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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.

Network241.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
241.0.0.0
Broadcast address
241.255.255.255
First usable
241.0.0.1
Last usable
241.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F1000000 · Integer 4043309056 to 4060086271
Reverse DNS zone
241.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110001..00000000.00000000.00000000241.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11110001..00000000.00000000.00000000241.0.0.0
Broadcast11110001..11111111.11111111.11111111241.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

241.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1241.0.0.0/18241.0.0.1 to 241.0.63.254241.0.63.25516,382
2241.0.64.0/18241.0.64.1 to 241.0.127.254241.0.127.25516,382
3241.0.128.0/18241.0.128.1 to 241.0.191.254241.0.191.25516,382
4241.0.192.0/18241.0.192.1 to 241.0.255.254241.0.255.25516,382
5241.1.0.0/18241.1.0.1 to 241.1.63.254241.1.63.25516,382
6241.1.64.0/18241.1.64.1 to 241.1.127.254241.1.127.25516,382
7241.1.128.0/18241.1.128.1 to 241.1.191.254241.1.191.25516,382
8241.1.192.0/18241.1.192.1 to 241.1.255.254241.1.255.25516,382
9241.2.0.0/18241.2.0.1 to 241.2.63.254241.2.63.25516,382
10241.2.64.0/18241.2.64.1 to 241.2.127.254241.2.127.25516,382
11241.2.128.0/18241.2.128.1 to 241.2.191.254241.2.191.25516,382
12241.2.192.0/18241.2.192.1 to 241.2.255.254241.2.255.25516,382
13241.3.0.0/18241.3.0.1 to 241.3.63.254241.3.63.25516,382
14241.3.64.0/18241.3.64.1 to 241.3.127.254241.3.127.25516,382
15241.3.128.0/18241.3.128.1 to 241.3.191.254241.3.191.25516,382
16241.3.192.0/18241.3.192.1 to 241.3.255.254241.3.255.25516,382
17241.4.0.0/18241.4.0.1 to 241.4.63.254241.4.63.25516,382
18241.4.64.0/18241.4.64.1 to 241.4.127.254241.4.127.25516,382
19241.4.128.0/18241.4.128.1 to 241.4.191.254241.4.191.25516,382
20241.4.192.0/18241.4.192.1 to 241.4.255.254241.4.255.25516,382
21241.5.0.0/18241.5.0.1 to 241.5.63.254241.5.63.25516,382
22241.5.64.0/18241.5.64.1 to 241.5.127.254241.5.127.25516,382
23241.5.128.0/18241.5.128.1 to 241.5.191.254241.5.191.25516,382
24241.5.192.0/18241.5.192.1 to 241.5.255.254241.5.255.25516,382
25241.6.0.0/18241.6.0.1 to 241.6.63.254241.6.63.25516,382
26241.6.64.0/18241.6.64.1 to 241.6.127.254241.6.127.25516,382
27241.6.128.0/18241.6.128.1 to 241.6.191.254241.6.191.25516,382
28241.6.192.0/18241.6.192.1 to 241.6.255.254241.6.255.25516,382
29241.7.0.0/18241.7.0.1 to 241.7.63.254241.7.63.25516,382
30241.7.64.0/18241.7.64.1 to 241.7.127.254241.7.127.25516,382
31241.7.128.0/18241.7.128.1 to 241.7.191.254241.7.191.25516,382
32241.7.192.0/18241.7.192.1 to 241.7.255.254241.7.255.25516,382
33241.8.0.0/18241.8.0.1 to 241.8.63.254241.8.63.25516,382
34241.8.64.0/18241.8.64.1 to 241.8.127.254241.8.127.25516,382
35241.8.128.0/18241.8.128.1 to 241.8.191.254241.8.191.25516,382
36241.8.192.0/18241.8.192.1 to 241.8.255.254241.8.255.25516,382
37241.9.0.0/18241.9.0.1 to 241.9.63.254241.9.63.25516,382
38241.9.64.0/18241.9.64.1 to 241.9.127.254241.9.127.25516,382
39241.9.128.0/18241.9.128.1 to 241.9.191.254241.9.191.25516,382
40241.9.192.0/18241.9.192.1 to 241.9.255.254241.9.255.25516,382
41241.10.0.0/18241.10.0.1 to 241.10.63.254241.10.63.25516,382
42241.10.64.0/18241.10.64.1 to 241.10.127.254241.10.127.25516,382
43241.10.128.0/18241.10.128.1 to 241.10.191.254241.10.191.25516,382
44241.10.192.0/18241.10.192.1 to 241.10.255.254241.10.255.25516,382
45241.11.0.0/18241.11.0.1 to 241.11.63.254241.11.63.25516,382
46241.11.64.0/18241.11.64.1 to 241.11.127.254241.11.127.25516,382
47241.11.128.0/18241.11.128.1 to 241.11.191.254241.11.191.25516,382
48241.11.192.0/18241.11.192.1 to 241.11.255.254241.11.255.25516,382
49241.12.0.0/18241.12.0.1 to 241.12.63.254241.12.63.25516,382
50241.12.64.0/18241.12.64.1 to 241.12.127.254241.12.127.25516,382
51241.12.128.0/18241.12.128.1 to 241.12.191.254241.12.191.25516,382
52241.12.192.0/18241.12.192.1 to 241.12.255.254241.12.255.25516,382
53241.13.0.0/18241.13.0.1 to 241.13.63.254241.13.63.25516,382
54241.13.64.0/18241.13.64.1 to 241.13.127.254241.13.127.25516,382
55241.13.128.0/18241.13.128.1 to 241.13.191.254241.13.191.25516,382
56241.13.192.0/18241.13.192.1 to 241.13.255.254241.13.255.25516,382
57241.14.0.0/18241.14.0.1 to 241.14.63.254241.14.63.25516,382
58241.14.64.0/18241.14.64.1 to 241.14.127.254241.14.127.25516,382
59241.14.128.0/18241.14.128.1 to 241.14.191.254241.14.191.25516,382
60241.14.192.0/18241.14.192.1 to 241.14.255.254241.14.255.25516,382
61241.15.0.0/18241.15.0.1 to 241.15.63.254241.15.63.25516,382
62241.15.64.0/18241.15.64.1 to 241.15.127.254241.15.127.25516,382
63241.15.128.0/18241.15.128.1 to 241.15.191.254241.15.191.25516,382
64241.15.192.0/18241.15.192.1 to 241.15.255.254241.15.255.25516,382
65241.16.0.0/18241.16.0.1 to 241.16.63.254241.16.63.25516,382
66241.16.64.0/18241.16.64.1 to 241.16.127.254241.16.127.25516,382
67241.16.128.0/18241.16.128.1 to 241.16.191.254241.16.191.25516,382
68241.16.192.0/18241.16.192.1 to 241.16.255.254241.16.255.25516,382
69241.17.0.0/18241.17.0.1 to 241.17.63.254241.17.63.25516,382
70241.17.64.0/18241.17.64.1 to 241.17.127.254241.17.127.25516,382
71241.17.128.0/18241.17.128.1 to 241.17.191.254241.17.191.25516,382
72241.17.192.0/18241.17.192.1 to 241.17.255.254241.17.255.25516,382
73241.18.0.0/18241.18.0.1 to 241.18.63.254241.18.63.25516,382
74241.18.64.0/18241.18.64.1 to 241.18.127.254241.18.127.25516,382
75241.18.128.0/18241.18.128.1 to 241.18.191.254241.18.191.25516,382
76241.18.192.0/18241.18.192.1 to 241.18.255.254241.18.255.25516,382
77241.19.0.0/18241.19.0.1 to 241.19.63.254241.19.63.25516,382
78241.19.64.0/18241.19.64.1 to 241.19.127.254241.19.127.25516,382
79241.19.128.0/18241.19.128.1 to 241.19.191.254241.19.191.25516,382
80241.19.192.0/18241.19.192.1 to 241.19.255.254241.19.255.25516,382
81241.20.0.0/18241.20.0.1 to 241.20.63.254241.20.63.25516,382
82241.20.64.0/18241.20.64.1 to 241.20.127.254241.20.127.25516,382
83241.20.128.0/18241.20.128.1 to 241.20.191.254241.20.191.25516,382
84241.20.192.0/18241.20.192.1 to 241.20.255.254241.20.255.25516,382
85241.21.0.0/18241.21.0.1 to 241.21.63.254241.21.63.25516,382
86241.21.64.0/18241.21.64.1 to 241.21.127.254241.21.127.25516,382
87241.21.128.0/18241.21.128.1 to 241.21.191.254241.21.191.25516,382
88241.21.192.0/18241.21.192.1 to 241.21.255.254241.21.255.25516,382
89241.22.0.0/18241.22.0.1 to 241.22.63.254241.22.63.25516,382
90241.22.64.0/18241.22.64.1 to 241.22.127.254241.22.127.25516,382
91241.22.128.0/18241.22.128.1 to 241.22.191.254241.22.191.25516,382
92241.22.192.0/18241.22.192.1 to 241.22.255.254241.22.255.25516,382
93241.23.0.0/18241.23.0.1 to 241.23.63.254241.23.63.25516,382
94241.23.64.0/18241.23.64.1 to 241.23.127.254241.23.127.25516,382
95241.23.128.0/18241.23.128.1 to 241.23.191.254241.23.191.25516,382
96241.23.192.0/18241.23.192.1 to 241.23.255.254241.23.255.25516,382
97241.24.0.0/18241.24.0.1 to 241.24.63.254241.24.63.25516,382
98241.24.64.0/18241.24.64.1 to 241.24.127.254241.24.127.25516,382
99241.24.128.0/18241.24.128.1 to 241.24.191.254241.24.191.25516,382
100241.24.192.0/18241.24.192.1 to 241.24.255.254241.24.255.25516,382
101241.25.0.0/18241.25.0.1 to 241.25.63.254241.25.63.25516,382
102241.25.64.0/18241.25.64.1 to 241.25.127.254241.25.127.25516,382
103241.25.128.0/18241.25.128.1 to 241.25.191.254241.25.191.25516,382
104241.25.192.0/18241.25.192.1 to 241.25.255.254241.25.255.25516,382
105241.26.0.0/18241.26.0.1 to 241.26.63.254241.26.63.25516,382
106241.26.64.0/18241.26.64.1 to 241.26.127.254241.26.127.25516,382
107241.26.128.0/18241.26.128.1 to 241.26.191.254241.26.191.25516,382
108241.26.192.0/18241.26.192.1 to 241.26.255.254241.26.255.25516,382
109241.27.0.0/18241.27.0.1 to 241.27.63.254241.27.63.25516,382
110241.27.64.0/18241.27.64.1 to 241.27.127.254241.27.127.25516,382
111241.27.128.0/18241.27.128.1 to 241.27.191.254241.27.191.25516,382
112241.27.192.0/18241.27.192.1 to 241.27.255.254241.27.255.25516,382
113241.28.0.0/18241.28.0.1 to 241.28.63.254241.28.63.25516,382
114241.28.64.0/18241.28.64.1 to 241.28.127.254241.28.127.25516,382
115241.28.128.0/18241.28.128.1 to 241.28.191.254241.28.191.25516,382
116241.28.192.0/18241.28.192.1 to 241.28.255.254241.28.255.25516,382
117241.29.0.0/18241.29.0.1 to 241.29.63.254241.29.63.25516,382
118241.29.64.0/18241.29.64.1 to 241.29.127.254241.29.127.25516,382
119241.29.128.0/18241.29.128.1 to 241.29.191.254241.29.191.25516,382
120241.29.192.0/18241.29.192.1 to 241.29.255.254241.29.255.25516,382
121241.30.0.0/18241.30.0.1 to 241.30.63.254241.30.63.25516,382
122241.30.64.0/18241.30.64.1 to 241.30.127.254241.30.127.25516,382
123241.30.128.0/18241.30.128.1 to 241.30.191.254241.30.191.25516,382
124241.30.192.0/18241.30.192.1 to 241.30.255.254241.30.255.25516,382
125241.31.0.0/18241.31.0.1 to 241.31.63.254241.31.63.25516,382
126241.31.64.0/18241.31.64.1 to 241.31.127.254241.31.127.25516,382
127241.31.128.0/18241.31.128.1 to 241.31.191.254241.31.191.25516,382
128241.31.192.0/18241.31.192.1 to 241.31.255.254241.31.255.25516,382
129241.32.0.0/18241.32.0.1 to 241.32.63.254241.32.63.25516,382
130241.32.64.0/18241.32.64.1 to 241.32.127.254241.32.127.25516,382
131241.32.128.0/18241.32.128.1 to 241.32.191.254241.32.191.25516,382
132241.32.192.0/18241.32.192.1 to 241.32.255.254241.32.255.25516,382
133241.33.0.0/18241.33.0.1 to 241.33.63.254241.33.63.25516,382
134241.33.64.0/18241.33.64.1 to 241.33.127.254241.33.127.25516,382
135241.33.128.0/18241.33.128.1 to 241.33.191.254241.33.191.25516,382
136241.33.192.0/18241.33.192.1 to 241.33.255.254241.33.255.25516,382
137241.34.0.0/18241.34.0.1 to 241.34.63.254241.34.63.25516,382
138241.34.64.0/18241.34.64.1 to 241.34.127.254241.34.127.25516,382
139241.34.128.0/18241.34.128.1 to 241.34.191.254241.34.191.25516,382
140241.34.192.0/18241.34.192.1 to 241.34.255.254241.34.255.25516,382
141241.35.0.0/18241.35.0.1 to 241.35.63.254241.35.63.25516,382
142241.35.64.0/18241.35.64.1 to 241.35.127.254241.35.127.25516,382
143241.35.128.0/18241.35.128.1 to 241.35.191.254241.35.191.25516,382
144241.35.192.0/18241.35.192.1 to 241.35.255.254241.35.255.25516,382
145241.36.0.0/18241.36.0.1 to 241.36.63.254241.36.63.25516,382
146241.36.64.0/18241.36.64.1 to 241.36.127.254241.36.127.25516,382
147241.36.128.0/18241.36.128.1 to 241.36.191.254241.36.191.25516,382
148241.36.192.0/18241.36.192.1 to 241.36.255.254241.36.255.25516,382
149241.37.0.0/18241.37.0.1 to 241.37.63.254241.37.63.25516,382
150241.37.64.0/18241.37.64.1 to 241.37.127.254241.37.127.25516,382
151241.37.128.0/18241.37.128.1 to 241.37.191.254241.37.191.25516,382
152241.37.192.0/18241.37.192.1 to 241.37.255.254241.37.255.25516,382
153241.38.0.0/18241.38.0.1 to 241.38.63.254241.38.63.25516,382
154241.38.64.0/18241.38.64.1 to 241.38.127.254241.38.127.25516,382
155241.38.128.0/18241.38.128.1 to 241.38.191.254241.38.191.25516,382
156241.38.192.0/18241.38.192.1 to 241.38.255.254241.38.255.25516,382
157241.39.0.0/18241.39.0.1 to 241.39.63.254241.39.63.25516,382
158241.39.64.0/18241.39.64.1 to 241.39.127.254241.39.127.25516,382
159241.39.128.0/18241.39.128.1 to 241.39.191.254241.39.191.25516,382
160241.39.192.0/18241.39.192.1 to 241.39.255.254241.39.255.25516,382
161241.40.0.0/18241.40.0.1 to 241.40.63.254241.40.63.25516,382
162241.40.64.0/18241.40.64.1 to 241.40.127.254241.40.127.25516,382
163241.40.128.0/18241.40.128.1 to 241.40.191.254241.40.191.25516,382
164241.40.192.0/18241.40.192.1 to 241.40.255.254241.40.255.25516,382
165241.41.0.0/18241.41.0.1 to 241.41.63.254241.41.63.25516,382
166241.41.64.0/18241.41.64.1 to 241.41.127.254241.41.127.25516,382
167241.41.128.0/18241.41.128.1 to 241.41.191.254241.41.191.25516,382
168241.41.192.0/18241.41.192.1 to 241.41.255.254241.41.255.25516,382
169241.42.0.0/18241.42.0.1 to 241.42.63.254241.42.63.25516,382
170241.42.64.0/18241.42.64.1 to 241.42.127.254241.42.127.25516,382
171241.42.128.0/18241.42.128.1 to 241.42.191.254241.42.191.25516,382
172241.42.192.0/18241.42.192.1 to 241.42.255.254241.42.255.25516,382
173241.43.0.0/18241.43.0.1 to 241.43.63.254241.43.63.25516,382
174241.43.64.0/18241.43.64.1 to 241.43.127.254241.43.127.25516,382
175241.43.128.0/18241.43.128.1 to 241.43.191.254241.43.191.25516,382
176241.43.192.0/18241.43.192.1 to 241.43.255.254241.43.255.25516,382
177241.44.0.0/18241.44.0.1 to 241.44.63.254241.44.63.25516,382
178241.44.64.0/18241.44.64.1 to 241.44.127.254241.44.127.25516,382
179241.44.128.0/18241.44.128.1 to 241.44.191.254241.44.191.25516,382
180241.44.192.0/18241.44.192.1 to 241.44.255.254241.44.255.25516,382
181241.45.0.0/18241.45.0.1 to 241.45.63.254241.45.63.25516,382
182241.45.64.0/18241.45.64.1 to 241.45.127.254241.45.127.25516,382
183241.45.128.0/18241.45.128.1 to 241.45.191.254241.45.191.25516,382
184241.45.192.0/18241.45.192.1 to 241.45.255.254241.45.255.25516,382
185241.46.0.0/18241.46.0.1 to 241.46.63.254241.46.63.25516,382
186241.46.64.0/18241.46.64.1 to 241.46.127.254241.46.127.25516,382
187241.46.128.0/18241.46.128.1 to 241.46.191.254241.46.191.25516,382
188241.46.192.0/18241.46.192.1 to 241.46.255.254241.46.255.25516,382
189241.47.0.0/18241.47.0.1 to 241.47.63.254241.47.63.25516,382
190241.47.64.0/18241.47.64.1 to 241.47.127.254241.47.127.25516,382
191241.47.128.0/18241.47.128.1 to 241.47.191.254241.47.191.25516,382
192241.47.192.0/18241.47.192.1 to 241.47.255.254241.47.255.25516,382
193241.48.0.0/18241.48.0.1 to 241.48.63.254241.48.63.25516,382
194241.48.64.0/18241.48.64.1 to 241.48.127.254241.48.127.25516,382
195241.48.128.0/18241.48.128.1 to 241.48.191.254241.48.191.25516,382
196241.48.192.0/18241.48.192.1 to 241.48.255.254241.48.255.25516,382
197241.49.0.0/18241.49.0.1 to 241.49.63.254241.49.63.25516,382
198241.49.64.0/18241.49.64.1 to 241.49.127.254241.49.127.25516,382
199241.49.128.0/18241.49.128.1 to 241.49.191.254241.49.191.25516,382
200241.49.192.0/18241.49.192.1 to 241.49.255.254241.49.255.25516,382
201241.50.0.0/18241.50.0.1 to 241.50.63.254241.50.63.25516,382
202241.50.64.0/18241.50.64.1 to 241.50.127.254241.50.127.25516,382
203241.50.128.0/18241.50.128.1 to 241.50.191.254241.50.191.25516,382
204241.50.192.0/18241.50.192.1 to 241.50.255.254241.50.255.25516,382
205241.51.0.0/18241.51.0.1 to 241.51.63.254241.51.63.25516,382
206241.51.64.0/18241.51.64.1 to 241.51.127.254241.51.127.25516,382
207241.51.128.0/18241.51.128.1 to 241.51.191.254241.51.191.25516,382
208241.51.192.0/18241.51.192.1 to 241.51.255.254241.51.255.25516,382
209241.52.0.0/18241.52.0.1 to 241.52.63.254241.52.63.25516,382
210241.52.64.0/18241.52.64.1 to 241.52.127.254241.52.127.25516,382
211241.52.128.0/18241.52.128.1 to 241.52.191.254241.52.191.25516,382
212241.52.192.0/18241.52.192.1 to 241.52.255.254241.52.255.25516,382
213241.53.0.0/18241.53.0.1 to 241.53.63.254241.53.63.25516,382
214241.53.64.0/18241.53.64.1 to 241.53.127.254241.53.127.25516,382
215241.53.128.0/18241.53.128.1 to 241.53.191.254241.53.191.25516,382
216241.53.192.0/18241.53.192.1 to 241.53.255.254241.53.255.25516,382
217241.54.0.0/18241.54.0.1 to 241.54.63.254241.54.63.25516,382
218241.54.64.0/18241.54.64.1 to 241.54.127.254241.54.127.25516,382
219241.54.128.0/18241.54.128.1 to 241.54.191.254241.54.191.25516,382
220241.54.192.0/18241.54.192.1 to 241.54.255.254241.54.255.25516,382
221241.55.0.0/18241.55.0.1 to 241.55.63.254241.55.63.25516,382
222241.55.64.0/18241.55.64.1 to 241.55.127.254241.55.127.25516,382
223241.55.128.0/18241.55.128.1 to 241.55.191.254241.55.191.25516,382
224241.55.192.0/18241.55.192.1 to 241.55.255.254241.55.255.25516,382
225241.56.0.0/18241.56.0.1 to 241.56.63.254241.56.63.25516,382
226241.56.64.0/18241.56.64.1 to 241.56.127.254241.56.127.25516,382
227241.56.128.0/18241.56.128.1 to 241.56.191.254241.56.191.25516,382
228241.56.192.0/18241.56.192.1 to 241.56.255.254241.56.255.25516,382
229241.57.0.0/18241.57.0.1 to 241.57.63.254241.57.63.25516,382
230241.57.64.0/18241.57.64.1 to 241.57.127.254241.57.127.25516,382
231241.57.128.0/18241.57.128.1 to 241.57.191.254241.57.191.25516,382
232241.57.192.0/18241.57.192.1 to 241.57.255.254241.57.255.25516,382
233241.58.0.0/18241.58.0.1 to 241.58.63.254241.58.63.25516,382
234241.58.64.0/18241.58.64.1 to 241.58.127.254241.58.127.25516,382
235241.58.128.0/18241.58.128.1 to 241.58.191.254241.58.191.25516,382
236241.58.192.0/18241.58.192.1 to 241.58.255.254241.58.255.25516,382
237241.59.0.0/18241.59.0.1 to 241.59.63.254241.59.63.25516,382
238241.59.64.0/18241.59.64.1 to 241.59.127.254241.59.127.25516,382
239241.59.128.0/18241.59.128.1 to 241.59.191.254241.59.191.25516,382
240241.59.192.0/18241.59.192.1 to 241.59.255.254241.59.255.25516,382
241241.60.0.0/18241.60.0.1 to 241.60.63.254241.60.63.25516,382
242241.60.64.0/18241.60.64.1 to 241.60.127.254241.60.127.25516,382
243241.60.128.0/18241.60.128.1 to 241.60.191.254241.60.191.25516,382
244241.60.192.0/18241.60.192.1 to 241.60.255.254241.60.255.25516,382
245241.61.0.0/18241.61.0.1 to 241.61.63.254241.61.63.25516,382
246241.61.64.0/18241.61.64.1 to 241.61.127.254241.61.127.25516,382
247241.61.128.0/18241.61.128.1 to 241.61.191.254241.61.191.25516,382
248241.61.192.0/18241.61.192.1 to 241.61.255.254241.61.255.25516,382
249241.62.0.0/18241.62.0.1 to 241.62.63.254241.62.63.25516,382
250241.62.64.0/18241.62.64.1 to 241.62.127.254241.62.127.25516,382
251241.62.128.0/18241.62.128.1 to 241.62.191.254241.62.191.25516,382
252241.62.192.0/18241.62.192.1 to 241.62.255.254241.62.255.25516,382
253241.63.0.0/18241.63.0.1 to 241.63.63.254241.63.63.25516,382
254241.63.64.0/18241.63.64.1 to 241.63.127.254241.63.127.25516,382
255241.63.128.0/18241.63.128.1 to 241.63.191.254241.63.191.25516,382
256241.63.192.0/18241.63.192.1 to 241.63.255.254241.63.255.25516,382

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.