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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.

Network170.0.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
170.0.64.0
Broadcast address
170.0.127.255
First usable
170.0.64.1
Last usable
170.0.127.254
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
B (default /16)
As numbers
Hex AA004000 · Integer 2852143104 to 2852159487
Reverse DNS zones
64.0.170.in-addr.arpa
65.0.170.in-addr.arpa
66.0.170.in-addr.arpa
67.0.170.in-addr.arpa
68.0.170.in-addr.arpa
69.0.170.in-addr.arpa
70.0.170.in-addr.arpa
71.0.170.in-addr.arpa
72.0.170.in-addr.arpa
73.0.170.in-addr.arpa
74.0.170.in-addr.arpa
75.0.170.in-addr.arpa
76.0.170.in-addr.arpa
77.0.170.in-addr.arpa
78.0.170.in-addr.arpa
79.0.170.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
Address10101010.00000000.01000000.00000000170.0.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network10101010.00000000.01000000.00000000170.0.64.0
Broadcast10101010.00000000.01111111.11111111170.0.127.255
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)

170.0.64.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1170.0.64.0/29170.0.64.1 to 170.0.64.6170.0.64.76
2170.0.64.8/29170.0.64.9 to 170.0.64.14170.0.64.156
3170.0.64.16/29170.0.64.17 to 170.0.64.22170.0.64.236
4170.0.64.24/29170.0.64.25 to 170.0.64.30170.0.64.316
5170.0.64.32/29170.0.64.33 to 170.0.64.38170.0.64.396
6170.0.64.40/29170.0.64.41 to 170.0.64.46170.0.64.476
7170.0.64.48/29170.0.64.49 to 170.0.64.54170.0.64.556
8170.0.64.56/29170.0.64.57 to 170.0.64.62170.0.64.636
9170.0.64.64/29170.0.64.65 to 170.0.64.70170.0.64.716
10170.0.64.72/29170.0.64.73 to 170.0.64.78170.0.64.796
11170.0.64.80/29170.0.64.81 to 170.0.64.86170.0.64.876
12170.0.64.88/29170.0.64.89 to 170.0.64.94170.0.64.956
13170.0.64.96/29170.0.64.97 to 170.0.64.102170.0.64.1036
14170.0.64.104/29170.0.64.105 to 170.0.64.110170.0.64.1116
15170.0.64.112/29170.0.64.113 to 170.0.64.118170.0.64.1196
16170.0.64.120/29170.0.64.121 to 170.0.64.126170.0.64.1276
17170.0.64.128/29170.0.64.129 to 170.0.64.134170.0.64.1356
18170.0.64.136/29170.0.64.137 to 170.0.64.142170.0.64.1436
19170.0.64.144/29170.0.64.145 to 170.0.64.150170.0.64.1516
20170.0.64.152/29170.0.64.153 to 170.0.64.158170.0.64.1596
21170.0.64.160/29170.0.64.161 to 170.0.64.166170.0.64.1676
22170.0.64.168/29170.0.64.169 to 170.0.64.174170.0.64.1756
23170.0.64.176/29170.0.64.177 to 170.0.64.182170.0.64.1836
24170.0.64.184/29170.0.64.185 to 170.0.64.190170.0.64.1916
25170.0.64.192/29170.0.64.193 to 170.0.64.198170.0.64.1996
26170.0.64.200/29170.0.64.201 to 170.0.64.206170.0.64.2076
27170.0.64.208/29170.0.64.209 to 170.0.64.214170.0.64.2156
28170.0.64.216/29170.0.64.217 to 170.0.64.222170.0.64.2236
29170.0.64.224/29170.0.64.225 to 170.0.64.230170.0.64.2316
30170.0.64.232/29170.0.64.233 to 170.0.64.238170.0.64.2396
31170.0.64.240/29170.0.64.241 to 170.0.64.246170.0.64.2476
32170.0.64.248/29170.0.64.249 to 170.0.64.254170.0.64.2556
33170.0.65.0/29170.0.65.1 to 170.0.65.6170.0.65.76
34170.0.65.8/29170.0.65.9 to 170.0.65.14170.0.65.156
35170.0.65.16/29170.0.65.17 to 170.0.65.22170.0.65.236
36170.0.65.24/29170.0.65.25 to 170.0.65.30170.0.65.316
37170.0.65.32/29170.0.65.33 to 170.0.65.38170.0.65.396
38170.0.65.40/29170.0.65.41 to 170.0.65.46170.0.65.476
39170.0.65.48/29170.0.65.49 to 170.0.65.54170.0.65.556
40170.0.65.56/29170.0.65.57 to 170.0.65.62170.0.65.636
41170.0.65.64/29170.0.65.65 to 170.0.65.70170.0.65.716
42170.0.65.72/29170.0.65.73 to 170.0.65.78170.0.65.796
43170.0.65.80/29170.0.65.81 to 170.0.65.86170.0.65.876
44170.0.65.88/29170.0.65.89 to 170.0.65.94170.0.65.956
45170.0.65.96/29170.0.65.97 to 170.0.65.102170.0.65.1036
46170.0.65.104/29170.0.65.105 to 170.0.65.110170.0.65.1116
47170.0.65.112/29170.0.65.113 to 170.0.65.118170.0.65.1196
48170.0.65.120/29170.0.65.121 to 170.0.65.126170.0.65.1276
49170.0.65.128/29170.0.65.129 to 170.0.65.134170.0.65.1356
50170.0.65.136/29170.0.65.137 to 170.0.65.142170.0.65.1436
51170.0.65.144/29170.0.65.145 to 170.0.65.150170.0.65.1516
52170.0.65.152/29170.0.65.153 to 170.0.65.158170.0.65.1596
53170.0.65.160/29170.0.65.161 to 170.0.65.166170.0.65.1676
54170.0.65.168/29170.0.65.169 to 170.0.65.174170.0.65.1756
55170.0.65.176/29170.0.65.177 to 170.0.65.182170.0.65.1836
56170.0.65.184/29170.0.65.185 to 170.0.65.190170.0.65.1916
57170.0.65.192/29170.0.65.193 to 170.0.65.198170.0.65.1996
58170.0.65.200/29170.0.65.201 to 170.0.65.206170.0.65.2076
59170.0.65.208/29170.0.65.209 to 170.0.65.214170.0.65.2156
60170.0.65.216/29170.0.65.217 to 170.0.65.222170.0.65.2236
61170.0.65.224/29170.0.65.225 to 170.0.65.230170.0.65.2316
62170.0.65.232/29170.0.65.233 to 170.0.65.238170.0.65.2396
63170.0.65.240/29170.0.65.241 to 170.0.65.246170.0.65.2476
64170.0.65.248/29170.0.65.249 to 170.0.65.254170.0.65.2556
65170.0.66.0/29170.0.66.1 to 170.0.66.6170.0.66.76
66170.0.66.8/29170.0.66.9 to 170.0.66.14170.0.66.156
67170.0.66.16/29170.0.66.17 to 170.0.66.22170.0.66.236
68170.0.66.24/29170.0.66.25 to 170.0.66.30170.0.66.316
69170.0.66.32/29170.0.66.33 to 170.0.66.38170.0.66.396
70170.0.66.40/29170.0.66.41 to 170.0.66.46170.0.66.476
71170.0.66.48/29170.0.66.49 to 170.0.66.54170.0.66.556
72170.0.66.56/29170.0.66.57 to 170.0.66.62170.0.66.636
73170.0.66.64/29170.0.66.65 to 170.0.66.70170.0.66.716
74170.0.66.72/29170.0.66.73 to 170.0.66.78170.0.66.796
75170.0.66.80/29170.0.66.81 to 170.0.66.86170.0.66.876
76170.0.66.88/29170.0.66.89 to 170.0.66.94170.0.66.956
77170.0.66.96/29170.0.66.97 to 170.0.66.102170.0.66.1036
78170.0.66.104/29170.0.66.105 to 170.0.66.110170.0.66.1116
79170.0.66.112/29170.0.66.113 to 170.0.66.118170.0.66.1196
80170.0.66.120/29170.0.66.121 to 170.0.66.126170.0.66.1276
81170.0.66.128/29170.0.66.129 to 170.0.66.134170.0.66.1356
82170.0.66.136/29170.0.66.137 to 170.0.66.142170.0.66.1436
83170.0.66.144/29170.0.66.145 to 170.0.66.150170.0.66.1516
84170.0.66.152/29170.0.66.153 to 170.0.66.158170.0.66.1596
85170.0.66.160/29170.0.66.161 to 170.0.66.166170.0.66.1676
86170.0.66.168/29170.0.66.169 to 170.0.66.174170.0.66.1756
87170.0.66.176/29170.0.66.177 to 170.0.66.182170.0.66.1836
88170.0.66.184/29170.0.66.185 to 170.0.66.190170.0.66.1916
89170.0.66.192/29170.0.66.193 to 170.0.66.198170.0.66.1996
90170.0.66.200/29170.0.66.201 to 170.0.66.206170.0.66.2076
91170.0.66.208/29170.0.66.209 to 170.0.66.214170.0.66.2156
92170.0.66.216/29170.0.66.217 to 170.0.66.222170.0.66.2236
93170.0.66.224/29170.0.66.225 to 170.0.66.230170.0.66.2316
94170.0.66.232/29170.0.66.233 to 170.0.66.238170.0.66.2396
95170.0.66.240/29170.0.66.241 to 170.0.66.246170.0.66.2476
96170.0.66.248/29170.0.66.249 to 170.0.66.254170.0.66.2556
97170.0.67.0/29170.0.67.1 to 170.0.67.6170.0.67.76
98170.0.67.8/29170.0.67.9 to 170.0.67.14170.0.67.156
99170.0.67.16/29170.0.67.17 to 170.0.67.22170.0.67.236
100170.0.67.24/29170.0.67.25 to 170.0.67.30170.0.67.316
101170.0.67.32/29170.0.67.33 to 170.0.67.38170.0.67.396
102170.0.67.40/29170.0.67.41 to 170.0.67.46170.0.67.476
103170.0.67.48/29170.0.67.49 to 170.0.67.54170.0.67.556
104170.0.67.56/29170.0.67.57 to 170.0.67.62170.0.67.636
105170.0.67.64/29170.0.67.65 to 170.0.67.70170.0.67.716
106170.0.67.72/29170.0.67.73 to 170.0.67.78170.0.67.796
107170.0.67.80/29170.0.67.81 to 170.0.67.86170.0.67.876
108170.0.67.88/29170.0.67.89 to 170.0.67.94170.0.67.956
109170.0.67.96/29170.0.67.97 to 170.0.67.102170.0.67.1036
110170.0.67.104/29170.0.67.105 to 170.0.67.110170.0.67.1116
111170.0.67.112/29170.0.67.113 to 170.0.67.118170.0.67.1196
112170.0.67.120/29170.0.67.121 to 170.0.67.126170.0.67.1276
113170.0.67.128/29170.0.67.129 to 170.0.67.134170.0.67.1356
114170.0.67.136/29170.0.67.137 to 170.0.67.142170.0.67.1436
115170.0.67.144/29170.0.67.145 to 170.0.67.150170.0.67.1516
116170.0.67.152/29170.0.67.153 to 170.0.67.158170.0.67.1596
117170.0.67.160/29170.0.67.161 to 170.0.67.166170.0.67.1676
118170.0.67.168/29170.0.67.169 to 170.0.67.174170.0.67.1756
119170.0.67.176/29170.0.67.177 to 170.0.67.182170.0.67.1836
120170.0.67.184/29170.0.67.185 to 170.0.67.190170.0.67.1916
121170.0.67.192/29170.0.67.193 to 170.0.67.198170.0.67.1996
122170.0.67.200/29170.0.67.201 to 170.0.67.206170.0.67.2076
123170.0.67.208/29170.0.67.209 to 170.0.67.214170.0.67.2156
124170.0.67.216/29170.0.67.217 to 170.0.67.222170.0.67.2236
125170.0.67.224/29170.0.67.225 to 170.0.67.230170.0.67.2316
126170.0.67.232/29170.0.67.233 to 170.0.67.238170.0.67.2396
127170.0.67.240/29170.0.67.241 to 170.0.67.246170.0.67.2476
128170.0.67.248/29170.0.67.249 to 170.0.67.254170.0.67.2556
129170.0.68.0/29170.0.68.1 to 170.0.68.6170.0.68.76
130170.0.68.8/29170.0.68.9 to 170.0.68.14170.0.68.156
131170.0.68.16/29170.0.68.17 to 170.0.68.22170.0.68.236
132170.0.68.24/29170.0.68.25 to 170.0.68.30170.0.68.316
133170.0.68.32/29170.0.68.33 to 170.0.68.38170.0.68.396
134170.0.68.40/29170.0.68.41 to 170.0.68.46170.0.68.476
135170.0.68.48/29170.0.68.49 to 170.0.68.54170.0.68.556
136170.0.68.56/29170.0.68.57 to 170.0.68.62170.0.68.636
137170.0.68.64/29170.0.68.65 to 170.0.68.70170.0.68.716
138170.0.68.72/29170.0.68.73 to 170.0.68.78170.0.68.796
139170.0.68.80/29170.0.68.81 to 170.0.68.86170.0.68.876
140170.0.68.88/29170.0.68.89 to 170.0.68.94170.0.68.956
141170.0.68.96/29170.0.68.97 to 170.0.68.102170.0.68.1036
142170.0.68.104/29170.0.68.105 to 170.0.68.110170.0.68.1116
143170.0.68.112/29170.0.68.113 to 170.0.68.118170.0.68.1196
144170.0.68.120/29170.0.68.121 to 170.0.68.126170.0.68.1276
145170.0.68.128/29170.0.68.129 to 170.0.68.134170.0.68.1356
146170.0.68.136/29170.0.68.137 to 170.0.68.142170.0.68.1436
147170.0.68.144/29170.0.68.145 to 170.0.68.150170.0.68.1516
148170.0.68.152/29170.0.68.153 to 170.0.68.158170.0.68.1596
149170.0.68.160/29170.0.68.161 to 170.0.68.166170.0.68.1676
150170.0.68.168/29170.0.68.169 to 170.0.68.174170.0.68.1756
151170.0.68.176/29170.0.68.177 to 170.0.68.182170.0.68.1836
152170.0.68.184/29170.0.68.185 to 170.0.68.190170.0.68.1916
153170.0.68.192/29170.0.68.193 to 170.0.68.198170.0.68.1996
154170.0.68.200/29170.0.68.201 to 170.0.68.206170.0.68.2076
155170.0.68.208/29170.0.68.209 to 170.0.68.214170.0.68.2156
156170.0.68.216/29170.0.68.217 to 170.0.68.222170.0.68.2236
157170.0.68.224/29170.0.68.225 to 170.0.68.230170.0.68.2316
158170.0.68.232/29170.0.68.233 to 170.0.68.238170.0.68.2396
159170.0.68.240/29170.0.68.241 to 170.0.68.246170.0.68.2476
160170.0.68.248/29170.0.68.249 to 170.0.68.254170.0.68.2556
161170.0.69.0/29170.0.69.1 to 170.0.69.6170.0.69.76
162170.0.69.8/29170.0.69.9 to 170.0.69.14170.0.69.156
163170.0.69.16/29170.0.69.17 to 170.0.69.22170.0.69.236
164170.0.69.24/29170.0.69.25 to 170.0.69.30170.0.69.316
165170.0.69.32/29170.0.69.33 to 170.0.69.38170.0.69.396
166170.0.69.40/29170.0.69.41 to 170.0.69.46170.0.69.476
167170.0.69.48/29170.0.69.49 to 170.0.69.54170.0.69.556
168170.0.69.56/29170.0.69.57 to 170.0.69.62170.0.69.636
169170.0.69.64/29170.0.69.65 to 170.0.69.70170.0.69.716
170170.0.69.72/29170.0.69.73 to 170.0.69.78170.0.69.796
171170.0.69.80/29170.0.69.81 to 170.0.69.86170.0.69.876
172170.0.69.88/29170.0.69.89 to 170.0.69.94170.0.69.956
173170.0.69.96/29170.0.69.97 to 170.0.69.102170.0.69.1036
174170.0.69.104/29170.0.69.105 to 170.0.69.110170.0.69.1116
175170.0.69.112/29170.0.69.113 to 170.0.69.118170.0.69.1196
176170.0.69.120/29170.0.69.121 to 170.0.69.126170.0.69.1276
177170.0.69.128/29170.0.69.129 to 170.0.69.134170.0.69.1356
178170.0.69.136/29170.0.69.137 to 170.0.69.142170.0.69.1436
179170.0.69.144/29170.0.69.145 to 170.0.69.150170.0.69.1516
180170.0.69.152/29170.0.69.153 to 170.0.69.158170.0.69.1596
181170.0.69.160/29170.0.69.161 to 170.0.69.166170.0.69.1676
182170.0.69.168/29170.0.69.169 to 170.0.69.174170.0.69.1756
183170.0.69.176/29170.0.69.177 to 170.0.69.182170.0.69.1836
184170.0.69.184/29170.0.69.185 to 170.0.69.190170.0.69.1916
185170.0.69.192/29170.0.69.193 to 170.0.69.198170.0.69.1996
186170.0.69.200/29170.0.69.201 to 170.0.69.206170.0.69.2076
187170.0.69.208/29170.0.69.209 to 170.0.69.214170.0.69.2156
188170.0.69.216/29170.0.69.217 to 170.0.69.222170.0.69.2236
189170.0.69.224/29170.0.69.225 to 170.0.69.230170.0.69.2316
190170.0.69.232/29170.0.69.233 to 170.0.69.238170.0.69.2396
191170.0.69.240/29170.0.69.241 to 170.0.69.246170.0.69.2476
192170.0.69.248/29170.0.69.249 to 170.0.69.254170.0.69.2556
193170.0.70.0/29170.0.70.1 to 170.0.70.6170.0.70.76
194170.0.70.8/29170.0.70.9 to 170.0.70.14170.0.70.156
195170.0.70.16/29170.0.70.17 to 170.0.70.22170.0.70.236
196170.0.70.24/29170.0.70.25 to 170.0.70.30170.0.70.316
197170.0.70.32/29170.0.70.33 to 170.0.70.38170.0.70.396
198170.0.70.40/29170.0.70.41 to 170.0.70.46170.0.70.476
199170.0.70.48/29170.0.70.49 to 170.0.70.54170.0.70.556
200170.0.70.56/29170.0.70.57 to 170.0.70.62170.0.70.636
201170.0.70.64/29170.0.70.65 to 170.0.70.70170.0.70.716
202170.0.70.72/29170.0.70.73 to 170.0.70.78170.0.70.796
203170.0.70.80/29170.0.70.81 to 170.0.70.86170.0.70.876
204170.0.70.88/29170.0.70.89 to 170.0.70.94170.0.70.956
205170.0.70.96/29170.0.70.97 to 170.0.70.102170.0.70.1036
206170.0.70.104/29170.0.70.105 to 170.0.70.110170.0.70.1116
207170.0.70.112/29170.0.70.113 to 170.0.70.118170.0.70.1196
208170.0.70.120/29170.0.70.121 to 170.0.70.126170.0.70.1276
209170.0.70.128/29170.0.70.129 to 170.0.70.134170.0.70.1356
210170.0.70.136/29170.0.70.137 to 170.0.70.142170.0.70.1436
211170.0.70.144/29170.0.70.145 to 170.0.70.150170.0.70.1516
212170.0.70.152/29170.0.70.153 to 170.0.70.158170.0.70.1596
213170.0.70.160/29170.0.70.161 to 170.0.70.166170.0.70.1676
214170.0.70.168/29170.0.70.169 to 170.0.70.174170.0.70.1756
215170.0.70.176/29170.0.70.177 to 170.0.70.182170.0.70.1836
216170.0.70.184/29170.0.70.185 to 170.0.70.190170.0.70.1916
217170.0.70.192/29170.0.70.193 to 170.0.70.198170.0.70.1996
218170.0.70.200/29170.0.70.201 to 170.0.70.206170.0.70.2076
219170.0.70.208/29170.0.70.209 to 170.0.70.214170.0.70.2156
220170.0.70.216/29170.0.70.217 to 170.0.70.222170.0.70.2236
221170.0.70.224/29170.0.70.225 to 170.0.70.230170.0.70.2316
222170.0.70.232/29170.0.70.233 to 170.0.70.238170.0.70.2396
223170.0.70.240/29170.0.70.241 to 170.0.70.246170.0.70.2476
224170.0.70.248/29170.0.70.249 to 170.0.70.254170.0.70.2556
225170.0.71.0/29170.0.71.1 to 170.0.71.6170.0.71.76
226170.0.71.8/29170.0.71.9 to 170.0.71.14170.0.71.156
227170.0.71.16/29170.0.71.17 to 170.0.71.22170.0.71.236
228170.0.71.24/29170.0.71.25 to 170.0.71.30170.0.71.316
229170.0.71.32/29170.0.71.33 to 170.0.71.38170.0.71.396
230170.0.71.40/29170.0.71.41 to 170.0.71.46170.0.71.476
231170.0.71.48/29170.0.71.49 to 170.0.71.54170.0.71.556
232170.0.71.56/29170.0.71.57 to 170.0.71.62170.0.71.636
233170.0.71.64/29170.0.71.65 to 170.0.71.70170.0.71.716
234170.0.71.72/29170.0.71.73 to 170.0.71.78170.0.71.796
235170.0.71.80/29170.0.71.81 to 170.0.71.86170.0.71.876
236170.0.71.88/29170.0.71.89 to 170.0.71.94170.0.71.956
237170.0.71.96/29170.0.71.97 to 170.0.71.102170.0.71.1036
238170.0.71.104/29170.0.71.105 to 170.0.71.110170.0.71.1116
239170.0.71.112/29170.0.71.113 to 170.0.71.118170.0.71.1196
240170.0.71.120/29170.0.71.121 to 170.0.71.126170.0.71.1276
241170.0.71.128/29170.0.71.129 to 170.0.71.134170.0.71.1356
242170.0.71.136/29170.0.71.137 to 170.0.71.142170.0.71.1436
243170.0.71.144/29170.0.71.145 to 170.0.71.150170.0.71.1516
244170.0.71.152/29170.0.71.153 to 170.0.71.158170.0.71.1596
245170.0.71.160/29170.0.71.161 to 170.0.71.166170.0.71.1676
246170.0.71.168/29170.0.71.169 to 170.0.71.174170.0.71.1756
247170.0.71.176/29170.0.71.177 to 170.0.71.182170.0.71.1836
248170.0.71.184/29170.0.71.185 to 170.0.71.190170.0.71.1916
249170.0.71.192/29170.0.71.193 to 170.0.71.198170.0.71.1996
250170.0.71.200/29170.0.71.201 to 170.0.71.206170.0.71.2076
251170.0.71.208/29170.0.71.209 to 170.0.71.214170.0.71.2156
252170.0.71.216/29170.0.71.217 to 170.0.71.222170.0.71.2236
253170.0.71.224/29170.0.71.225 to 170.0.71.230170.0.71.2316
254170.0.71.232/29170.0.71.233 to 170.0.71.238170.0.71.2396
255170.0.71.240/29170.0.71.241 to 170.0.71.246170.0.71.2476
256170.0.71.248/29170.0.71.249 to 170.0.71.254170.0.71.2556

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.