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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.

Network203.76.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
203.76.0.0
Broadcast address
203.79.255.255
First usable
203.76.0.1
Last usable
203.79.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
C (default /24)
As numbers
Hex CB4C0000 · Integer 3410755584 to 3411017727
Reverse DNS zones
76.203.in-addr.arpa
77.203.in-addr.arpa
78.203.in-addr.arpa
79.203.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001011.01001100.00000000.00000000203.76.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11001011.01001100.00000000.00000000203.76.0.0
Broadcast11001011.01001111.11111111.11111111203.79.255.255
Split into smaller subnets/25
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

203.76.0.0/14 makes 2,048 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1203.76.0.0/25203.76.0.1 to 203.76.0.126203.76.0.127126
2203.76.0.128/25203.76.0.129 to 203.76.0.254203.76.0.255126
3203.76.1.0/25203.76.1.1 to 203.76.1.126203.76.1.127126
4203.76.1.128/25203.76.1.129 to 203.76.1.254203.76.1.255126
5203.76.2.0/25203.76.2.1 to 203.76.2.126203.76.2.127126
6203.76.2.128/25203.76.2.129 to 203.76.2.254203.76.2.255126
7203.76.3.0/25203.76.3.1 to 203.76.3.126203.76.3.127126
8203.76.3.128/25203.76.3.129 to 203.76.3.254203.76.3.255126
9203.76.4.0/25203.76.4.1 to 203.76.4.126203.76.4.127126
10203.76.4.128/25203.76.4.129 to 203.76.4.254203.76.4.255126
11203.76.5.0/25203.76.5.1 to 203.76.5.126203.76.5.127126
12203.76.5.128/25203.76.5.129 to 203.76.5.254203.76.5.255126
13203.76.6.0/25203.76.6.1 to 203.76.6.126203.76.6.127126
14203.76.6.128/25203.76.6.129 to 203.76.6.254203.76.6.255126
15203.76.7.0/25203.76.7.1 to 203.76.7.126203.76.7.127126
16203.76.7.128/25203.76.7.129 to 203.76.7.254203.76.7.255126
17203.76.8.0/25203.76.8.1 to 203.76.8.126203.76.8.127126
18203.76.8.128/25203.76.8.129 to 203.76.8.254203.76.8.255126
19203.76.9.0/25203.76.9.1 to 203.76.9.126203.76.9.127126
20203.76.9.128/25203.76.9.129 to 203.76.9.254203.76.9.255126
21203.76.10.0/25203.76.10.1 to 203.76.10.126203.76.10.127126
22203.76.10.128/25203.76.10.129 to 203.76.10.254203.76.10.255126
23203.76.11.0/25203.76.11.1 to 203.76.11.126203.76.11.127126
24203.76.11.128/25203.76.11.129 to 203.76.11.254203.76.11.255126
25203.76.12.0/25203.76.12.1 to 203.76.12.126203.76.12.127126
26203.76.12.128/25203.76.12.129 to 203.76.12.254203.76.12.255126
27203.76.13.0/25203.76.13.1 to 203.76.13.126203.76.13.127126
28203.76.13.128/25203.76.13.129 to 203.76.13.254203.76.13.255126
29203.76.14.0/25203.76.14.1 to 203.76.14.126203.76.14.127126
30203.76.14.128/25203.76.14.129 to 203.76.14.254203.76.14.255126
31203.76.15.0/25203.76.15.1 to 203.76.15.126203.76.15.127126
32203.76.15.128/25203.76.15.129 to 203.76.15.254203.76.15.255126
33203.76.16.0/25203.76.16.1 to 203.76.16.126203.76.16.127126
34203.76.16.128/25203.76.16.129 to 203.76.16.254203.76.16.255126
35203.76.17.0/25203.76.17.1 to 203.76.17.126203.76.17.127126
36203.76.17.128/25203.76.17.129 to 203.76.17.254203.76.17.255126
37203.76.18.0/25203.76.18.1 to 203.76.18.126203.76.18.127126
38203.76.18.128/25203.76.18.129 to 203.76.18.254203.76.18.255126
39203.76.19.0/25203.76.19.1 to 203.76.19.126203.76.19.127126
40203.76.19.128/25203.76.19.129 to 203.76.19.254203.76.19.255126
41203.76.20.0/25203.76.20.1 to 203.76.20.126203.76.20.127126
42203.76.20.128/25203.76.20.129 to 203.76.20.254203.76.20.255126
43203.76.21.0/25203.76.21.1 to 203.76.21.126203.76.21.127126
44203.76.21.128/25203.76.21.129 to 203.76.21.254203.76.21.255126
45203.76.22.0/25203.76.22.1 to 203.76.22.126203.76.22.127126
46203.76.22.128/25203.76.22.129 to 203.76.22.254203.76.22.255126
47203.76.23.0/25203.76.23.1 to 203.76.23.126203.76.23.127126
48203.76.23.128/25203.76.23.129 to 203.76.23.254203.76.23.255126
49203.76.24.0/25203.76.24.1 to 203.76.24.126203.76.24.127126
50203.76.24.128/25203.76.24.129 to 203.76.24.254203.76.24.255126
51203.76.25.0/25203.76.25.1 to 203.76.25.126203.76.25.127126
52203.76.25.128/25203.76.25.129 to 203.76.25.254203.76.25.255126
53203.76.26.0/25203.76.26.1 to 203.76.26.126203.76.26.127126
54203.76.26.128/25203.76.26.129 to 203.76.26.254203.76.26.255126
55203.76.27.0/25203.76.27.1 to 203.76.27.126203.76.27.127126
56203.76.27.128/25203.76.27.129 to 203.76.27.254203.76.27.255126
57203.76.28.0/25203.76.28.1 to 203.76.28.126203.76.28.127126
58203.76.28.128/25203.76.28.129 to 203.76.28.254203.76.28.255126
59203.76.29.0/25203.76.29.1 to 203.76.29.126203.76.29.127126
60203.76.29.128/25203.76.29.129 to 203.76.29.254203.76.29.255126
61203.76.30.0/25203.76.30.1 to 203.76.30.126203.76.30.127126
62203.76.30.128/25203.76.30.129 to 203.76.30.254203.76.30.255126
63203.76.31.0/25203.76.31.1 to 203.76.31.126203.76.31.127126
64203.76.31.128/25203.76.31.129 to 203.76.31.254203.76.31.255126
65203.76.32.0/25203.76.32.1 to 203.76.32.126203.76.32.127126
66203.76.32.128/25203.76.32.129 to 203.76.32.254203.76.32.255126
67203.76.33.0/25203.76.33.1 to 203.76.33.126203.76.33.127126
68203.76.33.128/25203.76.33.129 to 203.76.33.254203.76.33.255126
69203.76.34.0/25203.76.34.1 to 203.76.34.126203.76.34.127126
70203.76.34.128/25203.76.34.129 to 203.76.34.254203.76.34.255126
71203.76.35.0/25203.76.35.1 to 203.76.35.126203.76.35.127126
72203.76.35.128/25203.76.35.129 to 203.76.35.254203.76.35.255126
73203.76.36.0/25203.76.36.1 to 203.76.36.126203.76.36.127126
74203.76.36.128/25203.76.36.129 to 203.76.36.254203.76.36.255126
75203.76.37.0/25203.76.37.1 to 203.76.37.126203.76.37.127126
76203.76.37.128/25203.76.37.129 to 203.76.37.254203.76.37.255126
77203.76.38.0/25203.76.38.1 to 203.76.38.126203.76.38.127126
78203.76.38.128/25203.76.38.129 to 203.76.38.254203.76.38.255126
79203.76.39.0/25203.76.39.1 to 203.76.39.126203.76.39.127126
80203.76.39.128/25203.76.39.129 to 203.76.39.254203.76.39.255126
81203.76.40.0/25203.76.40.1 to 203.76.40.126203.76.40.127126
82203.76.40.128/25203.76.40.129 to 203.76.40.254203.76.40.255126
83203.76.41.0/25203.76.41.1 to 203.76.41.126203.76.41.127126
84203.76.41.128/25203.76.41.129 to 203.76.41.254203.76.41.255126
85203.76.42.0/25203.76.42.1 to 203.76.42.126203.76.42.127126
86203.76.42.128/25203.76.42.129 to 203.76.42.254203.76.42.255126
87203.76.43.0/25203.76.43.1 to 203.76.43.126203.76.43.127126
88203.76.43.128/25203.76.43.129 to 203.76.43.254203.76.43.255126
89203.76.44.0/25203.76.44.1 to 203.76.44.126203.76.44.127126
90203.76.44.128/25203.76.44.129 to 203.76.44.254203.76.44.255126
91203.76.45.0/25203.76.45.1 to 203.76.45.126203.76.45.127126
92203.76.45.128/25203.76.45.129 to 203.76.45.254203.76.45.255126
93203.76.46.0/25203.76.46.1 to 203.76.46.126203.76.46.127126
94203.76.46.128/25203.76.46.129 to 203.76.46.254203.76.46.255126
95203.76.47.0/25203.76.47.1 to 203.76.47.126203.76.47.127126
96203.76.47.128/25203.76.47.129 to 203.76.47.254203.76.47.255126
97203.76.48.0/25203.76.48.1 to 203.76.48.126203.76.48.127126
98203.76.48.128/25203.76.48.129 to 203.76.48.254203.76.48.255126
99203.76.49.0/25203.76.49.1 to 203.76.49.126203.76.49.127126
100203.76.49.128/25203.76.49.129 to 203.76.49.254203.76.49.255126
101203.76.50.0/25203.76.50.1 to 203.76.50.126203.76.50.127126
102203.76.50.128/25203.76.50.129 to 203.76.50.254203.76.50.255126
103203.76.51.0/25203.76.51.1 to 203.76.51.126203.76.51.127126
104203.76.51.128/25203.76.51.129 to 203.76.51.254203.76.51.255126
105203.76.52.0/25203.76.52.1 to 203.76.52.126203.76.52.127126
106203.76.52.128/25203.76.52.129 to 203.76.52.254203.76.52.255126
107203.76.53.0/25203.76.53.1 to 203.76.53.126203.76.53.127126
108203.76.53.128/25203.76.53.129 to 203.76.53.254203.76.53.255126
109203.76.54.0/25203.76.54.1 to 203.76.54.126203.76.54.127126
110203.76.54.128/25203.76.54.129 to 203.76.54.254203.76.54.255126
111203.76.55.0/25203.76.55.1 to 203.76.55.126203.76.55.127126
112203.76.55.128/25203.76.55.129 to 203.76.55.254203.76.55.255126
113203.76.56.0/25203.76.56.1 to 203.76.56.126203.76.56.127126
114203.76.56.128/25203.76.56.129 to 203.76.56.254203.76.56.255126
115203.76.57.0/25203.76.57.1 to 203.76.57.126203.76.57.127126
116203.76.57.128/25203.76.57.129 to 203.76.57.254203.76.57.255126
117203.76.58.0/25203.76.58.1 to 203.76.58.126203.76.58.127126
118203.76.58.128/25203.76.58.129 to 203.76.58.254203.76.58.255126
119203.76.59.0/25203.76.59.1 to 203.76.59.126203.76.59.127126
120203.76.59.128/25203.76.59.129 to 203.76.59.254203.76.59.255126
121203.76.60.0/25203.76.60.1 to 203.76.60.126203.76.60.127126
122203.76.60.128/25203.76.60.129 to 203.76.60.254203.76.60.255126
123203.76.61.0/25203.76.61.1 to 203.76.61.126203.76.61.127126
124203.76.61.128/25203.76.61.129 to 203.76.61.254203.76.61.255126
125203.76.62.0/25203.76.62.1 to 203.76.62.126203.76.62.127126
126203.76.62.128/25203.76.62.129 to 203.76.62.254203.76.62.255126
127203.76.63.0/25203.76.63.1 to 203.76.63.126203.76.63.127126
128203.76.63.128/25203.76.63.129 to 203.76.63.254203.76.63.255126
129203.76.64.0/25203.76.64.1 to 203.76.64.126203.76.64.127126
130203.76.64.128/25203.76.64.129 to 203.76.64.254203.76.64.255126
131203.76.65.0/25203.76.65.1 to 203.76.65.126203.76.65.127126
132203.76.65.128/25203.76.65.129 to 203.76.65.254203.76.65.255126
133203.76.66.0/25203.76.66.1 to 203.76.66.126203.76.66.127126
134203.76.66.128/25203.76.66.129 to 203.76.66.254203.76.66.255126
135203.76.67.0/25203.76.67.1 to 203.76.67.126203.76.67.127126
136203.76.67.128/25203.76.67.129 to 203.76.67.254203.76.67.255126
137203.76.68.0/25203.76.68.1 to 203.76.68.126203.76.68.127126
138203.76.68.128/25203.76.68.129 to 203.76.68.254203.76.68.255126
139203.76.69.0/25203.76.69.1 to 203.76.69.126203.76.69.127126
140203.76.69.128/25203.76.69.129 to 203.76.69.254203.76.69.255126
141203.76.70.0/25203.76.70.1 to 203.76.70.126203.76.70.127126
142203.76.70.128/25203.76.70.129 to 203.76.70.254203.76.70.255126
143203.76.71.0/25203.76.71.1 to 203.76.71.126203.76.71.127126
144203.76.71.128/25203.76.71.129 to 203.76.71.254203.76.71.255126
145203.76.72.0/25203.76.72.1 to 203.76.72.126203.76.72.127126
146203.76.72.128/25203.76.72.129 to 203.76.72.254203.76.72.255126
147203.76.73.0/25203.76.73.1 to 203.76.73.126203.76.73.127126
148203.76.73.128/25203.76.73.129 to 203.76.73.254203.76.73.255126
149203.76.74.0/25203.76.74.1 to 203.76.74.126203.76.74.127126
150203.76.74.128/25203.76.74.129 to 203.76.74.254203.76.74.255126
151203.76.75.0/25203.76.75.1 to 203.76.75.126203.76.75.127126
152203.76.75.128/25203.76.75.129 to 203.76.75.254203.76.75.255126
153203.76.76.0/25203.76.76.1 to 203.76.76.126203.76.76.127126
154203.76.76.128/25203.76.76.129 to 203.76.76.254203.76.76.255126
155203.76.77.0/25203.76.77.1 to 203.76.77.126203.76.77.127126
156203.76.77.128/25203.76.77.129 to 203.76.77.254203.76.77.255126
157203.76.78.0/25203.76.78.1 to 203.76.78.126203.76.78.127126
158203.76.78.128/25203.76.78.129 to 203.76.78.254203.76.78.255126
159203.76.79.0/25203.76.79.1 to 203.76.79.126203.76.79.127126
160203.76.79.128/25203.76.79.129 to 203.76.79.254203.76.79.255126
161203.76.80.0/25203.76.80.1 to 203.76.80.126203.76.80.127126
162203.76.80.128/25203.76.80.129 to 203.76.80.254203.76.80.255126
163203.76.81.0/25203.76.81.1 to 203.76.81.126203.76.81.127126
164203.76.81.128/25203.76.81.129 to 203.76.81.254203.76.81.255126
165203.76.82.0/25203.76.82.1 to 203.76.82.126203.76.82.127126
166203.76.82.128/25203.76.82.129 to 203.76.82.254203.76.82.255126
167203.76.83.0/25203.76.83.1 to 203.76.83.126203.76.83.127126
168203.76.83.128/25203.76.83.129 to 203.76.83.254203.76.83.255126
169203.76.84.0/25203.76.84.1 to 203.76.84.126203.76.84.127126
170203.76.84.128/25203.76.84.129 to 203.76.84.254203.76.84.255126
171203.76.85.0/25203.76.85.1 to 203.76.85.126203.76.85.127126
172203.76.85.128/25203.76.85.129 to 203.76.85.254203.76.85.255126
173203.76.86.0/25203.76.86.1 to 203.76.86.126203.76.86.127126
174203.76.86.128/25203.76.86.129 to 203.76.86.254203.76.86.255126
175203.76.87.0/25203.76.87.1 to 203.76.87.126203.76.87.127126
176203.76.87.128/25203.76.87.129 to 203.76.87.254203.76.87.255126
177203.76.88.0/25203.76.88.1 to 203.76.88.126203.76.88.127126
178203.76.88.128/25203.76.88.129 to 203.76.88.254203.76.88.255126
179203.76.89.0/25203.76.89.1 to 203.76.89.126203.76.89.127126
180203.76.89.128/25203.76.89.129 to 203.76.89.254203.76.89.255126
181203.76.90.0/25203.76.90.1 to 203.76.90.126203.76.90.127126
182203.76.90.128/25203.76.90.129 to 203.76.90.254203.76.90.255126
183203.76.91.0/25203.76.91.1 to 203.76.91.126203.76.91.127126
184203.76.91.128/25203.76.91.129 to 203.76.91.254203.76.91.255126
185203.76.92.0/25203.76.92.1 to 203.76.92.126203.76.92.127126
186203.76.92.128/25203.76.92.129 to 203.76.92.254203.76.92.255126
187203.76.93.0/25203.76.93.1 to 203.76.93.126203.76.93.127126
188203.76.93.128/25203.76.93.129 to 203.76.93.254203.76.93.255126
189203.76.94.0/25203.76.94.1 to 203.76.94.126203.76.94.127126
190203.76.94.128/25203.76.94.129 to 203.76.94.254203.76.94.255126
191203.76.95.0/25203.76.95.1 to 203.76.95.126203.76.95.127126
192203.76.95.128/25203.76.95.129 to 203.76.95.254203.76.95.255126
193203.76.96.0/25203.76.96.1 to 203.76.96.126203.76.96.127126
194203.76.96.128/25203.76.96.129 to 203.76.96.254203.76.96.255126
195203.76.97.0/25203.76.97.1 to 203.76.97.126203.76.97.127126
196203.76.97.128/25203.76.97.129 to 203.76.97.254203.76.97.255126
197203.76.98.0/25203.76.98.1 to 203.76.98.126203.76.98.127126
198203.76.98.128/25203.76.98.129 to 203.76.98.254203.76.98.255126
199203.76.99.0/25203.76.99.1 to 203.76.99.126203.76.99.127126
200203.76.99.128/25203.76.99.129 to 203.76.99.254203.76.99.255126
201203.76.100.0/25203.76.100.1 to 203.76.100.126203.76.100.127126
202203.76.100.128/25203.76.100.129 to 203.76.100.254203.76.100.255126
203203.76.101.0/25203.76.101.1 to 203.76.101.126203.76.101.127126
204203.76.101.128/25203.76.101.129 to 203.76.101.254203.76.101.255126
205203.76.102.0/25203.76.102.1 to 203.76.102.126203.76.102.127126
206203.76.102.128/25203.76.102.129 to 203.76.102.254203.76.102.255126
207203.76.103.0/25203.76.103.1 to 203.76.103.126203.76.103.127126
208203.76.103.128/25203.76.103.129 to 203.76.103.254203.76.103.255126
209203.76.104.0/25203.76.104.1 to 203.76.104.126203.76.104.127126
210203.76.104.128/25203.76.104.129 to 203.76.104.254203.76.104.255126
211203.76.105.0/25203.76.105.1 to 203.76.105.126203.76.105.127126
212203.76.105.128/25203.76.105.129 to 203.76.105.254203.76.105.255126
213203.76.106.0/25203.76.106.1 to 203.76.106.126203.76.106.127126
214203.76.106.128/25203.76.106.129 to 203.76.106.254203.76.106.255126
215203.76.107.0/25203.76.107.1 to 203.76.107.126203.76.107.127126
216203.76.107.128/25203.76.107.129 to 203.76.107.254203.76.107.255126
217203.76.108.0/25203.76.108.1 to 203.76.108.126203.76.108.127126
218203.76.108.128/25203.76.108.129 to 203.76.108.254203.76.108.255126
219203.76.109.0/25203.76.109.1 to 203.76.109.126203.76.109.127126
220203.76.109.128/25203.76.109.129 to 203.76.109.254203.76.109.255126
221203.76.110.0/25203.76.110.1 to 203.76.110.126203.76.110.127126
222203.76.110.128/25203.76.110.129 to 203.76.110.254203.76.110.255126
223203.76.111.0/25203.76.111.1 to 203.76.111.126203.76.111.127126
224203.76.111.128/25203.76.111.129 to 203.76.111.254203.76.111.255126
225203.76.112.0/25203.76.112.1 to 203.76.112.126203.76.112.127126
226203.76.112.128/25203.76.112.129 to 203.76.112.254203.76.112.255126
227203.76.113.0/25203.76.113.1 to 203.76.113.126203.76.113.127126
228203.76.113.128/25203.76.113.129 to 203.76.113.254203.76.113.255126
229203.76.114.0/25203.76.114.1 to 203.76.114.126203.76.114.127126
230203.76.114.128/25203.76.114.129 to 203.76.114.254203.76.114.255126
231203.76.115.0/25203.76.115.1 to 203.76.115.126203.76.115.127126
232203.76.115.128/25203.76.115.129 to 203.76.115.254203.76.115.255126
233203.76.116.0/25203.76.116.1 to 203.76.116.126203.76.116.127126
234203.76.116.128/25203.76.116.129 to 203.76.116.254203.76.116.255126
235203.76.117.0/25203.76.117.1 to 203.76.117.126203.76.117.127126
236203.76.117.128/25203.76.117.129 to 203.76.117.254203.76.117.255126
237203.76.118.0/25203.76.118.1 to 203.76.118.126203.76.118.127126
238203.76.118.128/25203.76.118.129 to 203.76.118.254203.76.118.255126
239203.76.119.0/25203.76.119.1 to 203.76.119.126203.76.119.127126
240203.76.119.128/25203.76.119.129 to 203.76.119.254203.76.119.255126
241203.76.120.0/25203.76.120.1 to 203.76.120.126203.76.120.127126
242203.76.120.128/25203.76.120.129 to 203.76.120.254203.76.120.255126
243203.76.121.0/25203.76.121.1 to 203.76.121.126203.76.121.127126
244203.76.121.128/25203.76.121.129 to 203.76.121.254203.76.121.255126
245203.76.122.0/25203.76.122.1 to 203.76.122.126203.76.122.127126
246203.76.122.128/25203.76.122.129 to 203.76.122.254203.76.122.255126
247203.76.123.0/25203.76.123.1 to 203.76.123.126203.76.123.127126
248203.76.123.128/25203.76.123.129 to 203.76.123.254203.76.123.255126
249203.76.124.0/25203.76.124.1 to 203.76.124.126203.76.124.127126
250203.76.124.128/25203.76.124.129 to 203.76.124.254203.76.124.255126
251203.76.125.0/25203.76.125.1 to 203.76.125.126203.76.125.127126
252203.76.125.128/25203.76.125.129 to 203.76.125.254203.76.125.255126
253203.76.126.0/25203.76.126.1 to 203.76.126.126203.76.126.127126
254203.76.126.128/25203.76.126.129 to 203.76.126.254203.76.126.255126
255203.76.127.0/25203.76.127.1 to 203.76.127.126203.76.127.127126
256203.76.127.128/25203.76.127.129 to 203.76.127.254203.76.127.255126

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.