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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.

Network219.2.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
219.2.0.0
Broadcast address
219.2.63.255
First usable
219.2.0.1
Last usable
219.2.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
C (default /24)
As numbers
Hex DB020000 · Integer 3674341376 to 3674357759
Reverse DNS zones
0.2.219.in-addr.arpa
1.2.219.in-addr.arpa
2.2.219.in-addr.arpa
3.2.219.in-addr.arpa
4.2.219.in-addr.arpa
5.2.219.in-addr.arpa
6.2.219.in-addr.arpa
7.2.219.in-addr.arpa
8.2.219.in-addr.arpa
9.2.219.in-addr.arpa
10.2.219.in-addr.arpa
11.2.219.in-addr.arpa
12.2.219.in-addr.arpa
13.2.219.in-addr.arpa
14.2.219.in-addr.arpa
15.2.219.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011011.00000010.00000000.00000000219.2.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11011011.00000010.00000000.00000000219.2.0.0
Broadcast11011011.00000010.00111111.11111111219.2.63.255
Split into smaller subnets/26
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

219.2.0.0/18 makes 256 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1219.2.0.0/26219.2.0.1 to 219.2.0.62219.2.0.6362
2219.2.0.64/26219.2.0.65 to 219.2.0.126219.2.0.12762
3219.2.0.128/26219.2.0.129 to 219.2.0.190219.2.0.19162
4219.2.0.192/26219.2.0.193 to 219.2.0.254219.2.0.25562
5219.2.1.0/26219.2.1.1 to 219.2.1.62219.2.1.6362
6219.2.1.64/26219.2.1.65 to 219.2.1.126219.2.1.12762
7219.2.1.128/26219.2.1.129 to 219.2.1.190219.2.1.19162
8219.2.1.192/26219.2.1.193 to 219.2.1.254219.2.1.25562
9219.2.2.0/26219.2.2.1 to 219.2.2.62219.2.2.6362
10219.2.2.64/26219.2.2.65 to 219.2.2.126219.2.2.12762
11219.2.2.128/26219.2.2.129 to 219.2.2.190219.2.2.19162
12219.2.2.192/26219.2.2.193 to 219.2.2.254219.2.2.25562
13219.2.3.0/26219.2.3.1 to 219.2.3.62219.2.3.6362
14219.2.3.64/26219.2.3.65 to 219.2.3.126219.2.3.12762
15219.2.3.128/26219.2.3.129 to 219.2.3.190219.2.3.19162
16219.2.3.192/26219.2.3.193 to 219.2.3.254219.2.3.25562
17219.2.4.0/26219.2.4.1 to 219.2.4.62219.2.4.6362
18219.2.4.64/26219.2.4.65 to 219.2.4.126219.2.4.12762
19219.2.4.128/26219.2.4.129 to 219.2.4.190219.2.4.19162
20219.2.4.192/26219.2.4.193 to 219.2.4.254219.2.4.25562
21219.2.5.0/26219.2.5.1 to 219.2.5.62219.2.5.6362
22219.2.5.64/26219.2.5.65 to 219.2.5.126219.2.5.12762
23219.2.5.128/26219.2.5.129 to 219.2.5.190219.2.5.19162
24219.2.5.192/26219.2.5.193 to 219.2.5.254219.2.5.25562
25219.2.6.0/26219.2.6.1 to 219.2.6.62219.2.6.6362
26219.2.6.64/26219.2.6.65 to 219.2.6.126219.2.6.12762
27219.2.6.128/26219.2.6.129 to 219.2.6.190219.2.6.19162
28219.2.6.192/26219.2.6.193 to 219.2.6.254219.2.6.25562
29219.2.7.0/26219.2.7.1 to 219.2.7.62219.2.7.6362
30219.2.7.64/26219.2.7.65 to 219.2.7.126219.2.7.12762
31219.2.7.128/26219.2.7.129 to 219.2.7.190219.2.7.19162
32219.2.7.192/26219.2.7.193 to 219.2.7.254219.2.7.25562
33219.2.8.0/26219.2.8.1 to 219.2.8.62219.2.8.6362
34219.2.8.64/26219.2.8.65 to 219.2.8.126219.2.8.12762
35219.2.8.128/26219.2.8.129 to 219.2.8.190219.2.8.19162
36219.2.8.192/26219.2.8.193 to 219.2.8.254219.2.8.25562
37219.2.9.0/26219.2.9.1 to 219.2.9.62219.2.9.6362
38219.2.9.64/26219.2.9.65 to 219.2.9.126219.2.9.12762
39219.2.9.128/26219.2.9.129 to 219.2.9.190219.2.9.19162
40219.2.9.192/26219.2.9.193 to 219.2.9.254219.2.9.25562
41219.2.10.0/26219.2.10.1 to 219.2.10.62219.2.10.6362
42219.2.10.64/26219.2.10.65 to 219.2.10.126219.2.10.12762
43219.2.10.128/26219.2.10.129 to 219.2.10.190219.2.10.19162
44219.2.10.192/26219.2.10.193 to 219.2.10.254219.2.10.25562
45219.2.11.0/26219.2.11.1 to 219.2.11.62219.2.11.6362
46219.2.11.64/26219.2.11.65 to 219.2.11.126219.2.11.12762
47219.2.11.128/26219.2.11.129 to 219.2.11.190219.2.11.19162
48219.2.11.192/26219.2.11.193 to 219.2.11.254219.2.11.25562
49219.2.12.0/26219.2.12.1 to 219.2.12.62219.2.12.6362
50219.2.12.64/26219.2.12.65 to 219.2.12.126219.2.12.12762
51219.2.12.128/26219.2.12.129 to 219.2.12.190219.2.12.19162
52219.2.12.192/26219.2.12.193 to 219.2.12.254219.2.12.25562
53219.2.13.0/26219.2.13.1 to 219.2.13.62219.2.13.6362
54219.2.13.64/26219.2.13.65 to 219.2.13.126219.2.13.12762
55219.2.13.128/26219.2.13.129 to 219.2.13.190219.2.13.19162
56219.2.13.192/26219.2.13.193 to 219.2.13.254219.2.13.25562
57219.2.14.0/26219.2.14.1 to 219.2.14.62219.2.14.6362
58219.2.14.64/26219.2.14.65 to 219.2.14.126219.2.14.12762
59219.2.14.128/26219.2.14.129 to 219.2.14.190219.2.14.19162
60219.2.14.192/26219.2.14.193 to 219.2.14.254219.2.14.25562
61219.2.15.0/26219.2.15.1 to 219.2.15.62219.2.15.6362
62219.2.15.64/26219.2.15.65 to 219.2.15.126219.2.15.12762
63219.2.15.128/26219.2.15.129 to 219.2.15.190219.2.15.19162
64219.2.15.192/26219.2.15.193 to 219.2.15.254219.2.15.25562
65219.2.16.0/26219.2.16.1 to 219.2.16.62219.2.16.6362
66219.2.16.64/26219.2.16.65 to 219.2.16.126219.2.16.12762
67219.2.16.128/26219.2.16.129 to 219.2.16.190219.2.16.19162
68219.2.16.192/26219.2.16.193 to 219.2.16.254219.2.16.25562
69219.2.17.0/26219.2.17.1 to 219.2.17.62219.2.17.6362
70219.2.17.64/26219.2.17.65 to 219.2.17.126219.2.17.12762
71219.2.17.128/26219.2.17.129 to 219.2.17.190219.2.17.19162
72219.2.17.192/26219.2.17.193 to 219.2.17.254219.2.17.25562
73219.2.18.0/26219.2.18.1 to 219.2.18.62219.2.18.6362
74219.2.18.64/26219.2.18.65 to 219.2.18.126219.2.18.12762
75219.2.18.128/26219.2.18.129 to 219.2.18.190219.2.18.19162
76219.2.18.192/26219.2.18.193 to 219.2.18.254219.2.18.25562
77219.2.19.0/26219.2.19.1 to 219.2.19.62219.2.19.6362
78219.2.19.64/26219.2.19.65 to 219.2.19.126219.2.19.12762
79219.2.19.128/26219.2.19.129 to 219.2.19.190219.2.19.19162
80219.2.19.192/26219.2.19.193 to 219.2.19.254219.2.19.25562
81219.2.20.0/26219.2.20.1 to 219.2.20.62219.2.20.6362
82219.2.20.64/26219.2.20.65 to 219.2.20.126219.2.20.12762
83219.2.20.128/26219.2.20.129 to 219.2.20.190219.2.20.19162
84219.2.20.192/26219.2.20.193 to 219.2.20.254219.2.20.25562
85219.2.21.0/26219.2.21.1 to 219.2.21.62219.2.21.6362
86219.2.21.64/26219.2.21.65 to 219.2.21.126219.2.21.12762
87219.2.21.128/26219.2.21.129 to 219.2.21.190219.2.21.19162
88219.2.21.192/26219.2.21.193 to 219.2.21.254219.2.21.25562
89219.2.22.0/26219.2.22.1 to 219.2.22.62219.2.22.6362
90219.2.22.64/26219.2.22.65 to 219.2.22.126219.2.22.12762
91219.2.22.128/26219.2.22.129 to 219.2.22.190219.2.22.19162
92219.2.22.192/26219.2.22.193 to 219.2.22.254219.2.22.25562
93219.2.23.0/26219.2.23.1 to 219.2.23.62219.2.23.6362
94219.2.23.64/26219.2.23.65 to 219.2.23.126219.2.23.12762
95219.2.23.128/26219.2.23.129 to 219.2.23.190219.2.23.19162
96219.2.23.192/26219.2.23.193 to 219.2.23.254219.2.23.25562
97219.2.24.0/26219.2.24.1 to 219.2.24.62219.2.24.6362
98219.2.24.64/26219.2.24.65 to 219.2.24.126219.2.24.12762
99219.2.24.128/26219.2.24.129 to 219.2.24.190219.2.24.19162
100219.2.24.192/26219.2.24.193 to 219.2.24.254219.2.24.25562
101219.2.25.0/26219.2.25.1 to 219.2.25.62219.2.25.6362
102219.2.25.64/26219.2.25.65 to 219.2.25.126219.2.25.12762
103219.2.25.128/26219.2.25.129 to 219.2.25.190219.2.25.19162
104219.2.25.192/26219.2.25.193 to 219.2.25.254219.2.25.25562
105219.2.26.0/26219.2.26.1 to 219.2.26.62219.2.26.6362
106219.2.26.64/26219.2.26.65 to 219.2.26.126219.2.26.12762
107219.2.26.128/26219.2.26.129 to 219.2.26.190219.2.26.19162
108219.2.26.192/26219.2.26.193 to 219.2.26.254219.2.26.25562
109219.2.27.0/26219.2.27.1 to 219.2.27.62219.2.27.6362
110219.2.27.64/26219.2.27.65 to 219.2.27.126219.2.27.12762
111219.2.27.128/26219.2.27.129 to 219.2.27.190219.2.27.19162
112219.2.27.192/26219.2.27.193 to 219.2.27.254219.2.27.25562
113219.2.28.0/26219.2.28.1 to 219.2.28.62219.2.28.6362
114219.2.28.64/26219.2.28.65 to 219.2.28.126219.2.28.12762
115219.2.28.128/26219.2.28.129 to 219.2.28.190219.2.28.19162
116219.2.28.192/26219.2.28.193 to 219.2.28.254219.2.28.25562
117219.2.29.0/26219.2.29.1 to 219.2.29.62219.2.29.6362
118219.2.29.64/26219.2.29.65 to 219.2.29.126219.2.29.12762
119219.2.29.128/26219.2.29.129 to 219.2.29.190219.2.29.19162
120219.2.29.192/26219.2.29.193 to 219.2.29.254219.2.29.25562
121219.2.30.0/26219.2.30.1 to 219.2.30.62219.2.30.6362
122219.2.30.64/26219.2.30.65 to 219.2.30.126219.2.30.12762
123219.2.30.128/26219.2.30.129 to 219.2.30.190219.2.30.19162
124219.2.30.192/26219.2.30.193 to 219.2.30.254219.2.30.25562
125219.2.31.0/26219.2.31.1 to 219.2.31.62219.2.31.6362
126219.2.31.64/26219.2.31.65 to 219.2.31.126219.2.31.12762
127219.2.31.128/26219.2.31.129 to 219.2.31.190219.2.31.19162
128219.2.31.192/26219.2.31.193 to 219.2.31.254219.2.31.25562
129219.2.32.0/26219.2.32.1 to 219.2.32.62219.2.32.6362
130219.2.32.64/26219.2.32.65 to 219.2.32.126219.2.32.12762
131219.2.32.128/26219.2.32.129 to 219.2.32.190219.2.32.19162
132219.2.32.192/26219.2.32.193 to 219.2.32.254219.2.32.25562
133219.2.33.0/26219.2.33.1 to 219.2.33.62219.2.33.6362
134219.2.33.64/26219.2.33.65 to 219.2.33.126219.2.33.12762
135219.2.33.128/26219.2.33.129 to 219.2.33.190219.2.33.19162
136219.2.33.192/26219.2.33.193 to 219.2.33.254219.2.33.25562
137219.2.34.0/26219.2.34.1 to 219.2.34.62219.2.34.6362
138219.2.34.64/26219.2.34.65 to 219.2.34.126219.2.34.12762
139219.2.34.128/26219.2.34.129 to 219.2.34.190219.2.34.19162
140219.2.34.192/26219.2.34.193 to 219.2.34.254219.2.34.25562
141219.2.35.0/26219.2.35.1 to 219.2.35.62219.2.35.6362
142219.2.35.64/26219.2.35.65 to 219.2.35.126219.2.35.12762
143219.2.35.128/26219.2.35.129 to 219.2.35.190219.2.35.19162
144219.2.35.192/26219.2.35.193 to 219.2.35.254219.2.35.25562
145219.2.36.0/26219.2.36.1 to 219.2.36.62219.2.36.6362
146219.2.36.64/26219.2.36.65 to 219.2.36.126219.2.36.12762
147219.2.36.128/26219.2.36.129 to 219.2.36.190219.2.36.19162
148219.2.36.192/26219.2.36.193 to 219.2.36.254219.2.36.25562
149219.2.37.0/26219.2.37.1 to 219.2.37.62219.2.37.6362
150219.2.37.64/26219.2.37.65 to 219.2.37.126219.2.37.12762
151219.2.37.128/26219.2.37.129 to 219.2.37.190219.2.37.19162
152219.2.37.192/26219.2.37.193 to 219.2.37.254219.2.37.25562
153219.2.38.0/26219.2.38.1 to 219.2.38.62219.2.38.6362
154219.2.38.64/26219.2.38.65 to 219.2.38.126219.2.38.12762
155219.2.38.128/26219.2.38.129 to 219.2.38.190219.2.38.19162
156219.2.38.192/26219.2.38.193 to 219.2.38.254219.2.38.25562
157219.2.39.0/26219.2.39.1 to 219.2.39.62219.2.39.6362
158219.2.39.64/26219.2.39.65 to 219.2.39.126219.2.39.12762
159219.2.39.128/26219.2.39.129 to 219.2.39.190219.2.39.19162
160219.2.39.192/26219.2.39.193 to 219.2.39.254219.2.39.25562
161219.2.40.0/26219.2.40.1 to 219.2.40.62219.2.40.6362
162219.2.40.64/26219.2.40.65 to 219.2.40.126219.2.40.12762
163219.2.40.128/26219.2.40.129 to 219.2.40.190219.2.40.19162
164219.2.40.192/26219.2.40.193 to 219.2.40.254219.2.40.25562
165219.2.41.0/26219.2.41.1 to 219.2.41.62219.2.41.6362
166219.2.41.64/26219.2.41.65 to 219.2.41.126219.2.41.12762
167219.2.41.128/26219.2.41.129 to 219.2.41.190219.2.41.19162
168219.2.41.192/26219.2.41.193 to 219.2.41.254219.2.41.25562
169219.2.42.0/26219.2.42.1 to 219.2.42.62219.2.42.6362
170219.2.42.64/26219.2.42.65 to 219.2.42.126219.2.42.12762
171219.2.42.128/26219.2.42.129 to 219.2.42.190219.2.42.19162
172219.2.42.192/26219.2.42.193 to 219.2.42.254219.2.42.25562
173219.2.43.0/26219.2.43.1 to 219.2.43.62219.2.43.6362
174219.2.43.64/26219.2.43.65 to 219.2.43.126219.2.43.12762
175219.2.43.128/26219.2.43.129 to 219.2.43.190219.2.43.19162
176219.2.43.192/26219.2.43.193 to 219.2.43.254219.2.43.25562
177219.2.44.0/26219.2.44.1 to 219.2.44.62219.2.44.6362
178219.2.44.64/26219.2.44.65 to 219.2.44.126219.2.44.12762
179219.2.44.128/26219.2.44.129 to 219.2.44.190219.2.44.19162
180219.2.44.192/26219.2.44.193 to 219.2.44.254219.2.44.25562
181219.2.45.0/26219.2.45.1 to 219.2.45.62219.2.45.6362
182219.2.45.64/26219.2.45.65 to 219.2.45.126219.2.45.12762
183219.2.45.128/26219.2.45.129 to 219.2.45.190219.2.45.19162
184219.2.45.192/26219.2.45.193 to 219.2.45.254219.2.45.25562
185219.2.46.0/26219.2.46.1 to 219.2.46.62219.2.46.6362
186219.2.46.64/26219.2.46.65 to 219.2.46.126219.2.46.12762
187219.2.46.128/26219.2.46.129 to 219.2.46.190219.2.46.19162
188219.2.46.192/26219.2.46.193 to 219.2.46.254219.2.46.25562
189219.2.47.0/26219.2.47.1 to 219.2.47.62219.2.47.6362
190219.2.47.64/26219.2.47.65 to 219.2.47.126219.2.47.12762
191219.2.47.128/26219.2.47.129 to 219.2.47.190219.2.47.19162
192219.2.47.192/26219.2.47.193 to 219.2.47.254219.2.47.25562
193219.2.48.0/26219.2.48.1 to 219.2.48.62219.2.48.6362
194219.2.48.64/26219.2.48.65 to 219.2.48.126219.2.48.12762
195219.2.48.128/26219.2.48.129 to 219.2.48.190219.2.48.19162
196219.2.48.192/26219.2.48.193 to 219.2.48.254219.2.48.25562
197219.2.49.0/26219.2.49.1 to 219.2.49.62219.2.49.6362
198219.2.49.64/26219.2.49.65 to 219.2.49.126219.2.49.12762
199219.2.49.128/26219.2.49.129 to 219.2.49.190219.2.49.19162
200219.2.49.192/26219.2.49.193 to 219.2.49.254219.2.49.25562
201219.2.50.0/26219.2.50.1 to 219.2.50.62219.2.50.6362
202219.2.50.64/26219.2.50.65 to 219.2.50.126219.2.50.12762
203219.2.50.128/26219.2.50.129 to 219.2.50.190219.2.50.19162
204219.2.50.192/26219.2.50.193 to 219.2.50.254219.2.50.25562
205219.2.51.0/26219.2.51.1 to 219.2.51.62219.2.51.6362
206219.2.51.64/26219.2.51.65 to 219.2.51.126219.2.51.12762
207219.2.51.128/26219.2.51.129 to 219.2.51.190219.2.51.19162
208219.2.51.192/26219.2.51.193 to 219.2.51.254219.2.51.25562
209219.2.52.0/26219.2.52.1 to 219.2.52.62219.2.52.6362
210219.2.52.64/26219.2.52.65 to 219.2.52.126219.2.52.12762
211219.2.52.128/26219.2.52.129 to 219.2.52.190219.2.52.19162
212219.2.52.192/26219.2.52.193 to 219.2.52.254219.2.52.25562
213219.2.53.0/26219.2.53.1 to 219.2.53.62219.2.53.6362
214219.2.53.64/26219.2.53.65 to 219.2.53.126219.2.53.12762
215219.2.53.128/26219.2.53.129 to 219.2.53.190219.2.53.19162
216219.2.53.192/26219.2.53.193 to 219.2.53.254219.2.53.25562
217219.2.54.0/26219.2.54.1 to 219.2.54.62219.2.54.6362
218219.2.54.64/26219.2.54.65 to 219.2.54.126219.2.54.12762
219219.2.54.128/26219.2.54.129 to 219.2.54.190219.2.54.19162
220219.2.54.192/26219.2.54.193 to 219.2.54.254219.2.54.25562
221219.2.55.0/26219.2.55.1 to 219.2.55.62219.2.55.6362
222219.2.55.64/26219.2.55.65 to 219.2.55.126219.2.55.12762
223219.2.55.128/26219.2.55.129 to 219.2.55.190219.2.55.19162
224219.2.55.192/26219.2.55.193 to 219.2.55.254219.2.55.25562
225219.2.56.0/26219.2.56.1 to 219.2.56.62219.2.56.6362
226219.2.56.64/26219.2.56.65 to 219.2.56.126219.2.56.12762
227219.2.56.128/26219.2.56.129 to 219.2.56.190219.2.56.19162
228219.2.56.192/26219.2.56.193 to 219.2.56.254219.2.56.25562
229219.2.57.0/26219.2.57.1 to 219.2.57.62219.2.57.6362
230219.2.57.64/26219.2.57.65 to 219.2.57.126219.2.57.12762
231219.2.57.128/26219.2.57.129 to 219.2.57.190219.2.57.19162
232219.2.57.192/26219.2.57.193 to 219.2.57.254219.2.57.25562
233219.2.58.0/26219.2.58.1 to 219.2.58.62219.2.58.6362
234219.2.58.64/26219.2.58.65 to 219.2.58.126219.2.58.12762
235219.2.58.128/26219.2.58.129 to 219.2.58.190219.2.58.19162
236219.2.58.192/26219.2.58.193 to 219.2.58.254219.2.58.25562
237219.2.59.0/26219.2.59.1 to 219.2.59.62219.2.59.6362
238219.2.59.64/26219.2.59.65 to 219.2.59.126219.2.59.12762
239219.2.59.128/26219.2.59.129 to 219.2.59.190219.2.59.19162
240219.2.59.192/26219.2.59.193 to 219.2.59.254219.2.59.25562
241219.2.60.0/26219.2.60.1 to 219.2.60.62219.2.60.6362
242219.2.60.64/26219.2.60.65 to 219.2.60.126219.2.60.12762
243219.2.60.128/26219.2.60.129 to 219.2.60.190219.2.60.19162
244219.2.60.192/26219.2.60.193 to 219.2.60.254219.2.60.25562
245219.2.61.0/26219.2.61.1 to 219.2.61.62219.2.61.6362
246219.2.61.64/26219.2.61.65 to 219.2.61.126219.2.61.12762
247219.2.61.128/26219.2.61.129 to 219.2.61.190219.2.61.19162
248219.2.61.192/26219.2.61.193 to 219.2.61.254219.2.61.25562
249219.2.62.0/26219.2.62.1 to 219.2.62.62219.2.62.6362
250219.2.62.64/26219.2.62.65 to 219.2.62.126219.2.62.12762
251219.2.62.128/26219.2.62.129 to 219.2.62.190219.2.62.19162
252219.2.62.192/26219.2.62.193 to 219.2.62.254219.2.62.25562
253219.2.63.0/26219.2.63.1 to 219.2.63.62219.2.63.6362
254219.2.63.64/26219.2.63.65 to 219.2.63.126219.2.63.12762
255219.2.63.128/26219.2.63.129 to 219.2.63.190219.2.63.19162
256219.2.63.192/26219.2.63.193 to 219.2.63.254219.2.63.25562

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.