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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.

Network231.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
231.0.0.0
Broadcast address
231.255.255.255
First usable
231.0.0.1
Last usable
231.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E7000000 · Integer 3875536896 to 3892314111
Reverse DNS zone
231.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100111..00000000.00000000.00000000231.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11100111..00000000.00000000.00000000231.0.0.0
Broadcast11100111..11111111.11111111.11111111231.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

231.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1231.0.0.0/18231.0.0.1 to 231.0.63.254231.0.63.25516,382
2231.0.64.0/18231.0.64.1 to 231.0.127.254231.0.127.25516,382
3231.0.128.0/18231.0.128.1 to 231.0.191.254231.0.191.25516,382
4231.0.192.0/18231.0.192.1 to 231.0.255.254231.0.255.25516,382
5231.1.0.0/18231.1.0.1 to 231.1.63.254231.1.63.25516,382
6231.1.64.0/18231.1.64.1 to 231.1.127.254231.1.127.25516,382
7231.1.128.0/18231.1.128.1 to 231.1.191.254231.1.191.25516,382
8231.1.192.0/18231.1.192.1 to 231.1.255.254231.1.255.25516,382
9231.2.0.0/18231.2.0.1 to 231.2.63.254231.2.63.25516,382
10231.2.64.0/18231.2.64.1 to 231.2.127.254231.2.127.25516,382
11231.2.128.0/18231.2.128.1 to 231.2.191.254231.2.191.25516,382
12231.2.192.0/18231.2.192.1 to 231.2.255.254231.2.255.25516,382
13231.3.0.0/18231.3.0.1 to 231.3.63.254231.3.63.25516,382
14231.3.64.0/18231.3.64.1 to 231.3.127.254231.3.127.25516,382
15231.3.128.0/18231.3.128.1 to 231.3.191.254231.3.191.25516,382
16231.3.192.0/18231.3.192.1 to 231.3.255.254231.3.255.25516,382
17231.4.0.0/18231.4.0.1 to 231.4.63.254231.4.63.25516,382
18231.4.64.0/18231.4.64.1 to 231.4.127.254231.4.127.25516,382
19231.4.128.0/18231.4.128.1 to 231.4.191.254231.4.191.25516,382
20231.4.192.0/18231.4.192.1 to 231.4.255.254231.4.255.25516,382
21231.5.0.0/18231.5.0.1 to 231.5.63.254231.5.63.25516,382
22231.5.64.0/18231.5.64.1 to 231.5.127.254231.5.127.25516,382
23231.5.128.0/18231.5.128.1 to 231.5.191.254231.5.191.25516,382
24231.5.192.0/18231.5.192.1 to 231.5.255.254231.5.255.25516,382
25231.6.0.0/18231.6.0.1 to 231.6.63.254231.6.63.25516,382
26231.6.64.0/18231.6.64.1 to 231.6.127.254231.6.127.25516,382
27231.6.128.0/18231.6.128.1 to 231.6.191.254231.6.191.25516,382
28231.6.192.0/18231.6.192.1 to 231.6.255.254231.6.255.25516,382
29231.7.0.0/18231.7.0.1 to 231.7.63.254231.7.63.25516,382
30231.7.64.0/18231.7.64.1 to 231.7.127.254231.7.127.25516,382
31231.7.128.0/18231.7.128.1 to 231.7.191.254231.7.191.25516,382
32231.7.192.0/18231.7.192.1 to 231.7.255.254231.7.255.25516,382
33231.8.0.0/18231.8.0.1 to 231.8.63.254231.8.63.25516,382
34231.8.64.0/18231.8.64.1 to 231.8.127.254231.8.127.25516,382
35231.8.128.0/18231.8.128.1 to 231.8.191.254231.8.191.25516,382
36231.8.192.0/18231.8.192.1 to 231.8.255.254231.8.255.25516,382
37231.9.0.0/18231.9.0.1 to 231.9.63.254231.9.63.25516,382
38231.9.64.0/18231.9.64.1 to 231.9.127.254231.9.127.25516,382
39231.9.128.0/18231.9.128.1 to 231.9.191.254231.9.191.25516,382
40231.9.192.0/18231.9.192.1 to 231.9.255.254231.9.255.25516,382
41231.10.0.0/18231.10.0.1 to 231.10.63.254231.10.63.25516,382
42231.10.64.0/18231.10.64.1 to 231.10.127.254231.10.127.25516,382
43231.10.128.0/18231.10.128.1 to 231.10.191.254231.10.191.25516,382
44231.10.192.0/18231.10.192.1 to 231.10.255.254231.10.255.25516,382
45231.11.0.0/18231.11.0.1 to 231.11.63.254231.11.63.25516,382
46231.11.64.0/18231.11.64.1 to 231.11.127.254231.11.127.25516,382
47231.11.128.0/18231.11.128.1 to 231.11.191.254231.11.191.25516,382
48231.11.192.0/18231.11.192.1 to 231.11.255.254231.11.255.25516,382
49231.12.0.0/18231.12.0.1 to 231.12.63.254231.12.63.25516,382
50231.12.64.0/18231.12.64.1 to 231.12.127.254231.12.127.25516,382
51231.12.128.0/18231.12.128.1 to 231.12.191.254231.12.191.25516,382
52231.12.192.0/18231.12.192.1 to 231.12.255.254231.12.255.25516,382
53231.13.0.0/18231.13.0.1 to 231.13.63.254231.13.63.25516,382
54231.13.64.0/18231.13.64.1 to 231.13.127.254231.13.127.25516,382
55231.13.128.0/18231.13.128.1 to 231.13.191.254231.13.191.25516,382
56231.13.192.0/18231.13.192.1 to 231.13.255.254231.13.255.25516,382
57231.14.0.0/18231.14.0.1 to 231.14.63.254231.14.63.25516,382
58231.14.64.0/18231.14.64.1 to 231.14.127.254231.14.127.25516,382
59231.14.128.0/18231.14.128.1 to 231.14.191.254231.14.191.25516,382
60231.14.192.0/18231.14.192.1 to 231.14.255.254231.14.255.25516,382
61231.15.0.0/18231.15.0.1 to 231.15.63.254231.15.63.25516,382
62231.15.64.0/18231.15.64.1 to 231.15.127.254231.15.127.25516,382
63231.15.128.0/18231.15.128.1 to 231.15.191.254231.15.191.25516,382
64231.15.192.0/18231.15.192.1 to 231.15.255.254231.15.255.25516,382
65231.16.0.0/18231.16.0.1 to 231.16.63.254231.16.63.25516,382
66231.16.64.0/18231.16.64.1 to 231.16.127.254231.16.127.25516,382
67231.16.128.0/18231.16.128.1 to 231.16.191.254231.16.191.25516,382
68231.16.192.0/18231.16.192.1 to 231.16.255.254231.16.255.25516,382
69231.17.0.0/18231.17.0.1 to 231.17.63.254231.17.63.25516,382
70231.17.64.0/18231.17.64.1 to 231.17.127.254231.17.127.25516,382
71231.17.128.0/18231.17.128.1 to 231.17.191.254231.17.191.25516,382
72231.17.192.0/18231.17.192.1 to 231.17.255.254231.17.255.25516,382
73231.18.0.0/18231.18.0.1 to 231.18.63.254231.18.63.25516,382
74231.18.64.0/18231.18.64.1 to 231.18.127.254231.18.127.25516,382
75231.18.128.0/18231.18.128.1 to 231.18.191.254231.18.191.25516,382
76231.18.192.0/18231.18.192.1 to 231.18.255.254231.18.255.25516,382
77231.19.0.0/18231.19.0.1 to 231.19.63.254231.19.63.25516,382
78231.19.64.0/18231.19.64.1 to 231.19.127.254231.19.127.25516,382
79231.19.128.0/18231.19.128.1 to 231.19.191.254231.19.191.25516,382
80231.19.192.0/18231.19.192.1 to 231.19.255.254231.19.255.25516,382
81231.20.0.0/18231.20.0.1 to 231.20.63.254231.20.63.25516,382
82231.20.64.0/18231.20.64.1 to 231.20.127.254231.20.127.25516,382
83231.20.128.0/18231.20.128.1 to 231.20.191.254231.20.191.25516,382
84231.20.192.0/18231.20.192.1 to 231.20.255.254231.20.255.25516,382
85231.21.0.0/18231.21.0.1 to 231.21.63.254231.21.63.25516,382
86231.21.64.0/18231.21.64.1 to 231.21.127.254231.21.127.25516,382
87231.21.128.0/18231.21.128.1 to 231.21.191.254231.21.191.25516,382
88231.21.192.0/18231.21.192.1 to 231.21.255.254231.21.255.25516,382
89231.22.0.0/18231.22.0.1 to 231.22.63.254231.22.63.25516,382
90231.22.64.0/18231.22.64.1 to 231.22.127.254231.22.127.25516,382
91231.22.128.0/18231.22.128.1 to 231.22.191.254231.22.191.25516,382
92231.22.192.0/18231.22.192.1 to 231.22.255.254231.22.255.25516,382
93231.23.0.0/18231.23.0.1 to 231.23.63.254231.23.63.25516,382
94231.23.64.0/18231.23.64.1 to 231.23.127.254231.23.127.25516,382
95231.23.128.0/18231.23.128.1 to 231.23.191.254231.23.191.25516,382
96231.23.192.0/18231.23.192.1 to 231.23.255.254231.23.255.25516,382
97231.24.0.0/18231.24.0.1 to 231.24.63.254231.24.63.25516,382
98231.24.64.0/18231.24.64.1 to 231.24.127.254231.24.127.25516,382
99231.24.128.0/18231.24.128.1 to 231.24.191.254231.24.191.25516,382
100231.24.192.0/18231.24.192.1 to 231.24.255.254231.24.255.25516,382
101231.25.0.0/18231.25.0.1 to 231.25.63.254231.25.63.25516,382
102231.25.64.0/18231.25.64.1 to 231.25.127.254231.25.127.25516,382
103231.25.128.0/18231.25.128.1 to 231.25.191.254231.25.191.25516,382
104231.25.192.0/18231.25.192.1 to 231.25.255.254231.25.255.25516,382
105231.26.0.0/18231.26.0.1 to 231.26.63.254231.26.63.25516,382
106231.26.64.0/18231.26.64.1 to 231.26.127.254231.26.127.25516,382
107231.26.128.0/18231.26.128.1 to 231.26.191.254231.26.191.25516,382
108231.26.192.0/18231.26.192.1 to 231.26.255.254231.26.255.25516,382
109231.27.0.0/18231.27.0.1 to 231.27.63.254231.27.63.25516,382
110231.27.64.0/18231.27.64.1 to 231.27.127.254231.27.127.25516,382
111231.27.128.0/18231.27.128.1 to 231.27.191.254231.27.191.25516,382
112231.27.192.0/18231.27.192.1 to 231.27.255.254231.27.255.25516,382
113231.28.0.0/18231.28.0.1 to 231.28.63.254231.28.63.25516,382
114231.28.64.0/18231.28.64.1 to 231.28.127.254231.28.127.25516,382
115231.28.128.0/18231.28.128.1 to 231.28.191.254231.28.191.25516,382
116231.28.192.0/18231.28.192.1 to 231.28.255.254231.28.255.25516,382
117231.29.0.0/18231.29.0.1 to 231.29.63.254231.29.63.25516,382
118231.29.64.0/18231.29.64.1 to 231.29.127.254231.29.127.25516,382
119231.29.128.0/18231.29.128.1 to 231.29.191.254231.29.191.25516,382
120231.29.192.0/18231.29.192.1 to 231.29.255.254231.29.255.25516,382
121231.30.0.0/18231.30.0.1 to 231.30.63.254231.30.63.25516,382
122231.30.64.0/18231.30.64.1 to 231.30.127.254231.30.127.25516,382
123231.30.128.0/18231.30.128.1 to 231.30.191.254231.30.191.25516,382
124231.30.192.0/18231.30.192.1 to 231.30.255.254231.30.255.25516,382
125231.31.0.0/18231.31.0.1 to 231.31.63.254231.31.63.25516,382
126231.31.64.0/18231.31.64.1 to 231.31.127.254231.31.127.25516,382
127231.31.128.0/18231.31.128.1 to 231.31.191.254231.31.191.25516,382
128231.31.192.0/18231.31.192.1 to 231.31.255.254231.31.255.25516,382
129231.32.0.0/18231.32.0.1 to 231.32.63.254231.32.63.25516,382
130231.32.64.0/18231.32.64.1 to 231.32.127.254231.32.127.25516,382
131231.32.128.0/18231.32.128.1 to 231.32.191.254231.32.191.25516,382
132231.32.192.0/18231.32.192.1 to 231.32.255.254231.32.255.25516,382
133231.33.0.0/18231.33.0.1 to 231.33.63.254231.33.63.25516,382
134231.33.64.0/18231.33.64.1 to 231.33.127.254231.33.127.25516,382
135231.33.128.0/18231.33.128.1 to 231.33.191.254231.33.191.25516,382
136231.33.192.0/18231.33.192.1 to 231.33.255.254231.33.255.25516,382
137231.34.0.0/18231.34.0.1 to 231.34.63.254231.34.63.25516,382
138231.34.64.0/18231.34.64.1 to 231.34.127.254231.34.127.25516,382
139231.34.128.0/18231.34.128.1 to 231.34.191.254231.34.191.25516,382
140231.34.192.0/18231.34.192.1 to 231.34.255.254231.34.255.25516,382
141231.35.0.0/18231.35.0.1 to 231.35.63.254231.35.63.25516,382
142231.35.64.0/18231.35.64.1 to 231.35.127.254231.35.127.25516,382
143231.35.128.0/18231.35.128.1 to 231.35.191.254231.35.191.25516,382
144231.35.192.0/18231.35.192.1 to 231.35.255.254231.35.255.25516,382
145231.36.0.0/18231.36.0.1 to 231.36.63.254231.36.63.25516,382
146231.36.64.0/18231.36.64.1 to 231.36.127.254231.36.127.25516,382
147231.36.128.0/18231.36.128.1 to 231.36.191.254231.36.191.25516,382
148231.36.192.0/18231.36.192.1 to 231.36.255.254231.36.255.25516,382
149231.37.0.0/18231.37.0.1 to 231.37.63.254231.37.63.25516,382
150231.37.64.0/18231.37.64.1 to 231.37.127.254231.37.127.25516,382
151231.37.128.0/18231.37.128.1 to 231.37.191.254231.37.191.25516,382
152231.37.192.0/18231.37.192.1 to 231.37.255.254231.37.255.25516,382
153231.38.0.0/18231.38.0.1 to 231.38.63.254231.38.63.25516,382
154231.38.64.0/18231.38.64.1 to 231.38.127.254231.38.127.25516,382
155231.38.128.0/18231.38.128.1 to 231.38.191.254231.38.191.25516,382
156231.38.192.0/18231.38.192.1 to 231.38.255.254231.38.255.25516,382
157231.39.0.0/18231.39.0.1 to 231.39.63.254231.39.63.25516,382
158231.39.64.0/18231.39.64.1 to 231.39.127.254231.39.127.25516,382
159231.39.128.0/18231.39.128.1 to 231.39.191.254231.39.191.25516,382
160231.39.192.0/18231.39.192.1 to 231.39.255.254231.39.255.25516,382
161231.40.0.0/18231.40.0.1 to 231.40.63.254231.40.63.25516,382
162231.40.64.0/18231.40.64.1 to 231.40.127.254231.40.127.25516,382
163231.40.128.0/18231.40.128.1 to 231.40.191.254231.40.191.25516,382
164231.40.192.0/18231.40.192.1 to 231.40.255.254231.40.255.25516,382
165231.41.0.0/18231.41.0.1 to 231.41.63.254231.41.63.25516,382
166231.41.64.0/18231.41.64.1 to 231.41.127.254231.41.127.25516,382
167231.41.128.0/18231.41.128.1 to 231.41.191.254231.41.191.25516,382
168231.41.192.0/18231.41.192.1 to 231.41.255.254231.41.255.25516,382
169231.42.0.0/18231.42.0.1 to 231.42.63.254231.42.63.25516,382
170231.42.64.0/18231.42.64.1 to 231.42.127.254231.42.127.25516,382
171231.42.128.0/18231.42.128.1 to 231.42.191.254231.42.191.25516,382
172231.42.192.0/18231.42.192.1 to 231.42.255.254231.42.255.25516,382
173231.43.0.0/18231.43.0.1 to 231.43.63.254231.43.63.25516,382
174231.43.64.0/18231.43.64.1 to 231.43.127.254231.43.127.25516,382
175231.43.128.0/18231.43.128.1 to 231.43.191.254231.43.191.25516,382
176231.43.192.0/18231.43.192.1 to 231.43.255.254231.43.255.25516,382
177231.44.0.0/18231.44.0.1 to 231.44.63.254231.44.63.25516,382
178231.44.64.0/18231.44.64.1 to 231.44.127.254231.44.127.25516,382
179231.44.128.0/18231.44.128.1 to 231.44.191.254231.44.191.25516,382
180231.44.192.0/18231.44.192.1 to 231.44.255.254231.44.255.25516,382
181231.45.0.0/18231.45.0.1 to 231.45.63.254231.45.63.25516,382
182231.45.64.0/18231.45.64.1 to 231.45.127.254231.45.127.25516,382
183231.45.128.0/18231.45.128.1 to 231.45.191.254231.45.191.25516,382
184231.45.192.0/18231.45.192.1 to 231.45.255.254231.45.255.25516,382
185231.46.0.0/18231.46.0.1 to 231.46.63.254231.46.63.25516,382
186231.46.64.0/18231.46.64.1 to 231.46.127.254231.46.127.25516,382
187231.46.128.0/18231.46.128.1 to 231.46.191.254231.46.191.25516,382
188231.46.192.0/18231.46.192.1 to 231.46.255.254231.46.255.25516,382
189231.47.0.0/18231.47.0.1 to 231.47.63.254231.47.63.25516,382
190231.47.64.0/18231.47.64.1 to 231.47.127.254231.47.127.25516,382
191231.47.128.0/18231.47.128.1 to 231.47.191.254231.47.191.25516,382
192231.47.192.0/18231.47.192.1 to 231.47.255.254231.47.255.25516,382
193231.48.0.0/18231.48.0.1 to 231.48.63.254231.48.63.25516,382
194231.48.64.0/18231.48.64.1 to 231.48.127.254231.48.127.25516,382
195231.48.128.0/18231.48.128.1 to 231.48.191.254231.48.191.25516,382
196231.48.192.0/18231.48.192.1 to 231.48.255.254231.48.255.25516,382
197231.49.0.0/18231.49.0.1 to 231.49.63.254231.49.63.25516,382
198231.49.64.0/18231.49.64.1 to 231.49.127.254231.49.127.25516,382
199231.49.128.0/18231.49.128.1 to 231.49.191.254231.49.191.25516,382
200231.49.192.0/18231.49.192.1 to 231.49.255.254231.49.255.25516,382
201231.50.0.0/18231.50.0.1 to 231.50.63.254231.50.63.25516,382
202231.50.64.0/18231.50.64.1 to 231.50.127.254231.50.127.25516,382
203231.50.128.0/18231.50.128.1 to 231.50.191.254231.50.191.25516,382
204231.50.192.0/18231.50.192.1 to 231.50.255.254231.50.255.25516,382
205231.51.0.0/18231.51.0.1 to 231.51.63.254231.51.63.25516,382
206231.51.64.0/18231.51.64.1 to 231.51.127.254231.51.127.25516,382
207231.51.128.0/18231.51.128.1 to 231.51.191.254231.51.191.25516,382
208231.51.192.0/18231.51.192.1 to 231.51.255.254231.51.255.25516,382
209231.52.0.0/18231.52.0.1 to 231.52.63.254231.52.63.25516,382
210231.52.64.0/18231.52.64.1 to 231.52.127.254231.52.127.25516,382
211231.52.128.0/18231.52.128.1 to 231.52.191.254231.52.191.25516,382
212231.52.192.0/18231.52.192.1 to 231.52.255.254231.52.255.25516,382
213231.53.0.0/18231.53.0.1 to 231.53.63.254231.53.63.25516,382
214231.53.64.0/18231.53.64.1 to 231.53.127.254231.53.127.25516,382
215231.53.128.0/18231.53.128.1 to 231.53.191.254231.53.191.25516,382
216231.53.192.0/18231.53.192.1 to 231.53.255.254231.53.255.25516,382
217231.54.0.0/18231.54.0.1 to 231.54.63.254231.54.63.25516,382
218231.54.64.0/18231.54.64.1 to 231.54.127.254231.54.127.25516,382
219231.54.128.0/18231.54.128.1 to 231.54.191.254231.54.191.25516,382
220231.54.192.0/18231.54.192.1 to 231.54.255.254231.54.255.25516,382
221231.55.0.0/18231.55.0.1 to 231.55.63.254231.55.63.25516,382
222231.55.64.0/18231.55.64.1 to 231.55.127.254231.55.127.25516,382
223231.55.128.0/18231.55.128.1 to 231.55.191.254231.55.191.25516,382
224231.55.192.0/18231.55.192.1 to 231.55.255.254231.55.255.25516,382
225231.56.0.0/18231.56.0.1 to 231.56.63.254231.56.63.25516,382
226231.56.64.0/18231.56.64.1 to 231.56.127.254231.56.127.25516,382
227231.56.128.0/18231.56.128.1 to 231.56.191.254231.56.191.25516,382
228231.56.192.0/18231.56.192.1 to 231.56.255.254231.56.255.25516,382
229231.57.0.0/18231.57.0.1 to 231.57.63.254231.57.63.25516,382
230231.57.64.0/18231.57.64.1 to 231.57.127.254231.57.127.25516,382
231231.57.128.0/18231.57.128.1 to 231.57.191.254231.57.191.25516,382
232231.57.192.0/18231.57.192.1 to 231.57.255.254231.57.255.25516,382
233231.58.0.0/18231.58.0.1 to 231.58.63.254231.58.63.25516,382
234231.58.64.0/18231.58.64.1 to 231.58.127.254231.58.127.25516,382
235231.58.128.0/18231.58.128.1 to 231.58.191.254231.58.191.25516,382
236231.58.192.0/18231.58.192.1 to 231.58.255.254231.58.255.25516,382
237231.59.0.0/18231.59.0.1 to 231.59.63.254231.59.63.25516,382
238231.59.64.0/18231.59.64.1 to 231.59.127.254231.59.127.25516,382
239231.59.128.0/18231.59.128.1 to 231.59.191.254231.59.191.25516,382
240231.59.192.0/18231.59.192.1 to 231.59.255.254231.59.255.25516,382
241231.60.0.0/18231.60.0.1 to 231.60.63.254231.60.63.25516,382
242231.60.64.0/18231.60.64.1 to 231.60.127.254231.60.127.25516,382
243231.60.128.0/18231.60.128.1 to 231.60.191.254231.60.191.25516,382
244231.60.192.0/18231.60.192.1 to 231.60.255.254231.60.255.25516,382
245231.61.0.0/18231.61.0.1 to 231.61.63.254231.61.63.25516,382
246231.61.64.0/18231.61.64.1 to 231.61.127.254231.61.127.25516,382
247231.61.128.0/18231.61.128.1 to 231.61.191.254231.61.191.25516,382
248231.61.192.0/18231.61.192.1 to 231.61.255.254231.61.255.25516,382
249231.62.0.0/18231.62.0.1 to 231.62.63.254231.62.63.25516,382
250231.62.64.0/18231.62.64.1 to 231.62.127.254231.62.127.25516,382
251231.62.128.0/18231.62.128.1 to 231.62.191.254231.62.191.25516,382
252231.62.192.0/18231.62.192.1 to 231.62.255.254231.62.255.25516,382
253231.63.0.0/18231.63.0.1 to 231.63.63.254231.63.63.25516,382
254231.63.64.0/18231.63.64.1 to 231.63.127.254231.63.127.25516,382
255231.63.128.0/18231.63.128.1 to 231.63.191.254231.63.191.25516,382
256231.63.192.0/18231.63.192.1 to 231.63.255.254231.63.255.25516,382

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.