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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.

Network125.76.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
125.76.0.0
Broadcast address
125.76.127.255
First usable
125.76.0.1
Last usable
125.76.127.254
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
Public public
Old class
A (default /8)
As numbers
Hex 7D4C0000 · Integer 2102132736 to 2102165503
Reverse DNS zones
0.76.125.in-addr.arpa
1.76.125.in-addr.arpa
2.76.125.in-addr.arpa
3.76.125.in-addr.arpa
4.76.125.in-addr.arpa
5.76.125.in-addr.arpa
6.76.125.in-addr.arpa
7.76.125.in-addr.arpa
8.76.125.in-addr.arpa
9.76.125.in-addr.arpa
10.76.125.in-addr.arpa
11.76.125.in-addr.arpa
12.76.125.in-addr.arpa
13.76.125.in-addr.arpa
14.76.125.in-addr.arpa
15.76.125.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
Address01111101.01001100.00000000.00000000125.76.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01111101.01001100.00000000.00000000125.76.0.0
Broadcast01111101.01001100.01111111.11111111125.76.127.255
Split into smaller subnets/27
/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)

125.76.0.0/17 makes 1,024 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1125.76.0.0/27125.76.0.1 to 125.76.0.30125.76.0.3130
2125.76.0.32/27125.76.0.33 to 125.76.0.62125.76.0.6330
3125.76.0.64/27125.76.0.65 to 125.76.0.94125.76.0.9530
4125.76.0.96/27125.76.0.97 to 125.76.0.126125.76.0.12730
5125.76.0.128/27125.76.0.129 to 125.76.0.158125.76.0.15930
6125.76.0.160/27125.76.0.161 to 125.76.0.190125.76.0.19130
7125.76.0.192/27125.76.0.193 to 125.76.0.222125.76.0.22330
8125.76.0.224/27125.76.0.225 to 125.76.0.254125.76.0.25530
9125.76.1.0/27125.76.1.1 to 125.76.1.30125.76.1.3130
10125.76.1.32/27125.76.1.33 to 125.76.1.62125.76.1.6330
11125.76.1.64/27125.76.1.65 to 125.76.1.94125.76.1.9530
12125.76.1.96/27125.76.1.97 to 125.76.1.126125.76.1.12730
13125.76.1.128/27125.76.1.129 to 125.76.1.158125.76.1.15930
14125.76.1.160/27125.76.1.161 to 125.76.1.190125.76.1.19130
15125.76.1.192/27125.76.1.193 to 125.76.1.222125.76.1.22330
16125.76.1.224/27125.76.1.225 to 125.76.1.254125.76.1.25530
17125.76.2.0/27125.76.2.1 to 125.76.2.30125.76.2.3130
18125.76.2.32/27125.76.2.33 to 125.76.2.62125.76.2.6330
19125.76.2.64/27125.76.2.65 to 125.76.2.94125.76.2.9530
20125.76.2.96/27125.76.2.97 to 125.76.2.126125.76.2.12730
21125.76.2.128/27125.76.2.129 to 125.76.2.158125.76.2.15930
22125.76.2.160/27125.76.2.161 to 125.76.2.190125.76.2.19130
23125.76.2.192/27125.76.2.193 to 125.76.2.222125.76.2.22330
24125.76.2.224/27125.76.2.225 to 125.76.2.254125.76.2.25530
25125.76.3.0/27125.76.3.1 to 125.76.3.30125.76.3.3130
26125.76.3.32/27125.76.3.33 to 125.76.3.62125.76.3.6330
27125.76.3.64/27125.76.3.65 to 125.76.3.94125.76.3.9530
28125.76.3.96/27125.76.3.97 to 125.76.3.126125.76.3.12730
29125.76.3.128/27125.76.3.129 to 125.76.3.158125.76.3.15930
30125.76.3.160/27125.76.3.161 to 125.76.3.190125.76.3.19130
31125.76.3.192/27125.76.3.193 to 125.76.3.222125.76.3.22330
32125.76.3.224/27125.76.3.225 to 125.76.3.254125.76.3.25530
33125.76.4.0/27125.76.4.1 to 125.76.4.30125.76.4.3130
34125.76.4.32/27125.76.4.33 to 125.76.4.62125.76.4.6330
35125.76.4.64/27125.76.4.65 to 125.76.4.94125.76.4.9530
36125.76.4.96/27125.76.4.97 to 125.76.4.126125.76.4.12730
37125.76.4.128/27125.76.4.129 to 125.76.4.158125.76.4.15930
38125.76.4.160/27125.76.4.161 to 125.76.4.190125.76.4.19130
39125.76.4.192/27125.76.4.193 to 125.76.4.222125.76.4.22330
40125.76.4.224/27125.76.4.225 to 125.76.4.254125.76.4.25530
41125.76.5.0/27125.76.5.1 to 125.76.5.30125.76.5.3130
42125.76.5.32/27125.76.5.33 to 125.76.5.62125.76.5.6330
43125.76.5.64/27125.76.5.65 to 125.76.5.94125.76.5.9530
44125.76.5.96/27125.76.5.97 to 125.76.5.126125.76.5.12730
45125.76.5.128/27125.76.5.129 to 125.76.5.158125.76.5.15930
46125.76.5.160/27125.76.5.161 to 125.76.5.190125.76.5.19130
47125.76.5.192/27125.76.5.193 to 125.76.5.222125.76.5.22330
48125.76.5.224/27125.76.5.225 to 125.76.5.254125.76.5.25530
49125.76.6.0/27125.76.6.1 to 125.76.6.30125.76.6.3130
50125.76.6.32/27125.76.6.33 to 125.76.6.62125.76.6.6330
51125.76.6.64/27125.76.6.65 to 125.76.6.94125.76.6.9530
52125.76.6.96/27125.76.6.97 to 125.76.6.126125.76.6.12730
53125.76.6.128/27125.76.6.129 to 125.76.6.158125.76.6.15930
54125.76.6.160/27125.76.6.161 to 125.76.6.190125.76.6.19130
55125.76.6.192/27125.76.6.193 to 125.76.6.222125.76.6.22330
56125.76.6.224/27125.76.6.225 to 125.76.6.254125.76.6.25530
57125.76.7.0/27125.76.7.1 to 125.76.7.30125.76.7.3130
58125.76.7.32/27125.76.7.33 to 125.76.7.62125.76.7.6330
59125.76.7.64/27125.76.7.65 to 125.76.7.94125.76.7.9530
60125.76.7.96/27125.76.7.97 to 125.76.7.126125.76.7.12730
61125.76.7.128/27125.76.7.129 to 125.76.7.158125.76.7.15930
62125.76.7.160/27125.76.7.161 to 125.76.7.190125.76.7.19130
63125.76.7.192/27125.76.7.193 to 125.76.7.222125.76.7.22330
64125.76.7.224/27125.76.7.225 to 125.76.7.254125.76.7.25530
65125.76.8.0/27125.76.8.1 to 125.76.8.30125.76.8.3130
66125.76.8.32/27125.76.8.33 to 125.76.8.62125.76.8.6330
67125.76.8.64/27125.76.8.65 to 125.76.8.94125.76.8.9530
68125.76.8.96/27125.76.8.97 to 125.76.8.126125.76.8.12730
69125.76.8.128/27125.76.8.129 to 125.76.8.158125.76.8.15930
70125.76.8.160/27125.76.8.161 to 125.76.8.190125.76.8.19130
71125.76.8.192/27125.76.8.193 to 125.76.8.222125.76.8.22330
72125.76.8.224/27125.76.8.225 to 125.76.8.254125.76.8.25530
73125.76.9.0/27125.76.9.1 to 125.76.9.30125.76.9.3130
74125.76.9.32/27125.76.9.33 to 125.76.9.62125.76.9.6330
75125.76.9.64/27125.76.9.65 to 125.76.9.94125.76.9.9530
76125.76.9.96/27125.76.9.97 to 125.76.9.126125.76.9.12730
77125.76.9.128/27125.76.9.129 to 125.76.9.158125.76.9.15930
78125.76.9.160/27125.76.9.161 to 125.76.9.190125.76.9.19130
79125.76.9.192/27125.76.9.193 to 125.76.9.222125.76.9.22330
80125.76.9.224/27125.76.9.225 to 125.76.9.254125.76.9.25530
81125.76.10.0/27125.76.10.1 to 125.76.10.30125.76.10.3130
82125.76.10.32/27125.76.10.33 to 125.76.10.62125.76.10.6330
83125.76.10.64/27125.76.10.65 to 125.76.10.94125.76.10.9530
84125.76.10.96/27125.76.10.97 to 125.76.10.126125.76.10.12730
85125.76.10.128/27125.76.10.129 to 125.76.10.158125.76.10.15930
86125.76.10.160/27125.76.10.161 to 125.76.10.190125.76.10.19130
87125.76.10.192/27125.76.10.193 to 125.76.10.222125.76.10.22330
88125.76.10.224/27125.76.10.225 to 125.76.10.254125.76.10.25530
89125.76.11.0/27125.76.11.1 to 125.76.11.30125.76.11.3130
90125.76.11.32/27125.76.11.33 to 125.76.11.62125.76.11.6330
91125.76.11.64/27125.76.11.65 to 125.76.11.94125.76.11.9530
92125.76.11.96/27125.76.11.97 to 125.76.11.126125.76.11.12730
93125.76.11.128/27125.76.11.129 to 125.76.11.158125.76.11.15930
94125.76.11.160/27125.76.11.161 to 125.76.11.190125.76.11.19130
95125.76.11.192/27125.76.11.193 to 125.76.11.222125.76.11.22330
96125.76.11.224/27125.76.11.225 to 125.76.11.254125.76.11.25530
97125.76.12.0/27125.76.12.1 to 125.76.12.30125.76.12.3130
98125.76.12.32/27125.76.12.33 to 125.76.12.62125.76.12.6330
99125.76.12.64/27125.76.12.65 to 125.76.12.94125.76.12.9530
100125.76.12.96/27125.76.12.97 to 125.76.12.126125.76.12.12730
101125.76.12.128/27125.76.12.129 to 125.76.12.158125.76.12.15930
102125.76.12.160/27125.76.12.161 to 125.76.12.190125.76.12.19130
103125.76.12.192/27125.76.12.193 to 125.76.12.222125.76.12.22330
104125.76.12.224/27125.76.12.225 to 125.76.12.254125.76.12.25530
105125.76.13.0/27125.76.13.1 to 125.76.13.30125.76.13.3130
106125.76.13.32/27125.76.13.33 to 125.76.13.62125.76.13.6330
107125.76.13.64/27125.76.13.65 to 125.76.13.94125.76.13.9530
108125.76.13.96/27125.76.13.97 to 125.76.13.126125.76.13.12730
109125.76.13.128/27125.76.13.129 to 125.76.13.158125.76.13.15930
110125.76.13.160/27125.76.13.161 to 125.76.13.190125.76.13.19130
111125.76.13.192/27125.76.13.193 to 125.76.13.222125.76.13.22330
112125.76.13.224/27125.76.13.225 to 125.76.13.254125.76.13.25530
113125.76.14.0/27125.76.14.1 to 125.76.14.30125.76.14.3130
114125.76.14.32/27125.76.14.33 to 125.76.14.62125.76.14.6330
115125.76.14.64/27125.76.14.65 to 125.76.14.94125.76.14.9530
116125.76.14.96/27125.76.14.97 to 125.76.14.126125.76.14.12730
117125.76.14.128/27125.76.14.129 to 125.76.14.158125.76.14.15930
118125.76.14.160/27125.76.14.161 to 125.76.14.190125.76.14.19130
119125.76.14.192/27125.76.14.193 to 125.76.14.222125.76.14.22330
120125.76.14.224/27125.76.14.225 to 125.76.14.254125.76.14.25530
121125.76.15.0/27125.76.15.1 to 125.76.15.30125.76.15.3130
122125.76.15.32/27125.76.15.33 to 125.76.15.62125.76.15.6330
123125.76.15.64/27125.76.15.65 to 125.76.15.94125.76.15.9530
124125.76.15.96/27125.76.15.97 to 125.76.15.126125.76.15.12730
125125.76.15.128/27125.76.15.129 to 125.76.15.158125.76.15.15930
126125.76.15.160/27125.76.15.161 to 125.76.15.190125.76.15.19130
127125.76.15.192/27125.76.15.193 to 125.76.15.222125.76.15.22330
128125.76.15.224/27125.76.15.225 to 125.76.15.254125.76.15.25530
129125.76.16.0/27125.76.16.1 to 125.76.16.30125.76.16.3130
130125.76.16.32/27125.76.16.33 to 125.76.16.62125.76.16.6330
131125.76.16.64/27125.76.16.65 to 125.76.16.94125.76.16.9530
132125.76.16.96/27125.76.16.97 to 125.76.16.126125.76.16.12730
133125.76.16.128/27125.76.16.129 to 125.76.16.158125.76.16.15930
134125.76.16.160/27125.76.16.161 to 125.76.16.190125.76.16.19130
135125.76.16.192/27125.76.16.193 to 125.76.16.222125.76.16.22330
136125.76.16.224/27125.76.16.225 to 125.76.16.254125.76.16.25530
137125.76.17.0/27125.76.17.1 to 125.76.17.30125.76.17.3130
138125.76.17.32/27125.76.17.33 to 125.76.17.62125.76.17.6330
139125.76.17.64/27125.76.17.65 to 125.76.17.94125.76.17.9530
140125.76.17.96/27125.76.17.97 to 125.76.17.126125.76.17.12730
141125.76.17.128/27125.76.17.129 to 125.76.17.158125.76.17.15930
142125.76.17.160/27125.76.17.161 to 125.76.17.190125.76.17.19130
143125.76.17.192/27125.76.17.193 to 125.76.17.222125.76.17.22330
144125.76.17.224/27125.76.17.225 to 125.76.17.254125.76.17.25530
145125.76.18.0/27125.76.18.1 to 125.76.18.30125.76.18.3130
146125.76.18.32/27125.76.18.33 to 125.76.18.62125.76.18.6330
147125.76.18.64/27125.76.18.65 to 125.76.18.94125.76.18.9530
148125.76.18.96/27125.76.18.97 to 125.76.18.126125.76.18.12730
149125.76.18.128/27125.76.18.129 to 125.76.18.158125.76.18.15930
150125.76.18.160/27125.76.18.161 to 125.76.18.190125.76.18.19130
151125.76.18.192/27125.76.18.193 to 125.76.18.222125.76.18.22330
152125.76.18.224/27125.76.18.225 to 125.76.18.254125.76.18.25530
153125.76.19.0/27125.76.19.1 to 125.76.19.30125.76.19.3130
154125.76.19.32/27125.76.19.33 to 125.76.19.62125.76.19.6330
155125.76.19.64/27125.76.19.65 to 125.76.19.94125.76.19.9530
156125.76.19.96/27125.76.19.97 to 125.76.19.126125.76.19.12730
157125.76.19.128/27125.76.19.129 to 125.76.19.158125.76.19.15930
158125.76.19.160/27125.76.19.161 to 125.76.19.190125.76.19.19130
159125.76.19.192/27125.76.19.193 to 125.76.19.222125.76.19.22330
160125.76.19.224/27125.76.19.225 to 125.76.19.254125.76.19.25530
161125.76.20.0/27125.76.20.1 to 125.76.20.30125.76.20.3130
162125.76.20.32/27125.76.20.33 to 125.76.20.62125.76.20.6330
163125.76.20.64/27125.76.20.65 to 125.76.20.94125.76.20.9530
164125.76.20.96/27125.76.20.97 to 125.76.20.126125.76.20.12730
165125.76.20.128/27125.76.20.129 to 125.76.20.158125.76.20.15930
166125.76.20.160/27125.76.20.161 to 125.76.20.190125.76.20.19130
167125.76.20.192/27125.76.20.193 to 125.76.20.222125.76.20.22330
168125.76.20.224/27125.76.20.225 to 125.76.20.254125.76.20.25530
169125.76.21.0/27125.76.21.1 to 125.76.21.30125.76.21.3130
170125.76.21.32/27125.76.21.33 to 125.76.21.62125.76.21.6330
171125.76.21.64/27125.76.21.65 to 125.76.21.94125.76.21.9530
172125.76.21.96/27125.76.21.97 to 125.76.21.126125.76.21.12730
173125.76.21.128/27125.76.21.129 to 125.76.21.158125.76.21.15930
174125.76.21.160/27125.76.21.161 to 125.76.21.190125.76.21.19130
175125.76.21.192/27125.76.21.193 to 125.76.21.222125.76.21.22330
176125.76.21.224/27125.76.21.225 to 125.76.21.254125.76.21.25530
177125.76.22.0/27125.76.22.1 to 125.76.22.30125.76.22.3130
178125.76.22.32/27125.76.22.33 to 125.76.22.62125.76.22.6330
179125.76.22.64/27125.76.22.65 to 125.76.22.94125.76.22.9530
180125.76.22.96/27125.76.22.97 to 125.76.22.126125.76.22.12730
181125.76.22.128/27125.76.22.129 to 125.76.22.158125.76.22.15930
182125.76.22.160/27125.76.22.161 to 125.76.22.190125.76.22.19130
183125.76.22.192/27125.76.22.193 to 125.76.22.222125.76.22.22330
184125.76.22.224/27125.76.22.225 to 125.76.22.254125.76.22.25530
185125.76.23.0/27125.76.23.1 to 125.76.23.30125.76.23.3130
186125.76.23.32/27125.76.23.33 to 125.76.23.62125.76.23.6330
187125.76.23.64/27125.76.23.65 to 125.76.23.94125.76.23.9530
188125.76.23.96/27125.76.23.97 to 125.76.23.126125.76.23.12730
189125.76.23.128/27125.76.23.129 to 125.76.23.158125.76.23.15930
190125.76.23.160/27125.76.23.161 to 125.76.23.190125.76.23.19130
191125.76.23.192/27125.76.23.193 to 125.76.23.222125.76.23.22330
192125.76.23.224/27125.76.23.225 to 125.76.23.254125.76.23.25530
193125.76.24.0/27125.76.24.1 to 125.76.24.30125.76.24.3130
194125.76.24.32/27125.76.24.33 to 125.76.24.62125.76.24.6330
195125.76.24.64/27125.76.24.65 to 125.76.24.94125.76.24.9530
196125.76.24.96/27125.76.24.97 to 125.76.24.126125.76.24.12730
197125.76.24.128/27125.76.24.129 to 125.76.24.158125.76.24.15930
198125.76.24.160/27125.76.24.161 to 125.76.24.190125.76.24.19130
199125.76.24.192/27125.76.24.193 to 125.76.24.222125.76.24.22330
200125.76.24.224/27125.76.24.225 to 125.76.24.254125.76.24.25530
201125.76.25.0/27125.76.25.1 to 125.76.25.30125.76.25.3130
202125.76.25.32/27125.76.25.33 to 125.76.25.62125.76.25.6330
203125.76.25.64/27125.76.25.65 to 125.76.25.94125.76.25.9530
204125.76.25.96/27125.76.25.97 to 125.76.25.126125.76.25.12730
205125.76.25.128/27125.76.25.129 to 125.76.25.158125.76.25.15930
206125.76.25.160/27125.76.25.161 to 125.76.25.190125.76.25.19130
207125.76.25.192/27125.76.25.193 to 125.76.25.222125.76.25.22330
208125.76.25.224/27125.76.25.225 to 125.76.25.254125.76.25.25530
209125.76.26.0/27125.76.26.1 to 125.76.26.30125.76.26.3130
210125.76.26.32/27125.76.26.33 to 125.76.26.62125.76.26.6330
211125.76.26.64/27125.76.26.65 to 125.76.26.94125.76.26.9530
212125.76.26.96/27125.76.26.97 to 125.76.26.126125.76.26.12730
213125.76.26.128/27125.76.26.129 to 125.76.26.158125.76.26.15930
214125.76.26.160/27125.76.26.161 to 125.76.26.190125.76.26.19130
215125.76.26.192/27125.76.26.193 to 125.76.26.222125.76.26.22330
216125.76.26.224/27125.76.26.225 to 125.76.26.254125.76.26.25530
217125.76.27.0/27125.76.27.1 to 125.76.27.30125.76.27.3130
218125.76.27.32/27125.76.27.33 to 125.76.27.62125.76.27.6330
219125.76.27.64/27125.76.27.65 to 125.76.27.94125.76.27.9530
220125.76.27.96/27125.76.27.97 to 125.76.27.126125.76.27.12730
221125.76.27.128/27125.76.27.129 to 125.76.27.158125.76.27.15930
222125.76.27.160/27125.76.27.161 to 125.76.27.190125.76.27.19130
223125.76.27.192/27125.76.27.193 to 125.76.27.222125.76.27.22330
224125.76.27.224/27125.76.27.225 to 125.76.27.254125.76.27.25530
225125.76.28.0/27125.76.28.1 to 125.76.28.30125.76.28.3130
226125.76.28.32/27125.76.28.33 to 125.76.28.62125.76.28.6330
227125.76.28.64/27125.76.28.65 to 125.76.28.94125.76.28.9530
228125.76.28.96/27125.76.28.97 to 125.76.28.126125.76.28.12730
229125.76.28.128/27125.76.28.129 to 125.76.28.158125.76.28.15930
230125.76.28.160/27125.76.28.161 to 125.76.28.190125.76.28.19130
231125.76.28.192/27125.76.28.193 to 125.76.28.222125.76.28.22330
232125.76.28.224/27125.76.28.225 to 125.76.28.254125.76.28.25530
233125.76.29.0/27125.76.29.1 to 125.76.29.30125.76.29.3130
234125.76.29.32/27125.76.29.33 to 125.76.29.62125.76.29.6330
235125.76.29.64/27125.76.29.65 to 125.76.29.94125.76.29.9530
236125.76.29.96/27125.76.29.97 to 125.76.29.126125.76.29.12730
237125.76.29.128/27125.76.29.129 to 125.76.29.158125.76.29.15930
238125.76.29.160/27125.76.29.161 to 125.76.29.190125.76.29.19130
239125.76.29.192/27125.76.29.193 to 125.76.29.222125.76.29.22330
240125.76.29.224/27125.76.29.225 to 125.76.29.254125.76.29.25530
241125.76.30.0/27125.76.30.1 to 125.76.30.30125.76.30.3130
242125.76.30.32/27125.76.30.33 to 125.76.30.62125.76.30.6330
243125.76.30.64/27125.76.30.65 to 125.76.30.94125.76.30.9530
244125.76.30.96/27125.76.30.97 to 125.76.30.126125.76.30.12730
245125.76.30.128/27125.76.30.129 to 125.76.30.158125.76.30.15930
246125.76.30.160/27125.76.30.161 to 125.76.30.190125.76.30.19130
247125.76.30.192/27125.76.30.193 to 125.76.30.222125.76.30.22330
248125.76.30.224/27125.76.30.225 to 125.76.30.254125.76.30.25530
249125.76.31.0/27125.76.31.1 to 125.76.31.30125.76.31.3130
250125.76.31.32/27125.76.31.33 to 125.76.31.62125.76.31.6330
251125.76.31.64/27125.76.31.65 to 125.76.31.94125.76.31.9530
252125.76.31.96/27125.76.31.97 to 125.76.31.126125.76.31.12730
253125.76.31.128/27125.76.31.129 to 125.76.31.158125.76.31.15930
254125.76.31.160/27125.76.31.161 to 125.76.31.190125.76.31.19130
255125.76.31.192/27125.76.31.193 to 125.76.31.222125.76.31.22330
256125.76.31.224/27125.76.31.225 to 125.76.31.254125.76.31.25530

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.