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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.

Network193.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
193.0.0.0
Broadcast address
193.255.255.255
First usable
193.0.0.1
Last usable
193.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex C1000000 · Integer 3238002688 to 3254779903
Reverse DNS zone
193.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000001..00000000.00000000.00000000193.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11000001..00000000.00000000.00000000193.0.0.0
Broadcast11000001..11111111.11111111.11111111193.255.255.255
Split into smaller subnets/17
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

193.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1193.0.0.0/17193.0.0.1 to 193.0.127.254193.0.127.25532,766
2193.0.128.0/17193.0.128.1 to 193.0.255.254193.0.255.25532,766
3193.1.0.0/17193.1.0.1 to 193.1.127.254193.1.127.25532,766
4193.1.128.0/17193.1.128.1 to 193.1.255.254193.1.255.25532,766
5193.2.0.0/17193.2.0.1 to 193.2.127.254193.2.127.25532,766
6193.2.128.0/17193.2.128.1 to 193.2.255.254193.2.255.25532,766
7193.3.0.0/17193.3.0.1 to 193.3.127.254193.3.127.25532,766
8193.3.128.0/17193.3.128.1 to 193.3.255.254193.3.255.25532,766
9193.4.0.0/17193.4.0.1 to 193.4.127.254193.4.127.25532,766
10193.4.128.0/17193.4.128.1 to 193.4.255.254193.4.255.25532,766
11193.5.0.0/17193.5.0.1 to 193.5.127.254193.5.127.25532,766
12193.5.128.0/17193.5.128.1 to 193.5.255.254193.5.255.25532,766
13193.6.0.0/17193.6.0.1 to 193.6.127.254193.6.127.25532,766
14193.6.128.0/17193.6.128.1 to 193.6.255.254193.6.255.25532,766
15193.7.0.0/17193.7.0.1 to 193.7.127.254193.7.127.25532,766
16193.7.128.0/17193.7.128.1 to 193.7.255.254193.7.255.25532,766
17193.8.0.0/17193.8.0.1 to 193.8.127.254193.8.127.25532,766
18193.8.128.0/17193.8.128.1 to 193.8.255.254193.8.255.25532,766
19193.9.0.0/17193.9.0.1 to 193.9.127.254193.9.127.25532,766
20193.9.128.0/17193.9.128.1 to 193.9.255.254193.9.255.25532,766
21193.10.0.0/17193.10.0.1 to 193.10.127.254193.10.127.25532,766
22193.10.128.0/17193.10.128.1 to 193.10.255.254193.10.255.25532,766
23193.11.0.0/17193.11.0.1 to 193.11.127.254193.11.127.25532,766
24193.11.128.0/17193.11.128.1 to 193.11.255.254193.11.255.25532,766
25193.12.0.0/17193.12.0.1 to 193.12.127.254193.12.127.25532,766
26193.12.128.0/17193.12.128.1 to 193.12.255.254193.12.255.25532,766
27193.13.0.0/17193.13.0.1 to 193.13.127.254193.13.127.25532,766
28193.13.128.0/17193.13.128.1 to 193.13.255.254193.13.255.25532,766
29193.14.0.0/17193.14.0.1 to 193.14.127.254193.14.127.25532,766
30193.14.128.0/17193.14.128.1 to 193.14.255.254193.14.255.25532,766
31193.15.0.0/17193.15.0.1 to 193.15.127.254193.15.127.25532,766
32193.15.128.0/17193.15.128.1 to 193.15.255.254193.15.255.25532,766
33193.16.0.0/17193.16.0.1 to 193.16.127.254193.16.127.25532,766
34193.16.128.0/17193.16.128.1 to 193.16.255.254193.16.255.25532,766
35193.17.0.0/17193.17.0.1 to 193.17.127.254193.17.127.25532,766
36193.17.128.0/17193.17.128.1 to 193.17.255.254193.17.255.25532,766
37193.18.0.0/17193.18.0.1 to 193.18.127.254193.18.127.25532,766
38193.18.128.0/17193.18.128.1 to 193.18.255.254193.18.255.25532,766
39193.19.0.0/17193.19.0.1 to 193.19.127.254193.19.127.25532,766
40193.19.128.0/17193.19.128.1 to 193.19.255.254193.19.255.25532,766
41193.20.0.0/17193.20.0.1 to 193.20.127.254193.20.127.25532,766
42193.20.128.0/17193.20.128.1 to 193.20.255.254193.20.255.25532,766
43193.21.0.0/17193.21.0.1 to 193.21.127.254193.21.127.25532,766
44193.21.128.0/17193.21.128.1 to 193.21.255.254193.21.255.25532,766
45193.22.0.0/17193.22.0.1 to 193.22.127.254193.22.127.25532,766
46193.22.128.0/17193.22.128.1 to 193.22.255.254193.22.255.25532,766
47193.23.0.0/17193.23.0.1 to 193.23.127.254193.23.127.25532,766
48193.23.128.0/17193.23.128.1 to 193.23.255.254193.23.255.25532,766
49193.24.0.0/17193.24.0.1 to 193.24.127.254193.24.127.25532,766
50193.24.128.0/17193.24.128.1 to 193.24.255.254193.24.255.25532,766
51193.25.0.0/17193.25.0.1 to 193.25.127.254193.25.127.25532,766
52193.25.128.0/17193.25.128.1 to 193.25.255.254193.25.255.25532,766
53193.26.0.0/17193.26.0.1 to 193.26.127.254193.26.127.25532,766
54193.26.128.0/17193.26.128.1 to 193.26.255.254193.26.255.25532,766
55193.27.0.0/17193.27.0.1 to 193.27.127.254193.27.127.25532,766
56193.27.128.0/17193.27.128.1 to 193.27.255.254193.27.255.25532,766
57193.28.0.0/17193.28.0.1 to 193.28.127.254193.28.127.25532,766
58193.28.128.0/17193.28.128.1 to 193.28.255.254193.28.255.25532,766
59193.29.0.0/17193.29.0.1 to 193.29.127.254193.29.127.25532,766
60193.29.128.0/17193.29.128.1 to 193.29.255.254193.29.255.25532,766
61193.30.0.0/17193.30.0.1 to 193.30.127.254193.30.127.25532,766
62193.30.128.0/17193.30.128.1 to 193.30.255.254193.30.255.25532,766
63193.31.0.0/17193.31.0.1 to 193.31.127.254193.31.127.25532,766
64193.31.128.0/17193.31.128.1 to 193.31.255.254193.31.255.25532,766
65193.32.0.0/17193.32.0.1 to 193.32.127.254193.32.127.25532,766
66193.32.128.0/17193.32.128.1 to 193.32.255.254193.32.255.25532,766
67193.33.0.0/17193.33.0.1 to 193.33.127.254193.33.127.25532,766
68193.33.128.0/17193.33.128.1 to 193.33.255.254193.33.255.25532,766
69193.34.0.0/17193.34.0.1 to 193.34.127.254193.34.127.25532,766
70193.34.128.0/17193.34.128.1 to 193.34.255.254193.34.255.25532,766
71193.35.0.0/17193.35.0.1 to 193.35.127.254193.35.127.25532,766
72193.35.128.0/17193.35.128.1 to 193.35.255.254193.35.255.25532,766
73193.36.0.0/17193.36.0.1 to 193.36.127.254193.36.127.25532,766
74193.36.128.0/17193.36.128.1 to 193.36.255.254193.36.255.25532,766
75193.37.0.0/17193.37.0.1 to 193.37.127.254193.37.127.25532,766
76193.37.128.0/17193.37.128.1 to 193.37.255.254193.37.255.25532,766
77193.38.0.0/17193.38.0.1 to 193.38.127.254193.38.127.25532,766
78193.38.128.0/17193.38.128.1 to 193.38.255.254193.38.255.25532,766
79193.39.0.0/17193.39.0.1 to 193.39.127.254193.39.127.25532,766
80193.39.128.0/17193.39.128.1 to 193.39.255.254193.39.255.25532,766
81193.40.0.0/17193.40.0.1 to 193.40.127.254193.40.127.25532,766
82193.40.128.0/17193.40.128.1 to 193.40.255.254193.40.255.25532,766
83193.41.0.0/17193.41.0.1 to 193.41.127.254193.41.127.25532,766
84193.41.128.0/17193.41.128.1 to 193.41.255.254193.41.255.25532,766
85193.42.0.0/17193.42.0.1 to 193.42.127.254193.42.127.25532,766
86193.42.128.0/17193.42.128.1 to 193.42.255.254193.42.255.25532,766
87193.43.0.0/17193.43.0.1 to 193.43.127.254193.43.127.25532,766
88193.43.128.0/17193.43.128.1 to 193.43.255.254193.43.255.25532,766
89193.44.0.0/17193.44.0.1 to 193.44.127.254193.44.127.25532,766
90193.44.128.0/17193.44.128.1 to 193.44.255.254193.44.255.25532,766
91193.45.0.0/17193.45.0.1 to 193.45.127.254193.45.127.25532,766
92193.45.128.0/17193.45.128.1 to 193.45.255.254193.45.255.25532,766
93193.46.0.0/17193.46.0.1 to 193.46.127.254193.46.127.25532,766
94193.46.128.0/17193.46.128.1 to 193.46.255.254193.46.255.25532,766
95193.47.0.0/17193.47.0.1 to 193.47.127.254193.47.127.25532,766
96193.47.128.0/17193.47.128.1 to 193.47.255.254193.47.255.25532,766
97193.48.0.0/17193.48.0.1 to 193.48.127.254193.48.127.25532,766
98193.48.128.0/17193.48.128.1 to 193.48.255.254193.48.255.25532,766
99193.49.0.0/17193.49.0.1 to 193.49.127.254193.49.127.25532,766
100193.49.128.0/17193.49.128.1 to 193.49.255.254193.49.255.25532,766
101193.50.0.0/17193.50.0.1 to 193.50.127.254193.50.127.25532,766
102193.50.128.0/17193.50.128.1 to 193.50.255.254193.50.255.25532,766
103193.51.0.0/17193.51.0.1 to 193.51.127.254193.51.127.25532,766
104193.51.128.0/17193.51.128.1 to 193.51.255.254193.51.255.25532,766
105193.52.0.0/17193.52.0.1 to 193.52.127.254193.52.127.25532,766
106193.52.128.0/17193.52.128.1 to 193.52.255.254193.52.255.25532,766
107193.53.0.0/17193.53.0.1 to 193.53.127.254193.53.127.25532,766
108193.53.128.0/17193.53.128.1 to 193.53.255.254193.53.255.25532,766
109193.54.0.0/17193.54.0.1 to 193.54.127.254193.54.127.25532,766
110193.54.128.0/17193.54.128.1 to 193.54.255.254193.54.255.25532,766
111193.55.0.0/17193.55.0.1 to 193.55.127.254193.55.127.25532,766
112193.55.128.0/17193.55.128.1 to 193.55.255.254193.55.255.25532,766
113193.56.0.0/17193.56.0.1 to 193.56.127.254193.56.127.25532,766
114193.56.128.0/17193.56.128.1 to 193.56.255.254193.56.255.25532,766
115193.57.0.0/17193.57.0.1 to 193.57.127.254193.57.127.25532,766
116193.57.128.0/17193.57.128.1 to 193.57.255.254193.57.255.25532,766
117193.58.0.0/17193.58.0.1 to 193.58.127.254193.58.127.25532,766
118193.58.128.0/17193.58.128.1 to 193.58.255.254193.58.255.25532,766
119193.59.0.0/17193.59.0.1 to 193.59.127.254193.59.127.25532,766
120193.59.128.0/17193.59.128.1 to 193.59.255.254193.59.255.25532,766
121193.60.0.0/17193.60.0.1 to 193.60.127.254193.60.127.25532,766
122193.60.128.0/17193.60.128.1 to 193.60.255.254193.60.255.25532,766
123193.61.0.0/17193.61.0.1 to 193.61.127.254193.61.127.25532,766
124193.61.128.0/17193.61.128.1 to 193.61.255.254193.61.255.25532,766
125193.62.0.0/17193.62.0.1 to 193.62.127.254193.62.127.25532,766
126193.62.128.0/17193.62.128.1 to 193.62.255.254193.62.255.25532,766
127193.63.0.0/17193.63.0.1 to 193.63.127.254193.63.127.25532,766
128193.63.128.0/17193.63.128.1 to 193.63.255.254193.63.255.25532,766
129193.64.0.0/17193.64.0.1 to 193.64.127.254193.64.127.25532,766
130193.64.128.0/17193.64.128.1 to 193.64.255.254193.64.255.25532,766
131193.65.0.0/17193.65.0.1 to 193.65.127.254193.65.127.25532,766
132193.65.128.0/17193.65.128.1 to 193.65.255.254193.65.255.25532,766
133193.66.0.0/17193.66.0.1 to 193.66.127.254193.66.127.25532,766
134193.66.128.0/17193.66.128.1 to 193.66.255.254193.66.255.25532,766
135193.67.0.0/17193.67.0.1 to 193.67.127.254193.67.127.25532,766
136193.67.128.0/17193.67.128.1 to 193.67.255.254193.67.255.25532,766
137193.68.0.0/17193.68.0.1 to 193.68.127.254193.68.127.25532,766
138193.68.128.0/17193.68.128.1 to 193.68.255.254193.68.255.25532,766
139193.69.0.0/17193.69.0.1 to 193.69.127.254193.69.127.25532,766
140193.69.128.0/17193.69.128.1 to 193.69.255.254193.69.255.25532,766
141193.70.0.0/17193.70.0.1 to 193.70.127.254193.70.127.25532,766
142193.70.128.0/17193.70.128.1 to 193.70.255.254193.70.255.25532,766
143193.71.0.0/17193.71.0.1 to 193.71.127.254193.71.127.25532,766
144193.71.128.0/17193.71.128.1 to 193.71.255.254193.71.255.25532,766
145193.72.0.0/17193.72.0.1 to 193.72.127.254193.72.127.25532,766
146193.72.128.0/17193.72.128.1 to 193.72.255.254193.72.255.25532,766
147193.73.0.0/17193.73.0.1 to 193.73.127.254193.73.127.25532,766
148193.73.128.0/17193.73.128.1 to 193.73.255.254193.73.255.25532,766
149193.74.0.0/17193.74.0.1 to 193.74.127.254193.74.127.25532,766
150193.74.128.0/17193.74.128.1 to 193.74.255.254193.74.255.25532,766
151193.75.0.0/17193.75.0.1 to 193.75.127.254193.75.127.25532,766
152193.75.128.0/17193.75.128.1 to 193.75.255.254193.75.255.25532,766
153193.76.0.0/17193.76.0.1 to 193.76.127.254193.76.127.25532,766
154193.76.128.0/17193.76.128.1 to 193.76.255.254193.76.255.25532,766
155193.77.0.0/17193.77.0.1 to 193.77.127.254193.77.127.25532,766
156193.77.128.0/17193.77.128.1 to 193.77.255.254193.77.255.25532,766
157193.78.0.0/17193.78.0.1 to 193.78.127.254193.78.127.25532,766
158193.78.128.0/17193.78.128.1 to 193.78.255.254193.78.255.25532,766
159193.79.0.0/17193.79.0.1 to 193.79.127.254193.79.127.25532,766
160193.79.128.0/17193.79.128.1 to 193.79.255.254193.79.255.25532,766
161193.80.0.0/17193.80.0.1 to 193.80.127.254193.80.127.25532,766
162193.80.128.0/17193.80.128.1 to 193.80.255.254193.80.255.25532,766
163193.81.0.0/17193.81.0.1 to 193.81.127.254193.81.127.25532,766
164193.81.128.0/17193.81.128.1 to 193.81.255.254193.81.255.25532,766
165193.82.0.0/17193.82.0.1 to 193.82.127.254193.82.127.25532,766
166193.82.128.0/17193.82.128.1 to 193.82.255.254193.82.255.25532,766
167193.83.0.0/17193.83.0.1 to 193.83.127.254193.83.127.25532,766
168193.83.128.0/17193.83.128.1 to 193.83.255.254193.83.255.25532,766
169193.84.0.0/17193.84.0.1 to 193.84.127.254193.84.127.25532,766
170193.84.128.0/17193.84.128.1 to 193.84.255.254193.84.255.25532,766
171193.85.0.0/17193.85.0.1 to 193.85.127.254193.85.127.25532,766
172193.85.128.0/17193.85.128.1 to 193.85.255.254193.85.255.25532,766
173193.86.0.0/17193.86.0.1 to 193.86.127.254193.86.127.25532,766
174193.86.128.0/17193.86.128.1 to 193.86.255.254193.86.255.25532,766
175193.87.0.0/17193.87.0.1 to 193.87.127.254193.87.127.25532,766
176193.87.128.0/17193.87.128.1 to 193.87.255.254193.87.255.25532,766
177193.88.0.0/17193.88.0.1 to 193.88.127.254193.88.127.25532,766
178193.88.128.0/17193.88.128.1 to 193.88.255.254193.88.255.25532,766
179193.89.0.0/17193.89.0.1 to 193.89.127.254193.89.127.25532,766
180193.89.128.0/17193.89.128.1 to 193.89.255.254193.89.255.25532,766
181193.90.0.0/17193.90.0.1 to 193.90.127.254193.90.127.25532,766
182193.90.128.0/17193.90.128.1 to 193.90.255.254193.90.255.25532,766
183193.91.0.0/17193.91.0.1 to 193.91.127.254193.91.127.25532,766
184193.91.128.0/17193.91.128.1 to 193.91.255.254193.91.255.25532,766
185193.92.0.0/17193.92.0.1 to 193.92.127.254193.92.127.25532,766
186193.92.128.0/17193.92.128.1 to 193.92.255.254193.92.255.25532,766
187193.93.0.0/17193.93.0.1 to 193.93.127.254193.93.127.25532,766
188193.93.128.0/17193.93.128.1 to 193.93.255.254193.93.255.25532,766
189193.94.0.0/17193.94.0.1 to 193.94.127.254193.94.127.25532,766
190193.94.128.0/17193.94.128.1 to 193.94.255.254193.94.255.25532,766
191193.95.0.0/17193.95.0.1 to 193.95.127.254193.95.127.25532,766
192193.95.128.0/17193.95.128.1 to 193.95.255.254193.95.255.25532,766
193193.96.0.0/17193.96.0.1 to 193.96.127.254193.96.127.25532,766
194193.96.128.0/17193.96.128.1 to 193.96.255.254193.96.255.25532,766
195193.97.0.0/17193.97.0.1 to 193.97.127.254193.97.127.25532,766
196193.97.128.0/17193.97.128.1 to 193.97.255.254193.97.255.25532,766
197193.98.0.0/17193.98.0.1 to 193.98.127.254193.98.127.25532,766
198193.98.128.0/17193.98.128.1 to 193.98.255.254193.98.255.25532,766
199193.99.0.0/17193.99.0.1 to 193.99.127.254193.99.127.25532,766
200193.99.128.0/17193.99.128.1 to 193.99.255.254193.99.255.25532,766
201193.100.0.0/17193.100.0.1 to 193.100.127.254193.100.127.25532,766
202193.100.128.0/17193.100.128.1 to 193.100.255.254193.100.255.25532,766
203193.101.0.0/17193.101.0.1 to 193.101.127.254193.101.127.25532,766
204193.101.128.0/17193.101.128.1 to 193.101.255.254193.101.255.25532,766
205193.102.0.0/17193.102.0.1 to 193.102.127.254193.102.127.25532,766
206193.102.128.0/17193.102.128.1 to 193.102.255.254193.102.255.25532,766
207193.103.0.0/17193.103.0.1 to 193.103.127.254193.103.127.25532,766
208193.103.128.0/17193.103.128.1 to 193.103.255.254193.103.255.25532,766
209193.104.0.0/17193.104.0.1 to 193.104.127.254193.104.127.25532,766
210193.104.128.0/17193.104.128.1 to 193.104.255.254193.104.255.25532,766
211193.105.0.0/17193.105.0.1 to 193.105.127.254193.105.127.25532,766
212193.105.128.0/17193.105.128.1 to 193.105.255.254193.105.255.25532,766
213193.106.0.0/17193.106.0.1 to 193.106.127.254193.106.127.25532,766
214193.106.128.0/17193.106.128.1 to 193.106.255.254193.106.255.25532,766
215193.107.0.0/17193.107.0.1 to 193.107.127.254193.107.127.25532,766
216193.107.128.0/17193.107.128.1 to 193.107.255.254193.107.255.25532,766
217193.108.0.0/17193.108.0.1 to 193.108.127.254193.108.127.25532,766
218193.108.128.0/17193.108.128.1 to 193.108.255.254193.108.255.25532,766
219193.109.0.0/17193.109.0.1 to 193.109.127.254193.109.127.25532,766
220193.109.128.0/17193.109.128.1 to 193.109.255.254193.109.255.25532,766
221193.110.0.0/17193.110.0.1 to 193.110.127.254193.110.127.25532,766
222193.110.128.0/17193.110.128.1 to 193.110.255.254193.110.255.25532,766
223193.111.0.0/17193.111.0.1 to 193.111.127.254193.111.127.25532,766
224193.111.128.0/17193.111.128.1 to 193.111.255.254193.111.255.25532,766
225193.112.0.0/17193.112.0.1 to 193.112.127.254193.112.127.25532,766
226193.112.128.0/17193.112.128.1 to 193.112.255.254193.112.255.25532,766
227193.113.0.0/17193.113.0.1 to 193.113.127.254193.113.127.25532,766
228193.113.128.0/17193.113.128.1 to 193.113.255.254193.113.255.25532,766
229193.114.0.0/17193.114.0.1 to 193.114.127.254193.114.127.25532,766
230193.114.128.0/17193.114.128.1 to 193.114.255.254193.114.255.25532,766
231193.115.0.0/17193.115.0.1 to 193.115.127.254193.115.127.25532,766
232193.115.128.0/17193.115.128.1 to 193.115.255.254193.115.255.25532,766
233193.116.0.0/17193.116.0.1 to 193.116.127.254193.116.127.25532,766
234193.116.128.0/17193.116.128.1 to 193.116.255.254193.116.255.25532,766
235193.117.0.0/17193.117.0.1 to 193.117.127.254193.117.127.25532,766
236193.117.128.0/17193.117.128.1 to 193.117.255.254193.117.255.25532,766
237193.118.0.0/17193.118.0.1 to 193.118.127.254193.118.127.25532,766
238193.118.128.0/17193.118.128.1 to 193.118.255.254193.118.255.25532,766
239193.119.0.0/17193.119.0.1 to 193.119.127.254193.119.127.25532,766
240193.119.128.0/17193.119.128.1 to 193.119.255.254193.119.255.25532,766
241193.120.0.0/17193.120.0.1 to 193.120.127.254193.120.127.25532,766
242193.120.128.0/17193.120.128.1 to 193.120.255.254193.120.255.25532,766
243193.121.0.0/17193.121.0.1 to 193.121.127.254193.121.127.25532,766
244193.121.128.0/17193.121.128.1 to 193.121.255.254193.121.255.25532,766
245193.122.0.0/17193.122.0.1 to 193.122.127.254193.122.127.25532,766
246193.122.128.0/17193.122.128.1 to 193.122.255.254193.122.255.25532,766
247193.123.0.0/17193.123.0.1 to 193.123.127.254193.123.127.25532,766
248193.123.128.0/17193.123.128.1 to 193.123.255.254193.123.255.25532,766
249193.124.0.0/17193.124.0.1 to 193.124.127.254193.124.127.25532,766
250193.124.128.0/17193.124.128.1 to 193.124.255.254193.124.255.25532,766
251193.125.0.0/17193.125.0.1 to 193.125.127.254193.125.127.25532,766
252193.125.128.0/17193.125.128.1 to 193.125.255.254193.125.255.25532,766
253193.126.0.0/17193.126.0.1 to 193.126.127.254193.126.127.25532,766
254193.126.128.0/17193.126.128.1 to 193.126.255.254193.126.255.25532,766
255193.127.0.0/17193.127.0.1 to 193.127.127.254193.127.127.25532,766
256193.127.128.0/17193.127.128.1 to 193.127.255.254193.127.255.25532,766

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.