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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.

Network157.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
157.0.0.0
Broadcast address
157.255.255.255
First usable
157.0.0.1
Last usable
157.255.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 9D000000 · Integer 2634022912 to 2650800127
Reverse DNS zone
157.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011101..00000000.00000000.00000000157.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011101..00000000.00000000.00000000157.0.0.0
Broadcast10011101..11111111.11111111.11111111157.255.255.255
Split into smaller subnets/19
/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)

157.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1157.0.0.0/19157.0.0.1 to 157.0.31.254157.0.31.2558,190
2157.0.32.0/19157.0.32.1 to 157.0.63.254157.0.63.2558,190
3157.0.64.0/19157.0.64.1 to 157.0.95.254157.0.95.2558,190
4157.0.96.0/19157.0.96.1 to 157.0.127.254157.0.127.2558,190
5157.0.128.0/19157.0.128.1 to 157.0.159.254157.0.159.2558,190
6157.0.160.0/19157.0.160.1 to 157.0.191.254157.0.191.2558,190
7157.0.192.0/19157.0.192.1 to 157.0.223.254157.0.223.2558,190
8157.0.224.0/19157.0.224.1 to 157.0.255.254157.0.255.2558,190
9157.1.0.0/19157.1.0.1 to 157.1.31.254157.1.31.2558,190
10157.1.32.0/19157.1.32.1 to 157.1.63.254157.1.63.2558,190
11157.1.64.0/19157.1.64.1 to 157.1.95.254157.1.95.2558,190
12157.1.96.0/19157.1.96.1 to 157.1.127.254157.1.127.2558,190
13157.1.128.0/19157.1.128.1 to 157.1.159.254157.1.159.2558,190
14157.1.160.0/19157.1.160.1 to 157.1.191.254157.1.191.2558,190
15157.1.192.0/19157.1.192.1 to 157.1.223.254157.1.223.2558,190
16157.1.224.0/19157.1.224.1 to 157.1.255.254157.1.255.2558,190
17157.2.0.0/19157.2.0.1 to 157.2.31.254157.2.31.2558,190
18157.2.32.0/19157.2.32.1 to 157.2.63.254157.2.63.2558,190
19157.2.64.0/19157.2.64.1 to 157.2.95.254157.2.95.2558,190
20157.2.96.0/19157.2.96.1 to 157.2.127.254157.2.127.2558,190
21157.2.128.0/19157.2.128.1 to 157.2.159.254157.2.159.2558,190
22157.2.160.0/19157.2.160.1 to 157.2.191.254157.2.191.2558,190
23157.2.192.0/19157.2.192.1 to 157.2.223.254157.2.223.2558,190
24157.2.224.0/19157.2.224.1 to 157.2.255.254157.2.255.2558,190
25157.3.0.0/19157.3.0.1 to 157.3.31.254157.3.31.2558,190
26157.3.32.0/19157.3.32.1 to 157.3.63.254157.3.63.2558,190
27157.3.64.0/19157.3.64.1 to 157.3.95.254157.3.95.2558,190
28157.3.96.0/19157.3.96.1 to 157.3.127.254157.3.127.2558,190
29157.3.128.0/19157.3.128.1 to 157.3.159.254157.3.159.2558,190
30157.3.160.0/19157.3.160.1 to 157.3.191.254157.3.191.2558,190
31157.3.192.0/19157.3.192.1 to 157.3.223.254157.3.223.2558,190
32157.3.224.0/19157.3.224.1 to 157.3.255.254157.3.255.2558,190
33157.4.0.0/19157.4.0.1 to 157.4.31.254157.4.31.2558,190
34157.4.32.0/19157.4.32.1 to 157.4.63.254157.4.63.2558,190
35157.4.64.0/19157.4.64.1 to 157.4.95.254157.4.95.2558,190
36157.4.96.0/19157.4.96.1 to 157.4.127.254157.4.127.2558,190
37157.4.128.0/19157.4.128.1 to 157.4.159.254157.4.159.2558,190
38157.4.160.0/19157.4.160.1 to 157.4.191.254157.4.191.2558,190
39157.4.192.0/19157.4.192.1 to 157.4.223.254157.4.223.2558,190
40157.4.224.0/19157.4.224.1 to 157.4.255.254157.4.255.2558,190
41157.5.0.0/19157.5.0.1 to 157.5.31.254157.5.31.2558,190
42157.5.32.0/19157.5.32.1 to 157.5.63.254157.5.63.2558,190
43157.5.64.0/19157.5.64.1 to 157.5.95.254157.5.95.2558,190
44157.5.96.0/19157.5.96.1 to 157.5.127.254157.5.127.2558,190
45157.5.128.0/19157.5.128.1 to 157.5.159.254157.5.159.2558,190
46157.5.160.0/19157.5.160.1 to 157.5.191.254157.5.191.2558,190
47157.5.192.0/19157.5.192.1 to 157.5.223.254157.5.223.2558,190
48157.5.224.0/19157.5.224.1 to 157.5.255.254157.5.255.2558,190
49157.6.0.0/19157.6.0.1 to 157.6.31.254157.6.31.2558,190
50157.6.32.0/19157.6.32.1 to 157.6.63.254157.6.63.2558,190
51157.6.64.0/19157.6.64.1 to 157.6.95.254157.6.95.2558,190
52157.6.96.0/19157.6.96.1 to 157.6.127.254157.6.127.2558,190
53157.6.128.0/19157.6.128.1 to 157.6.159.254157.6.159.2558,190
54157.6.160.0/19157.6.160.1 to 157.6.191.254157.6.191.2558,190
55157.6.192.0/19157.6.192.1 to 157.6.223.254157.6.223.2558,190
56157.6.224.0/19157.6.224.1 to 157.6.255.254157.6.255.2558,190
57157.7.0.0/19157.7.0.1 to 157.7.31.254157.7.31.2558,190
58157.7.32.0/19157.7.32.1 to 157.7.63.254157.7.63.2558,190
59157.7.64.0/19157.7.64.1 to 157.7.95.254157.7.95.2558,190
60157.7.96.0/19157.7.96.1 to 157.7.127.254157.7.127.2558,190
61157.7.128.0/19157.7.128.1 to 157.7.159.254157.7.159.2558,190
62157.7.160.0/19157.7.160.1 to 157.7.191.254157.7.191.2558,190
63157.7.192.0/19157.7.192.1 to 157.7.223.254157.7.223.2558,190
64157.7.224.0/19157.7.224.1 to 157.7.255.254157.7.255.2558,190
65157.8.0.0/19157.8.0.1 to 157.8.31.254157.8.31.2558,190
66157.8.32.0/19157.8.32.1 to 157.8.63.254157.8.63.2558,190
67157.8.64.0/19157.8.64.1 to 157.8.95.254157.8.95.2558,190
68157.8.96.0/19157.8.96.1 to 157.8.127.254157.8.127.2558,190
69157.8.128.0/19157.8.128.1 to 157.8.159.254157.8.159.2558,190
70157.8.160.0/19157.8.160.1 to 157.8.191.254157.8.191.2558,190
71157.8.192.0/19157.8.192.1 to 157.8.223.254157.8.223.2558,190
72157.8.224.0/19157.8.224.1 to 157.8.255.254157.8.255.2558,190
73157.9.0.0/19157.9.0.1 to 157.9.31.254157.9.31.2558,190
74157.9.32.0/19157.9.32.1 to 157.9.63.254157.9.63.2558,190
75157.9.64.0/19157.9.64.1 to 157.9.95.254157.9.95.2558,190
76157.9.96.0/19157.9.96.1 to 157.9.127.254157.9.127.2558,190
77157.9.128.0/19157.9.128.1 to 157.9.159.254157.9.159.2558,190
78157.9.160.0/19157.9.160.1 to 157.9.191.254157.9.191.2558,190
79157.9.192.0/19157.9.192.1 to 157.9.223.254157.9.223.2558,190
80157.9.224.0/19157.9.224.1 to 157.9.255.254157.9.255.2558,190
81157.10.0.0/19157.10.0.1 to 157.10.31.254157.10.31.2558,190
82157.10.32.0/19157.10.32.1 to 157.10.63.254157.10.63.2558,190
83157.10.64.0/19157.10.64.1 to 157.10.95.254157.10.95.2558,190
84157.10.96.0/19157.10.96.1 to 157.10.127.254157.10.127.2558,190
85157.10.128.0/19157.10.128.1 to 157.10.159.254157.10.159.2558,190
86157.10.160.0/19157.10.160.1 to 157.10.191.254157.10.191.2558,190
87157.10.192.0/19157.10.192.1 to 157.10.223.254157.10.223.2558,190
88157.10.224.0/19157.10.224.1 to 157.10.255.254157.10.255.2558,190
89157.11.0.0/19157.11.0.1 to 157.11.31.254157.11.31.2558,190
90157.11.32.0/19157.11.32.1 to 157.11.63.254157.11.63.2558,190
91157.11.64.0/19157.11.64.1 to 157.11.95.254157.11.95.2558,190
92157.11.96.0/19157.11.96.1 to 157.11.127.254157.11.127.2558,190
93157.11.128.0/19157.11.128.1 to 157.11.159.254157.11.159.2558,190
94157.11.160.0/19157.11.160.1 to 157.11.191.254157.11.191.2558,190
95157.11.192.0/19157.11.192.1 to 157.11.223.254157.11.223.2558,190
96157.11.224.0/19157.11.224.1 to 157.11.255.254157.11.255.2558,190
97157.12.0.0/19157.12.0.1 to 157.12.31.254157.12.31.2558,190
98157.12.32.0/19157.12.32.1 to 157.12.63.254157.12.63.2558,190
99157.12.64.0/19157.12.64.1 to 157.12.95.254157.12.95.2558,190
100157.12.96.0/19157.12.96.1 to 157.12.127.254157.12.127.2558,190
101157.12.128.0/19157.12.128.1 to 157.12.159.254157.12.159.2558,190
102157.12.160.0/19157.12.160.1 to 157.12.191.254157.12.191.2558,190
103157.12.192.0/19157.12.192.1 to 157.12.223.254157.12.223.2558,190
104157.12.224.0/19157.12.224.1 to 157.12.255.254157.12.255.2558,190
105157.13.0.0/19157.13.0.1 to 157.13.31.254157.13.31.2558,190
106157.13.32.0/19157.13.32.1 to 157.13.63.254157.13.63.2558,190
107157.13.64.0/19157.13.64.1 to 157.13.95.254157.13.95.2558,190
108157.13.96.0/19157.13.96.1 to 157.13.127.254157.13.127.2558,190
109157.13.128.0/19157.13.128.1 to 157.13.159.254157.13.159.2558,190
110157.13.160.0/19157.13.160.1 to 157.13.191.254157.13.191.2558,190
111157.13.192.0/19157.13.192.1 to 157.13.223.254157.13.223.2558,190
112157.13.224.0/19157.13.224.1 to 157.13.255.254157.13.255.2558,190
113157.14.0.0/19157.14.0.1 to 157.14.31.254157.14.31.2558,190
114157.14.32.0/19157.14.32.1 to 157.14.63.254157.14.63.2558,190
115157.14.64.0/19157.14.64.1 to 157.14.95.254157.14.95.2558,190
116157.14.96.0/19157.14.96.1 to 157.14.127.254157.14.127.2558,190
117157.14.128.0/19157.14.128.1 to 157.14.159.254157.14.159.2558,190
118157.14.160.0/19157.14.160.1 to 157.14.191.254157.14.191.2558,190
119157.14.192.0/19157.14.192.1 to 157.14.223.254157.14.223.2558,190
120157.14.224.0/19157.14.224.1 to 157.14.255.254157.14.255.2558,190
121157.15.0.0/19157.15.0.1 to 157.15.31.254157.15.31.2558,190
122157.15.32.0/19157.15.32.1 to 157.15.63.254157.15.63.2558,190
123157.15.64.0/19157.15.64.1 to 157.15.95.254157.15.95.2558,190
124157.15.96.0/19157.15.96.1 to 157.15.127.254157.15.127.2558,190
125157.15.128.0/19157.15.128.1 to 157.15.159.254157.15.159.2558,190
126157.15.160.0/19157.15.160.1 to 157.15.191.254157.15.191.2558,190
127157.15.192.0/19157.15.192.1 to 157.15.223.254157.15.223.2558,190
128157.15.224.0/19157.15.224.1 to 157.15.255.254157.15.255.2558,190
129157.16.0.0/19157.16.0.1 to 157.16.31.254157.16.31.2558,190
130157.16.32.0/19157.16.32.1 to 157.16.63.254157.16.63.2558,190
131157.16.64.0/19157.16.64.1 to 157.16.95.254157.16.95.2558,190
132157.16.96.0/19157.16.96.1 to 157.16.127.254157.16.127.2558,190
133157.16.128.0/19157.16.128.1 to 157.16.159.254157.16.159.2558,190
134157.16.160.0/19157.16.160.1 to 157.16.191.254157.16.191.2558,190
135157.16.192.0/19157.16.192.1 to 157.16.223.254157.16.223.2558,190
136157.16.224.0/19157.16.224.1 to 157.16.255.254157.16.255.2558,190
137157.17.0.0/19157.17.0.1 to 157.17.31.254157.17.31.2558,190
138157.17.32.0/19157.17.32.1 to 157.17.63.254157.17.63.2558,190
139157.17.64.0/19157.17.64.1 to 157.17.95.254157.17.95.2558,190
140157.17.96.0/19157.17.96.1 to 157.17.127.254157.17.127.2558,190
141157.17.128.0/19157.17.128.1 to 157.17.159.254157.17.159.2558,190
142157.17.160.0/19157.17.160.1 to 157.17.191.254157.17.191.2558,190
143157.17.192.0/19157.17.192.1 to 157.17.223.254157.17.223.2558,190
144157.17.224.0/19157.17.224.1 to 157.17.255.254157.17.255.2558,190
145157.18.0.0/19157.18.0.1 to 157.18.31.254157.18.31.2558,190
146157.18.32.0/19157.18.32.1 to 157.18.63.254157.18.63.2558,190
147157.18.64.0/19157.18.64.1 to 157.18.95.254157.18.95.2558,190
148157.18.96.0/19157.18.96.1 to 157.18.127.254157.18.127.2558,190
149157.18.128.0/19157.18.128.1 to 157.18.159.254157.18.159.2558,190
150157.18.160.0/19157.18.160.1 to 157.18.191.254157.18.191.2558,190
151157.18.192.0/19157.18.192.1 to 157.18.223.254157.18.223.2558,190
152157.18.224.0/19157.18.224.1 to 157.18.255.254157.18.255.2558,190
153157.19.0.0/19157.19.0.1 to 157.19.31.254157.19.31.2558,190
154157.19.32.0/19157.19.32.1 to 157.19.63.254157.19.63.2558,190
155157.19.64.0/19157.19.64.1 to 157.19.95.254157.19.95.2558,190
156157.19.96.0/19157.19.96.1 to 157.19.127.254157.19.127.2558,190
157157.19.128.0/19157.19.128.1 to 157.19.159.254157.19.159.2558,190
158157.19.160.0/19157.19.160.1 to 157.19.191.254157.19.191.2558,190
159157.19.192.0/19157.19.192.1 to 157.19.223.254157.19.223.2558,190
160157.19.224.0/19157.19.224.1 to 157.19.255.254157.19.255.2558,190
161157.20.0.0/19157.20.0.1 to 157.20.31.254157.20.31.2558,190
162157.20.32.0/19157.20.32.1 to 157.20.63.254157.20.63.2558,190
163157.20.64.0/19157.20.64.1 to 157.20.95.254157.20.95.2558,190
164157.20.96.0/19157.20.96.1 to 157.20.127.254157.20.127.2558,190
165157.20.128.0/19157.20.128.1 to 157.20.159.254157.20.159.2558,190
166157.20.160.0/19157.20.160.1 to 157.20.191.254157.20.191.2558,190
167157.20.192.0/19157.20.192.1 to 157.20.223.254157.20.223.2558,190
168157.20.224.0/19157.20.224.1 to 157.20.255.254157.20.255.2558,190
169157.21.0.0/19157.21.0.1 to 157.21.31.254157.21.31.2558,190
170157.21.32.0/19157.21.32.1 to 157.21.63.254157.21.63.2558,190
171157.21.64.0/19157.21.64.1 to 157.21.95.254157.21.95.2558,190
172157.21.96.0/19157.21.96.1 to 157.21.127.254157.21.127.2558,190
173157.21.128.0/19157.21.128.1 to 157.21.159.254157.21.159.2558,190
174157.21.160.0/19157.21.160.1 to 157.21.191.254157.21.191.2558,190
175157.21.192.0/19157.21.192.1 to 157.21.223.254157.21.223.2558,190
176157.21.224.0/19157.21.224.1 to 157.21.255.254157.21.255.2558,190
177157.22.0.0/19157.22.0.1 to 157.22.31.254157.22.31.2558,190
178157.22.32.0/19157.22.32.1 to 157.22.63.254157.22.63.2558,190
179157.22.64.0/19157.22.64.1 to 157.22.95.254157.22.95.2558,190
180157.22.96.0/19157.22.96.1 to 157.22.127.254157.22.127.2558,190
181157.22.128.0/19157.22.128.1 to 157.22.159.254157.22.159.2558,190
182157.22.160.0/19157.22.160.1 to 157.22.191.254157.22.191.2558,190
183157.22.192.0/19157.22.192.1 to 157.22.223.254157.22.223.2558,190
184157.22.224.0/19157.22.224.1 to 157.22.255.254157.22.255.2558,190
185157.23.0.0/19157.23.0.1 to 157.23.31.254157.23.31.2558,190
186157.23.32.0/19157.23.32.1 to 157.23.63.254157.23.63.2558,190
187157.23.64.0/19157.23.64.1 to 157.23.95.254157.23.95.2558,190
188157.23.96.0/19157.23.96.1 to 157.23.127.254157.23.127.2558,190
189157.23.128.0/19157.23.128.1 to 157.23.159.254157.23.159.2558,190
190157.23.160.0/19157.23.160.1 to 157.23.191.254157.23.191.2558,190
191157.23.192.0/19157.23.192.1 to 157.23.223.254157.23.223.2558,190
192157.23.224.0/19157.23.224.1 to 157.23.255.254157.23.255.2558,190
193157.24.0.0/19157.24.0.1 to 157.24.31.254157.24.31.2558,190
194157.24.32.0/19157.24.32.1 to 157.24.63.254157.24.63.2558,190
195157.24.64.0/19157.24.64.1 to 157.24.95.254157.24.95.2558,190
196157.24.96.0/19157.24.96.1 to 157.24.127.254157.24.127.2558,190
197157.24.128.0/19157.24.128.1 to 157.24.159.254157.24.159.2558,190
198157.24.160.0/19157.24.160.1 to 157.24.191.254157.24.191.2558,190
199157.24.192.0/19157.24.192.1 to 157.24.223.254157.24.223.2558,190
200157.24.224.0/19157.24.224.1 to 157.24.255.254157.24.255.2558,190
201157.25.0.0/19157.25.0.1 to 157.25.31.254157.25.31.2558,190
202157.25.32.0/19157.25.32.1 to 157.25.63.254157.25.63.2558,190
203157.25.64.0/19157.25.64.1 to 157.25.95.254157.25.95.2558,190
204157.25.96.0/19157.25.96.1 to 157.25.127.254157.25.127.2558,190
205157.25.128.0/19157.25.128.1 to 157.25.159.254157.25.159.2558,190
206157.25.160.0/19157.25.160.1 to 157.25.191.254157.25.191.2558,190
207157.25.192.0/19157.25.192.1 to 157.25.223.254157.25.223.2558,190
208157.25.224.0/19157.25.224.1 to 157.25.255.254157.25.255.2558,190
209157.26.0.0/19157.26.0.1 to 157.26.31.254157.26.31.2558,190
210157.26.32.0/19157.26.32.1 to 157.26.63.254157.26.63.2558,190
211157.26.64.0/19157.26.64.1 to 157.26.95.254157.26.95.2558,190
212157.26.96.0/19157.26.96.1 to 157.26.127.254157.26.127.2558,190
213157.26.128.0/19157.26.128.1 to 157.26.159.254157.26.159.2558,190
214157.26.160.0/19157.26.160.1 to 157.26.191.254157.26.191.2558,190
215157.26.192.0/19157.26.192.1 to 157.26.223.254157.26.223.2558,190
216157.26.224.0/19157.26.224.1 to 157.26.255.254157.26.255.2558,190
217157.27.0.0/19157.27.0.1 to 157.27.31.254157.27.31.2558,190
218157.27.32.0/19157.27.32.1 to 157.27.63.254157.27.63.2558,190
219157.27.64.0/19157.27.64.1 to 157.27.95.254157.27.95.2558,190
220157.27.96.0/19157.27.96.1 to 157.27.127.254157.27.127.2558,190
221157.27.128.0/19157.27.128.1 to 157.27.159.254157.27.159.2558,190
222157.27.160.0/19157.27.160.1 to 157.27.191.254157.27.191.2558,190
223157.27.192.0/19157.27.192.1 to 157.27.223.254157.27.223.2558,190
224157.27.224.0/19157.27.224.1 to 157.27.255.254157.27.255.2558,190
225157.28.0.0/19157.28.0.1 to 157.28.31.254157.28.31.2558,190
226157.28.32.0/19157.28.32.1 to 157.28.63.254157.28.63.2558,190
227157.28.64.0/19157.28.64.1 to 157.28.95.254157.28.95.2558,190
228157.28.96.0/19157.28.96.1 to 157.28.127.254157.28.127.2558,190
229157.28.128.0/19157.28.128.1 to 157.28.159.254157.28.159.2558,190
230157.28.160.0/19157.28.160.1 to 157.28.191.254157.28.191.2558,190
231157.28.192.0/19157.28.192.1 to 157.28.223.254157.28.223.2558,190
232157.28.224.0/19157.28.224.1 to 157.28.255.254157.28.255.2558,190
233157.29.0.0/19157.29.0.1 to 157.29.31.254157.29.31.2558,190
234157.29.32.0/19157.29.32.1 to 157.29.63.254157.29.63.2558,190
235157.29.64.0/19157.29.64.1 to 157.29.95.254157.29.95.2558,190
236157.29.96.0/19157.29.96.1 to 157.29.127.254157.29.127.2558,190
237157.29.128.0/19157.29.128.1 to 157.29.159.254157.29.159.2558,190
238157.29.160.0/19157.29.160.1 to 157.29.191.254157.29.191.2558,190
239157.29.192.0/19157.29.192.1 to 157.29.223.254157.29.223.2558,190
240157.29.224.0/19157.29.224.1 to 157.29.255.254157.29.255.2558,190
241157.30.0.0/19157.30.0.1 to 157.30.31.254157.30.31.2558,190
242157.30.32.0/19157.30.32.1 to 157.30.63.254157.30.63.2558,190
243157.30.64.0/19157.30.64.1 to 157.30.95.254157.30.95.2558,190
244157.30.96.0/19157.30.96.1 to 157.30.127.254157.30.127.2558,190
245157.30.128.0/19157.30.128.1 to 157.30.159.254157.30.159.2558,190
246157.30.160.0/19157.30.160.1 to 157.30.191.254157.30.191.2558,190
247157.30.192.0/19157.30.192.1 to 157.30.223.254157.30.223.2558,190
248157.30.224.0/19157.30.224.1 to 157.30.255.254157.30.255.2558,190
249157.31.0.0/19157.31.0.1 to 157.31.31.254157.31.31.2558,190
250157.31.32.0/19157.31.32.1 to 157.31.63.254157.31.63.2558,190
251157.31.64.0/19157.31.64.1 to 157.31.95.254157.31.95.2558,190
252157.31.96.0/19157.31.96.1 to 157.31.127.254157.31.127.2558,190
253157.31.128.0/19157.31.128.1 to 157.31.159.254157.31.159.2558,190
254157.31.160.0/19157.31.160.1 to 157.31.191.254157.31.191.2558,190
255157.31.192.0/19157.31.192.1 to 157.31.223.254157.31.223.2558,190
256157.31.224.0/19157.31.224.1 to 157.31.255.254157.31.255.2558,190

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.