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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.

Network247.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
247.0.0.0
Broadcast address
247.63.255.255
First usable
247.0.0.1
Last usable
247.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F7000000 · Integer 4143972352 to 4148166655
Reverse DNS zones
0.247.in-addr.arpa
1.247.in-addr.arpa
2.247.in-addr.arpa
3.247.in-addr.arpa
4.247.in-addr.arpa
5.247.in-addr.arpa
6.247.in-addr.arpa
7.247.in-addr.arpa
8.247.in-addr.arpa
9.247.in-addr.arpa
10.247.in-addr.arpa
11.247.in-addr.arpa
12.247.in-addr.arpa
13.247.in-addr.arpa
14.247.in-addr.arpa
15.247.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110111.00000000.00000000.00000000247.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11110111.00000000.00000000.00000000247.0.0.0
Broadcast11110111.00111111.11111111.11111111247.63.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

247.0.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1247.0.0.0/18247.0.0.1 to 247.0.63.254247.0.63.25516,382
2247.0.64.0/18247.0.64.1 to 247.0.127.254247.0.127.25516,382
3247.0.128.0/18247.0.128.1 to 247.0.191.254247.0.191.25516,382
4247.0.192.0/18247.0.192.1 to 247.0.255.254247.0.255.25516,382
5247.1.0.0/18247.1.0.1 to 247.1.63.254247.1.63.25516,382
6247.1.64.0/18247.1.64.1 to 247.1.127.254247.1.127.25516,382
7247.1.128.0/18247.1.128.1 to 247.1.191.254247.1.191.25516,382
8247.1.192.0/18247.1.192.1 to 247.1.255.254247.1.255.25516,382
9247.2.0.0/18247.2.0.1 to 247.2.63.254247.2.63.25516,382
10247.2.64.0/18247.2.64.1 to 247.2.127.254247.2.127.25516,382
11247.2.128.0/18247.2.128.1 to 247.2.191.254247.2.191.25516,382
12247.2.192.0/18247.2.192.1 to 247.2.255.254247.2.255.25516,382
13247.3.0.0/18247.3.0.1 to 247.3.63.254247.3.63.25516,382
14247.3.64.0/18247.3.64.1 to 247.3.127.254247.3.127.25516,382
15247.3.128.0/18247.3.128.1 to 247.3.191.254247.3.191.25516,382
16247.3.192.0/18247.3.192.1 to 247.3.255.254247.3.255.25516,382
17247.4.0.0/18247.4.0.1 to 247.4.63.254247.4.63.25516,382
18247.4.64.0/18247.4.64.1 to 247.4.127.254247.4.127.25516,382
19247.4.128.0/18247.4.128.1 to 247.4.191.254247.4.191.25516,382
20247.4.192.0/18247.4.192.1 to 247.4.255.254247.4.255.25516,382
21247.5.0.0/18247.5.0.1 to 247.5.63.254247.5.63.25516,382
22247.5.64.0/18247.5.64.1 to 247.5.127.254247.5.127.25516,382
23247.5.128.0/18247.5.128.1 to 247.5.191.254247.5.191.25516,382
24247.5.192.0/18247.5.192.1 to 247.5.255.254247.5.255.25516,382
25247.6.0.0/18247.6.0.1 to 247.6.63.254247.6.63.25516,382
26247.6.64.0/18247.6.64.1 to 247.6.127.254247.6.127.25516,382
27247.6.128.0/18247.6.128.1 to 247.6.191.254247.6.191.25516,382
28247.6.192.0/18247.6.192.1 to 247.6.255.254247.6.255.25516,382
29247.7.0.0/18247.7.0.1 to 247.7.63.254247.7.63.25516,382
30247.7.64.0/18247.7.64.1 to 247.7.127.254247.7.127.25516,382
31247.7.128.0/18247.7.128.1 to 247.7.191.254247.7.191.25516,382
32247.7.192.0/18247.7.192.1 to 247.7.255.254247.7.255.25516,382
33247.8.0.0/18247.8.0.1 to 247.8.63.254247.8.63.25516,382
34247.8.64.0/18247.8.64.1 to 247.8.127.254247.8.127.25516,382
35247.8.128.0/18247.8.128.1 to 247.8.191.254247.8.191.25516,382
36247.8.192.0/18247.8.192.1 to 247.8.255.254247.8.255.25516,382
37247.9.0.0/18247.9.0.1 to 247.9.63.254247.9.63.25516,382
38247.9.64.0/18247.9.64.1 to 247.9.127.254247.9.127.25516,382
39247.9.128.0/18247.9.128.1 to 247.9.191.254247.9.191.25516,382
40247.9.192.0/18247.9.192.1 to 247.9.255.254247.9.255.25516,382
41247.10.0.0/18247.10.0.1 to 247.10.63.254247.10.63.25516,382
42247.10.64.0/18247.10.64.1 to 247.10.127.254247.10.127.25516,382
43247.10.128.0/18247.10.128.1 to 247.10.191.254247.10.191.25516,382
44247.10.192.0/18247.10.192.1 to 247.10.255.254247.10.255.25516,382
45247.11.0.0/18247.11.0.1 to 247.11.63.254247.11.63.25516,382
46247.11.64.0/18247.11.64.1 to 247.11.127.254247.11.127.25516,382
47247.11.128.0/18247.11.128.1 to 247.11.191.254247.11.191.25516,382
48247.11.192.0/18247.11.192.1 to 247.11.255.254247.11.255.25516,382
49247.12.0.0/18247.12.0.1 to 247.12.63.254247.12.63.25516,382
50247.12.64.0/18247.12.64.1 to 247.12.127.254247.12.127.25516,382
51247.12.128.0/18247.12.128.1 to 247.12.191.254247.12.191.25516,382
52247.12.192.0/18247.12.192.1 to 247.12.255.254247.12.255.25516,382
53247.13.0.0/18247.13.0.1 to 247.13.63.254247.13.63.25516,382
54247.13.64.0/18247.13.64.1 to 247.13.127.254247.13.127.25516,382
55247.13.128.0/18247.13.128.1 to 247.13.191.254247.13.191.25516,382
56247.13.192.0/18247.13.192.1 to 247.13.255.254247.13.255.25516,382
57247.14.0.0/18247.14.0.1 to 247.14.63.254247.14.63.25516,382
58247.14.64.0/18247.14.64.1 to 247.14.127.254247.14.127.25516,382
59247.14.128.0/18247.14.128.1 to 247.14.191.254247.14.191.25516,382
60247.14.192.0/18247.14.192.1 to 247.14.255.254247.14.255.25516,382
61247.15.0.0/18247.15.0.1 to 247.15.63.254247.15.63.25516,382
62247.15.64.0/18247.15.64.1 to 247.15.127.254247.15.127.25516,382
63247.15.128.0/18247.15.128.1 to 247.15.191.254247.15.191.25516,382
64247.15.192.0/18247.15.192.1 to 247.15.255.254247.15.255.25516,382
65247.16.0.0/18247.16.0.1 to 247.16.63.254247.16.63.25516,382
66247.16.64.0/18247.16.64.1 to 247.16.127.254247.16.127.25516,382
67247.16.128.0/18247.16.128.1 to 247.16.191.254247.16.191.25516,382
68247.16.192.0/18247.16.192.1 to 247.16.255.254247.16.255.25516,382
69247.17.0.0/18247.17.0.1 to 247.17.63.254247.17.63.25516,382
70247.17.64.0/18247.17.64.1 to 247.17.127.254247.17.127.25516,382
71247.17.128.0/18247.17.128.1 to 247.17.191.254247.17.191.25516,382
72247.17.192.0/18247.17.192.1 to 247.17.255.254247.17.255.25516,382
73247.18.0.0/18247.18.0.1 to 247.18.63.254247.18.63.25516,382
74247.18.64.0/18247.18.64.1 to 247.18.127.254247.18.127.25516,382
75247.18.128.0/18247.18.128.1 to 247.18.191.254247.18.191.25516,382
76247.18.192.0/18247.18.192.1 to 247.18.255.254247.18.255.25516,382
77247.19.0.0/18247.19.0.1 to 247.19.63.254247.19.63.25516,382
78247.19.64.0/18247.19.64.1 to 247.19.127.254247.19.127.25516,382
79247.19.128.0/18247.19.128.1 to 247.19.191.254247.19.191.25516,382
80247.19.192.0/18247.19.192.1 to 247.19.255.254247.19.255.25516,382
81247.20.0.0/18247.20.0.1 to 247.20.63.254247.20.63.25516,382
82247.20.64.0/18247.20.64.1 to 247.20.127.254247.20.127.25516,382
83247.20.128.0/18247.20.128.1 to 247.20.191.254247.20.191.25516,382
84247.20.192.0/18247.20.192.1 to 247.20.255.254247.20.255.25516,382
85247.21.0.0/18247.21.0.1 to 247.21.63.254247.21.63.25516,382
86247.21.64.0/18247.21.64.1 to 247.21.127.254247.21.127.25516,382
87247.21.128.0/18247.21.128.1 to 247.21.191.254247.21.191.25516,382
88247.21.192.0/18247.21.192.1 to 247.21.255.254247.21.255.25516,382
89247.22.0.0/18247.22.0.1 to 247.22.63.254247.22.63.25516,382
90247.22.64.0/18247.22.64.1 to 247.22.127.254247.22.127.25516,382
91247.22.128.0/18247.22.128.1 to 247.22.191.254247.22.191.25516,382
92247.22.192.0/18247.22.192.1 to 247.22.255.254247.22.255.25516,382
93247.23.0.0/18247.23.0.1 to 247.23.63.254247.23.63.25516,382
94247.23.64.0/18247.23.64.1 to 247.23.127.254247.23.127.25516,382
95247.23.128.0/18247.23.128.1 to 247.23.191.254247.23.191.25516,382
96247.23.192.0/18247.23.192.1 to 247.23.255.254247.23.255.25516,382
97247.24.0.0/18247.24.0.1 to 247.24.63.254247.24.63.25516,382
98247.24.64.0/18247.24.64.1 to 247.24.127.254247.24.127.25516,382
99247.24.128.0/18247.24.128.1 to 247.24.191.254247.24.191.25516,382
100247.24.192.0/18247.24.192.1 to 247.24.255.254247.24.255.25516,382
101247.25.0.0/18247.25.0.1 to 247.25.63.254247.25.63.25516,382
102247.25.64.0/18247.25.64.1 to 247.25.127.254247.25.127.25516,382
103247.25.128.0/18247.25.128.1 to 247.25.191.254247.25.191.25516,382
104247.25.192.0/18247.25.192.1 to 247.25.255.254247.25.255.25516,382
105247.26.0.0/18247.26.0.1 to 247.26.63.254247.26.63.25516,382
106247.26.64.0/18247.26.64.1 to 247.26.127.254247.26.127.25516,382
107247.26.128.0/18247.26.128.1 to 247.26.191.254247.26.191.25516,382
108247.26.192.0/18247.26.192.1 to 247.26.255.254247.26.255.25516,382
109247.27.0.0/18247.27.0.1 to 247.27.63.254247.27.63.25516,382
110247.27.64.0/18247.27.64.1 to 247.27.127.254247.27.127.25516,382
111247.27.128.0/18247.27.128.1 to 247.27.191.254247.27.191.25516,382
112247.27.192.0/18247.27.192.1 to 247.27.255.254247.27.255.25516,382
113247.28.0.0/18247.28.0.1 to 247.28.63.254247.28.63.25516,382
114247.28.64.0/18247.28.64.1 to 247.28.127.254247.28.127.25516,382
115247.28.128.0/18247.28.128.1 to 247.28.191.254247.28.191.25516,382
116247.28.192.0/18247.28.192.1 to 247.28.255.254247.28.255.25516,382
117247.29.0.0/18247.29.0.1 to 247.29.63.254247.29.63.25516,382
118247.29.64.0/18247.29.64.1 to 247.29.127.254247.29.127.25516,382
119247.29.128.0/18247.29.128.1 to 247.29.191.254247.29.191.25516,382
120247.29.192.0/18247.29.192.1 to 247.29.255.254247.29.255.25516,382
121247.30.0.0/18247.30.0.1 to 247.30.63.254247.30.63.25516,382
122247.30.64.0/18247.30.64.1 to 247.30.127.254247.30.127.25516,382
123247.30.128.0/18247.30.128.1 to 247.30.191.254247.30.191.25516,382
124247.30.192.0/18247.30.192.1 to 247.30.255.254247.30.255.25516,382
125247.31.0.0/18247.31.0.1 to 247.31.63.254247.31.63.25516,382
126247.31.64.0/18247.31.64.1 to 247.31.127.254247.31.127.25516,382
127247.31.128.0/18247.31.128.1 to 247.31.191.254247.31.191.25516,382
128247.31.192.0/18247.31.192.1 to 247.31.255.254247.31.255.25516,382
129247.32.0.0/18247.32.0.1 to 247.32.63.254247.32.63.25516,382
130247.32.64.0/18247.32.64.1 to 247.32.127.254247.32.127.25516,382
131247.32.128.0/18247.32.128.1 to 247.32.191.254247.32.191.25516,382
132247.32.192.0/18247.32.192.1 to 247.32.255.254247.32.255.25516,382
133247.33.0.0/18247.33.0.1 to 247.33.63.254247.33.63.25516,382
134247.33.64.0/18247.33.64.1 to 247.33.127.254247.33.127.25516,382
135247.33.128.0/18247.33.128.1 to 247.33.191.254247.33.191.25516,382
136247.33.192.0/18247.33.192.1 to 247.33.255.254247.33.255.25516,382
137247.34.0.0/18247.34.0.1 to 247.34.63.254247.34.63.25516,382
138247.34.64.0/18247.34.64.1 to 247.34.127.254247.34.127.25516,382
139247.34.128.0/18247.34.128.1 to 247.34.191.254247.34.191.25516,382
140247.34.192.0/18247.34.192.1 to 247.34.255.254247.34.255.25516,382
141247.35.0.0/18247.35.0.1 to 247.35.63.254247.35.63.25516,382
142247.35.64.0/18247.35.64.1 to 247.35.127.254247.35.127.25516,382
143247.35.128.0/18247.35.128.1 to 247.35.191.254247.35.191.25516,382
144247.35.192.0/18247.35.192.1 to 247.35.255.254247.35.255.25516,382
145247.36.0.0/18247.36.0.1 to 247.36.63.254247.36.63.25516,382
146247.36.64.0/18247.36.64.1 to 247.36.127.254247.36.127.25516,382
147247.36.128.0/18247.36.128.1 to 247.36.191.254247.36.191.25516,382
148247.36.192.0/18247.36.192.1 to 247.36.255.254247.36.255.25516,382
149247.37.0.0/18247.37.0.1 to 247.37.63.254247.37.63.25516,382
150247.37.64.0/18247.37.64.1 to 247.37.127.254247.37.127.25516,382
151247.37.128.0/18247.37.128.1 to 247.37.191.254247.37.191.25516,382
152247.37.192.0/18247.37.192.1 to 247.37.255.254247.37.255.25516,382
153247.38.0.0/18247.38.0.1 to 247.38.63.254247.38.63.25516,382
154247.38.64.0/18247.38.64.1 to 247.38.127.254247.38.127.25516,382
155247.38.128.0/18247.38.128.1 to 247.38.191.254247.38.191.25516,382
156247.38.192.0/18247.38.192.1 to 247.38.255.254247.38.255.25516,382
157247.39.0.0/18247.39.0.1 to 247.39.63.254247.39.63.25516,382
158247.39.64.0/18247.39.64.1 to 247.39.127.254247.39.127.25516,382
159247.39.128.0/18247.39.128.1 to 247.39.191.254247.39.191.25516,382
160247.39.192.0/18247.39.192.1 to 247.39.255.254247.39.255.25516,382
161247.40.0.0/18247.40.0.1 to 247.40.63.254247.40.63.25516,382
162247.40.64.0/18247.40.64.1 to 247.40.127.254247.40.127.25516,382
163247.40.128.0/18247.40.128.1 to 247.40.191.254247.40.191.25516,382
164247.40.192.0/18247.40.192.1 to 247.40.255.254247.40.255.25516,382
165247.41.0.0/18247.41.0.1 to 247.41.63.254247.41.63.25516,382
166247.41.64.0/18247.41.64.1 to 247.41.127.254247.41.127.25516,382
167247.41.128.0/18247.41.128.1 to 247.41.191.254247.41.191.25516,382
168247.41.192.0/18247.41.192.1 to 247.41.255.254247.41.255.25516,382
169247.42.0.0/18247.42.0.1 to 247.42.63.254247.42.63.25516,382
170247.42.64.0/18247.42.64.1 to 247.42.127.254247.42.127.25516,382
171247.42.128.0/18247.42.128.1 to 247.42.191.254247.42.191.25516,382
172247.42.192.0/18247.42.192.1 to 247.42.255.254247.42.255.25516,382
173247.43.0.0/18247.43.0.1 to 247.43.63.254247.43.63.25516,382
174247.43.64.0/18247.43.64.1 to 247.43.127.254247.43.127.25516,382
175247.43.128.0/18247.43.128.1 to 247.43.191.254247.43.191.25516,382
176247.43.192.0/18247.43.192.1 to 247.43.255.254247.43.255.25516,382
177247.44.0.0/18247.44.0.1 to 247.44.63.254247.44.63.25516,382
178247.44.64.0/18247.44.64.1 to 247.44.127.254247.44.127.25516,382
179247.44.128.0/18247.44.128.1 to 247.44.191.254247.44.191.25516,382
180247.44.192.0/18247.44.192.1 to 247.44.255.254247.44.255.25516,382
181247.45.0.0/18247.45.0.1 to 247.45.63.254247.45.63.25516,382
182247.45.64.0/18247.45.64.1 to 247.45.127.254247.45.127.25516,382
183247.45.128.0/18247.45.128.1 to 247.45.191.254247.45.191.25516,382
184247.45.192.0/18247.45.192.1 to 247.45.255.254247.45.255.25516,382
185247.46.0.0/18247.46.0.1 to 247.46.63.254247.46.63.25516,382
186247.46.64.0/18247.46.64.1 to 247.46.127.254247.46.127.25516,382
187247.46.128.0/18247.46.128.1 to 247.46.191.254247.46.191.25516,382
188247.46.192.0/18247.46.192.1 to 247.46.255.254247.46.255.25516,382
189247.47.0.0/18247.47.0.1 to 247.47.63.254247.47.63.25516,382
190247.47.64.0/18247.47.64.1 to 247.47.127.254247.47.127.25516,382
191247.47.128.0/18247.47.128.1 to 247.47.191.254247.47.191.25516,382
192247.47.192.0/18247.47.192.1 to 247.47.255.254247.47.255.25516,382
193247.48.0.0/18247.48.0.1 to 247.48.63.254247.48.63.25516,382
194247.48.64.0/18247.48.64.1 to 247.48.127.254247.48.127.25516,382
195247.48.128.0/18247.48.128.1 to 247.48.191.254247.48.191.25516,382
196247.48.192.0/18247.48.192.1 to 247.48.255.254247.48.255.25516,382
197247.49.0.0/18247.49.0.1 to 247.49.63.254247.49.63.25516,382
198247.49.64.0/18247.49.64.1 to 247.49.127.254247.49.127.25516,382
199247.49.128.0/18247.49.128.1 to 247.49.191.254247.49.191.25516,382
200247.49.192.0/18247.49.192.1 to 247.49.255.254247.49.255.25516,382
201247.50.0.0/18247.50.0.1 to 247.50.63.254247.50.63.25516,382
202247.50.64.0/18247.50.64.1 to 247.50.127.254247.50.127.25516,382
203247.50.128.0/18247.50.128.1 to 247.50.191.254247.50.191.25516,382
204247.50.192.0/18247.50.192.1 to 247.50.255.254247.50.255.25516,382
205247.51.0.0/18247.51.0.1 to 247.51.63.254247.51.63.25516,382
206247.51.64.0/18247.51.64.1 to 247.51.127.254247.51.127.25516,382
207247.51.128.0/18247.51.128.1 to 247.51.191.254247.51.191.25516,382
208247.51.192.0/18247.51.192.1 to 247.51.255.254247.51.255.25516,382
209247.52.0.0/18247.52.0.1 to 247.52.63.254247.52.63.25516,382
210247.52.64.0/18247.52.64.1 to 247.52.127.254247.52.127.25516,382
211247.52.128.0/18247.52.128.1 to 247.52.191.254247.52.191.25516,382
212247.52.192.0/18247.52.192.1 to 247.52.255.254247.52.255.25516,382
213247.53.0.0/18247.53.0.1 to 247.53.63.254247.53.63.25516,382
214247.53.64.0/18247.53.64.1 to 247.53.127.254247.53.127.25516,382
215247.53.128.0/18247.53.128.1 to 247.53.191.254247.53.191.25516,382
216247.53.192.0/18247.53.192.1 to 247.53.255.254247.53.255.25516,382
217247.54.0.0/18247.54.0.1 to 247.54.63.254247.54.63.25516,382
218247.54.64.0/18247.54.64.1 to 247.54.127.254247.54.127.25516,382
219247.54.128.0/18247.54.128.1 to 247.54.191.254247.54.191.25516,382
220247.54.192.0/18247.54.192.1 to 247.54.255.254247.54.255.25516,382
221247.55.0.0/18247.55.0.1 to 247.55.63.254247.55.63.25516,382
222247.55.64.0/18247.55.64.1 to 247.55.127.254247.55.127.25516,382
223247.55.128.0/18247.55.128.1 to 247.55.191.254247.55.191.25516,382
224247.55.192.0/18247.55.192.1 to 247.55.255.254247.55.255.25516,382
225247.56.0.0/18247.56.0.1 to 247.56.63.254247.56.63.25516,382
226247.56.64.0/18247.56.64.1 to 247.56.127.254247.56.127.25516,382
227247.56.128.0/18247.56.128.1 to 247.56.191.254247.56.191.25516,382
228247.56.192.0/18247.56.192.1 to 247.56.255.254247.56.255.25516,382
229247.57.0.0/18247.57.0.1 to 247.57.63.254247.57.63.25516,382
230247.57.64.0/18247.57.64.1 to 247.57.127.254247.57.127.25516,382
231247.57.128.0/18247.57.128.1 to 247.57.191.254247.57.191.25516,382
232247.57.192.0/18247.57.192.1 to 247.57.255.254247.57.255.25516,382
233247.58.0.0/18247.58.0.1 to 247.58.63.254247.58.63.25516,382
234247.58.64.0/18247.58.64.1 to 247.58.127.254247.58.127.25516,382
235247.58.128.0/18247.58.128.1 to 247.58.191.254247.58.191.25516,382
236247.58.192.0/18247.58.192.1 to 247.58.255.254247.58.255.25516,382
237247.59.0.0/18247.59.0.1 to 247.59.63.254247.59.63.25516,382
238247.59.64.0/18247.59.64.1 to 247.59.127.254247.59.127.25516,382
239247.59.128.0/18247.59.128.1 to 247.59.191.254247.59.191.25516,382
240247.59.192.0/18247.59.192.1 to 247.59.255.254247.59.255.25516,382
241247.60.0.0/18247.60.0.1 to 247.60.63.254247.60.63.25516,382
242247.60.64.0/18247.60.64.1 to 247.60.127.254247.60.127.25516,382
243247.60.128.0/18247.60.128.1 to 247.60.191.254247.60.191.25516,382
244247.60.192.0/18247.60.192.1 to 247.60.255.254247.60.255.25516,382
245247.61.0.0/18247.61.0.1 to 247.61.63.254247.61.63.25516,382
246247.61.64.0/18247.61.64.1 to 247.61.127.254247.61.127.25516,382
247247.61.128.0/18247.61.128.1 to 247.61.191.254247.61.191.25516,382
248247.61.192.0/18247.61.192.1 to 247.61.255.254247.61.255.25516,382
249247.62.0.0/18247.62.0.1 to 247.62.63.254247.62.63.25516,382
250247.62.64.0/18247.62.64.1 to 247.62.127.254247.62.127.25516,382
251247.62.128.0/18247.62.128.1 to 247.62.191.254247.62.191.25516,382
252247.62.192.0/18247.62.192.1 to 247.62.255.254247.62.255.25516,382
253247.63.0.0/18247.63.0.1 to 247.63.63.254247.63.63.25516,382
254247.63.64.0/18247.63.64.1 to 247.63.127.254247.63.127.25516,382
255247.63.128.0/18247.63.128.1 to 247.63.191.254247.63.191.25516,382
256247.63.192.0/18247.63.192.1 to 247.63.255.254247.63.255.25516,382

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.