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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.

Network169.254.80.0/21
Usable hosts2,046
Subnet mask255.255.248.0
Addresses2,048
Network address
169.254.80.0
Broadcast address
169.254.87.255
First usable
169.254.80.1
Last usable
169.254.87.254
Usable hosts
2,046 (2,048 less the network and broadcast addresses)
Subnet mask
255.255.248.0
Wildcard mask
0.0.7.255 (Cisco ACLs, OSPF)
Prefix length
/21
Type
Link-local (APIPA) 169.254.0.0/16
Self-assigned when no DHCP server answers
Old class
B (default /16)
As numbers
Hex A9FE5000 · Integer 2852016128 to 2852018175
Reverse DNS zones
80.254.169.in-addr.arpa
81.254.169.in-addr.arpa
82.254.169.in-addr.arpa
83.254.169.in-addr.arpa
84.254.169.in-addr.arpa
85.254.169.in-addr.arpa
86.254.169.in-addr.arpa
87.254.169.in-addr.arpa
/21 is not on a 8-bit boundary, so it takes 8 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101001.11111110.01010000.00000000169.254.80.0
Subnet mask11111111.11111111.11111000.00000000255.255.248.0
Network10101001.11111110.01010000.00000000169.254.80.0
Broadcast10101001.11111110.01010111.11111111169.254.87.255
Split into smaller subnets/29
/22 (2)/23 (4)/24 (8)/25 (16)/26 (32)/27 (64)/28 (128)/29 (256)/30 (512)/31 (1,024)/32 (2,048)

169.254.80.0/21 makes 256 subnets of /29.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1169.254.80.0/29169.254.80.1 to 169.254.80.6169.254.80.76
2169.254.80.8/29169.254.80.9 to 169.254.80.14169.254.80.156
3169.254.80.16/29169.254.80.17 to 169.254.80.22169.254.80.236
4169.254.80.24/29169.254.80.25 to 169.254.80.30169.254.80.316
5169.254.80.32/29169.254.80.33 to 169.254.80.38169.254.80.396
6169.254.80.40/29169.254.80.41 to 169.254.80.46169.254.80.476
7169.254.80.48/29169.254.80.49 to 169.254.80.54169.254.80.556
8169.254.80.56/29169.254.80.57 to 169.254.80.62169.254.80.636
9169.254.80.64/29169.254.80.65 to 169.254.80.70169.254.80.716
10169.254.80.72/29169.254.80.73 to 169.254.80.78169.254.80.796
11169.254.80.80/29169.254.80.81 to 169.254.80.86169.254.80.876
12169.254.80.88/29169.254.80.89 to 169.254.80.94169.254.80.956
13169.254.80.96/29169.254.80.97 to 169.254.80.102169.254.80.1036
14169.254.80.104/29169.254.80.105 to 169.254.80.110169.254.80.1116
15169.254.80.112/29169.254.80.113 to 169.254.80.118169.254.80.1196
16169.254.80.120/29169.254.80.121 to 169.254.80.126169.254.80.1276
17169.254.80.128/29169.254.80.129 to 169.254.80.134169.254.80.1356
18169.254.80.136/29169.254.80.137 to 169.254.80.142169.254.80.1436
19169.254.80.144/29169.254.80.145 to 169.254.80.150169.254.80.1516
20169.254.80.152/29169.254.80.153 to 169.254.80.158169.254.80.1596
21169.254.80.160/29169.254.80.161 to 169.254.80.166169.254.80.1676
22169.254.80.168/29169.254.80.169 to 169.254.80.174169.254.80.1756
23169.254.80.176/29169.254.80.177 to 169.254.80.182169.254.80.1836
24169.254.80.184/29169.254.80.185 to 169.254.80.190169.254.80.1916
25169.254.80.192/29169.254.80.193 to 169.254.80.198169.254.80.1996
26169.254.80.200/29169.254.80.201 to 169.254.80.206169.254.80.2076
27169.254.80.208/29169.254.80.209 to 169.254.80.214169.254.80.2156
28169.254.80.216/29169.254.80.217 to 169.254.80.222169.254.80.2236
29169.254.80.224/29169.254.80.225 to 169.254.80.230169.254.80.2316
30169.254.80.232/29169.254.80.233 to 169.254.80.238169.254.80.2396
31169.254.80.240/29169.254.80.241 to 169.254.80.246169.254.80.2476
32169.254.80.248/29169.254.80.249 to 169.254.80.254169.254.80.2556
33169.254.81.0/29169.254.81.1 to 169.254.81.6169.254.81.76
34169.254.81.8/29169.254.81.9 to 169.254.81.14169.254.81.156
35169.254.81.16/29169.254.81.17 to 169.254.81.22169.254.81.236
36169.254.81.24/29169.254.81.25 to 169.254.81.30169.254.81.316
37169.254.81.32/29169.254.81.33 to 169.254.81.38169.254.81.396
38169.254.81.40/29169.254.81.41 to 169.254.81.46169.254.81.476
39169.254.81.48/29169.254.81.49 to 169.254.81.54169.254.81.556
40169.254.81.56/29169.254.81.57 to 169.254.81.62169.254.81.636
41169.254.81.64/29169.254.81.65 to 169.254.81.70169.254.81.716
42169.254.81.72/29169.254.81.73 to 169.254.81.78169.254.81.796
43169.254.81.80/29169.254.81.81 to 169.254.81.86169.254.81.876
44169.254.81.88/29169.254.81.89 to 169.254.81.94169.254.81.956
45169.254.81.96/29169.254.81.97 to 169.254.81.102169.254.81.1036
46169.254.81.104/29169.254.81.105 to 169.254.81.110169.254.81.1116
47169.254.81.112/29169.254.81.113 to 169.254.81.118169.254.81.1196
48169.254.81.120/29169.254.81.121 to 169.254.81.126169.254.81.1276
49169.254.81.128/29169.254.81.129 to 169.254.81.134169.254.81.1356
50169.254.81.136/29169.254.81.137 to 169.254.81.142169.254.81.1436
51169.254.81.144/29169.254.81.145 to 169.254.81.150169.254.81.1516
52169.254.81.152/29169.254.81.153 to 169.254.81.158169.254.81.1596
53169.254.81.160/29169.254.81.161 to 169.254.81.166169.254.81.1676
54169.254.81.168/29169.254.81.169 to 169.254.81.174169.254.81.1756
55169.254.81.176/29169.254.81.177 to 169.254.81.182169.254.81.1836
56169.254.81.184/29169.254.81.185 to 169.254.81.190169.254.81.1916
57169.254.81.192/29169.254.81.193 to 169.254.81.198169.254.81.1996
58169.254.81.200/29169.254.81.201 to 169.254.81.206169.254.81.2076
59169.254.81.208/29169.254.81.209 to 169.254.81.214169.254.81.2156
60169.254.81.216/29169.254.81.217 to 169.254.81.222169.254.81.2236
61169.254.81.224/29169.254.81.225 to 169.254.81.230169.254.81.2316
62169.254.81.232/29169.254.81.233 to 169.254.81.238169.254.81.2396
63169.254.81.240/29169.254.81.241 to 169.254.81.246169.254.81.2476
64169.254.81.248/29169.254.81.249 to 169.254.81.254169.254.81.2556
65169.254.82.0/29169.254.82.1 to 169.254.82.6169.254.82.76
66169.254.82.8/29169.254.82.9 to 169.254.82.14169.254.82.156
67169.254.82.16/29169.254.82.17 to 169.254.82.22169.254.82.236
68169.254.82.24/29169.254.82.25 to 169.254.82.30169.254.82.316
69169.254.82.32/29169.254.82.33 to 169.254.82.38169.254.82.396
70169.254.82.40/29169.254.82.41 to 169.254.82.46169.254.82.476
71169.254.82.48/29169.254.82.49 to 169.254.82.54169.254.82.556
72169.254.82.56/29169.254.82.57 to 169.254.82.62169.254.82.636
73169.254.82.64/29169.254.82.65 to 169.254.82.70169.254.82.716
74169.254.82.72/29169.254.82.73 to 169.254.82.78169.254.82.796
75169.254.82.80/29169.254.82.81 to 169.254.82.86169.254.82.876
76169.254.82.88/29169.254.82.89 to 169.254.82.94169.254.82.956
77169.254.82.96/29169.254.82.97 to 169.254.82.102169.254.82.1036
78169.254.82.104/29169.254.82.105 to 169.254.82.110169.254.82.1116
79169.254.82.112/29169.254.82.113 to 169.254.82.118169.254.82.1196
80169.254.82.120/29169.254.82.121 to 169.254.82.126169.254.82.1276
81169.254.82.128/29169.254.82.129 to 169.254.82.134169.254.82.1356
82169.254.82.136/29169.254.82.137 to 169.254.82.142169.254.82.1436
83169.254.82.144/29169.254.82.145 to 169.254.82.150169.254.82.1516
84169.254.82.152/29169.254.82.153 to 169.254.82.158169.254.82.1596
85169.254.82.160/29169.254.82.161 to 169.254.82.166169.254.82.1676
86169.254.82.168/29169.254.82.169 to 169.254.82.174169.254.82.1756
87169.254.82.176/29169.254.82.177 to 169.254.82.182169.254.82.1836
88169.254.82.184/29169.254.82.185 to 169.254.82.190169.254.82.1916
89169.254.82.192/29169.254.82.193 to 169.254.82.198169.254.82.1996
90169.254.82.200/29169.254.82.201 to 169.254.82.206169.254.82.2076
91169.254.82.208/29169.254.82.209 to 169.254.82.214169.254.82.2156
92169.254.82.216/29169.254.82.217 to 169.254.82.222169.254.82.2236
93169.254.82.224/29169.254.82.225 to 169.254.82.230169.254.82.2316
94169.254.82.232/29169.254.82.233 to 169.254.82.238169.254.82.2396
95169.254.82.240/29169.254.82.241 to 169.254.82.246169.254.82.2476
96169.254.82.248/29169.254.82.249 to 169.254.82.254169.254.82.2556
97169.254.83.0/29169.254.83.1 to 169.254.83.6169.254.83.76
98169.254.83.8/29169.254.83.9 to 169.254.83.14169.254.83.156
99169.254.83.16/29169.254.83.17 to 169.254.83.22169.254.83.236
100169.254.83.24/29169.254.83.25 to 169.254.83.30169.254.83.316
101169.254.83.32/29169.254.83.33 to 169.254.83.38169.254.83.396
102169.254.83.40/29169.254.83.41 to 169.254.83.46169.254.83.476
103169.254.83.48/29169.254.83.49 to 169.254.83.54169.254.83.556
104169.254.83.56/29169.254.83.57 to 169.254.83.62169.254.83.636
105169.254.83.64/29169.254.83.65 to 169.254.83.70169.254.83.716
106169.254.83.72/29169.254.83.73 to 169.254.83.78169.254.83.796
107169.254.83.80/29169.254.83.81 to 169.254.83.86169.254.83.876
108169.254.83.88/29169.254.83.89 to 169.254.83.94169.254.83.956
109169.254.83.96/29169.254.83.97 to 169.254.83.102169.254.83.1036
110169.254.83.104/29169.254.83.105 to 169.254.83.110169.254.83.1116
111169.254.83.112/29169.254.83.113 to 169.254.83.118169.254.83.1196
112169.254.83.120/29169.254.83.121 to 169.254.83.126169.254.83.1276
113169.254.83.128/29169.254.83.129 to 169.254.83.134169.254.83.1356
114169.254.83.136/29169.254.83.137 to 169.254.83.142169.254.83.1436
115169.254.83.144/29169.254.83.145 to 169.254.83.150169.254.83.1516
116169.254.83.152/29169.254.83.153 to 169.254.83.158169.254.83.1596
117169.254.83.160/29169.254.83.161 to 169.254.83.166169.254.83.1676
118169.254.83.168/29169.254.83.169 to 169.254.83.174169.254.83.1756
119169.254.83.176/29169.254.83.177 to 169.254.83.182169.254.83.1836
120169.254.83.184/29169.254.83.185 to 169.254.83.190169.254.83.1916
121169.254.83.192/29169.254.83.193 to 169.254.83.198169.254.83.1996
122169.254.83.200/29169.254.83.201 to 169.254.83.206169.254.83.2076
123169.254.83.208/29169.254.83.209 to 169.254.83.214169.254.83.2156
124169.254.83.216/29169.254.83.217 to 169.254.83.222169.254.83.2236
125169.254.83.224/29169.254.83.225 to 169.254.83.230169.254.83.2316
126169.254.83.232/29169.254.83.233 to 169.254.83.238169.254.83.2396
127169.254.83.240/29169.254.83.241 to 169.254.83.246169.254.83.2476
128169.254.83.248/29169.254.83.249 to 169.254.83.254169.254.83.2556
129169.254.84.0/29169.254.84.1 to 169.254.84.6169.254.84.76
130169.254.84.8/29169.254.84.9 to 169.254.84.14169.254.84.156
131169.254.84.16/29169.254.84.17 to 169.254.84.22169.254.84.236
132169.254.84.24/29169.254.84.25 to 169.254.84.30169.254.84.316
133169.254.84.32/29169.254.84.33 to 169.254.84.38169.254.84.396
134169.254.84.40/29169.254.84.41 to 169.254.84.46169.254.84.476
135169.254.84.48/29169.254.84.49 to 169.254.84.54169.254.84.556
136169.254.84.56/29169.254.84.57 to 169.254.84.62169.254.84.636
137169.254.84.64/29169.254.84.65 to 169.254.84.70169.254.84.716
138169.254.84.72/29169.254.84.73 to 169.254.84.78169.254.84.796
139169.254.84.80/29169.254.84.81 to 169.254.84.86169.254.84.876
140169.254.84.88/29169.254.84.89 to 169.254.84.94169.254.84.956
141169.254.84.96/29169.254.84.97 to 169.254.84.102169.254.84.1036
142169.254.84.104/29169.254.84.105 to 169.254.84.110169.254.84.1116
143169.254.84.112/29169.254.84.113 to 169.254.84.118169.254.84.1196
144169.254.84.120/29169.254.84.121 to 169.254.84.126169.254.84.1276
145169.254.84.128/29169.254.84.129 to 169.254.84.134169.254.84.1356
146169.254.84.136/29169.254.84.137 to 169.254.84.142169.254.84.1436
147169.254.84.144/29169.254.84.145 to 169.254.84.150169.254.84.1516
148169.254.84.152/29169.254.84.153 to 169.254.84.158169.254.84.1596
149169.254.84.160/29169.254.84.161 to 169.254.84.166169.254.84.1676
150169.254.84.168/29169.254.84.169 to 169.254.84.174169.254.84.1756
151169.254.84.176/29169.254.84.177 to 169.254.84.182169.254.84.1836
152169.254.84.184/29169.254.84.185 to 169.254.84.190169.254.84.1916
153169.254.84.192/29169.254.84.193 to 169.254.84.198169.254.84.1996
154169.254.84.200/29169.254.84.201 to 169.254.84.206169.254.84.2076
155169.254.84.208/29169.254.84.209 to 169.254.84.214169.254.84.2156
156169.254.84.216/29169.254.84.217 to 169.254.84.222169.254.84.2236
157169.254.84.224/29169.254.84.225 to 169.254.84.230169.254.84.2316
158169.254.84.232/29169.254.84.233 to 169.254.84.238169.254.84.2396
159169.254.84.240/29169.254.84.241 to 169.254.84.246169.254.84.2476
160169.254.84.248/29169.254.84.249 to 169.254.84.254169.254.84.2556
161169.254.85.0/29169.254.85.1 to 169.254.85.6169.254.85.76
162169.254.85.8/29169.254.85.9 to 169.254.85.14169.254.85.156
163169.254.85.16/29169.254.85.17 to 169.254.85.22169.254.85.236
164169.254.85.24/29169.254.85.25 to 169.254.85.30169.254.85.316
165169.254.85.32/29169.254.85.33 to 169.254.85.38169.254.85.396
166169.254.85.40/29169.254.85.41 to 169.254.85.46169.254.85.476
167169.254.85.48/29169.254.85.49 to 169.254.85.54169.254.85.556
168169.254.85.56/29169.254.85.57 to 169.254.85.62169.254.85.636
169169.254.85.64/29169.254.85.65 to 169.254.85.70169.254.85.716
170169.254.85.72/29169.254.85.73 to 169.254.85.78169.254.85.796
171169.254.85.80/29169.254.85.81 to 169.254.85.86169.254.85.876
172169.254.85.88/29169.254.85.89 to 169.254.85.94169.254.85.956
173169.254.85.96/29169.254.85.97 to 169.254.85.102169.254.85.1036
174169.254.85.104/29169.254.85.105 to 169.254.85.110169.254.85.1116
175169.254.85.112/29169.254.85.113 to 169.254.85.118169.254.85.1196
176169.254.85.120/29169.254.85.121 to 169.254.85.126169.254.85.1276
177169.254.85.128/29169.254.85.129 to 169.254.85.134169.254.85.1356
178169.254.85.136/29169.254.85.137 to 169.254.85.142169.254.85.1436
179169.254.85.144/29169.254.85.145 to 169.254.85.150169.254.85.1516
180169.254.85.152/29169.254.85.153 to 169.254.85.158169.254.85.1596
181169.254.85.160/29169.254.85.161 to 169.254.85.166169.254.85.1676
182169.254.85.168/29169.254.85.169 to 169.254.85.174169.254.85.1756
183169.254.85.176/29169.254.85.177 to 169.254.85.182169.254.85.1836
184169.254.85.184/29169.254.85.185 to 169.254.85.190169.254.85.1916
185169.254.85.192/29169.254.85.193 to 169.254.85.198169.254.85.1996
186169.254.85.200/29169.254.85.201 to 169.254.85.206169.254.85.2076
187169.254.85.208/29169.254.85.209 to 169.254.85.214169.254.85.2156
188169.254.85.216/29169.254.85.217 to 169.254.85.222169.254.85.2236
189169.254.85.224/29169.254.85.225 to 169.254.85.230169.254.85.2316
190169.254.85.232/29169.254.85.233 to 169.254.85.238169.254.85.2396
191169.254.85.240/29169.254.85.241 to 169.254.85.246169.254.85.2476
192169.254.85.248/29169.254.85.249 to 169.254.85.254169.254.85.2556
193169.254.86.0/29169.254.86.1 to 169.254.86.6169.254.86.76
194169.254.86.8/29169.254.86.9 to 169.254.86.14169.254.86.156
195169.254.86.16/29169.254.86.17 to 169.254.86.22169.254.86.236
196169.254.86.24/29169.254.86.25 to 169.254.86.30169.254.86.316
197169.254.86.32/29169.254.86.33 to 169.254.86.38169.254.86.396
198169.254.86.40/29169.254.86.41 to 169.254.86.46169.254.86.476
199169.254.86.48/29169.254.86.49 to 169.254.86.54169.254.86.556
200169.254.86.56/29169.254.86.57 to 169.254.86.62169.254.86.636
201169.254.86.64/29169.254.86.65 to 169.254.86.70169.254.86.716
202169.254.86.72/29169.254.86.73 to 169.254.86.78169.254.86.796
203169.254.86.80/29169.254.86.81 to 169.254.86.86169.254.86.876
204169.254.86.88/29169.254.86.89 to 169.254.86.94169.254.86.956
205169.254.86.96/29169.254.86.97 to 169.254.86.102169.254.86.1036
206169.254.86.104/29169.254.86.105 to 169.254.86.110169.254.86.1116
207169.254.86.112/29169.254.86.113 to 169.254.86.118169.254.86.1196
208169.254.86.120/29169.254.86.121 to 169.254.86.126169.254.86.1276
209169.254.86.128/29169.254.86.129 to 169.254.86.134169.254.86.1356
210169.254.86.136/29169.254.86.137 to 169.254.86.142169.254.86.1436
211169.254.86.144/29169.254.86.145 to 169.254.86.150169.254.86.1516
212169.254.86.152/29169.254.86.153 to 169.254.86.158169.254.86.1596
213169.254.86.160/29169.254.86.161 to 169.254.86.166169.254.86.1676
214169.254.86.168/29169.254.86.169 to 169.254.86.174169.254.86.1756
215169.254.86.176/29169.254.86.177 to 169.254.86.182169.254.86.1836
216169.254.86.184/29169.254.86.185 to 169.254.86.190169.254.86.1916
217169.254.86.192/29169.254.86.193 to 169.254.86.198169.254.86.1996
218169.254.86.200/29169.254.86.201 to 169.254.86.206169.254.86.2076
219169.254.86.208/29169.254.86.209 to 169.254.86.214169.254.86.2156
220169.254.86.216/29169.254.86.217 to 169.254.86.222169.254.86.2236
221169.254.86.224/29169.254.86.225 to 169.254.86.230169.254.86.2316
222169.254.86.232/29169.254.86.233 to 169.254.86.238169.254.86.2396
223169.254.86.240/29169.254.86.241 to 169.254.86.246169.254.86.2476
224169.254.86.248/29169.254.86.249 to 169.254.86.254169.254.86.2556
225169.254.87.0/29169.254.87.1 to 169.254.87.6169.254.87.76
226169.254.87.8/29169.254.87.9 to 169.254.87.14169.254.87.156
227169.254.87.16/29169.254.87.17 to 169.254.87.22169.254.87.236
228169.254.87.24/29169.254.87.25 to 169.254.87.30169.254.87.316
229169.254.87.32/29169.254.87.33 to 169.254.87.38169.254.87.396
230169.254.87.40/29169.254.87.41 to 169.254.87.46169.254.87.476
231169.254.87.48/29169.254.87.49 to 169.254.87.54169.254.87.556
232169.254.87.56/29169.254.87.57 to 169.254.87.62169.254.87.636
233169.254.87.64/29169.254.87.65 to 169.254.87.70169.254.87.716
234169.254.87.72/29169.254.87.73 to 169.254.87.78169.254.87.796
235169.254.87.80/29169.254.87.81 to 169.254.87.86169.254.87.876
236169.254.87.88/29169.254.87.89 to 169.254.87.94169.254.87.956
237169.254.87.96/29169.254.87.97 to 169.254.87.102169.254.87.1036
238169.254.87.104/29169.254.87.105 to 169.254.87.110169.254.87.1116
239169.254.87.112/29169.254.87.113 to 169.254.87.118169.254.87.1196
240169.254.87.120/29169.254.87.121 to 169.254.87.126169.254.87.1276
241169.254.87.128/29169.254.87.129 to 169.254.87.134169.254.87.1356
242169.254.87.136/29169.254.87.137 to 169.254.87.142169.254.87.1436
243169.254.87.144/29169.254.87.145 to 169.254.87.150169.254.87.1516
244169.254.87.152/29169.254.87.153 to 169.254.87.158169.254.87.1596
245169.254.87.160/29169.254.87.161 to 169.254.87.166169.254.87.1676
246169.254.87.168/29169.254.87.169 to 169.254.87.174169.254.87.1756
247169.254.87.176/29169.254.87.177 to 169.254.87.182169.254.87.1836
248169.254.87.184/29169.254.87.185 to 169.254.87.190169.254.87.1916
249169.254.87.192/29169.254.87.193 to 169.254.87.198169.254.87.1996
250169.254.87.200/29169.254.87.201 to 169.254.87.206169.254.87.2076
251169.254.87.208/29169.254.87.209 to 169.254.87.214169.254.87.2156
252169.254.87.216/29169.254.87.217 to 169.254.87.222169.254.87.2236
253169.254.87.224/29169.254.87.225 to 169.254.87.230169.254.87.2316
254169.254.87.232/29169.254.87.233 to 169.254.87.238169.254.87.2396
255169.254.87.240/29169.254.87.241 to 169.254.87.246169.254.87.2476
256169.254.87.248/29169.254.87.249 to 169.254.87.254169.254.87.2556

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.