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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.

Network193.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
193.2.0.0
Broadcast address
193.3.255.255
First usable
193.2.0.1
Last usable
193.3.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
C (default /24)
As numbers
Hex C1020000 · Integer 3238133760 to 3238264831
Reverse DNS zones
2.193.in-addr.arpa
3.193.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000001.00000010.00000000.00000000193.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11000001.00000010.00000000.00000000193.2.0.0
Broadcast11000001.00000011.11111111.11111111193.3.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

193.2.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1193.2.0.0/25193.2.0.1 to 193.2.0.126193.2.0.127126
2193.2.0.128/25193.2.0.129 to 193.2.0.254193.2.0.255126
3193.2.1.0/25193.2.1.1 to 193.2.1.126193.2.1.127126
4193.2.1.128/25193.2.1.129 to 193.2.1.254193.2.1.255126
5193.2.2.0/25193.2.2.1 to 193.2.2.126193.2.2.127126
6193.2.2.128/25193.2.2.129 to 193.2.2.254193.2.2.255126
7193.2.3.0/25193.2.3.1 to 193.2.3.126193.2.3.127126
8193.2.3.128/25193.2.3.129 to 193.2.3.254193.2.3.255126
9193.2.4.0/25193.2.4.1 to 193.2.4.126193.2.4.127126
10193.2.4.128/25193.2.4.129 to 193.2.4.254193.2.4.255126
11193.2.5.0/25193.2.5.1 to 193.2.5.126193.2.5.127126
12193.2.5.128/25193.2.5.129 to 193.2.5.254193.2.5.255126
13193.2.6.0/25193.2.6.1 to 193.2.6.126193.2.6.127126
14193.2.6.128/25193.2.6.129 to 193.2.6.254193.2.6.255126
15193.2.7.0/25193.2.7.1 to 193.2.7.126193.2.7.127126
16193.2.7.128/25193.2.7.129 to 193.2.7.254193.2.7.255126
17193.2.8.0/25193.2.8.1 to 193.2.8.126193.2.8.127126
18193.2.8.128/25193.2.8.129 to 193.2.8.254193.2.8.255126
19193.2.9.0/25193.2.9.1 to 193.2.9.126193.2.9.127126
20193.2.9.128/25193.2.9.129 to 193.2.9.254193.2.9.255126
21193.2.10.0/25193.2.10.1 to 193.2.10.126193.2.10.127126
22193.2.10.128/25193.2.10.129 to 193.2.10.254193.2.10.255126
23193.2.11.0/25193.2.11.1 to 193.2.11.126193.2.11.127126
24193.2.11.128/25193.2.11.129 to 193.2.11.254193.2.11.255126
25193.2.12.0/25193.2.12.1 to 193.2.12.126193.2.12.127126
26193.2.12.128/25193.2.12.129 to 193.2.12.254193.2.12.255126
27193.2.13.0/25193.2.13.1 to 193.2.13.126193.2.13.127126
28193.2.13.128/25193.2.13.129 to 193.2.13.254193.2.13.255126
29193.2.14.0/25193.2.14.1 to 193.2.14.126193.2.14.127126
30193.2.14.128/25193.2.14.129 to 193.2.14.254193.2.14.255126
31193.2.15.0/25193.2.15.1 to 193.2.15.126193.2.15.127126
32193.2.15.128/25193.2.15.129 to 193.2.15.254193.2.15.255126
33193.2.16.0/25193.2.16.1 to 193.2.16.126193.2.16.127126
34193.2.16.128/25193.2.16.129 to 193.2.16.254193.2.16.255126
35193.2.17.0/25193.2.17.1 to 193.2.17.126193.2.17.127126
36193.2.17.128/25193.2.17.129 to 193.2.17.254193.2.17.255126
37193.2.18.0/25193.2.18.1 to 193.2.18.126193.2.18.127126
38193.2.18.128/25193.2.18.129 to 193.2.18.254193.2.18.255126
39193.2.19.0/25193.2.19.1 to 193.2.19.126193.2.19.127126
40193.2.19.128/25193.2.19.129 to 193.2.19.254193.2.19.255126
41193.2.20.0/25193.2.20.1 to 193.2.20.126193.2.20.127126
42193.2.20.128/25193.2.20.129 to 193.2.20.254193.2.20.255126
43193.2.21.0/25193.2.21.1 to 193.2.21.126193.2.21.127126
44193.2.21.128/25193.2.21.129 to 193.2.21.254193.2.21.255126
45193.2.22.0/25193.2.22.1 to 193.2.22.126193.2.22.127126
46193.2.22.128/25193.2.22.129 to 193.2.22.254193.2.22.255126
47193.2.23.0/25193.2.23.1 to 193.2.23.126193.2.23.127126
48193.2.23.128/25193.2.23.129 to 193.2.23.254193.2.23.255126
49193.2.24.0/25193.2.24.1 to 193.2.24.126193.2.24.127126
50193.2.24.128/25193.2.24.129 to 193.2.24.254193.2.24.255126
51193.2.25.0/25193.2.25.1 to 193.2.25.126193.2.25.127126
52193.2.25.128/25193.2.25.129 to 193.2.25.254193.2.25.255126
53193.2.26.0/25193.2.26.1 to 193.2.26.126193.2.26.127126
54193.2.26.128/25193.2.26.129 to 193.2.26.254193.2.26.255126
55193.2.27.0/25193.2.27.1 to 193.2.27.126193.2.27.127126
56193.2.27.128/25193.2.27.129 to 193.2.27.254193.2.27.255126
57193.2.28.0/25193.2.28.1 to 193.2.28.126193.2.28.127126
58193.2.28.128/25193.2.28.129 to 193.2.28.254193.2.28.255126
59193.2.29.0/25193.2.29.1 to 193.2.29.126193.2.29.127126
60193.2.29.128/25193.2.29.129 to 193.2.29.254193.2.29.255126
61193.2.30.0/25193.2.30.1 to 193.2.30.126193.2.30.127126
62193.2.30.128/25193.2.30.129 to 193.2.30.254193.2.30.255126
63193.2.31.0/25193.2.31.1 to 193.2.31.126193.2.31.127126
64193.2.31.128/25193.2.31.129 to 193.2.31.254193.2.31.255126
65193.2.32.0/25193.2.32.1 to 193.2.32.126193.2.32.127126
66193.2.32.128/25193.2.32.129 to 193.2.32.254193.2.32.255126
67193.2.33.0/25193.2.33.1 to 193.2.33.126193.2.33.127126
68193.2.33.128/25193.2.33.129 to 193.2.33.254193.2.33.255126
69193.2.34.0/25193.2.34.1 to 193.2.34.126193.2.34.127126
70193.2.34.128/25193.2.34.129 to 193.2.34.254193.2.34.255126
71193.2.35.0/25193.2.35.1 to 193.2.35.126193.2.35.127126
72193.2.35.128/25193.2.35.129 to 193.2.35.254193.2.35.255126
73193.2.36.0/25193.2.36.1 to 193.2.36.126193.2.36.127126
74193.2.36.128/25193.2.36.129 to 193.2.36.254193.2.36.255126
75193.2.37.0/25193.2.37.1 to 193.2.37.126193.2.37.127126
76193.2.37.128/25193.2.37.129 to 193.2.37.254193.2.37.255126
77193.2.38.0/25193.2.38.1 to 193.2.38.126193.2.38.127126
78193.2.38.128/25193.2.38.129 to 193.2.38.254193.2.38.255126
79193.2.39.0/25193.2.39.1 to 193.2.39.126193.2.39.127126
80193.2.39.128/25193.2.39.129 to 193.2.39.254193.2.39.255126
81193.2.40.0/25193.2.40.1 to 193.2.40.126193.2.40.127126
82193.2.40.128/25193.2.40.129 to 193.2.40.254193.2.40.255126
83193.2.41.0/25193.2.41.1 to 193.2.41.126193.2.41.127126
84193.2.41.128/25193.2.41.129 to 193.2.41.254193.2.41.255126
85193.2.42.0/25193.2.42.1 to 193.2.42.126193.2.42.127126
86193.2.42.128/25193.2.42.129 to 193.2.42.254193.2.42.255126
87193.2.43.0/25193.2.43.1 to 193.2.43.126193.2.43.127126
88193.2.43.128/25193.2.43.129 to 193.2.43.254193.2.43.255126
89193.2.44.0/25193.2.44.1 to 193.2.44.126193.2.44.127126
90193.2.44.128/25193.2.44.129 to 193.2.44.254193.2.44.255126
91193.2.45.0/25193.2.45.1 to 193.2.45.126193.2.45.127126
92193.2.45.128/25193.2.45.129 to 193.2.45.254193.2.45.255126
93193.2.46.0/25193.2.46.1 to 193.2.46.126193.2.46.127126
94193.2.46.128/25193.2.46.129 to 193.2.46.254193.2.46.255126
95193.2.47.0/25193.2.47.1 to 193.2.47.126193.2.47.127126
96193.2.47.128/25193.2.47.129 to 193.2.47.254193.2.47.255126
97193.2.48.0/25193.2.48.1 to 193.2.48.126193.2.48.127126
98193.2.48.128/25193.2.48.129 to 193.2.48.254193.2.48.255126
99193.2.49.0/25193.2.49.1 to 193.2.49.126193.2.49.127126
100193.2.49.128/25193.2.49.129 to 193.2.49.254193.2.49.255126
101193.2.50.0/25193.2.50.1 to 193.2.50.126193.2.50.127126
102193.2.50.128/25193.2.50.129 to 193.2.50.254193.2.50.255126
103193.2.51.0/25193.2.51.1 to 193.2.51.126193.2.51.127126
104193.2.51.128/25193.2.51.129 to 193.2.51.254193.2.51.255126
105193.2.52.0/25193.2.52.1 to 193.2.52.126193.2.52.127126
106193.2.52.128/25193.2.52.129 to 193.2.52.254193.2.52.255126
107193.2.53.0/25193.2.53.1 to 193.2.53.126193.2.53.127126
108193.2.53.128/25193.2.53.129 to 193.2.53.254193.2.53.255126
109193.2.54.0/25193.2.54.1 to 193.2.54.126193.2.54.127126
110193.2.54.128/25193.2.54.129 to 193.2.54.254193.2.54.255126
111193.2.55.0/25193.2.55.1 to 193.2.55.126193.2.55.127126
112193.2.55.128/25193.2.55.129 to 193.2.55.254193.2.55.255126
113193.2.56.0/25193.2.56.1 to 193.2.56.126193.2.56.127126
114193.2.56.128/25193.2.56.129 to 193.2.56.254193.2.56.255126
115193.2.57.0/25193.2.57.1 to 193.2.57.126193.2.57.127126
116193.2.57.128/25193.2.57.129 to 193.2.57.254193.2.57.255126
117193.2.58.0/25193.2.58.1 to 193.2.58.126193.2.58.127126
118193.2.58.128/25193.2.58.129 to 193.2.58.254193.2.58.255126
119193.2.59.0/25193.2.59.1 to 193.2.59.126193.2.59.127126
120193.2.59.128/25193.2.59.129 to 193.2.59.254193.2.59.255126
121193.2.60.0/25193.2.60.1 to 193.2.60.126193.2.60.127126
122193.2.60.128/25193.2.60.129 to 193.2.60.254193.2.60.255126
123193.2.61.0/25193.2.61.1 to 193.2.61.126193.2.61.127126
124193.2.61.128/25193.2.61.129 to 193.2.61.254193.2.61.255126
125193.2.62.0/25193.2.62.1 to 193.2.62.126193.2.62.127126
126193.2.62.128/25193.2.62.129 to 193.2.62.254193.2.62.255126
127193.2.63.0/25193.2.63.1 to 193.2.63.126193.2.63.127126
128193.2.63.128/25193.2.63.129 to 193.2.63.254193.2.63.255126
129193.2.64.0/25193.2.64.1 to 193.2.64.126193.2.64.127126
130193.2.64.128/25193.2.64.129 to 193.2.64.254193.2.64.255126
131193.2.65.0/25193.2.65.1 to 193.2.65.126193.2.65.127126
132193.2.65.128/25193.2.65.129 to 193.2.65.254193.2.65.255126
133193.2.66.0/25193.2.66.1 to 193.2.66.126193.2.66.127126
134193.2.66.128/25193.2.66.129 to 193.2.66.254193.2.66.255126
135193.2.67.0/25193.2.67.1 to 193.2.67.126193.2.67.127126
136193.2.67.128/25193.2.67.129 to 193.2.67.254193.2.67.255126
137193.2.68.0/25193.2.68.1 to 193.2.68.126193.2.68.127126
138193.2.68.128/25193.2.68.129 to 193.2.68.254193.2.68.255126
139193.2.69.0/25193.2.69.1 to 193.2.69.126193.2.69.127126
140193.2.69.128/25193.2.69.129 to 193.2.69.254193.2.69.255126
141193.2.70.0/25193.2.70.1 to 193.2.70.126193.2.70.127126
142193.2.70.128/25193.2.70.129 to 193.2.70.254193.2.70.255126
143193.2.71.0/25193.2.71.1 to 193.2.71.126193.2.71.127126
144193.2.71.128/25193.2.71.129 to 193.2.71.254193.2.71.255126
145193.2.72.0/25193.2.72.1 to 193.2.72.126193.2.72.127126
146193.2.72.128/25193.2.72.129 to 193.2.72.254193.2.72.255126
147193.2.73.0/25193.2.73.1 to 193.2.73.126193.2.73.127126
148193.2.73.128/25193.2.73.129 to 193.2.73.254193.2.73.255126
149193.2.74.0/25193.2.74.1 to 193.2.74.126193.2.74.127126
150193.2.74.128/25193.2.74.129 to 193.2.74.254193.2.74.255126
151193.2.75.0/25193.2.75.1 to 193.2.75.126193.2.75.127126
152193.2.75.128/25193.2.75.129 to 193.2.75.254193.2.75.255126
153193.2.76.0/25193.2.76.1 to 193.2.76.126193.2.76.127126
154193.2.76.128/25193.2.76.129 to 193.2.76.254193.2.76.255126
155193.2.77.0/25193.2.77.1 to 193.2.77.126193.2.77.127126
156193.2.77.128/25193.2.77.129 to 193.2.77.254193.2.77.255126
157193.2.78.0/25193.2.78.1 to 193.2.78.126193.2.78.127126
158193.2.78.128/25193.2.78.129 to 193.2.78.254193.2.78.255126
159193.2.79.0/25193.2.79.1 to 193.2.79.126193.2.79.127126
160193.2.79.128/25193.2.79.129 to 193.2.79.254193.2.79.255126
161193.2.80.0/25193.2.80.1 to 193.2.80.126193.2.80.127126
162193.2.80.128/25193.2.80.129 to 193.2.80.254193.2.80.255126
163193.2.81.0/25193.2.81.1 to 193.2.81.126193.2.81.127126
164193.2.81.128/25193.2.81.129 to 193.2.81.254193.2.81.255126
165193.2.82.0/25193.2.82.1 to 193.2.82.126193.2.82.127126
166193.2.82.128/25193.2.82.129 to 193.2.82.254193.2.82.255126
167193.2.83.0/25193.2.83.1 to 193.2.83.126193.2.83.127126
168193.2.83.128/25193.2.83.129 to 193.2.83.254193.2.83.255126
169193.2.84.0/25193.2.84.1 to 193.2.84.126193.2.84.127126
170193.2.84.128/25193.2.84.129 to 193.2.84.254193.2.84.255126
171193.2.85.0/25193.2.85.1 to 193.2.85.126193.2.85.127126
172193.2.85.128/25193.2.85.129 to 193.2.85.254193.2.85.255126
173193.2.86.0/25193.2.86.1 to 193.2.86.126193.2.86.127126
174193.2.86.128/25193.2.86.129 to 193.2.86.254193.2.86.255126
175193.2.87.0/25193.2.87.1 to 193.2.87.126193.2.87.127126
176193.2.87.128/25193.2.87.129 to 193.2.87.254193.2.87.255126
177193.2.88.0/25193.2.88.1 to 193.2.88.126193.2.88.127126
178193.2.88.128/25193.2.88.129 to 193.2.88.254193.2.88.255126
179193.2.89.0/25193.2.89.1 to 193.2.89.126193.2.89.127126
180193.2.89.128/25193.2.89.129 to 193.2.89.254193.2.89.255126
181193.2.90.0/25193.2.90.1 to 193.2.90.126193.2.90.127126
182193.2.90.128/25193.2.90.129 to 193.2.90.254193.2.90.255126
183193.2.91.0/25193.2.91.1 to 193.2.91.126193.2.91.127126
184193.2.91.128/25193.2.91.129 to 193.2.91.254193.2.91.255126
185193.2.92.0/25193.2.92.1 to 193.2.92.126193.2.92.127126
186193.2.92.128/25193.2.92.129 to 193.2.92.254193.2.92.255126
187193.2.93.0/25193.2.93.1 to 193.2.93.126193.2.93.127126
188193.2.93.128/25193.2.93.129 to 193.2.93.254193.2.93.255126
189193.2.94.0/25193.2.94.1 to 193.2.94.126193.2.94.127126
190193.2.94.128/25193.2.94.129 to 193.2.94.254193.2.94.255126
191193.2.95.0/25193.2.95.1 to 193.2.95.126193.2.95.127126
192193.2.95.128/25193.2.95.129 to 193.2.95.254193.2.95.255126
193193.2.96.0/25193.2.96.1 to 193.2.96.126193.2.96.127126
194193.2.96.128/25193.2.96.129 to 193.2.96.254193.2.96.255126
195193.2.97.0/25193.2.97.1 to 193.2.97.126193.2.97.127126
196193.2.97.128/25193.2.97.129 to 193.2.97.254193.2.97.255126
197193.2.98.0/25193.2.98.1 to 193.2.98.126193.2.98.127126
198193.2.98.128/25193.2.98.129 to 193.2.98.254193.2.98.255126
199193.2.99.0/25193.2.99.1 to 193.2.99.126193.2.99.127126
200193.2.99.128/25193.2.99.129 to 193.2.99.254193.2.99.255126
201193.2.100.0/25193.2.100.1 to 193.2.100.126193.2.100.127126
202193.2.100.128/25193.2.100.129 to 193.2.100.254193.2.100.255126
203193.2.101.0/25193.2.101.1 to 193.2.101.126193.2.101.127126
204193.2.101.128/25193.2.101.129 to 193.2.101.254193.2.101.255126
205193.2.102.0/25193.2.102.1 to 193.2.102.126193.2.102.127126
206193.2.102.128/25193.2.102.129 to 193.2.102.254193.2.102.255126
207193.2.103.0/25193.2.103.1 to 193.2.103.126193.2.103.127126
208193.2.103.128/25193.2.103.129 to 193.2.103.254193.2.103.255126
209193.2.104.0/25193.2.104.1 to 193.2.104.126193.2.104.127126
210193.2.104.128/25193.2.104.129 to 193.2.104.254193.2.104.255126
211193.2.105.0/25193.2.105.1 to 193.2.105.126193.2.105.127126
212193.2.105.128/25193.2.105.129 to 193.2.105.254193.2.105.255126
213193.2.106.0/25193.2.106.1 to 193.2.106.126193.2.106.127126
214193.2.106.128/25193.2.106.129 to 193.2.106.254193.2.106.255126
215193.2.107.0/25193.2.107.1 to 193.2.107.126193.2.107.127126
216193.2.107.128/25193.2.107.129 to 193.2.107.254193.2.107.255126
217193.2.108.0/25193.2.108.1 to 193.2.108.126193.2.108.127126
218193.2.108.128/25193.2.108.129 to 193.2.108.254193.2.108.255126
219193.2.109.0/25193.2.109.1 to 193.2.109.126193.2.109.127126
220193.2.109.128/25193.2.109.129 to 193.2.109.254193.2.109.255126
221193.2.110.0/25193.2.110.1 to 193.2.110.126193.2.110.127126
222193.2.110.128/25193.2.110.129 to 193.2.110.254193.2.110.255126
223193.2.111.0/25193.2.111.1 to 193.2.111.126193.2.111.127126
224193.2.111.128/25193.2.111.129 to 193.2.111.254193.2.111.255126
225193.2.112.0/25193.2.112.1 to 193.2.112.126193.2.112.127126
226193.2.112.128/25193.2.112.129 to 193.2.112.254193.2.112.255126
227193.2.113.0/25193.2.113.1 to 193.2.113.126193.2.113.127126
228193.2.113.128/25193.2.113.129 to 193.2.113.254193.2.113.255126
229193.2.114.0/25193.2.114.1 to 193.2.114.126193.2.114.127126
230193.2.114.128/25193.2.114.129 to 193.2.114.254193.2.114.255126
231193.2.115.0/25193.2.115.1 to 193.2.115.126193.2.115.127126
232193.2.115.128/25193.2.115.129 to 193.2.115.254193.2.115.255126
233193.2.116.0/25193.2.116.1 to 193.2.116.126193.2.116.127126
234193.2.116.128/25193.2.116.129 to 193.2.116.254193.2.116.255126
235193.2.117.0/25193.2.117.1 to 193.2.117.126193.2.117.127126
236193.2.117.128/25193.2.117.129 to 193.2.117.254193.2.117.255126
237193.2.118.0/25193.2.118.1 to 193.2.118.126193.2.118.127126
238193.2.118.128/25193.2.118.129 to 193.2.118.254193.2.118.255126
239193.2.119.0/25193.2.119.1 to 193.2.119.126193.2.119.127126
240193.2.119.128/25193.2.119.129 to 193.2.119.254193.2.119.255126
241193.2.120.0/25193.2.120.1 to 193.2.120.126193.2.120.127126
242193.2.120.128/25193.2.120.129 to 193.2.120.254193.2.120.255126
243193.2.121.0/25193.2.121.1 to 193.2.121.126193.2.121.127126
244193.2.121.128/25193.2.121.129 to 193.2.121.254193.2.121.255126
245193.2.122.0/25193.2.122.1 to 193.2.122.126193.2.122.127126
246193.2.122.128/25193.2.122.129 to 193.2.122.254193.2.122.255126
247193.2.123.0/25193.2.123.1 to 193.2.123.126193.2.123.127126
248193.2.123.128/25193.2.123.129 to 193.2.123.254193.2.123.255126
249193.2.124.0/25193.2.124.1 to 193.2.124.126193.2.124.127126
250193.2.124.128/25193.2.124.129 to 193.2.124.254193.2.124.255126
251193.2.125.0/25193.2.125.1 to 193.2.125.126193.2.125.127126
252193.2.125.128/25193.2.125.129 to 193.2.125.254193.2.125.255126
253193.2.126.0/25193.2.126.1 to 193.2.126.126193.2.126.127126
254193.2.126.128/25193.2.126.129 to 193.2.126.254193.2.126.255126
255193.2.127.0/25193.2.127.1 to 193.2.127.126193.2.127.127126
256193.2.127.128/25193.2.127.129 to 193.2.127.254193.2.127.255126

IPv4 CIDR reference (/0 to /32)

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

IPv6 prefix reference

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

Private and special ranges

IPv4

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

IPv6

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

About this tool

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

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

Common questions

Why are two addresses lost in every IPv4 subnet?

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

What size of IPv6 network should a LAN use?

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

What is a wildcard mask?

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

Which ranges can I use inside an office?

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