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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.

Network241.232.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
241.232.0.0
Broadcast address
241.232.127.255
First usable
241.232.0.1
Last usable
241.232.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F1E80000 · Integer 4058513408 to 4058546175
Reverse DNS zones
0.232.241.in-addr.arpa
1.232.241.in-addr.arpa
2.232.241.in-addr.arpa
3.232.241.in-addr.arpa
4.232.241.in-addr.arpa
5.232.241.in-addr.arpa
6.232.241.in-addr.arpa
7.232.241.in-addr.arpa
8.232.241.in-addr.arpa
9.232.241.in-addr.arpa
10.232.241.in-addr.arpa
11.232.241.in-addr.arpa
12.232.241.in-addr.arpa
13.232.241.in-addr.arpa
14.232.241.in-addr.arpa
15.232.241.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110001.11101000.00000000.00000000241.232.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11110001.11101000.00000000.00000000241.232.0.0
Broadcast11110001.11101000.01111111.11111111241.232.127.255
Split into smaller subnets/29
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

241.232.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1241.232.0.0/29241.232.0.1 to 241.232.0.6241.232.0.76
2241.232.0.8/29241.232.0.9 to 241.232.0.14241.232.0.156
3241.232.0.16/29241.232.0.17 to 241.232.0.22241.232.0.236
4241.232.0.24/29241.232.0.25 to 241.232.0.30241.232.0.316
5241.232.0.32/29241.232.0.33 to 241.232.0.38241.232.0.396
6241.232.0.40/29241.232.0.41 to 241.232.0.46241.232.0.476
7241.232.0.48/29241.232.0.49 to 241.232.0.54241.232.0.556
8241.232.0.56/29241.232.0.57 to 241.232.0.62241.232.0.636
9241.232.0.64/29241.232.0.65 to 241.232.0.70241.232.0.716
10241.232.0.72/29241.232.0.73 to 241.232.0.78241.232.0.796
11241.232.0.80/29241.232.0.81 to 241.232.0.86241.232.0.876
12241.232.0.88/29241.232.0.89 to 241.232.0.94241.232.0.956
13241.232.0.96/29241.232.0.97 to 241.232.0.102241.232.0.1036
14241.232.0.104/29241.232.0.105 to 241.232.0.110241.232.0.1116
15241.232.0.112/29241.232.0.113 to 241.232.0.118241.232.0.1196
16241.232.0.120/29241.232.0.121 to 241.232.0.126241.232.0.1276
17241.232.0.128/29241.232.0.129 to 241.232.0.134241.232.0.1356
18241.232.0.136/29241.232.0.137 to 241.232.0.142241.232.0.1436
19241.232.0.144/29241.232.0.145 to 241.232.0.150241.232.0.1516
20241.232.0.152/29241.232.0.153 to 241.232.0.158241.232.0.1596
21241.232.0.160/29241.232.0.161 to 241.232.0.166241.232.0.1676
22241.232.0.168/29241.232.0.169 to 241.232.0.174241.232.0.1756
23241.232.0.176/29241.232.0.177 to 241.232.0.182241.232.0.1836
24241.232.0.184/29241.232.0.185 to 241.232.0.190241.232.0.1916
25241.232.0.192/29241.232.0.193 to 241.232.0.198241.232.0.1996
26241.232.0.200/29241.232.0.201 to 241.232.0.206241.232.0.2076
27241.232.0.208/29241.232.0.209 to 241.232.0.214241.232.0.2156
28241.232.0.216/29241.232.0.217 to 241.232.0.222241.232.0.2236
29241.232.0.224/29241.232.0.225 to 241.232.0.230241.232.0.2316
30241.232.0.232/29241.232.0.233 to 241.232.0.238241.232.0.2396
31241.232.0.240/29241.232.0.241 to 241.232.0.246241.232.0.2476
32241.232.0.248/29241.232.0.249 to 241.232.0.254241.232.0.2556
33241.232.1.0/29241.232.1.1 to 241.232.1.6241.232.1.76
34241.232.1.8/29241.232.1.9 to 241.232.1.14241.232.1.156
35241.232.1.16/29241.232.1.17 to 241.232.1.22241.232.1.236
36241.232.1.24/29241.232.1.25 to 241.232.1.30241.232.1.316
37241.232.1.32/29241.232.1.33 to 241.232.1.38241.232.1.396
38241.232.1.40/29241.232.1.41 to 241.232.1.46241.232.1.476
39241.232.1.48/29241.232.1.49 to 241.232.1.54241.232.1.556
40241.232.1.56/29241.232.1.57 to 241.232.1.62241.232.1.636
41241.232.1.64/29241.232.1.65 to 241.232.1.70241.232.1.716
42241.232.1.72/29241.232.1.73 to 241.232.1.78241.232.1.796
43241.232.1.80/29241.232.1.81 to 241.232.1.86241.232.1.876
44241.232.1.88/29241.232.1.89 to 241.232.1.94241.232.1.956
45241.232.1.96/29241.232.1.97 to 241.232.1.102241.232.1.1036
46241.232.1.104/29241.232.1.105 to 241.232.1.110241.232.1.1116
47241.232.1.112/29241.232.1.113 to 241.232.1.118241.232.1.1196
48241.232.1.120/29241.232.1.121 to 241.232.1.126241.232.1.1276
49241.232.1.128/29241.232.1.129 to 241.232.1.134241.232.1.1356
50241.232.1.136/29241.232.1.137 to 241.232.1.142241.232.1.1436
51241.232.1.144/29241.232.1.145 to 241.232.1.150241.232.1.1516
52241.232.1.152/29241.232.1.153 to 241.232.1.158241.232.1.1596
53241.232.1.160/29241.232.1.161 to 241.232.1.166241.232.1.1676
54241.232.1.168/29241.232.1.169 to 241.232.1.174241.232.1.1756
55241.232.1.176/29241.232.1.177 to 241.232.1.182241.232.1.1836
56241.232.1.184/29241.232.1.185 to 241.232.1.190241.232.1.1916
57241.232.1.192/29241.232.1.193 to 241.232.1.198241.232.1.1996
58241.232.1.200/29241.232.1.201 to 241.232.1.206241.232.1.2076
59241.232.1.208/29241.232.1.209 to 241.232.1.214241.232.1.2156
60241.232.1.216/29241.232.1.217 to 241.232.1.222241.232.1.2236
61241.232.1.224/29241.232.1.225 to 241.232.1.230241.232.1.2316
62241.232.1.232/29241.232.1.233 to 241.232.1.238241.232.1.2396
63241.232.1.240/29241.232.1.241 to 241.232.1.246241.232.1.2476
64241.232.1.248/29241.232.1.249 to 241.232.1.254241.232.1.2556
65241.232.2.0/29241.232.2.1 to 241.232.2.6241.232.2.76
66241.232.2.8/29241.232.2.9 to 241.232.2.14241.232.2.156
67241.232.2.16/29241.232.2.17 to 241.232.2.22241.232.2.236
68241.232.2.24/29241.232.2.25 to 241.232.2.30241.232.2.316
69241.232.2.32/29241.232.2.33 to 241.232.2.38241.232.2.396
70241.232.2.40/29241.232.2.41 to 241.232.2.46241.232.2.476
71241.232.2.48/29241.232.2.49 to 241.232.2.54241.232.2.556
72241.232.2.56/29241.232.2.57 to 241.232.2.62241.232.2.636
73241.232.2.64/29241.232.2.65 to 241.232.2.70241.232.2.716
74241.232.2.72/29241.232.2.73 to 241.232.2.78241.232.2.796
75241.232.2.80/29241.232.2.81 to 241.232.2.86241.232.2.876
76241.232.2.88/29241.232.2.89 to 241.232.2.94241.232.2.956
77241.232.2.96/29241.232.2.97 to 241.232.2.102241.232.2.1036
78241.232.2.104/29241.232.2.105 to 241.232.2.110241.232.2.1116
79241.232.2.112/29241.232.2.113 to 241.232.2.118241.232.2.1196
80241.232.2.120/29241.232.2.121 to 241.232.2.126241.232.2.1276
81241.232.2.128/29241.232.2.129 to 241.232.2.134241.232.2.1356
82241.232.2.136/29241.232.2.137 to 241.232.2.142241.232.2.1436
83241.232.2.144/29241.232.2.145 to 241.232.2.150241.232.2.1516
84241.232.2.152/29241.232.2.153 to 241.232.2.158241.232.2.1596
85241.232.2.160/29241.232.2.161 to 241.232.2.166241.232.2.1676
86241.232.2.168/29241.232.2.169 to 241.232.2.174241.232.2.1756
87241.232.2.176/29241.232.2.177 to 241.232.2.182241.232.2.1836
88241.232.2.184/29241.232.2.185 to 241.232.2.190241.232.2.1916
89241.232.2.192/29241.232.2.193 to 241.232.2.198241.232.2.1996
90241.232.2.200/29241.232.2.201 to 241.232.2.206241.232.2.2076
91241.232.2.208/29241.232.2.209 to 241.232.2.214241.232.2.2156
92241.232.2.216/29241.232.2.217 to 241.232.2.222241.232.2.2236
93241.232.2.224/29241.232.2.225 to 241.232.2.230241.232.2.2316
94241.232.2.232/29241.232.2.233 to 241.232.2.238241.232.2.2396
95241.232.2.240/29241.232.2.241 to 241.232.2.246241.232.2.2476
96241.232.2.248/29241.232.2.249 to 241.232.2.254241.232.2.2556
97241.232.3.0/29241.232.3.1 to 241.232.3.6241.232.3.76
98241.232.3.8/29241.232.3.9 to 241.232.3.14241.232.3.156
99241.232.3.16/29241.232.3.17 to 241.232.3.22241.232.3.236
100241.232.3.24/29241.232.3.25 to 241.232.3.30241.232.3.316
101241.232.3.32/29241.232.3.33 to 241.232.3.38241.232.3.396
102241.232.3.40/29241.232.3.41 to 241.232.3.46241.232.3.476
103241.232.3.48/29241.232.3.49 to 241.232.3.54241.232.3.556
104241.232.3.56/29241.232.3.57 to 241.232.3.62241.232.3.636
105241.232.3.64/29241.232.3.65 to 241.232.3.70241.232.3.716
106241.232.3.72/29241.232.3.73 to 241.232.3.78241.232.3.796
107241.232.3.80/29241.232.3.81 to 241.232.3.86241.232.3.876
108241.232.3.88/29241.232.3.89 to 241.232.3.94241.232.3.956
109241.232.3.96/29241.232.3.97 to 241.232.3.102241.232.3.1036
110241.232.3.104/29241.232.3.105 to 241.232.3.110241.232.3.1116
111241.232.3.112/29241.232.3.113 to 241.232.3.118241.232.3.1196
112241.232.3.120/29241.232.3.121 to 241.232.3.126241.232.3.1276
113241.232.3.128/29241.232.3.129 to 241.232.3.134241.232.3.1356
114241.232.3.136/29241.232.3.137 to 241.232.3.142241.232.3.1436
115241.232.3.144/29241.232.3.145 to 241.232.3.150241.232.3.1516
116241.232.3.152/29241.232.3.153 to 241.232.3.158241.232.3.1596
117241.232.3.160/29241.232.3.161 to 241.232.3.166241.232.3.1676
118241.232.3.168/29241.232.3.169 to 241.232.3.174241.232.3.1756
119241.232.3.176/29241.232.3.177 to 241.232.3.182241.232.3.1836
120241.232.3.184/29241.232.3.185 to 241.232.3.190241.232.3.1916
121241.232.3.192/29241.232.3.193 to 241.232.3.198241.232.3.1996
122241.232.3.200/29241.232.3.201 to 241.232.3.206241.232.3.2076
123241.232.3.208/29241.232.3.209 to 241.232.3.214241.232.3.2156
124241.232.3.216/29241.232.3.217 to 241.232.3.222241.232.3.2236
125241.232.3.224/29241.232.3.225 to 241.232.3.230241.232.3.2316
126241.232.3.232/29241.232.3.233 to 241.232.3.238241.232.3.2396
127241.232.3.240/29241.232.3.241 to 241.232.3.246241.232.3.2476
128241.232.3.248/29241.232.3.249 to 241.232.3.254241.232.3.2556
129241.232.4.0/29241.232.4.1 to 241.232.4.6241.232.4.76
130241.232.4.8/29241.232.4.9 to 241.232.4.14241.232.4.156
131241.232.4.16/29241.232.4.17 to 241.232.4.22241.232.4.236
132241.232.4.24/29241.232.4.25 to 241.232.4.30241.232.4.316
133241.232.4.32/29241.232.4.33 to 241.232.4.38241.232.4.396
134241.232.4.40/29241.232.4.41 to 241.232.4.46241.232.4.476
135241.232.4.48/29241.232.4.49 to 241.232.4.54241.232.4.556
136241.232.4.56/29241.232.4.57 to 241.232.4.62241.232.4.636
137241.232.4.64/29241.232.4.65 to 241.232.4.70241.232.4.716
138241.232.4.72/29241.232.4.73 to 241.232.4.78241.232.4.796
139241.232.4.80/29241.232.4.81 to 241.232.4.86241.232.4.876
140241.232.4.88/29241.232.4.89 to 241.232.4.94241.232.4.956
141241.232.4.96/29241.232.4.97 to 241.232.4.102241.232.4.1036
142241.232.4.104/29241.232.4.105 to 241.232.4.110241.232.4.1116
143241.232.4.112/29241.232.4.113 to 241.232.4.118241.232.4.1196
144241.232.4.120/29241.232.4.121 to 241.232.4.126241.232.4.1276
145241.232.4.128/29241.232.4.129 to 241.232.4.134241.232.4.1356
146241.232.4.136/29241.232.4.137 to 241.232.4.142241.232.4.1436
147241.232.4.144/29241.232.4.145 to 241.232.4.150241.232.4.1516
148241.232.4.152/29241.232.4.153 to 241.232.4.158241.232.4.1596
149241.232.4.160/29241.232.4.161 to 241.232.4.166241.232.4.1676
150241.232.4.168/29241.232.4.169 to 241.232.4.174241.232.4.1756
151241.232.4.176/29241.232.4.177 to 241.232.4.182241.232.4.1836
152241.232.4.184/29241.232.4.185 to 241.232.4.190241.232.4.1916
153241.232.4.192/29241.232.4.193 to 241.232.4.198241.232.4.1996
154241.232.4.200/29241.232.4.201 to 241.232.4.206241.232.4.2076
155241.232.4.208/29241.232.4.209 to 241.232.4.214241.232.4.2156
156241.232.4.216/29241.232.4.217 to 241.232.4.222241.232.4.2236
157241.232.4.224/29241.232.4.225 to 241.232.4.230241.232.4.2316
158241.232.4.232/29241.232.4.233 to 241.232.4.238241.232.4.2396
159241.232.4.240/29241.232.4.241 to 241.232.4.246241.232.4.2476
160241.232.4.248/29241.232.4.249 to 241.232.4.254241.232.4.2556
161241.232.5.0/29241.232.5.1 to 241.232.5.6241.232.5.76
162241.232.5.8/29241.232.5.9 to 241.232.5.14241.232.5.156
163241.232.5.16/29241.232.5.17 to 241.232.5.22241.232.5.236
164241.232.5.24/29241.232.5.25 to 241.232.5.30241.232.5.316
165241.232.5.32/29241.232.5.33 to 241.232.5.38241.232.5.396
166241.232.5.40/29241.232.5.41 to 241.232.5.46241.232.5.476
167241.232.5.48/29241.232.5.49 to 241.232.5.54241.232.5.556
168241.232.5.56/29241.232.5.57 to 241.232.5.62241.232.5.636
169241.232.5.64/29241.232.5.65 to 241.232.5.70241.232.5.716
170241.232.5.72/29241.232.5.73 to 241.232.5.78241.232.5.796
171241.232.5.80/29241.232.5.81 to 241.232.5.86241.232.5.876
172241.232.5.88/29241.232.5.89 to 241.232.5.94241.232.5.956
173241.232.5.96/29241.232.5.97 to 241.232.5.102241.232.5.1036
174241.232.5.104/29241.232.5.105 to 241.232.5.110241.232.5.1116
175241.232.5.112/29241.232.5.113 to 241.232.5.118241.232.5.1196
176241.232.5.120/29241.232.5.121 to 241.232.5.126241.232.5.1276
177241.232.5.128/29241.232.5.129 to 241.232.5.134241.232.5.1356
178241.232.5.136/29241.232.5.137 to 241.232.5.142241.232.5.1436
179241.232.5.144/29241.232.5.145 to 241.232.5.150241.232.5.1516
180241.232.5.152/29241.232.5.153 to 241.232.5.158241.232.5.1596
181241.232.5.160/29241.232.5.161 to 241.232.5.166241.232.5.1676
182241.232.5.168/29241.232.5.169 to 241.232.5.174241.232.5.1756
183241.232.5.176/29241.232.5.177 to 241.232.5.182241.232.5.1836
184241.232.5.184/29241.232.5.185 to 241.232.5.190241.232.5.1916
185241.232.5.192/29241.232.5.193 to 241.232.5.198241.232.5.1996
186241.232.5.200/29241.232.5.201 to 241.232.5.206241.232.5.2076
187241.232.5.208/29241.232.5.209 to 241.232.5.214241.232.5.2156
188241.232.5.216/29241.232.5.217 to 241.232.5.222241.232.5.2236
189241.232.5.224/29241.232.5.225 to 241.232.5.230241.232.5.2316
190241.232.5.232/29241.232.5.233 to 241.232.5.238241.232.5.2396
191241.232.5.240/29241.232.5.241 to 241.232.5.246241.232.5.2476
192241.232.5.248/29241.232.5.249 to 241.232.5.254241.232.5.2556
193241.232.6.0/29241.232.6.1 to 241.232.6.6241.232.6.76
194241.232.6.8/29241.232.6.9 to 241.232.6.14241.232.6.156
195241.232.6.16/29241.232.6.17 to 241.232.6.22241.232.6.236
196241.232.6.24/29241.232.6.25 to 241.232.6.30241.232.6.316
197241.232.6.32/29241.232.6.33 to 241.232.6.38241.232.6.396
198241.232.6.40/29241.232.6.41 to 241.232.6.46241.232.6.476
199241.232.6.48/29241.232.6.49 to 241.232.6.54241.232.6.556
200241.232.6.56/29241.232.6.57 to 241.232.6.62241.232.6.636
201241.232.6.64/29241.232.6.65 to 241.232.6.70241.232.6.716
202241.232.6.72/29241.232.6.73 to 241.232.6.78241.232.6.796
203241.232.6.80/29241.232.6.81 to 241.232.6.86241.232.6.876
204241.232.6.88/29241.232.6.89 to 241.232.6.94241.232.6.956
205241.232.6.96/29241.232.6.97 to 241.232.6.102241.232.6.1036
206241.232.6.104/29241.232.6.105 to 241.232.6.110241.232.6.1116
207241.232.6.112/29241.232.6.113 to 241.232.6.118241.232.6.1196
208241.232.6.120/29241.232.6.121 to 241.232.6.126241.232.6.1276
209241.232.6.128/29241.232.6.129 to 241.232.6.134241.232.6.1356
210241.232.6.136/29241.232.6.137 to 241.232.6.142241.232.6.1436
211241.232.6.144/29241.232.6.145 to 241.232.6.150241.232.6.1516
212241.232.6.152/29241.232.6.153 to 241.232.6.158241.232.6.1596
213241.232.6.160/29241.232.6.161 to 241.232.6.166241.232.6.1676
214241.232.6.168/29241.232.6.169 to 241.232.6.174241.232.6.1756
215241.232.6.176/29241.232.6.177 to 241.232.6.182241.232.6.1836
216241.232.6.184/29241.232.6.185 to 241.232.6.190241.232.6.1916
217241.232.6.192/29241.232.6.193 to 241.232.6.198241.232.6.1996
218241.232.6.200/29241.232.6.201 to 241.232.6.206241.232.6.2076
219241.232.6.208/29241.232.6.209 to 241.232.6.214241.232.6.2156
220241.232.6.216/29241.232.6.217 to 241.232.6.222241.232.6.2236
221241.232.6.224/29241.232.6.225 to 241.232.6.230241.232.6.2316
222241.232.6.232/29241.232.6.233 to 241.232.6.238241.232.6.2396
223241.232.6.240/29241.232.6.241 to 241.232.6.246241.232.6.2476
224241.232.6.248/29241.232.6.249 to 241.232.6.254241.232.6.2556
225241.232.7.0/29241.232.7.1 to 241.232.7.6241.232.7.76
226241.232.7.8/29241.232.7.9 to 241.232.7.14241.232.7.156
227241.232.7.16/29241.232.7.17 to 241.232.7.22241.232.7.236
228241.232.7.24/29241.232.7.25 to 241.232.7.30241.232.7.316
229241.232.7.32/29241.232.7.33 to 241.232.7.38241.232.7.396
230241.232.7.40/29241.232.7.41 to 241.232.7.46241.232.7.476
231241.232.7.48/29241.232.7.49 to 241.232.7.54241.232.7.556
232241.232.7.56/29241.232.7.57 to 241.232.7.62241.232.7.636
233241.232.7.64/29241.232.7.65 to 241.232.7.70241.232.7.716
234241.232.7.72/29241.232.7.73 to 241.232.7.78241.232.7.796
235241.232.7.80/29241.232.7.81 to 241.232.7.86241.232.7.876
236241.232.7.88/29241.232.7.89 to 241.232.7.94241.232.7.956
237241.232.7.96/29241.232.7.97 to 241.232.7.102241.232.7.1036
238241.232.7.104/29241.232.7.105 to 241.232.7.110241.232.7.1116
239241.232.7.112/29241.232.7.113 to 241.232.7.118241.232.7.1196
240241.232.7.120/29241.232.7.121 to 241.232.7.126241.232.7.1276
241241.232.7.128/29241.232.7.129 to 241.232.7.134241.232.7.1356
242241.232.7.136/29241.232.7.137 to 241.232.7.142241.232.7.1436
243241.232.7.144/29241.232.7.145 to 241.232.7.150241.232.7.1516
244241.232.7.152/29241.232.7.153 to 241.232.7.158241.232.7.1596
245241.232.7.160/29241.232.7.161 to 241.232.7.166241.232.7.1676
246241.232.7.168/29241.232.7.169 to 241.232.7.174241.232.7.1756
247241.232.7.176/29241.232.7.177 to 241.232.7.182241.232.7.1836
248241.232.7.184/29241.232.7.185 to 241.232.7.190241.232.7.1916
249241.232.7.192/29241.232.7.193 to 241.232.7.198241.232.7.1996
250241.232.7.200/29241.232.7.201 to 241.232.7.206241.232.7.2076
251241.232.7.208/29241.232.7.209 to 241.232.7.214241.232.7.2156
252241.232.7.216/29241.232.7.217 to 241.232.7.222241.232.7.2236
253241.232.7.224/29241.232.7.225 to 241.232.7.230241.232.7.2316
254241.232.7.232/29241.232.7.233 to 241.232.7.238241.232.7.2396
255241.232.7.240/29241.232.7.241 to 241.232.7.246241.232.7.2476
256241.232.7.248/29241.232.7.249 to 241.232.7.254241.232.7.2556

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.