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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.

Network253.4.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
253.4.0.0
Broadcast address
253.4.127.255
First usable
253.4.0.1
Last usable
253.4.127.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FD040000 · Integer 4244897792 to 4244930559
Reverse DNS zones
0.4.253.in-addr.arpa
1.4.253.in-addr.arpa
2.4.253.in-addr.arpa
3.4.253.in-addr.arpa
4.4.253.in-addr.arpa
5.4.253.in-addr.arpa
6.4.253.in-addr.arpa
7.4.253.in-addr.arpa
8.4.253.in-addr.arpa
9.4.253.in-addr.arpa
10.4.253.in-addr.arpa
11.4.253.in-addr.arpa
12.4.253.in-addr.arpa
13.4.253.in-addr.arpa
14.4.253.in-addr.arpa
15.4.253.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
Address11111101.00000100.00000000.00000000253.4.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11111101.00000100.00000000.00000000253.4.0.0
Broadcast11111101.00000100.01111111.11111111253.4.127.255
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)

253.4.0.0/17 makes 512 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1253.4.0.0/26253.4.0.1 to 253.4.0.62253.4.0.6362
2253.4.0.64/26253.4.0.65 to 253.4.0.126253.4.0.12762
3253.4.0.128/26253.4.0.129 to 253.4.0.190253.4.0.19162
4253.4.0.192/26253.4.0.193 to 253.4.0.254253.4.0.25562
5253.4.1.0/26253.4.1.1 to 253.4.1.62253.4.1.6362
6253.4.1.64/26253.4.1.65 to 253.4.1.126253.4.1.12762
7253.4.1.128/26253.4.1.129 to 253.4.1.190253.4.1.19162
8253.4.1.192/26253.4.1.193 to 253.4.1.254253.4.1.25562
9253.4.2.0/26253.4.2.1 to 253.4.2.62253.4.2.6362
10253.4.2.64/26253.4.2.65 to 253.4.2.126253.4.2.12762
11253.4.2.128/26253.4.2.129 to 253.4.2.190253.4.2.19162
12253.4.2.192/26253.4.2.193 to 253.4.2.254253.4.2.25562
13253.4.3.0/26253.4.3.1 to 253.4.3.62253.4.3.6362
14253.4.3.64/26253.4.3.65 to 253.4.3.126253.4.3.12762
15253.4.3.128/26253.4.3.129 to 253.4.3.190253.4.3.19162
16253.4.3.192/26253.4.3.193 to 253.4.3.254253.4.3.25562
17253.4.4.0/26253.4.4.1 to 253.4.4.62253.4.4.6362
18253.4.4.64/26253.4.4.65 to 253.4.4.126253.4.4.12762
19253.4.4.128/26253.4.4.129 to 253.4.4.190253.4.4.19162
20253.4.4.192/26253.4.4.193 to 253.4.4.254253.4.4.25562
21253.4.5.0/26253.4.5.1 to 253.4.5.62253.4.5.6362
22253.4.5.64/26253.4.5.65 to 253.4.5.126253.4.5.12762
23253.4.5.128/26253.4.5.129 to 253.4.5.190253.4.5.19162
24253.4.5.192/26253.4.5.193 to 253.4.5.254253.4.5.25562
25253.4.6.0/26253.4.6.1 to 253.4.6.62253.4.6.6362
26253.4.6.64/26253.4.6.65 to 253.4.6.126253.4.6.12762
27253.4.6.128/26253.4.6.129 to 253.4.6.190253.4.6.19162
28253.4.6.192/26253.4.6.193 to 253.4.6.254253.4.6.25562
29253.4.7.0/26253.4.7.1 to 253.4.7.62253.4.7.6362
30253.4.7.64/26253.4.7.65 to 253.4.7.126253.4.7.12762
31253.4.7.128/26253.4.7.129 to 253.4.7.190253.4.7.19162
32253.4.7.192/26253.4.7.193 to 253.4.7.254253.4.7.25562
33253.4.8.0/26253.4.8.1 to 253.4.8.62253.4.8.6362
34253.4.8.64/26253.4.8.65 to 253.4.8.126253.4.8.12762
35253.4.8.128/26253.4.8.129 to 253.4.8.190253.4.8.19162
36253.4.8.192/26253.4.8.193 to 253.4.8.254253.4.8.25562
37253.4.9.0/26253.4.9.1 to 253.4.9.62253.4.9.6362
38253.4.9.64/26253.4.9.65 to 253.4.9.126253.4.9.12762
39253.4.9.128/26253.4.9.129 to 253.4.9.190253.4.9.19162
40253.4.9.192/26253.4.9.193 to 253.4.9.254253.4.9.25562
41253.4.10.0/26253.4.10.1 to 253.4.10.62253.4.10.6362
42253.4.10.64/26253.4.10.65 to 253.4.10.126253.4.10.12762
43253.4.10.128/26253.4.10.129 to 253.4.10.190253.4.10.19162
44253.4.10.192/26253.4.10.193 to 253.4.10.254253.4.10.25562
45253.4.11.0/26253.4.11.1 to 253.4.11.62253.4.11.6362
46253.4.11.64/26253.4.11.65 to 253.4.11.126253.4.11.12762
47253.4.11.128/26253.4.11.129 to 253.4.11.190253.4.11.19162
48253.4.11.192/26253.4.11.193 to 253.4.11.254253.4.11.25562
49253.4.12.0/26253.4.12.1 to 253.4.12.62253.4.12.6362
50253.4.12.64/26253.4.12.65 to 253.4.12.126253.4.12.12762
51253.4.12.128/26253.4.12.129 to 253.4.12.190253.4.12.19162
52253.4.12.192/26253.4.12.193 to 253.4.12.254253.4.12.25562
53253.4.13.0/26253.4.13.1 to 253.4.13.62253.4.13.6362
54253.4.13.64/26253.4.13.65 to 253.4.13.126253.4.13.12762
55253.4.13.128/26253.4.13.129 to 253.4.13.190253.4.13.19162
56253.4.13.192/26253.4.13.193 to 253.4.13.254253.4.13.25562
57253.4.14.0/26253.4.14.1 to 253.4.14.62253.4.14.6362
58253.4.14.64/26253.4.14.65 to 253.4.14.126253.4.14.12762
59253.4.14.128/26253.4.14.129 to 253.4.14.190253.4.14.19162
60253.4.14.192/26253.4.14.193 to 253.4.14.254253.4.14.25562
61253.4.15.0/26253.4.15.1 to 253.4.15.62253.4.15.6362
62253.4.15.64/26253.4.15.65 to 253.4.15.126253.4.15.12762
63253.4.15.128/26253.4.15.129 to 253.4.15.190253.4.15.19162
64253.4.15.192/26253.4.15.193 to 253.4.15.254253.4.15.25562
65253.4.16.0/26253.4.16.1 to 253.4.16.62253.4.16.6362
66253.4.16.64/26253.4.16.65 to 253.4.16.126253.4.16.12762
67253.4.16.128/26253.4.16.129 to 253.4.16.190253.4.16.19162
68253.4.16.192/26253.4.16.193 to 253.4.16.254253.4.16.25562
69253.4.17.0/26253.4.17.1 to 253.4.17.62253.4.17.6362
70253.4.17.64/26253.4.17.65 to 253.4.17.126253.4.17.12762
71253.4.17.128/26253.4.17.129 to 253.4.17.190253.4.17.19162
72253.4.17.192/26253.4.17.193 to 253.4.17.254253.4.17.25562
73253.4.18.0/26253.4.18.1 to 253.4.18.62253.4.18.6362
74253.4.18.64/26253.4.18.65 to 253.4.18.126253.4.18.12762
75253.4.18.128/26253.4.18.129 to 253.4.18.190253.4.18.19162
76253.4.18.192/26253.4.18.193 to 253.4.18.254253.4.18.25562
77253.4.19.0/26253.4.19.1 to 253.4.19.62253.4.19.6362
78253.4.19.64/26253.4.19.65 to 253.4.19.126253.4.19.12762
79253.4.19.128/26253.4.19.129 to 253.4.19.190253.4.19.19162
80253.4.19.192/26253.4.19.193 to 253.4.19.254253.4.19.25562
81253.4.20.0/26253.4.20.1 to 253.4.20.62253.4.20.6362
82253.4.20.64/26253.4.20.65 to 253.4.20.126253.4.20.12762
83253.4.20.128/26253.4.20.129 to 253.4.20.190253.4.20.19162
84253.4.20.192/26253.4.20.193 to 253.4.20.254253.4.20.25562
85253.4.21.0/26253.4.21.1 to 253.4.21.62253.4.21.6362
86253.4.21.64/26253.4.21.65 to 253.4.21.126253.4.21.12762
87253.4.21.128/26253.4.21.129 to 253.4.21.190253.4.21.19162
88253.4.21.192/26253.4.21.193 to 253.4.21.254253.4.21.25562
89253.4.22.0/26253.4.22.1 to 253.4.22.62253.4.22.6362
90253.4.22.64/26253.4.22.65 to 253.4.22.126253.4.22.12762
91253.4.22.128/26253.4.22.129 to 253.4.22.190253.4.22.19162
92253.4.22.192/26253.4.22.193 to 253.4.22.254253.4.22.25562
93253.4.23.0/26253.4.23.1 to 253.4.23.62253.4.23.6362
94253.4.23.64/26253.4.23.65 to 253.4.23.126253.4.23.12762
95253.4.23.128/26253.4.23.129 to 253.4.23.190253.4.23.19162
96253.4.23.192/26253.4.23.193 to 253.4.23.254253.4.23.25562
97253.4.24.0/26253.4.24.1 to 253.4.24.62253.4.24.6362
98253.4.24.64/26253.4.24.65 to 253.4.24.126253.4.24.12762
99253.4.24.128/26253.4.24.129 to 253.4.24.190253.4.24.19162
100253.4.24.192/26253.4.24.193 to 253.4.24.254253.4.24.25562
101253.4.25.0/26253.4.25.1 to 253.4.25.62253.4.25.6362
102253.4.25.64/26253.4.25.65 to 253.4.25.126253.4.25.12762
103253.4.25.128/26253.4.25.129 to 253.4.25.190253.4.25.19162
104253.4.25.192/26253.4.25.193 to 253.4.25.254253.4.25.25562
105253.4.26.0/26253.4.26.1 to 253.4.26.62253.4.26.6362
106253.4.26.64/26253.4.26.65 to 253.4.26.126253.4.26.12762
107253.4.26.128/26253.4.26.129 to 253.4.26.190253.4.26.19162
108253.4.26.192/26253.4.26.193 to 253.4.26.254253.4.26.25562
109253.4.27.0/26253.4.27.1 to 253.4.27.62253.4.27.6362
110253.4.27.64/26253.4.27.65 to 253.4.27.126253.4.27.12762
111253.4.27.128/26253.4.27.129 to 253.4.27.190253.4.27.19162
112253.4.27.192/26253.4.27.193 to 253.4.27.254253.4.27.25562
113253.4.28.0/26253.4.28.1 to 253.4.28.62253.4.28.6362
114253.4.28.64/26253.4.28.65 to 253.4.28.126253.4.28.12762
115253.4.28.128/26253.4.28.129 to 253.4.28.190253.4.28.19162
116253.4.28.192/26253.4.28.193 to 253.4.28.254253.4.28.25562
117253.4.29.0/26253.4.29.1 to 253.4.29.62253.4.29.6362
118253.4.29.64/26253.4.29.65 to 253.4.29.126253.4.29.12762
119253.4.29.128/26253.4.29.129 to 253.4.29.190253.4.29.19162
120253.4.29.192/26253.4.29.193 to 253.4.29.254253.4.29.25562
121253.4.30.0/26253.4.30.1 to 253.4.30.62253.4.30.6362
122253.4.30.64/26253.4.30.65 to 253.4.30.126253.4.30.12762
123253.4.30.128/26253.4.30.129 to 253.4.30.190253.4.30.19162
124253.4.30.192/26253.4.30.193 to 253.4.30.254253.4.30.25562
125253.4.31.0/26253.4.31.1 to 253.4.31.62253.4.31.6362
126253.4.31.64/26253.4.31.65 to 253.4.31.126253.4.31.12762
127253.4.31.128/26253.4.31.129 to 253.4.31.190253.4.31.19162
128253.4.31.192/26253.4.31.193 to 253.4.31.254253.4.31.25562
129253.4.32.0/26253.4.32.1 to 253.4.32.62253.4.32.6362
130253.4.32.64/26253.4.32.65 to 253.4.32.126253.4.32.12762
131253.4.32.128/26253.4.32.129 to 253.4.32.190253.4.32.19162
132253.4.32.192/26253.4.32.193 to 253.4.32.254253.4.32.25562
133253.4.33.0/26253.4.33.1 to 253.4.33.62253.4.33.6362
134253.4.33.64/26253.4.33.65 to 253.4.33.126253.4.33.12762
135253.4.33.128/26253.4.33.129 to 253.4.33.190253.4.33.19162
136253.4.33.192/26253.4.33.193 to 253.4.33.254253.4.33.25562
137253.4.34.0/26253.4.34.1 to 253.4.34.62253.4.34.6362
138253.4.34.64/26253.4.34.65 to 253.4.34.126253.4.34.12762
139253.4.34.128/26253.4.34.129 to 253.4.34.190253.4.34.19162
140253.4.34.192/26253.4.34.193 to 253.4.34.254253.4.34.25562
141253.4.35.0/26253.4.35.1 to 253.4.35.62253.4.35.6362
142253.4.35.64/26253.4.35.65 to 253.4.35.126253.4.35.12762
143253.4.35.128/26253.4.35.129 to 253.4.35.190253.4.35.19162
144253.4.35.192/26253.4.35.193 to 253.4.35.254253.4.35.25562
145253.4.36.0/26253.4.36.1 to 253.4.36.62253.4.36.6362
146253.4.36.64/26253.4.36.65 to 253.4.36.126253.4.36.12762
147253.4.36.128/26253.4.36.129 to 253.4.36.190253.4.36.19162
148253.4.36.192/26253.4.36.193 to 253.4.36.254253.4.36.25562
149253.4.37.0/26253.4.37.1 to 253.4.37.62253.4.37.6362
150253.4.37.64/26253.4.37.65 to 253.4.37.126253.4.37.12762
151253.4.37.128/26253.4.37.129 to 253.4.37.190253.4.37.19162
152253.4.37.192/26253.4.37.193 to 253.4.37.254253.4.37.25562
153253.4.38.0/26253.4.38.1 to 253.4.38.62253.4.38.6362
154253.4.38.64/26253.4.38.65 to 253.4.38.126253.4.38.12762
155253.4.38.128/26253.4.38.129 to 253.4.38.190253.4.38.19162
156253.4.38.192/26253.4.38.193 to 253.4.38.254253.4.38.25562
157253.4.39.0/26253.4.39.1 to 253.4.39.62253.4.39.6362
158253.4.39.64/26253.4.39.65 to 253.4.39.126253.4.39.12762
159253.4.39.128/26253.4.39.129 to 253.4.39.190253.4.39.19162
160253.4.39.192/26253.4.39.193 to 253.4.39.254253.4.39.25562
161253.4.40.0/26253.4.40.1 to 253.4.40.62253.4.40.6362
162253.4.40.64/26253.4.40.65 to 253.4.40.126253.4.40.12762
163253.4.40.128/26253.4.40.129 to 253.4.40.190253.4.40.19162
164253.4.40.192/26253.4.40.193 to 253.4.40.254253.4.40.25562
165253.4.41.0/26253.4.41.1 to 253.4.41.62253.4.41.6362
166253.4.41.64/26253.4.41.65 to 253.4.41.126253.4.41.12762
167253.4.41.128/26253.4.41.129 to 253.4.41.190253.4.41.19162
168253.4.41.192/26253.4.41.193 to 253.4.41.254253.4.41.25562
169253.4.42.0/26253.4.42.1 to 253.4.42.62253.4.42.6362
170253.4.42.64/26253.4.42.65 to 253.4.42.126253.4.42.12762
171253.4.42.128/26253.4.42.129 to 253.4.42.190253.4.42.19162
172253.4.42.192/26253.4.42.193 to 253.4.42.254253.4.42.25562
173253.4.43.0/26253.4.43.1 to 253.4.43.62253.4.43.6362
174253.4.43.64/26253.4.43.65 to 253.4.43.126253.4.43.12762
175253.4.43.128/26253.4.43.129 to 253.4.43.190253.4.43.19162
176253.4.43.192/26253.4.43.193 to 253.4.43.254253.4.43.25562
177253.4.44.0/26253.4.44.1 to 253.4.44.62253.4.44.6362
178253.4.44.64/26253.4.44.65 to 253.4.44.126253.4.44.12762
179253.4.44.128/26253.4.44.129 to 253.4.44.190253.4.44.19162
180253.4.44.192/26253.4.44.193 to 253.4.44.254253.4.44.25562
181253.4.45.0/26253.4.45.1 to 253.4.45.62253.4.45.6362
182253.4.45.64/26253.4.45.65 to 253.4.45.126253.4.45.12762
183253.4.45.128/26253.4.45.129 to 253.4.45.190253.4.45.19162
184253.4.45.192/26253.4.45.193 to 253.4.45.254253.4.45.25562
185253.4.46.0/26253.4.46.1 to 253.4.46.62253.4.46.6362
186253.4.46.64/26253.4.46.65 to 253.4.46.126253.4.46.12762
187253.4.46.128/26253.4.46.129 to 253.4.46.190253.4.46.19162
188253.4.46.192/26253.4.46.193 to 253.4.46.254253.4.46.25562
189253.4.47.0/26253.4.47.1 to 253.4.47.62253.4.47.6362
190253.4.47.64/26253.4.47.65 to 253.4.47.126253.4.47.12762
191253.4.47.128/26253.4.47.129 to 253.4.47.190253.4.47.19162
192253.4.47.192/26253.4.47.193 to 253.4.47.254253.4.47.25562
193253.4.48.0/26253.4.48.1 to 253.4.48.62253.4.48.6362
194253.4.48.64/26253.4.48.65 to 253.4.48.126253.4.48.12762
195253.4.48.128/26253.4.48.129 to 253.4.48.190253.4.48.19162
196253.4.48.192/26253.4.48.193 to 253.4.48.254253.4.48.25562
197253.4.49.0/26253.4.49.1 to 253.4.49.62253.4.49.6362
198253.4.49.64/26253.4.49.65 to 253.4.49.126253.4.49.12762
199253.4.49.128/26253.4.49.129 to 253.4.49.190253.4.49.19162
200253.4.49.192/26253.4.49.193 to 253.4.49.254253.4.49.25562
201253.4.50.0/26253.4.50.1 to 253.4.50.62253.4.50.6362
202253.4.50.64/26253.4.50.65 to 253.4.50.126253.4.50.12762
203253.4.50.128/26253.4.50.129 to 253.4.50.190253.4.50.19162
204253.4.50.192/26253.4.50.193 to 253.4.50.254253.4.50.25562
205253.4.51.0/26253.4.51.1 to 253.4.51.62253.4.51.6362
206253.4.51.64/26253.4.51.65 to 253.4.51.126253.4.51.12762
207253.4.51.128/26253.4.51.129 to 253.4.51.190253.4.51.19162
208253.4.51.192/26253.4.51.193 to 253.4.51.254253.4.51.25562
209253.4.52.0/26253.4.52.1 to 253.4.52.62253.4.52.6362
210253.4.52.64/26253.4.52.65 to 253.4.52.126253.4.52.12762
211253.4.52.128/26253.4.52.129 to 253.4.52.190253.4.52.19162
212253.4.52.192/26253.4.52.193 to 253.4.52.254253.4.52.25562
213253.4.53.0/26253.4.53.1 to 253.4.53.62253.4.53.6362
214253.4.53.64/26253.4.53.65 to 253.4.53.126253.4.53.12762
215253.4.53.128/26253.4.53.129 to 253.4.53.190253.4.53.19162
216253.4.53.192/26253.4.53.193 to 253.4.53.254253.4.53.25562
217253.4.54.0/26253.4.54.1 to 253.4.54.62253.4.54.6362
218253.4.54.64/26253.4.54.65 to 253.4.54.126253.4.54.12762
219253.4.54.128/26253.4.54.129 to 253.4.54.190253.4.54.19162
220253.4.54.192/26253.4.54.193 to 253.4.54.254253.4.54.25562
221253.4.55.0/26253.4.55.1 to 253.4.55.62253.4.55.6362
222253.4.55.64/26253.4.55.65 to 253.4.55.126253.4.55.12762
223253.4.55.128/26253.4.55.129 to 253.4.55.190253.4.55.19162
224253.4.55.192/26253.4.55.193 to 253.4.55.254253.4.55.25562
225253.4.56.0/26253.4.56.1 to 253.4.56.62253.4.56.6362
226253.4.56.64/26253.4.56.65 to 253.4.56.126253.4.56.12762
227253.4.56.128/26253.4.56.129 to 253.4.56.190253.4.56.19162
228253.4.56.192/26253.4.56.193 to 253.4.56.254253.4.56.25562
229253.4.57.0/26253.4.57.1 to 253.4.57.62253.4.57.6362
230253.4.57.64/26253.4.57.65 to 253.4.57.126253.4.57.12762
231253.4.57.128/26253.4.57.129 to 253.4.57.190253.4.57.19162
232253.4.57.192/26253.4.57.193 to 253.4.57.254253.4.57.25562
233253.4.58.0/26253.4.58.1 to 253.4.58.62253.4.58.6362
234253.4.58.64/26253.4.58.65 to 253.4.58.126253.4.58.12762
235253.4.58.128/26253.4.58.129 to 253.4.58.190253.4.58.19162
236253.4.58.192/26253.4.58.193 to 253.4.58.254253.4.58.25562
237253.4.59.0/26253.4.59.1 to 253.4.59.62253.4.59.6362
238253.4.59.64/26253.4.59.65 to 253.4.59.126253.4.59.12762
239253.4.59.128/26253.4.59.129 to 253.4.59.190253.4.59.19162
240253.4.59.192/26253.4.59.193 to 253.4.59.254253.4.59.25562
241253.4.60.0/26253.4.60.1 to 253.4.60.62253.4.60.6362
242253.4.60.64/26253.4.60.65 to 253.4.60.126253.4.60.12762
243253.4.60.128/26253.4.60.129 to 253.4.60.190253.4.60.19162
244253.4.60.192/26253.4.60.193 to 253.4.60.254253.4.60.25562
245253.4.61.0/26253.4.61.1 to 253.4.61.62253.4.61.6362
246253.4.61.64/26253.4.61.65 to 253.4.61.126253.4.61.12762
247253.4.61.128/26253.4.61.129 to 253.4.61.190253.4.61.19162
248253.4.61.192/26253.4.61.193 to 253.4.61.254253.4.61.25562
249253.4.62.0/26253.4.62.1 to 253.4.62.62253.4.62.6362
250253.4.62.64/26253.4.62.65 to 253.4.62.126253.4.62.12762
251253.4.62.128/26253.4.62.129 to 253.4.62.190253.4.62.19162
252253.4.62.192/26253.4.62.193 to 253.4.62.254253.4.62.25562
253253.4.63.0/26253.4.63.1 to 253.4.63.62253.4.63.6362
254253.4.63.64/26253.4.63.65 to 253.4.63.126253.4.63.12762
255253.4.63.128/26253.4.63.129 to 253.4.63.190253.4.63.19162
256253.4.63.192/26253.4.63.193 to 253.4.63.254253.4.63.25562

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.