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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.

Network151.58.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
151.58.0.0
Broadcast address
151.58.255.255
First usable
151.58.0.1
Last usable
151.58.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
B (default /16)
As numbers
Hex 973A0000 · Integer 2537160704 to 2537226239
Reverse DNS zone
58.151.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010111.00111010..00000000.00000000151.58.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network10010111.00111010..00000000.00000000151.58.0.0
Broadcast10010111.00111010..11111111.11111111151.58.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

151.58.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1151.58.0.0/25151.58.0.1 to 151.58.0.126151.58.0.127126
2151.58.0.128/25151.58.0.129 to 151.58.0.254151.58.0.255126
3151.58.1.0/25151.58.1.1 to 151.58.1.126151.58.1.127126
4151.58.1.128/25151.58.1.129 to 151.58.1.254151.58.1.255126
5151.58.2.0/25151.58.2.1 to 151.58.2.126151.58.2.127126
6151.58.2.128/25151.58.2.129 to 151.58.2.254151.58.2.255126
7151.58.3.0/25151.58.3.1 to 151.58.3.126151.58.3.127126
8151.58.3.128/25151.58.3.129 to 151.58.3.254151.58.3.255126
9151.58.4.0/25151.58.4.1 to 151.58.4.126151.58.4.127126
10151.58.4.128/25151.58.4.129 to 151.58.4.254151.58.4.255126
11151.58.5.0/25151.58.5.1 to 151.58.5.126151.58.5.127126
12151.58.5.128/25151.58.5.129 to 151.58.5.254151.58.5.255126
13151.58.6.0/25151.58.6.1 to 151.58.6.126151.58.6.127126
14151.58.6.128/25151.58.6.129 to 151.58.6.254151.58.6.255126
15151.58.7.0/25151.58.7.1 to 151.58.7.126151.58.7.127126
16151.58.7.128/25151.58.7.129 to 151.58.7.254151.58.7.255126
17151.58.8.0/25151.58.8.1 to 151.58.8.126151.58.8.127126
18151.58.8.128/25151.58.8.129 to 151.58.8.254151.58.8.255126
19151.58.9.0/25151.58.9.1 to 151.58.9.126151.58.9.127126
20151.58.9.128/25151.58.9.129 to 151.58.9.254151.58.9.255126
21151.58.10.0/25151.58.10.1 to 151.58.10.126151.58.10.127126
22151.58.10.128/25151.58.10.129 to 151.58.10.254151.58.10.255126
23151.58.11.0/25151.58.11.1 to 151.58.11.126151.58.11.127126
24151.58.11.128/25151.58.11.129 to 151.58.11.254151.58.11.255126
25151.58.12.0/25151.58.12.1 to 151.58.12.126151.58.12.127126
26151.58.12.128/25151.58.12.129 to 151.58.12.254151.58.12.255126
27151.58.13.0/25151.58.13.1 to 151.58.13.126151.58.13.127126
28151.58.13.128/25151.58.13.129 to 151.58.13.254151.58.13.255126
29151.58.14.0/25151.58.14.1 to 151.58.14.126151.58.14.127126
30151.58.14.128/25151.58.14.129 to 151.58.14.254151.58.14.255126
31151.58.15.0/25151.58.15.1 to 151.58.15.126151.58.15.127126
32151.58.15.128/25151.58.15.129 to 151.58.15.254151.58.15.255126
33151.58.16.0/25151.58.16.1 to 151.58.16.126151.58.16.127126
34151.58.16.128/25151.58.16.129 to 151.58.16.254151.58.16.255126
35151.58.17.0/25151.58.17.1 to 151.58.17.126151.58.17.127126
36151.58.17.128/25151.58.17.129 to 151.58.17.254151.58.17.255126
37151.58.18.0/25151.58.18.1 to 151.58.18.126151.58.18.127126
38151.58.18.128/25151.58.18.129 to 151.58.18.254151.58.18.255126
39151.58.19.0/25151.58.19.1 to 151.58.19.126151.58.19.127126
40151.58.19.128/25151.58.19.129 to 151.58.19.254151.58.19.255126
41151.58.20.0/25151.58.20.1 to 151.58.20.126151.58.20.127126
42151.58.20.128/25151.58.20.129 to 151.58.20.254151.58.20.255126
43151.58.21.0/25151.58.21.1 to 151.58.21.126151.58.21.127126
44151.58.21.128/25151.58.21.129 to 151.58.21.254151.58.21.255126
45151.58.22.0/25151.58.22.1 to 151.58.22.126151.58.22.127126
46151.58.22.128/25151.58.22.129 to 151.58.22.254151.58.22.255126
47151.58.23.0/25151.58.23.1 to 151.58.23.126151.58.23.127126
48151.58.23.128/25151.58.23.129 to 151.58.23.254151.58.23.255126
49151.58.24.0/25151.58.24.1 to 151.58.24.126151.58.24.127126
50151.58.24.128/25151.58.24.129 to 151.58.24.254151.58.24.255126
51151.58.25.0/25151.58.25.1 to 151.58.25.126151.58.25.127126
52151.58.25.128/25151.58.25.129 to 151.58.25.254151.58.25.255126
53151.58.26.0/25151.58.26.1 to 151.58.26.126151.58.26.127126
54151.58.26.128/25151.58.26.129 to 151.58.26.254151.58.26.255126
55151.58.27.0/25151.58.27.1 to 151.58.27.126151.58.27.127126
56151.58.27.128/25151.58.27.129 to 151.58.27.254151.58.27.255126
57151.58.28.0/25151.58.28.1 to 151.58.28.126151.58.28.127126
58151.58.28.128/25151.58.28.129 to 151.58.28.254151.58.28.255126
59151.58.29.0/25151.58.29.1 to 151.58.29.126151.58.29.127126
60151.58.29.128/25151.58.29.129 to 151.58.29.254151.58.29.255126
61151.58.30.0/25151.58.30.1 to 151.58.30.126151.58.30.127126
62151.58.30.128/25151.58.30.129 to 151.58.30.254151.58.30.255126
63151.58.31.0/25151.58.31.1 to 151.58.31.126151.58.31.127126
64151.58.31.128/25151.58.31.129 to 151.58.31.254151.58.31.255126
65151.58.32.0/25151.58.32.1 to 151.58.32.126151.58.32.127126
66151.58.32.128/25151.58.32.129 to 151.58.32.254151.58.32.255126
67151.58.33.0/25151.58.33.1 to 151.58.33.126151.58.33.127126
68151.58.33.128/25151.58.33.129 to 151.58.33.254151.58.33.255126
69151.58.34.0/25151.58.34.1 to 151.58.34.126151.58.34.127126
70151.58.34.128/25151.58.34.129 to 151.58.34.254151.58.34.255126
71151.58.35.0/25151.58.35.1 to 151.58.35.126151.58.35.127126
72151.58.35.128/25151.58.35.129 to 151.58.35.254151.58.35.255126
73151.58.36.0/25151.58.36.1 to 151.58.36.126151.58.36.127126
74151.58.36.128/25151.58.36.129 to 151.58.36.254151.58.36.255126
75151.58.37.0/25151.58.37.1 to 151.58.37.126151.58.37.127126
76151.58.37.128/25151.58.37.129 to 151.58.37.254151.58.37.255126
77151.58.38.0/25151.58.38.1 to 151.58.38.126151.58.38.127126
78151.58.38.128/25151.58.38.129 to 151.58.38.254151.58.38.255126
79151.58.39.0/25151.58.39.1 to 151.58.39.126151.58.39.127126
80151.58.39.128/25151.58.39.129 to 151.58.39.254151.58.39.255126
81151.58.40.0/25151.58.40.1 to 151.58.40.126151.58.40.127126
82151.58.40.128/25151.58.40.129 to 151.58.40.254151.58.40.255126
83151.58.41.0/25151.58.41.1 to 151.58.41.126151.58.41.127126
84151.58.41.128/25151.58.41.129 to 151.58.41.254151.58.41.255126
85151.58.42.0/25151.58.42.1 to 151.58.42.126151.58.42.127126
86151.58.42.128/25151.58.42.129 to 151.58.42.254151.58.42.255126
87151.58.43.0/25151.58.43.1 to 151.58.43.126151.58.43.127126
88151.58.43.128/25151.58.43.129 to 151.58.43.254151.58.43.255126
89151.58.44.0/25151.58.44.1 to 151.58.44.126151.58.44.127126
90151.58.44.128/25151.58.44.129 to 151.58.44.254151.58.44.255126
91151.58.45.0/25151.58.45.1 to 151.58.45.126151.58.45.127126
92151.58.45.128/25151.58.45.129 to 151.58.45.254151.58.45.255126
93151.58.46.0/25151.58.46.1 to 151.58.46.126151.58.46.127126
94151.58.46.128/25151.58.46.129 to 151.58.46.254151.58.46.255126
95151.58.47.0/25151.58.47.1 to 151.58.47.126151.58.47.127126
96151.58.47.128/25151.58.47.129 to 151.58.47.254151.58.47.255126
97151.58.48.0/25151.58.48.1 to 151.58.48.126151.58.48.127126
98151.58.48.128/25151.58.48.129 to 151.58.48.254151.58.48.255126
99151.58.49.0/25151.58.49.1 to 151.58.49.126151.58.49.127126
100151.58.49.128/25151.58.49.129 to 151.58.49.254151.58.49.255126
101151.58.50.0/25151.58.50.1 to 151.58.50.126151.58.50.127126
102151.58.50.128/25151.58.50.129 to 151.58.50.254151.58.50.255126
103151.58.51.0/25151.58.51.1 to 151.58.51.126151.58.51.127126
104151.58.51.128/25151.58.51.129 to 151.58.51.254151.58.51.255126
105151.58.52.0/25151.58.52.1 to 151.58.52.126151.58.52.127126
106151.58.52.128/25151.58.52.129 to 151.58.52.254151.58.52.255126
107151.58.53.0/25151.58.53.1 to 151.58.53.126151.58.53.127126
108151.58.53.128/25151.58.53.129 to 151.58.53.254151.58.53.255126
109151.58.54.0/25151.58.54.1 to 151.58.54.126151.58.54.127126
110151.58.54.128/25151.58.54.129 to 151.58.54.254151.58.54.255126
111151.58.55.0/25151.58.55.1 to 151.58.55.126151.58.55.127126
112151.58.55.128/25151.58.55.129 to 151.58.55.254151.58.55.255126
113151.58.56.0/25151.58.56.1 to 151.58.56.126151.58.56.127126
114151.58.56.128/25151.58.56.129 to 151.58.56.254151.58.56.255126
115151.58.57.0/25151.58.57.1 to 151.58.57.126151.58.57.127126
116151.58.57.128/25151.58.57.129 to 151.58.57.254151.58.57.255126
117151.58.58.0/25151.58.58.1 to 151.58.58.126151.58.58.127126
118151.58.58.128/25151.58.58.129 to 151.58.58.254151.58.58.255126
119151.58.59.0/25151.58.59.1 to 151.58.59.126151.58.59.127126
120151.58.59.128/25151.58.59.129 to 151.58.59.254151.58.59.255126
121151.58.60.0/25151.58.60.1 to 151.58.60.126151.58.60.127126
122151.58.60.128/25151.58.60.129 to 151.58.60.254151.58.60.255126
123151.58.61.0/25151.58.61.1 to 151.58.61.126151.58.61.127126
124151.58.61.128/25151.58.61.129 to 151.58.61.254151.58.61.255126
125151.58.62.0/25151.58.62.1 to 151.58.62.126151.58.62.127126
126151.58.62.128/25151.58.62.129 to 151.58.62.254151.58.62.255126
127151.58.63.0/25151.58.63.1 to 151.58.63.126151.58.63.127126
128151.58.63.128/25151.58.63.129 to 151.58.63.254151.58.63.255126
129151.58.64.0/25151.58.64.1 to 151.58.64.126151.58.64.127126
130151.58.64.128/25151.58.64.129 to 151.58.64.254151.58.64.255126
131151.58.65.0/25151.58.65.1 to 151.58.65.126151.58.65.127126
132151.58.65.128/25151.58.65.129 to 151.58.65.254151.58.65.255126
133151.58.66.0/25151.58.66.1 to 151.58.66.126151.58.66.127126
134151.58.66.128/25151.58.66.129 to 151.58.66.254151.58.66.255126
135151.58.67.0/25151.58.67.1 to 151.58.67.126151.58.67.127126
136151.58.67.128/25151.58.67.129 to 151.58.67.254151.58.67.255126
137151.58.68.0/25151.58.68.1 to 151.58.68.126151.58.68.127126
138151.58.68.128/25151.58.68.129 to 151.58.68.254151.58.68.255126
139151.58.69.0/25151.58.69.1 to 151.58.69.126151.58.69.127126
140151.58.69.128/25151.58.69.129 to 151.58.69.254151.58.69.255126
141151.58.70.0/25151.58.70.1 to 151.58.70.126151.58.70.127126
142151.58.70.128/25151.58.70.129 to 151.58.70.254151.58.70.255126
143151.58.71.0/25151.58.71.1 to 151.58.71.126151.58.71.127126
144151.58.71.128/25151.58.71.129 to 151.58.71.254151.58.71.255126
145151.58.72.0/25151.58.72.1 to 151.58.72.126151.58.72.127126
146151.58.72.128/25151.58.72.129 to 151.58.72.254151.58.72.255126
147151.58.73.0/25151.58.73.1 to 151.58.73.126151.58.73.127126
148151.58.73.128/25151.58.73.129 to 151.58.73.254151.58.73.255126
149151.58.74.0/25151.58.74.1 to 151.58.74.126151.58.74.127126
150151.58.74.128/25151.58.74.129 to 151.58.74.254151.58.74.255126
151151.58.75.0/25151.58.75.1 to 151.58.75.126151.58.75.127126
152151.58.75.128/25151.58.75.129 to 151.58.75.254151.58.75.255126
153151.58.76.0/25151.58.76.1 to 151.58.76.126151.58.76.127126
154151.58.76.128/25151.58.76.129 to 151.58.76.254151.58.76.255126
155151.58.77.0/25151.58.77.1 to 151.58.77.126151.58.77.127126
156151.58.77.128/25151.58.77.129 to 151.58.77.254151.58.77.255126
157151.58.78.0/25151.58.78.1 to 151.58.78.126151.58.78.127126
158151.58.78.128/25151.58.78.129 to 151.58.78.254151.58.78.255126
159151.58.79.0/25151.58.79.1 to 151.58.79.126151.58.79.127126
160151.58.79.128/25151.58.79.129 to 151.58.79.254151.58.79.255126
161151.58.80.0/25151.58.80.1 to 151.58.80.126151.58.80.127126
162151.58.80.128/25151.58.80.129 to 151.58.80.254151.58.80.255126
163151.58.81.0/25151.58.81.1 to 151.58.81.126151.58.81.127126
164151.58.81.128/25151.58.81.129 to 151.58.81.254151.58.81.255126
165151.58.82.0/25151.58.82.1 to 151.58.82.126151.58.82.127126
166151.58.82.128/25151.58.82.129 to 151.58.82.254151.58.82.255126
167151.58.83.0/25151.58.83.1 to 151.58.83.126151.58.83.127126
168151.58.83.128/25151.58.83.129 to 151.58.83.254151.58.83.255126
169151.58.84.0/25151.58.84.1 to 151.58.84.126151.58.84.127126
170151.58.84.128/25151.58.84.129 to 151.58.84.254151.58.84.255126
171151.58.85.0/25151.58.85.1 to 151.58.85.126151.58.85.127126
172151.58.85.128/25151.58.85.129 to 151.58.85.254151.58.85.255126
173151.58.86.0/25151.58.86.1 to 151.58.86.126151.58.86.127126
174151.58.86.128/25151.58.86.129 to 151.58.86.254151.58.86.255126
175151.58.87.0/25151.58.87.1 to 151.58.87.126151.58.87.127126
176151.58.87.128/25151.58.87.129 to 151.58.87.254151.58.87.255126
177151.58.88.0/25151.58.88.1 to 151.58.88.126151.58.88.127126
178151.58.88.128/25151.58.88.129 to 151.58.88.254151.58.88.255126
179151.58.89.0/25151.58.89.1 to 151.58.89.126151.58.89.127126
180151.58.89.128/25151.58.89.129 to 151.58.89.254151.58.89.255126
181151.58.90.0/25151.58.90.1 to 151.58.90.126151.58.90.127126
182151.58.90.128/25151.58.90.129 to 151.58.90.254151.58.90.255126
183151.58.91.0/25151.58.91.1 to 151.58.91.126151.58.91.127126
184151.58.91.128/25151.58.91.129 to 151.58.91.254151.58.91.255126
185151.58.92.0/25151.58.92.1 to 151.58.92.126151.58.92.127126
186151.58.92.128/25151.58.92.129 to 151.58.92.254151.58.92.255126
187151.58.93.0/25151.58.93.1 to 151.58.93.126151.58.93.127126
188151.58.93.128/25151.58.93.129 to 151.58.93.254151.58.93.255126
189151.58.94.0/25151.58.94.1 to 151.58.94.126151.58.94.127126
190151.58.94.128/25151.58.94.129 to 151.58.94.254151.58.94.255126
191151.58.95.0/25151.58.95.1 to 151.58.95.126151.58.95.127126
192151.58.95.128/25151.58.95.129 to 151.58.95.254151.58.95.255126
193151.58.96.0/25151.58.96.1 to 151.58.96.126151.58.96.127126
194151.58.96.128/25151.58.96.129 to 151.58.96.254151.58.96.255126
195151.58.97.0/25151.58.97.1 to 151.58.97.126151.58.97.127126
196151.58.97.128/25151.58.97.129 to 151.58.97.254151.58.97.255126
197151.58.98.0/25151.58.98.1 to 151.58.98.126151.58.98.127126
198151.58.98.128/25151.58.98.129 to 151.58.98.254151.58.98.255126
199151.58.99.0/25151.58.99.1 to 151.58.99.126151.58.99.127126
200151.58.99.128/25151.58.99.129 to 151.58.99.254151.58.99.255126
201151.58.100.0/25151.58.100.1 to 151.58.100.126151.58.100.127126
202151.58.100.128/25151.58.100.129 to 151.58.100.254151.58.100.255126
203151.58.101.0/25151.58.101.1 to 151.58.101.126151.58.101.127126
204151.58.101.128/25151.58.101.129 to 151.58.101.254151.58.101.255126
205151.58.102.0/25151.58.102.1 to 151.58.102.126151.58.102.127126
206151.58.102.128/25151.58.102.129 to 151.58.102.254151.58.102.255126
207151.58.103.0/25151.58.103.1 to 151.58.103.126151.58.103.127126
208151.58.103.128/25151.58.103.129 to 151.58.103.254151.58.103.255126
209151.58.104.0/25151.58.104.1 to 151.58.104.126151.58.104.127126
210151.58.104.128/25151.58.104.129 to 151.58.104.254151.58.104.255126
211151.58.105.0/25151.58.105.1 to 151.58.105.126151.58.105.127126
212151.58.105.128/25151.58.105.129 to 151.58.105.254151.58.105.255126
213151.58.106.0/25151.58.106.1 to 151.58.106.126151.58.106.127126
214151.58.106.128/25151.58.106.129 to 151.58.106.254151.58.106.255126
215151.58.107.0/25151.58.107.1 to 151.58.107.126151.58.107.127126
216151.58.107.128/25151.58.107.129 to 151.58.107.254151.58.107.255126
217151.58.108.0/25151.58.108.1 to 151.58.108.126151.58.108.127126
218151.58.108.128/25151.58.108.129 to 151.58.108.254151.58.108.255126
219151.58.109.0/25151.58.109.1 to 151.58.109.126151.58.109.127126
220151.58.109.128/25151.58.109.129 to 151.58.109.254151.58.109.255126
221151.58.110.0/25151.58.110.1 to 151.58.110.126151.58.110.127126
222151.58.110.128/25151.58.110.129 to 151.58.110.254151.58.110.255126
223151.58.111.0/25151.58.111.1 to 151.58.111.126151.58.111.127126
224151.58.111.128/25151.58.111.129 to 151.58.111.254151.58.111.255126
225151.58.112.0/25151.58.112.1 to 151.58.112.126151.58.112.127126
226151.58.112.128/25151.58.112.129 to 151.58.112.254151.58.112.255126
227151.58.113.0/25151.58.113.1 to 151.58.113.126151.58.113.127126
228151.58.113.128/25151.58.113.129 to 151.58.113.254151.58.113.255126
229151.58.114.0/25151.58.114.1 to 151.58.114.126151.58.114.127126
230151.58.114.128/25151.58.114.129 to 151.58.114.254151.58.114.255126
231151.58.115.0/25151.58.115.1 to 151.58.115.126151.58.115.127126
232151.58.115.128/25151.58.115.129 to 151.58.115.254151.58.115.255126
233151.58.116.0/25151.58.116.1 to 151.58.116.126151.58.116.127126
234151.58.116.128/25151.58.116.129 to 151.58.116.254151.58.116.255126
235151.58.117.0/25151.58.117.1 to 151.58.117.126151.58.117.127126
236151.58.117.128/25151.58.117.129 to 151.58.117.254151.58.117.255126
237151.58.118.0/25151.58.118.1 to 151.58.118.126151.58.118.127126
238151.58.118.128/25151.58.118.129 to 151.58.118.254151.58.118.255126
239151.58.119.0/25151.58.119.1 to 151.58.119.126151.58.119.127126
240151.58.119.128/25151.58.119.129 to 151.58.119.254151.58.119.255126
241151.58.120.0/25151.58.120.1 to 151.58.120.126151.58.120.127126
242151.58.120.128/25151.58.120.129 to 151.58.120.254151.58.120.255126
243151.58.121.0/25151.58.121.1 to 151.58.121.126151.58.121.127126
244151.58.121.128/25151.58.121.129 to 151.58.121.254151.58.121.255126
245151.58.122.0/25151.58.122.1 to 151.58.122.126151.58.122.127126
246151.58.122.128/25151.58.122.129 to 151.58.122.254151.58.122.255126
247151.58.123.0/25151.58.123.1 to 151.58.123.126151.58.123.127126
248151.58.123.128/25151.58.123.129 to 151.58.123.254151.58.123.255126
249151.58.124.0/25151.58.124.1 to 151.58.124.126151.58.124.127126
250151.58.124.128/25151.58.124.129 to 151.58.124.254151.58.124.255126
251151.58.125.0/25151.58.125.1 to 151.58.125.126151.58.125.127126
252151.58.125.128/25151.58.125.129 to 151.58.125.254151.58.125.255126
253151.58.126.0/25151.58.126.1 to 151.58.126.126151.58.126.127126
254151.58.126.128/25151.58.126.129 to 151.58.126.254151.58.126.255126
255151.58.127.0/25151.58.127.1 to 151.58.127.126151.58.127.127126
256151.58.127.128/25151.58.127.129 to 151.58.127.254151.58.127.255126

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.