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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network219.3.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
219.3.0.0
Broadcast address
219.3.63.255
First usable
219.3.0.1
Last usable
219.3.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
C (default /24)
As numbers
Hex DB030000 · Integer 3674406912 to 3674423295
Reverse DNS zones
0.3.219.in-addr.arpa
1.3.219.in-addr.arpa
2.3.219.in-addr.arpa
3.3.219.in-addr.arpa
4.3.219.in-addr.arpa
5.3.219.in-addr.arpa
6.3.219.in-addr.arpa
7.3.219.in-addr.arpa
8.3.219.in-addr.arpa
9.3.219.in-addr.arpa
10.3.219.in-addr.arpa
11.3.219.in-addr.arpa
12.3.219.in-addr.arpa
13.3.219.in-addr.arpa
14.3.219.in-addr.arpa
15.3.219.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011011.00000011.00000000.00000000219.3.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11011011.00000011.00000000.00000000219.3.0.0
Broadcast11011011.00000011.00111111.11111111219.3.63.255
Split into smaller subnets/30
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

219.3.0.0/18 makes 4,096 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1219.3.0.0/30219.3.0.1 to 219.3.0.2219.3.0.32
2219.3.0.4/30219.3.0.5 to 219.3.0.6219.3.0.72
3219.3.0.8/30219.3.0.9 to 219.3.0.10219.3.0.112
4219.3.0.12/30219.3.0.13 to 219.3.0.14219.3.0.152
5219.3.0.16/30219.3.0.17 to 219.3.0.18219.3.0.192
6219.3.0.20/30219.3.0.21 to 219.3.0.22219.3.0.232
7219.3.0.24/30219.3.0.25 to 219.3.0.26219.3.0.272
8219.3.0.28/30219.3.0.29 to 219.3.0.30219.3.0.312
9219.3.0.32/30219.3.0.33 to 219.3.0.34219.3.0.352
10219.3.0.36/30219.3.0.37 to 219.3.0.38219.3.0.392
11219.3.0.40/30219.3.0.41 to 219.3.0.42219.3.0.432
12219.3.0.44/30219.3.0.45 to 219.3.0.46219.3.0.472
13219.3.0.48/30219.3.0.49 to 219.3.0.50219.3.0.512
14219.3.0.52/30219.3.0.53 to 219.3.0.54219.3.0.552
15219.3.0.56/30219.3.0.57 to 219.3.0.58219.3.0.592
16219.3.0.60/30219.3.0.61 to 219.3.0.62219.3.0.632
17219.3.0.64/30219.3.0.65 to 219.3.0.66219.3.0.672
18219.3.0.68/30219.3.0.69 to 219.3.0.70219.3.0.712
19219.3.0.72/30219.3.0.73 to 219.3.0.74219.3.0.752
20219.3.0.76/30219.3.0.77 to 219.3.0.78219.3.0.792
21219.3.0.80/30219.3.0.81 to 219.3.0.82219.3.0.832
22219.3.0.84/30219.3.0.85 to 219.3.0.86219.3.0.872
23219.3.0.88/30219.3.0.89 to 219.3.0.90219.3.0.912
24219.3.0.92/30219.3.0.93 to 219.3.0.94219.3.0.952
25219.3.0.96/30219.3.0.97 to 219.3.0.98219.3.0.992
26219.3.0.100/30219.3.0.101 to 219.3.0.102219.3.0.1032
27219.3.0.104/30219.3.0.105 to 219.3.0.106219.3.0.1072
28219.3.0.108/30219.3.0.109 to 219.3.0.110219.3.0.1112
29219.3.0.112/30219.3.0.113 to 219.3.0.114219.3.0.1152
30219.3.0.116/30219.3.0.117 to 219.3.0.118219.3.0.1192
31219.3.0.120/30219.3.0.121 to 219.3.0.122219.3.0.1232
32219.3.0.124/30219.3.0.125 to 219.3.0.126219.3.0.1272
33219.3.0.128/30219.3.0.129 to 219.3.0.130219.3.0.1312
34219.3.0.132/30219.3.0.133 to 219.3.0.134219.3.0.1352
35219.3.0.136/30219.3.0.137 to 219.3.0.138219.3.0.1392
36219.3.0.140/30219.3.0.141 to 219.3.0.142219.3.0.1432
37219.3.0.144/30219.3.0.145 to 219.3.0.146219.3.0.1472
38219.3.0.148/30219.3.0.149 to 219.3.0.150219.3.0.1512
39219.3.0.152/30219.3.0.153 to 219.3.0.154219.3.0.1552
40219.3.0.156/30219.3.0.157 to 219.3.0.158219.3.0.1592
41219.3.0.160/30219.3.0.161 to 219.3.0.162219.3.0.1632
42219.3.0.164/30219.3.0.165 to 219.3.0.166219.3.0.1672
43219.3.0.168/30219.3.0.169 to 219.3.0.170219.3.0.1712
44219.3.0.172/30219.3.0.173 to 219.3.0.174219.3.0.1752
45219.3.0.176/30219.3.0.177 to 219.3.0.178219.3.0.1792
46219.3.0.180/30219.3.0.181 to 219.3.0.182219.3.0.1832
47219.3.0.184/30219.3.0.185 to 219.3.0.186219.3.0.1872
48219.3.0.188/30219.3.0.189 to 219.3.0.190219.3.0.1912
49219.3.0.192/30219.3.0.193 to 219.3.0.194219.3.0.1952
50219.3.0.196/30219.3.0.197 to 219.3.0.198219.3.0.1992
51219.3.0.200/30219.3.0.201 to 219.3.0.202219.3.0.2032
52219.3.0.204/30219.3.0.205 to 219.3.0.206219.3.0.2072
53219.3.0.208/30219.3.0.209 to 219.3.0.210219.3.0.2112
54219.3.0.212/30219.3.0.213 to 219.3.0.214219.3.0.2152
55219.3.0.216/30219.3.0.217 to 219.3.0.218219.3.0.2192
56219.3.0.220/30219.3.0.221 to 219.3.0.222219.3.0.2232
57219.3.0.224/30219.3.0.225 to 219.3.0.226219.3.0.2272
58219.3.0.228/30219.3.0.229 to 219.3.0.230219.3.0.2312
59219.3.0.232/30219.3.0.233 to 219.3.0.234219.3.0.2352
60219.3.0.236/30219.3.0.237 to 219.3.0.238219.3.0.2392
61219.3.0.240/30219.3.0.241 to 219.3.0.242219.3.0.2432
62219.3.0.244/30219.3.0.245 to 219.3.0.246219.3.0.2472
63219.3.0.248/30219.3.0.249 to 219.3.0.250219.3.0.2512
64219.3.0.252/30219.3.0.253 to 219.3.0.254219.3.0.2552
65219.3.1.0/30219.3.1.1 to 219.3.1.2219.3.1.32
66219.3.1.4/30219.3.1.5 to 219.3.1.6219.3.1.72
67219.3.1.8/30219.3.1.9 to 219.3.1.10219.3.1.112
68219.3.1.12/30219.3.1.13 to 219.3.1.14219.3.1.152
69219.3.1.16/30219.3.1.17 to 219.3.1.18219.3.1.192
70219.3.1.20/30219.3.1.21 to 219.3.1.22219.3.1.232
71219.3.1.24/30219.3.1.25 to 219.3.1.26219.3.1.272
72219.3.1.28/30219.3.1.29 to 219.3.1.30219.3.1.312
73219.3.1.32/30219.3.1.33 to 219.3.1.34219.3.1.352
74219.3.1.36/30219.3.1.37 to 219.3.1.38219.3.1.392
75219.3.1.40/30219.3.1.41 to 219.3.1.42219.3.1.432
76219.3.1.44/30219.3.1.45 to 219.3.1.46219.3.1.472
77219.3.1.48/30219.3.1.49 to 219.3.1.50219.3.1.512
78219.3.1.52/30219.3.1.53 to 219.3.1.54219.3.1.552
79219.3.1.56/30219.3.1.57 to 219.3.1.58219.3.1.592
80219.3.1.60/30219.3.1.61 to 219.3.1.62219.3.1.632
81219.3.1.64/30219.3.1.65 to 219.3.1.66219.3.1.672
82219.3.1.68/30219.3.1.69 to 219.3.1.70219.3.1.712
83219.3.1.72/30219.3.1.73 to 219.3.1.74219.3.1.752
84219.3.1.76/30219.3.1.77 to 219.3.1.78219.3.1.792
85219.3.1.80/30219.3.1.81 to 219.3.1.82219.3.1.832
86219.3.1.84/30219.3.1.85 to 219.3.1.86219.3.1.872
87219.3.1.88/30219.3.1.89 to 219.3.1.90219.3.1.912
88219.3.1.92/30219.3.1.93 to 219.3.1.94219.3.1.952
89219.3.1.96/30219.3.1.97 to 219.3.1.98219.3.1.992
90219.3.1.100/30219.3.1.101 to 219.3.1.102219.3.1.1032
91219.3.1.104/30219.3.1.105 to 219.3.1.106219.3.1.1072
92219.3.1.108/30219.3.1.109 to 219.3.1.110219.3.1.1112
93219.3.1.112/30219.3.1.113 to 219.3.1.114219.3.1.1152
94219.3.1.116/30219.3.1.117 to 219.3.1.118219.3.1.1192
95219.3.1.120/30219.3.1.121 to 219.3.1.122219.3.1.1232
96219.3.1.124/30219.3.1.125 to 219.3.1.126219.3.1.1272
97219.3.1.128/30219.3.1.129 to 219.3.1.130219.3.1.1312
98219.3.1.132/30219.3.1.133 to 219.3.1.134219.3.1.1352
99219.3.1.136/30219.3.1.137 to 219.3.1.138219.3.1.1392
100219.3.1.140/30219.3.1.141 to 219.3.1.142219.3.1.1432
101219.3.1.144/30219.3.1.145 to 219.3.1.146219.3.1.1472
102219.3.1.148/30219.3.1.149 to 219.3.1.150219.3.1.1512
103219.3.1.152/30219.3.1.153 to 219.3.1.154219.3.1.1552
104219.3.1.156/30219.3.1.157 to 219.3.1.158219.3.1.1592
105219.3.1.160/30219.3.1.161 to 219.3.1.162219.3.1.1632
106219.3.1.164/30219.3.1.165 to 219.3.1.166219.3.1.1672
107219.3.1.168/30219.3.1.169 to 219.3.1.170219.3.1.1712
108219.3.1.172/30219.3.1.173 to 219.3.1.174219.3.1.1752
109219.3.1.176/30219.3.1.177 to 219.3.1.178219.3.1.1792
110219.3.1.180/30219.3.1.181 to 219.3.1.182219.3.1.1832
111219.3.1.184/30219.3.1.185 to 219.3.1.186219.3.1.1872
112219.3.1.188/30219.3.1.189 to 219.3.1.190219.3.1.1912
113219.3.1.192/30219.3.1.193 to 219.3.1.194219.3.1.1952
114219.3.1.196/30219.3.1.197 to 219.3.1.198219.3.1.1992
115219.3.1.200/30219.3.1.201 to 219.3.1.202219.3.1.2032
116219.3.1.204/30219.3.1.205 to 219.3.1.206219.3.1.2072
117219.3.1.208/30219.3.1.209 to 219.3.1.210219.3.1.2112
118219.3.1.212/30219.3.1.213 to 219.3.1.214219.3.1.2152
119219.3.1.216/30219.3.1.217 to 219.3.1.218219.3.1.2192
120219.3.1.220/30219.3.1.221 to 219.3.1.222219.3.1.2232
121219.3.1.224/30219.3.1.225 to 219.3.1.226219.3.1.2272
122219.3.1.228/30219.3.1.229 to 219.3.1.230219.3.1.2312
123219.3.1.232/30219.3.1.233 to 219.3.1.234219.3.1.2352
124219.3.1.236/30219.3.1.237 to 219.3.1.238219.3.1.2392
125219.3.1.240/30219.3.1.241 to 219.3.1.242219.3.1.2432
126219.3.1.244/30219.3.1.245 to 219.3.1.246219.3.1.2472
127219.3.1.248/30219.3.1.249 to 219.3.1.250219.3.1.2512
128219.3.1.252/30219.3.1.253 to 219.3.1.254219.3.1.2552
129219.3.2.0/30219.3.2.1 to 219.3.2.2219.3.2.32
130219.3.2.4/30219.3.2.5 to 219.3.2.6219.3.2.72
131219.3.2.8/30219.3.2.9 to 219.3.2.10219.3.2.112
132219.3.2.12/30219.3.2.13 to 219.3.2.14219.3.2.152
133219.3.2.16/30219.3.2.17 to 219.3.2.18219.3.2.192
134219.3.2.20/30219.3.2.21 to 219.3.2.22219.3.2.232
135219.3.2.24/30219.3.2.25 to 219.3.2.26219.3.2.272
136219.3.2.28/30219.3.2.29 to 219.3.2.30219.3.2.312
137219.3.2.32/30219.3.2.33 to 219.3.2.34219.3.2.352
138219.3.2.36/30219.3.2.37 to 219.3.2.38219.3.2.392
139219.3.2.40/30219.3.2.41 to 219.3.2.42219.3.2.432
140219.3.2.44/30219.3.2.45 to 219.3.2.46219.3.2.472
141219.3.2.48/30219.3.2.49 to 219.3.2.50219.3.2.512
142219.3.2.52/30219.3.2.53 to 219.3.2.54219.3.2.552
143219.3.2.56/30219.3.2.57 to 219.3.2.58219.3.2.592
144219.3.2.60/30219.3.2.61 to 219.3.2.62219.3.2.632
145219.3.2.64/30219.3.2.65 to 219.3.2.66219.3.2.672
146219.3.2.68/30219.3.2.69 to 219.3.2.70219.3.2.712
147219.3.2.72/30219.3.2.73 to 219.3.2.74219.3.2.752
148219.3.2.76/30219.3.2.77 to 219.3.2.78219.3.2.792
149219.3.2.80/30219.3.2.81 to 219.3.2.82219.3.2.832
150219.3.2.84/30219.3.2.85 to 219.3.2.86219.3.2.872
151219.3.2.88/30219.3.2.89 to 219.3.2.90219.3.2.912
152219.3.2.92/30219.3.2.93 to 219.3.2.94219.3.2.952
153219.3.2.96/30219.3.2.97 to 219.3.2.98219.3.2.992
154219.3.2.100/30219.3.2.101 to 219.3.2.102219.3.2.1032
155219.3.2.104/30219.3.2.105 to 219.3.2.106219.3.2.1072
156219.3.2.108/30219.3.2.109 to 219.3.2.110219.3.2.1112
157219.3.2.112/30219.3.2.113 to 219.3.2.114219.3.2.1152
158219.3.2.116/30219.3.2.117 to 219.3.2.118219.3.2.1192
159219.3.2.120/30219.3.2.121 to 219.3.2.122219.3.2.1232
160219.3.2.124/30219.3.2.125 to 219.3.2.126219.3.2.1272
161219.3.2.128/30219.3.2.129 to 219.3.2.130219.3.2.1312
162219.3.2.132/30219.3.2.133 to 219.3.2.134219.3.2.1352
163219.3.2.136/30219.3.2.137 to 219.3.2.138219.3.2.1392
164219.3.2.140/30219.3.2.141 to 219.3.2.142219.3.2.1432
165219.3.2.144/30219.3.2.145 to 219.3.2.146219.3.2.1472
166219.3.2.148/30219.3.2.149 to 219.3.2.150219.3.2.1512
167219.3.2.152/30219.3.2.153 to 219.3.2.154219.3.2.1552
168219.3.2.156/30219.3.2.157 to 219.3.2.158219.3.2.1592
169219.3.2.160/30219.3.2.161 to 219.3.2.162219.3.2.1632
170219.3.2.164/30219.3.2.165 to 219.3.2.166219.3.2.1672
171219.3.2.168/30219.3.2.169 to 219.3.2.170219.3.2.1712
172219.3.2.172/30219.3.2.173 to 219.3.2.174219.3.2.1752
173219.3.2.176/30219.3.2.177 to 219.3.2.178219.3.2.1792
174219.3.2.180/30219.3.2.181 to 219.3.2.182219.3.2.1832
175219.3.2.184/30219.3.2.185 to 219.3.2.186219.3.2.1872
176219.3.2.188/30219.3.2.189 to 219.3.2.190219.3.2.1912
177219.3.2.192/30219.3.2.193 to 219.3.2.194219.3.2.1952
178219.3.2.196/30219.3.2.197 to 219.3.2.198219.3.2.1992
179219.3.2.200/30219.3.2.201 to 219.3.2.202219.3.2.2032
180219.3.2.204/30219.3.2.205 to 219.3.2.206219.3.2.2072
181219.3.2.208/30219.3.2.209 to 219.3.2.210219.3.2.2112
182219.3.2.212/30219.3.2.213 to 219.3.2.214219.3.2.2152
183219.3.2.216/30219.3.2.217 to 219.3.2.218219.3.2.2192
184219.3.2.220/30219.3.2.221 to 219.3.2.222219.3.2.2232
185219.3.2.224/30219.3.2.225 to 219.3.2.226219.3.2.2272
186219.3.2.228/30219.3.2.229 to 219.3.2.230219.3.2.2312
187219.3.2.232/30219.3.2.233 to 219.3.2.234219.3.2.2352
188219.3.2.236/30219.3.2.237 to 219.3.2.238219.3.2.2392
189219.3.2.240/30219.3.2.241 to 219.3.2.242219.3.2.2432
190219.3.2.244/30219.3.2.245 to 219.3.2.246219.3.2.2472
191219.3.2.248/30219.3.2.249 to 219.3.2.250219.3.2.2512
192219.3.2.252/30219.3.2.253 to 219.3.2.254219.3.2.2552
193219.3.3.0/30219.3.3.1 to 219.3.3.2219.3.3.32
194219.3.3.4/30219.3.3.5 to 219.3.3.6219.3.3.72
195219.3.3.8/30219.3.3.9 to 219.3.3.10219.3.3.112
196219.3.3.12/30219.3.3.13 to 219.3.3.14219.3.3.152
197219.3.3.16/30219.3.3.17 to 219.3.3.18219.3.3.192
198219.3.3.20/30219.3.3.21 to 219.3.3.22219.3.3.232
199219.3.3.24/30219.3.3.25 to 219.3.3.26219.3.3.272
200219.3.3.28/30219.3.3.29 to 219.3.3.30219.3.3.312
201219.3.3.32/30219.3.3.33 to 219.3.3.34219.3.3.352
202219.3.3.36/30219.3.3.37 to 219.3.3.38219.3.3.392
203219.3.3.40/30219.3.3.41 to 219.3.3.42219.3.3.432
204219.3.3.44/30219.3.3.45 to 219.3.3.46219.3.3.472
205219.3.3.48/30219.3.3.49 to 219.3.3.50219.3.3.512
206219.3.3.52/30219.3.3.53 to 219.3.3.54219.3.3.552
207219.3.3.56/30219.3.3.57 to 219.3.3.58219.3.3.592
208219.3.3.60/30219.3.3.61 to 219.3.3.62219.3.3.632
209219.3.3.64/30219.3.3.65 to 219.3.3.66219.3.3.672
210219.3.3.68/30219.3.3.69 to 219.3.3.70219.3.3.712
211219.3.3.72/30219.3.3.73 to 219.3.3.74219.3.3.752
212219.3.3.76/30219.3.3.77 to 219.3.3.78219.3.3.792
213219.3.3.80/30219.3.3.81 to 219.3.3.82219.3.3.832
214219.3.3.84/30219.3.3.85 to 219.3.3.86219.3.3.872
215219.3.3.88/30219.3.3.89 to 219.3.3.90219.3.3.912
216219.3.3.92/30219.3.3.93 to 219.3.3.94219.3.3.952
217219.3.3.96/30219.3.3.97 to 219.3.3.98219.3.3.992
218219.3.3.100/30219.3.3.101 to 219.3.3.102219.3.3.1032
219219.3.3.104/30219.3.3.105 to 219.3.3.106219.3.3.1072
220219.3.3.108/30219.3.3.109 to 219.3.3.110219.3.3.1112
221219.3.3.112/30219.3.3.113 to 219.3.3.114219.3.3.1152
222219.3.3.116/30219.3.3.117 to 219.3.3.118219.3.3.1192
223219.3.3.120/30219.3.3.121 to 219.3.3.122219.3.3.1232
224219.3.3.124/30219.3.3.125 to 219.3.3.126219.3.3.1272
225219.3.3.128/30219.3.3.129 to 219.3.3.130219.3.3.1312
226219.3.3.132/30219.3.3.133 to 219.3.3.134219.3.3.1352
227219.3.3.136/30219.3.3.137 to 219.3.3.138219.3.3.1392
228219.3.3.140/30219.3.3.141 to 219.3.3.142219.3.3.1432
229219.3.3.144/30219.3.3.145 to 219.3.3.146219.3.3.1472
230219.3.3.148/30219.3.3.149 to 219.3.3.150219.3.3.1512
231219.3.3.152/30219.3.3.153 to 219.3.3.154219.3.3.1552
232219.3.3.156/30219.3.3.157 to 219.3.3.158219.3.3.1592
233219.3.3.160/30219.3.3.161 to 219.3.3.162219.3.3.1632
234219.3.3.164/30219.3.3.165 to 219.3.3.166219.3.3.1672
235219.3.3.168/30219.3.3.169 to 219.3.3.170219.3.3.1712
236219.3.3.172/30219.3.3.173 to 219.3.3.174219.3.3.1752
237219.3.3.176/30219.3.3.177 to 219.3.3.178219.3.3.1792
238219.3.3.180/30219.3.3.181 to 219.3.3.182219.3.3.1832
239219.3.3.184/30219.3.3.185 to 219.3.3.186219.3.3.1872
240219.3.3.188/30219.3.3.189 to 219.3.3.190219.3.3.1912
241219.3.3.192/30219.3.3.193 to 219.3.3.194219.3.3.1952
242219.3.3.196/30219.3.3.197 to 219.3.3.198219.3.3.1992
243219.3.3.200/30219.3.3.201 to 219.3.3.202219.3.3.2032
244219.3.3.204/30219.3.3.205 to 219.3.3.206219.3.3.2072
245219.3.3.208/30219.3.3.209 to 219.3.3.210219.3.3.2112
246219.3.3.212/30219.3.3.213 to 219.3.3.214219.3.3.2152
247219.3.3.216/30219.3.3.217 to 219.3.3.218219.3.3.2192
248219.3.3.220/30219.3.3.221 to 219.3.3.222219.3.3.2232
249219.3.3.224/30219.3.3.225 to 219.3.3.226219.3.3.2272
250219.3.3.228/30219.3.3.229 to 219.3.3.230219.3.3.2312
251219.3.3.232/30219.3.3.233 to 219.3.3.234219.3.3.2352
252219.3.3.236/30219.3.3.237 to 219.3.3.238219.3.3.2392
253219.3.3.240/30219.3.3.241 to 219.3.3.242219.3.3.2432
254219.3.3.244/30219.3.3.245 to 219.3.3.246219.3.3.2472
255219.3.3.248/30219.3.3.249 to 219.3.3.250219.3.3.2512
256219.3.3.252/30219.3.3.253 to 219.3.3.254219.3.3.2552

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.