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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.

Network168.26.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
168.26.0.0
Broadcast address
168.26.127.255
First usable
168.26.0.1
Last usable
168.26.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex A81A0000 · Integer 2820276224 to 2820308991
Reverse DNS zones
0.26.168.in-addr.arpa
1.26.168.in-addr.arpa
2.26.168.in-addr.arpa
3.26.168.in-addr.arpa
4.26.168.in-addr.arpa
5.26.168.in-addr.arpa
6.26.168.in-addr.arpa
7.26.168.in-addr.arpa
8.26.168.in-addr.arpa
9.26.168.in-addr.arpa
10.26.168.in-addr.arpa
11.26.168.in-addr.arpa
12.26.168.in-addr.arpa
13.26.168.in-addr.arpa
14.26.168.in-addr.arpa
15.26.168.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101000.00011010.00000000.00000000168.26.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10101000.00011010.00000000.00000000168.26.0.0
Broadcast10101000.00011010.01111111.11111111168.26.127.255
Split into smaller subnets/26
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

168.26.0.0/17 makes 512 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1168.26.0.0/26168.26.0.1 to 168.26.0.62168.26.0.6362
2168.26.0.64/26168.26.0.65 to 168.26.0.126168.26.0.12762
3168.26.0.128/26168.26.0.129 to 168.26.0.190168.26.0.19162
4168.26.0.192/26168.26.0.193 to 168.26.0.254168.26.0.25562
5168.26.1.0/26168.26.1.1 to 168.26.1.62168.26.1.6362
6168.26.1.64/26168.26.1.65 to 168.26.1.126168.26.1.12762
7168.26.1.128/26168.26.1.129 to 168.26.1.190168.26.1.19162
8168.26.1.192/26168.26.1.193 to 168.26.1.254168.26.1.25562
9168.26.2.0/26168.26.2.1 to 168.26.2.62168.26.2.6362
10168.26.2.64/26168.26.2.65 to 168.26.2.126168.26.2.12762
11168.26.2.128/26168.26.2.129 to 168.26.2.190168.26.2.19162
12168.26.2.192/26168.26.2.193 to 168.26.2.254168.26.2.25562
13168.26.3.0/26168.26.3.1 to 168.26.3.62168.26.3.6362
14168.26.3.64/26168.26.3.65 to 168.26.3.126168.26.3.12762
15168.26.3.128/26168.26.3.129 to 168.26.3.190168.26.3.19162
16168.26.3.192/26168.26.3.193 to 168.26.3.254168.26.3.25562
17168.26.4.0/26168.26.4.1 to 168.26.4.62168.26.4.6362
18168.26.4.64/26168.26.4.65 to 168.26.4.126168.26.4.12762
19168.26.4.128/26168.26.4.129 to 168.26.4.190168.26.4.19162
20168.26.4.192/26168.26.4.193 to 168.26.4.254168.26.4.25562
21168.26.5.0/26168.26.5.1 to 168.26.5.62168.26.5.6362
22168.26.5.64/26168.26.5.65 to 168.26.5.126168.26.5.12762
23168.26.5.128/26168.26.5.129 to 168.26.5.190168.26.5.19162
24168.26.5.192/26168.26.5.193 to 168.26.5.254168.26.5.25562
25168.26.6.0/26168.26.6.1 to 168.26.6.62168.26.6.6362
26168.26.6.64/26168.26.6.65 to 168.26.6.126168.26.6.12762
27168.26.6.128/26168.26.6.129 to 168.26.6.190168.26.6.19162
28168.26.6.192/26168.26.6.193 to 168.26.6.254168.26.6.25562
29168.26.7.0/26168.26.7.1 to 168.26.7.62168.26.7.6362
30168.26.7.64/26168.26.7.65 to 168.26.7.126168.26.7.12762
31168.26.7.128/26168.26.7.129 to 168.26.7.190168.26.7.19162
32168.26.7.192/26168.26.7.193 to 168.26.7.254168.26.7.25562
33168.26.8.0/26168.26.8.1 to 168.26.8.62168.26.8.6362
34168.26.8.64/26168.26.8.65 to 168.26.8.126168.26.8.12762
35168.26.8.128/26168.26.8.129 to 168.26.8.190168.26.8.19162
36168.26.8.192/26168.26.8.193 to 168.26.8.254168.26.8.25562
37168.26.9.0/26168.26.9.1 to 168.26.9.62168.26.9.6362
38168.26.9.64/26168.26.9.65 to 168.26.9.126168.26.9.12762
39168.26.9.128/26168.26.9.129 to 168.26.9.190168.26.9.19162
40168.26.9.192/26168.26.9.193 to 168.26.9.254168.26.9.25562
41168.26.10.0/26168.26.10.1 to 168.26.10.62168.26.10.6362
42168.26.10.64/26168.26.10.65 to 168.26.10.126168.26.10.12762
43168.26.10.128/26168.26.10.129 to 168.26.10.190168.26.10.19162
44168.26.10.192/26168.26.10.193 to 168.26.10.254168.26.10.25562
45168.26.11.0/26168.26.11.1 to 168.26.11.62168.26.11.6362
46168.26.11.64/26168.26.11.65 to 168.26.11.126168.26.11.12762
47168.26.11.128/26168.26.11.129 to 168.26.11.190168.26.11.19162
48168.26.11.192/26168.26.11.193 to 168.26.11.254168.26.11.25562
49168.26.12.0/26168.26.12.1 to 168.26.12.62168.26.12.6362
50168.26.12.64/26168.26.12.65 to 168.26.12.126168.26.12.12762
51168.26.12.128/26168.26.12.129 to 168.26.12.190168.26.12.19162
52168.26.12.192/26168.26.12.193 to 168.26.12.254168.26.12.25562
53168.26.13.0/26168.26.13.1 to 168.26.13.62168.26.13.6362
54168.26.13.64/26168.26.13.65 to 168.26.13.126168.26.13.12762
55168.26.13.128/26168.26.13.129 to 168.26.13.190168.26.13.19162
56168.26.13.192/26168.26.13.193 to 168.26.13.254168.26.13.25562
57168.26.14.0/26168.26.14.1 to 168.26.14.62168.26.14.6362
58168.26.14.64/26168.26.14.65 to 168.26.14.126168.26.14.12762
59168.26.14.128/26168.26.14.129 to 168.26.14.190168.26.14.19162
60168.26.14.192/26168.26.14.193 to 168.26.14.254168.26.14.25562
61168.26.15.0/26168.26.15.1 to 168.26.15.62168.26.15.6362
62168.26.15.64/26168.26.15.65 to 168.26.15.126168.26.15.12762
63168.26.15.128/26168.26.15.129 to 168.26.15.190168.26.15.19162
64168.26.15.192/26168.26.15.193 to 168.26.15.254168.26.15.25562
65168.26.16.0/26168.26.16.1 to 168.26.16.62168.26.16.6362
66168.26.16.64/26168.26.16.65 to 168.26.16.126168.26.16.12762
67168.26.16.128/26168.26.16.129 to 168.26.16.190168.26.16.19162
68168.26.16.192/26168.26.16.193 to 168.26.16.254168.26.16.25562
69168.26.17.0/26168.26.17.1 to 168.26.17.62168.26.17.6362
70168.26.17.64/26168.26.17.65 to 168.26.17.126168.26.17.12762
71168.26.17.128/26168.26.17.129 to 168.26.17.190168.26.17.19162
72168.26.17.192/26168.26.17.193 to 168.26.17.254168.26.17.25562
73168.26.18.0/26168.26.18.1 to 168.26.18.62168.26.18.6362
74168.26.18.64/26168.26.18.65 to 168.26.18.126168.26.18.12762
75168.26.18.128/26168.26.18.129 to 168.26.18.190168.26.18.19162
76168.26.18.192/26168.26.18.193 to 168.26.18.254168.26.18.25562
77168.26.19.0/26168.26.19.1 to 168.26.19.62168.26.19.6362
78168.26.19.64/26168.26.19.65 to 168.26.19.126168.26.19.12762
79168.26.19.128/26168.26.19.129 to 168.26.19.190168.26.19.19162
80168.26.19.192/26168.26.19.193 to 168.26.19.254168.26.19.25562
81168.26.20.0/26168.26.20.1 to 168.26.20.62168.26.20.6362
82168.26.20.64/26168.26.20.65 to 168.26.20.126168.26.20.12762
83168.26.20.128/26168.26.20.129 to 168.26.20.190168.26.20.19162
84168.26.20.192/26168.26.20.193 to 168.26.20.254168.26.20.25562
85168.26.21.0/26168.26.21.1 to 168.26.21.62168.26.21.6362
86168.26.21.64/26168.26.21.65 to 168.26.21.126168.26.21.12762
87168.26.21.128/26168.26.21.129 to 168.26.21.190168.26.21.19162
88168.26.21.192/26168.26.21.193 to 168.26.21.254168.26.21.25562
89168.26.22.0/26168.26.22.1 to 168.26.22.62168.26.22.6362
90168.26.22.64/26168.26.22.65 to 168.26.22.126168.26.22.12762
91168.26.22.128/26168.26.22.129 to 168.26.22.190168.26.22.19162
92168.26.22.192/26168.26.22.193 to 168.26.22.254168.26.22.25562
93168.26.23.0/26168.26.23.1 to 168.26.23.62168.26.23.6362
94168.26.23.64/26168.26.23.65 to 168.26.23.126168.26.23.12762
95168.26.23.128/26168.26.23.129 to 168.26.23.190168.26.23.19162
96168.26.23.192/26168.26.23.193 to 168.26.23.254168.26.23.25562
97168.26.24.0/26168.26.24.1 to 168.26.24.62168.26.24.6362
98168.26.24.64/26168.26.24.65 to 168.26.24.126168.26.24.12762
99168.26.24.128/26168.26.24.129 to 168.26.24.190168.26.24.19162
100168.26.24.192/26168.26.24.193 to 168.26.24.254168.26.24.25562
101168.26.25.0/26168.26.25.1 to 168.26.25.62168.26.25.6362
102168.26.25.64/26168.26.25.65 to 168.26.25.126168.26.25.12762
103168.26.25.128/26168.26.25.129 to 168.26.25.190168.26.25.19162
104168.26.25.192/26168.26.25.193 to 168.26.25.254168.26.25.25562
105168.26.26.0/26168.26.26.1 to 168.26.26.62168.26.26.6362
106168.26.26.64/26168.26.26.65 to 168.26.26.126168.26.26.12762
107168.26.26.128/26168.26.26.129 to 168.26.26.190168.26.26.19162
108168.26.26.192/26168.26.26.193 to 168.26.26.254168.26.26.25562
109168.26.27.0/26168.26.27.1 to 168.26.27.62168.26.27.6362
110168.26.27.64/26168.26.27.65 to 168.26.27.126168.26.27.12762
111168.26.27.128/26168.26.27.129 to 168.26.27.190168.26.27.19162
112168.26.27.192/26168.26.27.193 to 168.26.27.254168.26.27.25562
113168.26.28.0/26168.26.28.1 to 168.26.28.62168.26.28.6362
114168.26.28.64/26168.26.28.65 to 168.26.28.126168.26.28.12762
115168.26.28.128/26168.26.28.129 to 168.26.28.190168.26.28.19162
116168.26.28.192/26168.26.28.193 to 168.26.28.254168.26.28.25562
117168.26.29.0/26168.26.29.1 to 168.26.29.62168.26.29.6362
118168.26.29.64/26168.26.29.65 to 168.26.29.126168.26.29.12762
119168.26.29.128/26168.26.29.129 to 168.26.29.190168.26.29.19162
120168.26.29.192/26168.26.29.193 to 168.26.29.254168.26.29.25562
121168.26.30.0/26168.26.30.1 to 168.26.30.62168.26.30.6362
122168.26.30.64/26168.26.30.65 to 168.26.30.126168.26.30.12762
123168.26.30.128/26168.26.30.129 to 168.26.30.190168.26.30.19162
124168.26.30.192/26168.26.30.193 to 168.26.30.254168.26.30.25562
125168.26.31.0/26168.26.31.1 to 168.26.31.62168.26.31.6362
126168.26.31.64/26168.26.31.65 to 168.26.31.126168.26.31.12762
127168.26.31.128/26168.26.31.129 to 168.26.31.190168.26.31.19162
128168.26.31.192/26168.26.31.193 to 168.26.31.254168.26.31.25562
129168.26.32.0/26168.26.32.1 to 168.26.32.62168.26.32.6362
130168.26.32.64/26168.26.32.65 to 168.26.32.126168.26.32.12762
131168.26.32.128/26168.26.32.129 to 168.26.32.190168.26.32.19162
132168.26.32.192/26168.26.32.193 to 168.26.32.254168.26.32.25562
133168.26.33.0/26168.26.33.1 to 168.26.33.62168.26.33.6362
134168.26.33.64/26168.26.33.65 to 168.26.33.126168.26.33.12762
135168.26.33.128/26168.26.33.129 to 168.26.33.190168.26.33.19162
136168.26.33.192/26168.26.33.193 to 168.26.33.254168.26.33.25562
137168.26.34.0/26168.26.34.1 to 168.26.34.62168.26.34.6362
138168.26.34.64/26168.26.34.65 to 168.26.34.126168.26.34.12762
139168.26.34.128/26168.26.34.129 to 168.26.34.190168.26.34.19162
140168.26.34.192/26168.26.34.193 to 168.26.34.254168.26.34.25562
141168.26.35.0/26168.26.35.1 to 168.26.35.62168.26.35.6362
142168.26.35.64/26168.26.35.65 to 168.26.35.126168.26.35.12762
143168.26.35.128/26168.26.35.129 to 168.26.35.190168.26.35.19162
144168.26.35.192/26168.26.35.193 to 168.26.35.254168.26.35.25562
145168.26.36.0/26168.26.36.1 to 168.26.36.62168.26.36.6362
146168.26.36.64/26168.26.36.65 to 168.26.36.126168.26.36.12762
147168.26.36.128/26168.26.36.129 to 168.26.36.190168.26.36.19162
148168.26.36.192/26168.26.36.193 to 168.26.36.254168.26.36.25562
149168.26.37.0/26168.26.37.1 to 168.26.37.62168.26.37.6362
150168.26.37.64/26168.26.37.65 to 168.26.37.126168.26.37.12762
151168.26.37.128/26168.26.37.129 to 168.26.37.190168.26.37.19162
152168.26.37.192/26168.26.37.193 to 168.26.37.254168.26.37.25562
153168.26.38.0/26168.26.38.1 to 168.26.38.62168.26.38.6362
154168.26.38.64/26168.26.38.65 to 168.26.38.126168.26.38.12762
155168.26.38.128/26168.26.38.129 to 168.26.38.190168.26.38.19162
156168.26.38.192/26168.26.38.193 to 168.26.38.254168.26.38.25562
157168.26.39.0/26168.26.39.1 to 168.26.39.62168.26.39.6362
158168.26.39.64/26168.26.39.65 to 168.26.39.126168.26.39.12762
159168.26.39.128/26168.26.39.129 to 168.26.39.190168.26.39.19162
160168.26.39.192/26168.26.39.193 to 168.26.39.254168.26.39.25562
161168.26.40.0/26168.26.40.1 to 168.26.40.62168.26.40.6362
162168.26.40.64/26168.26.40.65 to 168.26.40.126168.26.40.12762
163168.26.40.128/26168.26.40.129 to 168.26.40.190168.26.40.19162
164168.26.40.192/26168.26.40.193 to 168.26.40.254168.26.40.25562
165168.26.41.0/26168.26.41.1 to 168.26.41.62168.26.41.6362
166168.26.41.64/26168.26.41.65 to 168.26.41.126168.26.41.12762
167168.26.41.128/26168.26.41.129 to 168.26.41.190168.26.41.19162
168168.26.41.192/26168.26.41.193 to 168.26.41.254168.26.41.25562
169168.26.42.0/26168.26.42.1 to 168.26.42.62168.26.42.6362
170168.26.42.64/26168.26.42.65 to 168.26.42.126168.26.42.12762
171168.26.42.128/26168.26.42.129 to 168.26.42.190168.26.42.19162
172168.26.42.192/26168.26.42.193 to 168.26.42.254168.26.42.25562
173168.26.43.0/26168.26.43.1 to 168.26.43.62168.26.43.6362
174168.26.43.64/26168.26.43.65 to 168.26.43.126168.26.43.12762
175168.26.43.128/26168.26.43.129 to 168.26.43.190168.26.43.19162
176168.26.43.192/26168.26.43.193 to 168.26.43.254168.26.43.25562
177168.26.44.0/26168.26.44.1 to 168.26.44.62168.26.44.6362
178168.26.44.64/26168.26.44.65 to 168.26.44.126168.26.44.12762
179168.26.44.128/26168.26.44.129 to 168.26.44.190168.26.44.19162
180168.26.44.192/26168.26.44.193 to 168.26.44.254168.26.44.25562
181168.26.45.0/26168.26.45.1 to 168.26.45.62168.26.45.6362
182168.26.45.64/26168.26.45.65 to 168.26.45.126168.26.45.12762
183168.26.45.128/26168.26.45.129 to 168.26.45.190168.26.45.19162
184168.26.45.192/26168.26.45.193 to 168.26.45.254168.26.45.25562
185168.26.46.0/26168.26.46.1 to 168.26.46.62168.26.46.6362
186168.26.46.64/26168.26.46.65 to 168.26.46.126168.26.46.12762
187168.26.46.128/26168.26.46.129 to 168.26.46.190168.26.46.19162
188168.26.46.192/26168.26.46.193 to 168.26.46.254168.26.46.25562
189168.26.47.0/26168.26.47.1 to 168.26.47.62168.26.47.6362
190168.26.47.64/26168.26.47.65 to 168.26.47.126168.26.47.12762
191168.26.47.128/26168.26.47.129 to 168.26.47.190168.26.47.19162
192168.26.47.192/26168.26.47.193 to 168.26.47.254168.26.47.25562
193168.26.48.0/26168.26.48.1 to 168.26.48.62168.26.48.6362
194168.26.48.64/26168.26.48.65 to 168.26.48.126168.26.48.12762
195168.26.48.128/26168.26.48.129 to 168.26.48.190168.26.48.19162
196168.26.48.192/26168.26.48.193 to 168.26.48.254168.26.48.25562
197168.26.49.0/26168.26.49.1 to 168.26.49.62168.26.49.6362
198168.26.49.64/26168.26.49.65 to 168.26.49.126168.26.49.12762
199168.26.49.128/26168.26.49.129 to 168.26.49.190168.26.49.19162
200168.26.49.192/26168.26.49.193 to 168.26.49.254168.26.49.25562
201168.26.50.0/26168.26.50.1 to 168.26.50.62168.26.50.6362
202168.26.50.64/26168.26.50.65 to 168.26.50.126168.26.50.12762
203168.26.50.128/26168.26.50.129 to 168.26.50.190168.26.50.19162
204168.26.50.192/26168.26.50.193 to 168.26.50.254168.26.50.25562
205168.26.51.0/26168.26.51.1 to 168.26.51.62168.26.51.6362
206168.26.51.64/26168.26.51.65 to 168.26.51.126168.26.51.12762
207168.26.51.128/26168.26.51.129 to 168.26.51.190168.26.51.19162
208168.26.51.192/26168.26.51.193 to 168.26.51.254168.26.51.25562
209168.26.52.0/26168.26.52.1 to 168.26.52.62168.26.52.6362
210168.26.52.64/26168.26.52.65 to 168.26.52.126168.26.52.12762
211168.26.52.128/26168.26.52.129 to 168.26.52.190168.26.52.19162
212168.26.52.192/26168.26.52.193 to 168.26.52.254168.26.52.25562
213168.26.53.0/26168.26.53.1 to 168.26.53.62168.26.53.6362
214168.26.53.64/26168.26.53.65 to 168.26.53.126168.26.53.12762
215168.26.53.128/26168.26.53.129 to 168.26.53.190168.26.53.19162
216168.26.53.192/26168.26.53.193 to 168.26.53.254168.26.53.25562
217168.26.54.0/26168.26.54.1 to 168.26.54.62168.26.54.6362
218168.26.54.64/26168.26.54.65 to 168.26.54.126168.26.54.12762
219168.26.54.128/26168.26.54.129 to 168.26.54.190168.26.54.19162
220168.26.54.192/26168.26.54.193 to 168.26.54.254168.26.54.25562
221168.26.55.0/26168.26.55.1 to 168.26.55.62168.26.55.6362
222168.26.55.64/26168.26.55.65 to 168.26.55.126168.26.55.12762
223168.26.55.128/26168.26.55.129 to 168.26.55.190168.26.55.19162
224168.26.55.192/26168.26.55.193 to 168.26.55.254168.26.55.25562
225168.26.56.0/26168.26.56.1 to 168.26.56.62168.26.56.6362
226168.26.56.64/26168.26.56.65 to 168.26.56.126168.26.56.12762
227168.26.56.128/26168.26.56.129 to 168.26.56.190168.26.56.19162
228168.26.56.192/26168.26.56.193 to 168.26.56.254168.26.56.25562
229168.26.57.0/26168.26.57.1 to 168.26.57.62168.26.57.6362
230168.26.57.64/26168.26.57.65 to 168.26.57.126168.26.57.12762
231168.26.57.128/26168.26.57.129 to 168.26.57.190168.26.57.19162
232168.26.57.192/26168.26.57.193 to 168.26.57.254168.26.57.25562
233168.26.58.0/26168.26.58.1 to 168.26.58.62168.26.58.6362
234168.26.58.64/26168.26.58.65 to 168.26.58.126168.26.58.12762
235168.26.58.128/26168.26.58.129 to 168.26.58.190168.26.58.19162
236168.26.58.192/26168.26.58.193 to 168.26.58.254168.26.58.25562
237168.26.59.0/26168.26.59.1 to 168.26.59.62168.26.59.6362
238168.26.59.64/26168.26.59.65 to 168.26.59.126168.26.59.12762
239168.26.59.128/26168.26.59.129 to 168.26.59.190168.26.59.19162
240168.26.59.192/26168.26.59.193 to 168.26.59.254168.26.59.25562
241168.26.60.0/26168.26.60.1 to 168.26.60.62168.26.60.6362
242168.26.60.64/26168.26.60.65 to 168.26.60.126168.26.60.12762
243168.26.60.128/26168.26.60.129 to 168.26.60.190168.26.60.19162
244168.26.60.192/26168.26.60.193 to 168.26.60.254168.26.60.25562
245168.26.61.0/26168.26.61.1 to 168.26.61.62168.26.61.6362
246168.26.61.64/26168.26.61.65 to 168.26.61.126168.26.61.12762
247168.26.61.128/26168.26.61.129 to 168.26.61.190168.26.61.19162
248168.26.61.192/26168.26.61.193 to 168.26.61.254168.26.61.25562
249168.26.62.0/26168.26.62.1 to 168.26.62.62168.26.62.6362
250168.26.62.64/26168.26.62.65 to 168.26.62.126168.26.62.12762
251168.26.62.128/26168.26.62.129 to 168.26.62.190168.26.62.19162
252168.26.62.192/26168.26.62.193 to 168.26.62.254168.26.62.25562
253168.26.63.0/26168.26.63.1 to 168.26.63.62168.26.63.6362
254168.26.63.64/26168.26.63.65 to 168.26.63.126168.26.63.12762
255168.26.63.128/26168.26.63.129 to 168.26.63.190168.26.63.19162
256168.26.63.192/26168.26.63.193 to 168.26.63.254168.26.63.25562

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.