 to 193.13.63.254193.13.63.25516,382
54193.13.64.0/18193.13.64.1 to 193.13.127.254193.13.127.25516,382
55193.13.128.0/18193.13.128.1 to 193.13.191.254193.13.191.25516,382
56193.13.192.0/18193.13.192.1 to 193.13.255.254193.13.255.25516,382
57193.14.0.0/18193.14.0.1 to 193.14.63.254193.14.63.25516,382
58193.14.64.0/18193.14.64.1 to 193.14.127.254193.14.127.25516,382
59193.14.128.0/18193.14.128.1 to 193.14.191.254193.14.191.25516,382
60193.14.192.0/18193.14.192.1 to 193.14.255.254193.14.255.25516,382
61193.15.0.0/18193.15.0.1 to 193.15.63.254193.15.63.25516,382
62193.15.64.0/18193.15.64.1 to 193.15.127.254193.15.127.25516,382
63193.15.128.0/18193.15.128.1 to 193.15.191.254193.15.191.25516,382
64193.15.192.0/18193.15.192.1 to 193.15.255.254193.15.255.25516,382
65193.16.0.0/18193.16.0.1 to 193.16.63.254193.16.63.25516,382
66193.16.64.0/18193.16.64.1 to 193.16.127.254193.16.127.25516,382
67193.16.128.0/18193.16.128.1 to 193.16.191.254193.16.191.25516,382
68193.16.192.0/18193.16.192.1 to 193.16.255.254193.16.255.25516,382
69193.17.0.0/18193.17.0.1 to 193.17.63.254193.17.63.25516,382
70193.17.64.0/18193.17.64.1 to 193.17.127.254193.17.127.25516,382
71193.17.128.0/18193.17.128.1 to 193.17.191.254193.17.191.25516,382
72193.17.192.0/18193.17.192.1 to 193.17.255.254193.17.255.25516,382
73193.18.0.0/18193.18.0.1 to 193.18.63.254193.18.63.25516,382
74193.18.64.0/18193.18.64.1 to 193.18.127.254193.18.127.25516,382
75193.18.128.0/18193.18.128.1 to 193.18.191.254193.18.191.25516,382
76193.18.192.0/18193.18.192.1 to 193.18.255.254193.18.255.25516,382
77193.19.0.0/18193.19.0.1 to 193.19.63.254193.19.63.25516,382
78193.19.64.0/18193.19.64.1 to 193.19.127.254193.19.127.25516,382
79193.19.128.0/18193.19.128.1 to 193.19.191.254193.19.191.25516,382
80193.19.192.0/18193.19.192.1 to 193.19.255.254193.19.255.25516,382
81193.20.0.0/18193.20.0.1 to 193.20.63.254193.20.63.25516,382
82193.20.64.0/18193.20.64.1 to 193.20.127.254193.20.127.25516,382
83193.20.128.0/18193.20.128.1 to 193.20.191.254193.20.191.25516,382
84193.20.192.0/18193.20.192.1 to 193.20.255.254193.20.255.25516,382
85193.21.0.0/18193.21.0.1 to 193.21.63.254193.21.63.25516,382
86193.21.64.0/18193.21.64.1 to 193.21.127.254193.21.127.25516,382
87193.21.128.0/18193.21.128.1 to 193.21.191.254193.21.191.25516,382
88193.21.192.0/18193.21.192.1 to 193.21.255.254193.21.255.25516,382
89193.22.0.0/18193.22.0.1 to 193.22.63.254193.22.63.25516,382
90193.22.64.0/18193.22.64.1 to 193.22.127.254193.22.127.25516,382
91193.22.128.0/18193.22.128.1 to 193.22.191.254193.22.191.25516,382
92193.22.192.0/18193.22.192.1 to 193.22.255.254193.22.255.25516,382
93193.23.0.0/18193.23.0.1 to 193.23.63.254193.23.63.25516,382
94193.23.64.0/18193.23.64.1 to 193.23.127.254193.23.127.25516,382
95193.23.128.0/18193.23.128.1 to 193.23.191.254193.23.191.25516,382
96193.23.192.0/18193.23.192.1 to 193.23.255.254193.23.255.25516,382
97193.24.0.0/18193.24.0.1 to 193.24.63.254193.24.63.25516,382
98193.24.64.0/18193.24.64.1 to 193.24.127.254193.24.127.25516,382
99193.24.128.0/18193.24.128.1 to 193.24.191.254193.24.191.25516,382
100193.24.192.0/18193.24.192.1 to 193.24.255.254193.24.255.25516,382
101193.25.0.0/18193.25.0.1 to 193.25.63.254193.25.63.25516,382
102193.25.64.0/18193.25.64.1 to 193.25.127.254193.25.127.25516,382
103193.25.128.0/18193.25.128.1 to 193.25.191.254193.25.191.25516,382
104193.25.192.0/18193.25.192.1 to 193.25.255.254193.25.255.25516,382
105193.26.0.0/18193.26.0.1 to 193.26.63.254193.26.63.25516,382
106193.26.64.0/18193.26.64.1 to 193.26.127.254193.26.127.25516,382
107193.26.128.0/18193.26.128.1 to 193.26.191.254193.26.191.25516,382
108193.26.192.0/18193.26.192.1 to 193.26.255.254193.26.255.25516,382
109193.27.0.0/18193.27.0.1 to 193.27.63.254193.27.63.25516,382
110193.27.64.0/18193.27.64.1 to 193.27.127.254193.27.127.25516,382
111193.27.128.0/18193.27.128.1 to 193.27.191.254193.27.191.25516,382
112193.27.192.0/18193.27.192.1 to 193.27.255.254193.27.255.25516,382
113193.28.0.0/18193.28.0.1 to 193.28.63.254193.28.63.25516,382
114193.28.64.0/18193.28.64.1 to 193.28.127.254193.28.127.25516,382
115193.28.128.0/18193.28.128.1 to 193.28.191.254193.28.191.25516,382
116193.28.192.0/18193.28.192.1 to 193.28.255.254193.28.255.25516,382
117193.29.0.0/18193.29.0.1 to 193.29.63.254193.29.63.25516,382
118193.29.64.0/18193.29.64.1 to 193.29.127.254193.29.127.25516,382
119193.29.128.0/18193.29.128.1 to 193.29.191.254193.29.191.25516,382
120193.29.192.0/18193.29.192.1 to 193.29.255.254193.29.255.25516,382
121193.30.0.0/18193.30.0.1 to 193.30.63.254193.30.63.25516,382
122193.30.64.0/18193.30.64.1 to 193.30.127.254193.30.127.25516,382
123193.30.128.0/18193.30.128.1 to 193.30.191.254193.30.191.25516,382
124193.30.192.0/18193.30.192.1 to 193.30.255.254193.30.255.25516,382
125193.31.0.0/18193.31.0.1 to 193.31.63.254193.31.63.25516,382
126193.31.64.0/18193.31.64.1 to 193.31.127.254193.31.127.25516,382
127193.31.128.0/18193.31.128.1 to 193.31.191.254193.31.191.25516,382
128193.31.192.0/18193.31.192.1 to 193.31.255.254193.31.255.25516,382
129193.32.0.0/18193.32.0.1 to 193.32.63.254193.32.63.25516,382
130193.32.64.0/18193.32.64.1 to 193.32.127.254193.32.127.25516,382
131193.32.128.0/18193.32.128.1 to 193.32.191.254193.32.191.25516,382
132193.32.192.0/18193.32.192.1 to 193.32.255.254193.32.255.25516,382
133193.33.0.0/18193.33.0.1 to 193.33.63.254193.33.63.25516,382
134193.33.64.0/18193.33.64.1 to 193.33.127.254193.33.127.25516,382
135193.33.128.0/18193.33.128.1 to 193.33.191.254193.33.191.25516,382
136193.33.192.0/18193.33.192.1 to 193.33.255.254193.33.255.25516,382
137193.34.0.0/18193.34.0.1 to 193.34.63.254193.34.63.25516,382
138193.34.64.0/18193.34.64.1 to 193.34.127.254193.34.127.25516,382
139193.34.128.0/18193.34.128.1 to 193.34.191.254193.34.191.25516,382
140193.34.192.0/18193.34.192.1 to 193.34.255.254193.34.255.25516,382
141193.35.0.0/18193.35.0.1 to 193.35.63.254193.35.63.25516,382
142193.35.64.0/18193.35.64.1 to 193.35.127.254193.35.127.25516,382
143193.35.128.0/18193.35.128.1 to 193.35.191.254193.35.191.25516,382
144193.35.192.0/18193.35.192.1 to 193.35.255.254193.35.255.25516,382
145193.36.0.0/18193.36.0.1 to 193.36.63.254193.36.63.25516,382
146193.36.64.0/18193.36.64.1 to 193.36.127.254193.36.127.25516,382
147193.36.128.0/18193.36.128.1 to 193.36.191.254193.36.191.25516,382
148193.36.192.0/18193.36.192.1 to 193.36.255.254193.36.255.25516,382
149193.37.0.0/18193.37.0.1 to 193.37.63.254193.37.63.25516,382
150193.37.64.0/18193.37.64.1 to 193.37.127.254193.37.127.25516,382
151193.37.128.0/18193.37.128.1 to 193.37.191.254193.37.191.25516,382
152193.37.192.0/18193.37.192.1 to 193.37.255.254193.37.255.25516,382
153193.38.0.0/18193.38.0.1 to 193.38.63.254193.38.63.25516,382
154193.38.64.0/18193.38.64.1 to 193.38.127.254193.38.127.25516,382
155193.38.128.0/18193.38.128.1 to 193.38.191.254193.38.191.25516,382
156193.38.192.0/18193.38.192.1 to 193.38.255.254193.38.255.25516,382
157193.39.0.0/18193.39.0.1 to 193.39.63.254193.39.63.25516,382
158193.39.64.0/18193.39.64.1 to 193.39.127.254193.39.127.25516,382
159193.39.128.0/18193.39.128.1 to 193.39.191.254193.39.191.25516,382
160193.39.192.0/18193.39.192.1 to 193.39.255.254193.39.255.25516,382
161193.40.0.0/18193.40.0.1 to 193.40.63.254193.40.63.25516,382
162193.40.64.0/18193.40.64.1 to 193.40.127.254193.40.127.25516,382
163193.40.128.0/18193.40.128.1 to 193.40.191.254193.40.191.25516,382
164193.40.192.0/18193.40.192.1 to 193.40.255.254193.40.255.25516,382
165193.41.0.0/18193.41.0.1 to 193.41.63.254193.41.63.25516,382
166193.41.64.0/18193.41.64.1 to 193.41.127.254193.41.127.25516,382
167193.41.128.0/18193.41.128.1 to 193.41.191.254193.41.191.25516,382
168193.41.192.0/18193.41.192.1 to 193.41.255.254193.41.255.25516,382
169193.42.0.0/18193.42.0.1 to 193.42.63.254193.42.63.25516,382
170193.42.64.0/18193.42.64.1 to 193.42.127.254193.42.127.25516,382
171193.42.128.0/18193.42.128.1 to 193.42.191.254193.42.191.25516,382
172193.42.192.0/18193.42.192.1 to 193.42.255.254193.42.255.25516,382
173193.43.0.0/18193.43.0.1 to 193.43.63.254193.43.63.25516,382
174193.43.64.0/18193.43.64.1 to 193.43.127.254193.43.127.25516,382
175193.43.128.0/18193.43.128.1 to 193.43.191.254193.43.191.25516,382
176193.43.192.0/18193.43.192.1 to 193.43.255.254193.43.255.25516,382
177193.44.0.0/18193.44.0.1 to 193.44.63.254193.44.63.25516,382
178193.44.64.0/18193.44.64.1 to 193.44.127.254193.44.127.25516,382
179193.44.128.0/18193.44.128.1 to 193.44.191.254193.44.191.25516,382
180193.44.192.0/18193.44.192.1 to 193.44.255.254193.44.255.25516,382
181193.45.0.0/18193.45.0.1 to 193.45.63.254193.45.63.25516,382
182193.45.64.0/18193.45.64.1 to 193.45.127.254193.45.127.25516,382
183193.45.128.0/18193.45.128.1 to 193.45.191.254193.45.191.25516,382
184193.45.192.0/18193.45.192.1 to 193.45.255.254193.45.255.25516,382
185193.46.0.0/18193.46.0.1 to 193.46.63.254193.46.63.25516,382
186193.46.64.0/18193.46.64.1 to 193.46.127.254193.46.127.25516,382
187193.46.128.0/18193.46.128.1 to 193.46.191.254193.46.191.25516,382
188193.46.192.0/18193.46.192.1 to 193.46.255.254193.46.255.25516,382
189193.47.0.0/18193.47.0.1 to 193.47.63.254193.47.63.25516,382
190193.47.64.0/18193.47.64.1 to 193.47.127.254193.47.127.25516,382
191193.47.128.0/18193.47.128.1 to 193.47.191.254193.47.191.25516,382
192193.47.192.0/18193.47.192.1 to 193.47.255.254193.47.255.25516,382
193193.48.0.0/18193.48.0.1 to 193.48.63.254193.48.63.25516,382
194193.48.64.0/18193.48.64.1 to 193.48.127.254193.48.127.25516,382
195193.48.128.0/18193.48.128.1 to 193.48.191.254193.48.191.25516,382
196193.48.192.0/18193.48.192.1 to 193.48.255.254193.48.255.25516,382
197193.49.0.0/18193.49.0.1 to 193.49.63.254193.49.63.25516,382
198193.49.64.0/18193.49.64.1 to 193.49.127.254193.49.127.25516,382
199193.49.128.0/18193.49.128.1 to 193.49.191.254193.49.191.25516,382
200193.49.192.0/18193.49.192.1 to 193.49.255.254193.49.255.25516,382
201193.50.0.0/18193.50.0.1 to 193.50.63.254193.50.63.25516,382
202193.50.64.0/18193.50.64.1 to 193.50.127.254193.50.127.25516,382
203193.50.128.0/18193.50.128.1 to 193.50.191.254193.50.191.25516,382
204193.50.192.0/18193.50.192.1 to 193.50.255.254193.50.255.25516,382
205193.51.0.0/18193.51.0.1 to 193.51.63.254193.51.63.25516,382
206193.51.64.0/18193.51.64.1 to 193.51.127.254193.51.127.25516,382
207193.51.128.0/18193.51.128.1 to 193.51.191.254193.51.191.25516,382
208193.51.192.0/18193.51.192.1 to 193.51.255.254193.51.255.25516,382
209193.52.0.0/18193.52.0.1 to 193.52.63.254193.52.63.25516,382
210193.52.64.0/18193.52.64.1 to 193.52.127.254193.52.127.25516,382
211193.52.128.0/18193.52.128.1 to 193.52.191.254193.52.191.25516,382
212193.52.192.0/18193.52.192.1 to 193.52.255.254193.52.255.25516,382
213193.53.0.0/18193.53.0.1 to 193.53.63.254193.53.63.25516,382
214193.53.64.0/18193.53.64.1 to 193.53.127.254193.53.127.25516,382
215193.53.128.0/18193.53.128.1 to 193.53.191.254193.53.191.25516,382
216193.53.192.0/18193.53.192.1 to 193.53.255.254193.53.255.25516,382
217193.54.0.0/18193.54.0.1 to 193.54.63.254193.54.63.25516,382
218193.54.64.0/18193.54.64.1 to 193.54.127.254193.54.127.25516,382
219193.54.128.0/18193.54.128.1 to 193.54.191.254193.54.191.25516,382
220193.54.192.0/18193.54.192.1 to 193.54.255.254193.54.255.25516,382
221193.55.0.0/18193.55.0.1 to 193.55.63.254193.55.63.25516,382
222193.55.64.0/18193.55.64.1 to 193.55.127.254193.55.127.25516,382
223193.55.128.0/18193.55.128.1 to 193.55.191.254193.55.191.25516,382
224193.55.192.0/18193.55.192.1 to 193.55.255.254193.55.255.25516,382
225193.56.0.0/18193.56.0.1 to 193.56.63.254193.56.63.25516,382
226193.56.64.0/18193.56.64.1 to 193.56.127.254193.56.127.25516,382
227193.56.128.0/18193.56.128.1 to 193.56.191.254193.56.191.25516,382
228193.56.192.0/18193.56.192.1 to 193.56.255.254193.56.255.25516,382
229193.57.0.0/18193.57.0.1 to 193.57.63.254193.57.63.25516,382
230193.57.64.0/18193.57.64.1 to 193.57.127.254193.57.127.25516,382
231193.57.128.0/18193.57.128.1 to 193.57.191.254193.57.191.25516,382
232193.57.192.0/18193.57.192.1 to 193.57.255.254193.57.255.25516,382
233193.58.0.0/18193.58.0.1 to 193.58.63.254193.58.63.25516,382
234193.58.64.0/18193.58.64.1 to 193.58.127.254193.58.127.25516,382
235193.58.128.0/18193.58.128.1 to 193.58.191.254193.58.191.25516,382
236193.58.192.0/18193.58.192.1 to 193.58.255.254193.58.255.25516,382
237193.59.0.0/18193.59.0.1 to 193.59.63.254193.59.63.25516,382
238193.59.64.0/18193.59.64.1 to 193.59.127.254193.59.127.25516,382
239193.59.128.0/18193.59.128.1 to 193.59.191.254193.59.191.25516,382
240193.59.192.0/18193.59.192.1 to 193.59.255.254193.59.255.25516,382
241193.60.0.0/18193.60.0.1 to 193.60.63.254193.60.63.25516,382
242193.60.64.0/18193.60.64.1 to 193.60.127.254193.60.127.25516,382
243193.60.128.0/18193.60.128.1 to 193.60.191.254193.60.191.25516,382
244193.60.192.0/18193.60.192.1 to 193.60.255.254193.60.255.25516,382
245193.61.0.0/18193.61.0.1 to 193.61.63.254193.61.63.25516,382
246193.61.64.0/18193.61.64.1 to 193.61.127.254193.61.127.25516,382
247193.61.128.0/18193.61.128.1 to 193.61.191.254193.61.191.25516,382
248193.61.192.0/18193.61.192.1 to 193.61.255.254193.61.255.25516,382
249193.62.0.0/18193.62.0.1 to 193.62.63.254193.62.63.25516,382
250193.62.64.0/18193.62.64.1 to 193.62.127.254193.62.127.25516,382
251193.62.128.0/18193.62.128.1 to 193.62.191.254193.62.191.25516,382
252193.62.192.0/18193.62.192.1 to 193.62.255.254193.62.255.25516,382
253193.63.0.0/18193.63.0.1 to 193.63.63.254193.63.63.25516,382
254193.63.64.0/18193.63.64.1 to 193.63.127.254193.63.127.25516,382
255193.63.128.0/18193.63.128.1 to 193.63.191.254193.63.191.25516,382
256193.63.192.0/18193.63.192.1 to 193.63.255.254193.63.255.25516,382

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.