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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.

Network244.63.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
244.63.0.0
Broadcast address
244.63.63.255
First usable
244.63.0.1
Last usable
244.63.63.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F43F0000 · Integer 4097769472 to 4097785855
Reverse DNS zones
0.63.244.in-addr.arpa
1.63.244.in-addr.arpa
2.63.244.in-addr.arpa
3.63.244.in-addr.arpa
4.63.244.in-addr.arpa
5.63.244.in-addr.arpa
6.63.244.in-addr.arpa
7.63.244.in-addr.arpa
8.63.244.in-addr.arpa
9.63.244.in-addr.arpa
10.63.244.in-addr.arpa
11.63.244.in-addr.arpa
12.63.244.in-addr.arpa
13.63.244.in-addr.arpa
14.63.244.in-addr.arpa
15.63.244.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
Address11110100.00111111.00000000.00000000244.63.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11110100.00111111.00000000.00000000244.63.0.0
Broadcast11110100.00111111.00111111.11111111244.63.63.255
Split into smaller subnets/29
/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)

244.63.0.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1244.63.0.0/29244.63.0.1 to 244.63.0.6244.63.0.76
2244.63.0.8/29244.63.0.9 to 244.63.0.14244.63.0.156
3244.63.0.16/29244.63.0.17 to 244.63.0.22244.63.0.236
4244.63.0.24/29244.63.0.25 to 244.63.0.30244.63.0.316
5244.63.0.32/29244.63.0.33 to 244.63.0.38244.63.0.396
6244.63.0.40/29244.63.0.41 to 244.63.0.46244.63.0.476
7244.63.0.48/29244.63.0.49 to 244.63.0.54244.63.0.556
8244.63.0.56/29244.63.0.57 to 244.63.0.62244.63.0.636
9244.63.0.64/29244.63.0.65 to 244.63.0.70244.63.0.716
10244.63.0.72/29244.63.0.73 to 244.63.0.78244.63.0.796
11244.63.0.80/29244.63.0.81 to 244.63.0.86244.63.0.876
12244.63.0.88/29244.63.0.89 to 244.63.0.94244.63.0.956
13244.63.0.96/29244.63.0.97 to 244.63.0.102244.63.0.1036
14244.63.0.104/29244.63.0.105 to 244.63.0.110244.63.0.1116
15244.63.0.112/29244.63.0.113 to 244.63.0.118244.63.0.1196
16244.63.0.120/29244.63.0.121 to 244.63.0.126244.63.0.1276
17244.63.0.128/29244.63.0.129 to 244.63.0.134244.63.0.1356
18244.63.0.136/29244.63.0.137 to 244.63.0.142244.63.0.1436
19244.63.0.144/29244.63.0.145 to 244.63.0.150244.63.0.1516
20244.63.0.152/29244.63.0.153 to 244.63.0.158244.63.0.1596
21244.63.0.160/29244.63.0.161 to 244.63.0.166244.63.0.1676
22244.63.0.168/29244.63.0.169 to 244.63.0.174244.63.0.1756
23244.63.0.176/29244.63.0.177 to 244.63.0.182244.63.0.1836
24244.63.0.184/29244.63.0.185 to 244.63.0.190244.63.0.1916
25244.63.0.192/29244.63.0.193 to 244.63.0.198244.63.0.1996
26244.63.0.200/29244.63.0.201 to 244.63.0.206244.63.0.2076
27244.63.0.208/29244.63.0.209 to 244.63.0.214244.63.0.2156
28244.63.0.216/29244.63.0.217 to 244.63.0.222244.63.0.2236
29244.63.0.224/29244.63.0.225 to 244.63.0.230244.63.0.2316
30244.63.0.232/29244.63.0.233 to 244.63.0.238244.63.0.2396
31244.63.0.240/29244.63.0.241 to 244.63.0.246244.63.0.2476
32244.63.0.248/29244.63.0.249 to 244.63.0.254244.63.0.2556
33244.63.1.0/29244.63.1.1 to 244.63.1.6244.63.1.76
34244.63.1.8/29244.63.1.9 to 244.63.1.14244.63.1.156
35244.63.1.16/29244.63.1.17 to 244.63.1.22244.63.1.236
36244.63.1.24/29244.63.1.25 to 244.63.1.30244.63.1.316
37244.63.1.32/29244.63.1.33 to 244.63.1.38244.63.1.396
38244.63.1.40/29244.63.1.41 to 244.63.1.46244.63.1.476
39244.63.1.48/29244.63.1.49 to 244.63.1.54244.63.1.556
40244.63.1.56/29244.63.1.57 to 244.63.1.62244.63.1.636
41244.63.1.64/29244.63.1.65 to 244.63.1.70244.63.1.716
42244.63.1.72/29244.63.1.73 to 244.63.1.78244.63.1.796
43244.63.1.80/29244.63.1.81 to 244.63.1.86244.63.1.876
44244.63.1.88/29244.63.1.89 to 244.63.1.94244.63.1.956
45244.63.1.96/29244.63.1.97 to 244.63.1.102244.63.1.1036
46244.63.1.104/29244.63.1.105 to 244.63.1.110244.63.1.1116
47244.63.1.112/29244.63.1.113 to 244.63.1.118244.63.1.1196
48244.63.1.120/29244.63.1.121 to 244.63.1.126244.63.1.1276
49244.63.1.128/29244.63.1.129 to 244.63.1.134244.63.1.1356
50244.63.1.136/29244.63.1.137 to 244.63.1.142244.63.1.1436
51244.63.1.144/29244.63.1.145 to 244.63.1.150244.63.1.1516
52244.63.1.152/29244.63.1.153 to 244.63.1.158244.63.1.1596
53244.63.1.160/29244.63.1.161 to 244.63.1.166244.63.1.1676
54244.63.1.168/29244.63.1.169 to 244.63.1.174244.63.1.1756
55244.63.1.176/29244.63.1.177 to 244.63.1.182244.63.1.1836
56244.63.1.184/29244.63.1.185 to 244.63.1.190244.63.1.1916
57244.63.1.192/29244.63.1.193 to 244.63.1.198244.63.1.1996
58244.63.1.200/29244.63.1.201 to 244.63.1.206244.63.1.2076
59244.63.1.208/29244.63.1.209 to 244.63.1.214244.63.1.2156
60244.63.1.216/29244.63.1.217 to 244.63.1.222244.63.1.2236
61244.63.1.224/29244.63.1.225 to 244.63.1.230244.63.1.2316
62244.63.1.232/29244.63.1.233 to 244.63.1.238244.63.1.2396
63244.63.1.240/29244.63.1.241 to 244.63.1.246244.63.1.2476
64244.63.1.248/29244.63.1.249 to 244.63.1.254244.63.1.2556
65244.63.2.0/29244.63.2.1 to 244.63.2.6244.63.2.76
66244.63.2.8/29244.63.2.9 to 244.63.2.14244.63.2.156
67244.63.2.16/29244.63.2.17 to 244.63.2.22244.63.2.236
68244.63.2.24/29244.63.2.25 to 244.63.2.30244.63.2.316
69244.63.2.32/29244.63.2.33 to 244.63.2.38244.63.2.396
70244.63.2.40/29244.63.2.41 to 244.63.2.46244.63.2.476
71244.63.2.48/29244.63.2.49 to 244.63.2.54244.63.2.556
72244.63.2.56/29244.63.2.57 to 244.63.2.62244.63.2.636
73244.63.2.64/29244.63.2.65 to 244.63.2.70244.63.2.716
74244.63.2.72/29244.63.2.73 to 244.63.2.78244.63.2.796
75244.63.2.80/29244.63.2.81 to 244.63.2.86244.63.2.876
76244.63.2.88/29244.63.2.89 to 244.63.2.94244.63.2.956
77244.63.2.96/29244.63.2.97 to 244.63.2.102244.63.2.1036
78244.63.2.104/29244.63.2.105 to 244.63.2.110244.63.2.1116
79244.63.2.112/29244.63.2.113 to 244.63.2.118244.63.2.1196
80244.63.2.120/29244.63.2.121 to 244.63.2.126244.63.2.1276
81244.63.2.128/29244.63.2.129 to 244.63.2.134244.63.2.1356
82244.63.2.136/29244.63.2.137 to 244.63.2.142244.63.2.1436
83244.63.2.144/29244.63.2.145 to 244.63.2.150244.63.2.1516
84244.63.2.152/29244.63.2.153 to 244.63.2.158244.63.2.1596
85244.63.2.160/29244.63.2.161 to 244.63.2.166244.63.2.1676
86244.63.2.168/29244.63.2.169 to 244.63.2.174244.63.2.1756
87244.63.2.176/29244.63.2.177 to 244.63.2.182244.63.2.1836
88244.63.2.184/29244.63.2.185 to 244.63.2.190244.63.2.1916
89244.63.2.192/29244.63.2.193 to 244.63.2.198244.63.2.1996
90244.63.2.200/29244.63.2.201 to 244.63.2.206244.63.2.2076
91244.63.2.208/29244.63.2.209 to 244.63.2.214244.63.2.2156
92244.63.2.216/29244.63.2.217 to 244.63.2.222244.63.2.2236
93244.63.2.224/29244.63.2.225 to 244.63.2.230244.63.2.2316
94244.63.2.232/29244.63.2.233 to 244.63.2.238244.63.2.2396
95244.63.2.240/29244.63.2.241 to 244.63.2.246244.63.2.2476
96244.63.2.248/29244.63.2.249 to 244.63.2.254244.63.2.2556
97244.63.3.0/29244.63.3.1 to 244.63.3.6244.63.3.76
98244.63.3.8/29244.63.3.9 to 244.63.3.14244.63.3.156
99244.63.3.16/29244.63.3.17 to 244.63.3.22244.63.3.236
100244.63.3.24/29244.63.3.25 to 244.63.3.30244.63.3.316
101244.63.3.32/29244.63.3.33 to 244.63.3.38244.63.3.396
102244.63.3.40/29244.63.3.41 to 244.63.3.46244.63.3.476
103244.63.3.48/29244.63.3.49 to 244.63.3.54244.63.3.556
104244.63.3.56/29244.63.3.57 to 244.63.3.62244.63.3.636
105244.63.3.64/29244.63.3.65 to 244.63.3.70244.63.3.716
106244.63.3.72/29244.63.3.73 to 244.63.3.78244.63.3.796
107244.63.3.80/29244.63.3.81 to 244.63.3.86244.63.3.876
108244.63.3.88/29244.63.3.89 to 244.63.3.94244.63.3.956
109244.63.3.96/29244.63.3.97 to 244.63.3.102244.63.3.1036
110244.63.3.104/29244.63.3.105 to 244.63.3.110244.63.3.1116
111244.63.3.112/29244.63.3.113 to 244.63.3.118244.63.3.1196
112244.63.3.120/29244.63.3.121 to 244.63.3.126244.63.3.1276
113244.63.3.128/29244.63.3.129 to 244.63.3.134244.63.3.1356
114244.63.3.136/29244.63.3.137 to 244.63.3.142244.63.3.1436
115244.63.3.144/29244.63.3.145 to 244.63.3.150244.63.3.1516
116244.63.3.152/29244.63.3.153 to 244.63.3.158244.63.3.1596
117244.63.3.160/29244.63.3.161 to 244.63.3.166244.63.3.1676
118244.63.3.168/29244.63.3.169 to 244.63.3.174244.63.3.1756
119244.63.3.176/29244.63.3.177 to 244.63.3.182244.63.3.1836
120244.63.3.184/29244.63.3.185 to 244.63.3.190244.63.3.1916
121244.63.3.192/29244.63.3.193 to 244.63.3.198244.63.3.1996
122244.63.3.200/29244.63.3.201 to 244.63.3.206244.63.3.2076
123244.63.3.208/29244.63.3.209 to 244.63.3.214244.63.3.2156
124244.63.3.216/29244.63.3.217 to 244.63.3.222244.63.3.2236
125244.63.3.224/29244.63.3.225 to 244.63.3.230244.63.3.2316
126244.63.3.232/29244.63.3.233 to 244.63.3.238244.63.3.2396
127244.63.3.240/29244.63.3.241 to 244.63.3.246244.63.3.2476
128244.63.3.248/29244.63.3.249 to 244.63.3.254244.63.3.2556
129244.63.4.0/29244.63.4.1 to 244.63.4.6244.63.4.76
130244.63.4.8/29244.63.4.9 to 244.63.4.14244.63.4.156
131244.63.4.16/29244.63.4.17 to 244.63.4.22244.63.4.236
132244.63.4.24/29244.63.4.25 to 244.63.4.30244.63.4.316
133244.63.4.32/29244.63.4.33 to 244.63.4.38244.63.4.396
134244.63.4.40/29244.63.4.41 to 244.63.4.46244.63.4.476
135244.63.4.48/29244.63.4.49 to 244.63.4.54244.63.4.556
136244.63.4.56/29244.63.4.57 to 244.63.4.62244.63.4.636
137244.63.4.64/29244.63.4.65 to 244.63.4.70244.63.4.716
138244.63.4.72/29244.63.4.73 to 244.63.4.78244.63.4.796
139244.63.4.80/29244.63.4.81 to 244.63.4.86244.63.4.876
140244.63.4.88/29244.63.4.89 to 244.63.4.94244.63.4.956
141244.63.4.96/29244.63.4.97 to 244.63.4.102244.63.4.1036
142244.63.4.104/29244.63.4.105 to 244.63.4.110244.63.4.1116
143244.63.4.112/29244.63.4.113 to 244.63.4.118244.63.4.1196
144244.63.4.120/29244.63.4.121 to 244.63.4.126244.63.4.1276
145244.63.4.128/29244.63.4.129 to 244.63.4.134244.63.4.1356
146244.63.4.136/29244.63.4.137 to 244.63.4.142244.63.4.1436
147244.63.4.144/29244.63.4.145 to 244.63.4.150244.63.4.1516
148244.63.4.152/29244.63.4.153 to 244.63.4.158244.63.4.1596
149244.63.4.160/29244.63.4.161 to 244.63.4.166244.63.4.1676
150244.63.4.168/29244.63.4.169 to 244.63.4.174244.63.4.1756
151244.63.4.176/29244.63.4.177 to 244.63.4.182244.63.4.1836
152244.63.4.184/29244.63.4.185 to 244.63.4.190244.63.4.1916
153244.63.4.192/29244.63.4.193 to 244.63.4.198244.63.4.1996
154244.63.4.200/29244.63.4.201 to 244.63.4.206244.63.4.2076
155244.63.4.208/29244.63.4.209 to 244.63.4.214244.63.4.2156
156244.63.4.216/29244.63.4.217 to 244.63.4.222244.63.4.2236
157244.63.4.224/29244.63.4.225 to 244.63.4.230244.63.4.2316
158244.63.4.232/29244.63.4.233 to 244.63.4.238244.63.4.2396
159244.63.4.240/29244.63.4.241 to 244.63.4.246244.63.4.2476
160244.63.4.248/29244.63.4.249 to 244.63.4.254244.63.4.2556
161244.63.5.0/29244.63.5.1 to 244.63.5.6244.63.5.76
162244.63.5.8/29244.63.5.9 to 244.63.5.14244.63.5.156
163244.63.5.16/29244.63.5.17 to 244.63.5.22244.63.5.236
164244.63.5.24/29244.63.5.25 to 244.63.5.30244.63.5.316
165244.63.5.32/29244.63.5.33 to 244.63.5.38244.63.5.396
166244.63.5.40/29244.63.5.41 to 244.63.5.46244.63.5.476
167244.63.5.48/29244.63.5.49 to 244.63.5.54244.63.5.556
168244.63.5.56/29244.63.5.57 to 244.63.5.62244.63.5.636
169244.63.5.64/29244.63.5.65 to 244.63.5.70244.63.5.716
170244.63.5.72/29244.63.5.73 to 244.63.5.78244.63.5.796
171244.63.5.80/29244.63.5.81 to 244.63.5.86244.63.5.876
172244.63.5.88/29244.63.5.89 to 244.63.5.94244.63.5.956
173244.63.5.96/29244.63.5.97 to 244.63.5.102244.63.5.1036
174244.63.5.104/29244.63.5.105 to 244.63.5.110244.63.5.1116
175244.63.5.112/29244.63.5.113 to 244.63.5.118244.63.5.1196
176244.63.5.120/29244.63.5.121 to 244.63.5.126244.63.5.1276
177244.63.5.128/29244.63.5.129 to 244.63.5.134244.63.5.1356
178244.63.5.136/29244.63.5.137 to 244.63.5.142244.63.5.1436
179244.63.5.144/29244.63.5.145 to 244.63.5.150244.63.5.1516
180244.63.5.152/29244.63.5.153 to 244.63.5.158244.63.5.1596
181244.63.5.160/29244.63.5.161 to 244.63.5.166244.63.5.1676
182244.63.5.168/29244.63.5.169 to 244.63.5.174244.63.5.1756
183244.63.5.176/29244.63.5.177 to 244.63.5.182244.63.5.1836
184244.63.5.184/29244.63.5.185 to 244.63.5.190244.63.5.1916
185244.63.5.192/29244.63.5.193 to 244.63.5.198244.63.5.1996
186244.63.5.200/29244.63.5.201 to 244.63.5.206244.63.5.2076
187244.63.5.208/29244.63.5.209 to 244.63.5.214244.63.5.2156
188244.63.5.216/29244.63.5.217 to 244.63.5.222244.63.5.2236
189244.63.5.224/29244.63.5.225 to 244.63.5.230244.63.5.2316
190244.63.5.232/29244.63.5.233 to 244.63.5.238244.63.5.2396
191244.63.5.240/29244.63.5.241 to 244.63.5.246244.63.5.2476
192244.63.5.248/29244.63.5.249 to 244.63.5.254244.63.5.2556
193244.63.6.0/29244.63.6.1 to 244.63.6.6244.63.6.76
194244.63.6.8/29244.63.6.9 to 244.63.6.14244.63.6.156
195244.63.6.16/29244.63.6.17 to 244.63.6.22244.63.6.236
196244.63.6.24/29244.63.6.25 to 244.63.6.30244.63.6.316
197244.63.6.32/29244.63.6.33 to 244.63.6.38244.63.6.396
198244.63.6.40/29244.63.6.41 to 244.63.6.46244.63.6.476
199244.63.6.48/29244.63.6.49 to 244.63.6.54244.63.6.556
200244.63.6.56/29244.63.6.57 to 244.63.6.62244.63.6.636
201244.63.6.64/29244.63.6.65 to 244.63.6.70244.63.6.716
202244.63.6.72/29244.63.6.73 to 244.63.6.78244.63.6.796
203244.63.6.80/29244.63.6.81 to 244.63.6.86244.63.6.876
204244.63.6.88/29244.63.6.89 to 244.63.6.94244.63.6.956
205244.63.6.96/29244.63.6.97 to 244.63.6.102244.63.6.1036
206244.63.6.104/29244.63.6.105 to 244.63.6.110244.63.6.1116
207244.63.6.112/29244.63.6.113 to 244.63.6.118244.63.6.1196
208244.63.6.120/29244.63.6.121 to 244.63.6.126244.63.6.1276
209244.63.6.128/29244.63.6.129 to 244.63.6.134244.63.6.1356
210244.63.6.136/29244.63.6.137 to 244.63.6.142244.63.6.1436
211244.63.6.144/29244.63.6.145 to 244.63.6.150244.63.6.1516
212244.63.6.152/29244.63.6.153 to 244.63.6.158244.63.6.1596
213244.63.6.160/29244.63.6.161 to 244.63.6.166244.63.6.1676
214244.63.6.168/29244.63.6.169 to 244.63.6.174244.63.6.1756
215244.63.6.176/29244.63.6.177 to 244.63.6.182244.63.6.1836
216244.63.6.184/29244.63.6.185 to 244.63.6.190244.63.6.1916
217244.63.6.192/29244.63.6.193 to 244.63.6.198244.63.6.1996
218244.63.6.200/29244.63.6.201 to 244.63.6.206244.63.6.2076
219244.63.6.208/29244.63.6.209 to 244.63.6.214244.63.6.2156
220244.63.6.216/29244.63.6.217 to 244.63.6.222244.63.6.2236
221244.63.6.224/29244.63.6.225 to 244.63.6.230244.63.6.2316
222244.63.6.232/29244.63.6.233 to 244.63.6.238244.63.6.2396
223244.63.6.240/29244.63.6.241 to 244.63.6.246244.63.6.2476
224244.63.6.248/29244.63.6.249 to 244.63.6.254244.63.6.2556
225244.63.7.0/29244.63.7.1 to 244.63.7.6244.63.7.76
226244.63.7.8/29244.63.7.9 to 244.63.7.14244.63.7.156
227244.63.7.16/29244.63.7.17 to 244.63.7.22244.63.7.236
228244.63.7.24/29244.63.7.25 to 244.63.7.30244.63.7.316
229244.63.7.32/29244.63.7.33 to 244.63.7.38244.63.7.396
230244.63.7.40/29244.63.7.41 to 244.63.7.46244.63.7.476
231244.63.7.48/29244.63.7.49 to 244.63.7.54244.63.7.556
232244.63.7.56/29244.63.7.57 to 244.63.7.62244.63.7.636
233244.63.7.64/29244.63.7.65 to 244.63.7.70244.63.7.716
234244.63.7.72/29244.63.7.73 to 244.63.7.78244.63.7.796
235244.63.7.80/29244.63.7.81 to 244.63.7.86244.63.7.876
236244.63.7.88/29244.63.7.89 to 244.63.7.94244.63.7.956
237244.63.7.96/29244.63.7.97 to 244.63.7.102244.63.7.1036
238244.63.7.104/29244.63.7.105 to 244.63.7.110244.63.7.1116
239244.63.7.112/29244.63.7.113 to 244.63.7.118244.63.7.1196
240244.63.7.120/29244.63.7.121 to 244.63.7.126244.63.7.1276
241244.63.7.128/29244.63.7.129 to 244.63.7.134244.63.7.1356
242244.63.7.136/29244.63.7.137 to 244.63.7.142244.63.7.1436
243244.63.7.144/29244.63.7.145 to 244.63.7.150244.63.7.1516
244244.63.7.152/29244.63.7.153 to 244.63.7.158244.63.7.1596
245244.63.7.160/29244.63.7.161 to 244.63.7.166244.63.7.1676
246244.63.7.168/29244.63.7.169 to 244.63.7.174244.63.7.1756
247244.63.7.176/29244.63.7.177 to 244.63.7.182244.63.7.1836
248244.63.7.184/29244.63.7.185 to 244.63.7.190244.63.7.1916
249244.63.7.192/29244.63.7.193 to 244.63.7.198244.63.7.1996
250244.63.7.200/29244.63.7.201 to 244.63.7.206244.63.7.2076
251244.63.7.208/29244.63.7.209 to 244.63.7.214244.63.7.2156
252244.63.7.216/29244.63.7.217 to 244.63.7.222244.63.7.2236
253244.63.7.224/29244.63.7.225 to 244.63.7.230244.63.7.2316
254244.63.7.232/29244.63.7.233 to 244.63.7.238244.63.7.2396
255244.63.7.240/29244.63.7.241 to 244.63.7.246244.63.7.2476
256244.63.7.248/29244.63.7.249 to 244.63.7.254244.63.7.2556

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.