IPv4 Subnet Calculator

Enter an IP with a CIDR prefix or a subnet mask to see its network, broadcast, host range, and host count. You can also split the network into smaller subnets.

Try:192.168.1.10/24 10.0.0.0/8 172.16.5.4/20 203.0.113.9/29

IPv6 calculator →

private IP (RFC 1918)10.3.128.0/21

network10.3.128.0/21

broadcast10.3.135.255

first host10.3.128.1

last host10.3.135.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.128.0/21

address00001010.00000011.10000000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.10000000.00000000

broadcast00001010.00000011.10000111.11111111

green = network part, grey = host part

hex0x0a038000

decimal168001536

reverse dns0.128.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:8000

/21 split into /29 · 256 subnets

close ×

#	network	host range	broadcast
1	10.3.128.0/29	10.3.128.1 – 10.3.128.6	10.3.128.7
2	10.3.128.8/29	10.3.128.9 – 10.3.128.14	10.3.128.15
3	10.3.128.16/29	10.3.128.17 – 10.3.128.22	10.3.128.23
4	10.3.128.24/29	10.3.128.25 – 10.3.128.30	10.3.128.31
5	10.3.128.32/29	10.3.128.33 – 10.3.128.38	10.3.128.39
6	10.3.128.40/29	10.3.128.41 – 10.3.128.46	10.3.128.47
7	10.3.128.48/29	10.3.128.49 – 10.3.128.54	10.3.128.55
8	10.3.128.56/29	10.3.128.57 – 10.3.128.62	10.3.128.63
9	10.3.128.64/29	10.3.128.65 – 10.3.128.70	10.3.128.71
10	10.3.128.72/29	10.3.128.73 – 10.3.128.78	10.3.128.79
11	10.3.128.80/29	10.3.128.81 – 10.3.128.86	10.3.128.87
12	10.3.128.88/29	10.3.128.89 – 10.3.128.94	10.3.128.95
13	10.3.128.96/29	10.3.128.97 – 10.3.128.102	10.3.128.103
14	10.3.128.104/29	10.3.128.105 – 10.3.128.110	10.3.128.111
15	10.3.128.112/29	10.3.128.113 – 10.3.128.118	10.3.128.119
16	10.3.128.120/29	10.3.128.121 – 10.3.128.126	10.3.128.127
17	10.3.128.128/29	10.3.128.129 – 10.3.128.134	10.3.128.135
18	10.3.128.136/29	10.3.128.137 – 10.3.128.142	10.3.128.143
19	10.3.128.144/29	10.3.128.145 – 10.3.128.150	10.3.128.151
20	10.3.128.152/29	10.3.128.153 – 10.3.128.158	10.3.128.159
21	10.3.128.160/29	10.3.128.161 – 10.3.128.166	10.3.128.167
22	10.3.128.168/29	10.3.128.169 – 10.3.128.174	10.3.128.175
23	10.3.128.176/29	10.3.128.177 – 10.3.128.182	10.3.128.183
24	10.3.128.184/29	10.3.128.185 – 10.3.128.190	10.3.128.191
25	10.3.128.192/29	10.3.128.193 – 10.3.128.198	10.3.128.199
26	10.3.128.200/29	10.3.128.201 – 10.3.128.206	10.3.128.207
27	10.3.128.208/29	10.3.128.209 – 10.3.128.214	10.3.128.215
28	10.3.128.216/29	10.3.128.217 – 10.3.128.222	10.3.128.223
29	10.3.128.224/29	10.3.128.225 – 10.3.128.230	10.3.128.231
30	10.3.128.232/29	10.3.128.233 – 10.3.128.238	10.3.128.239
31	10.3.128.240/29	10.3.128.241 – 10.3.128.246	10.3.128.247
32	10.3.128.248/29	10.3.128.249 – 10.3.128.254	10.3.128.255
33	10.3.129.0/29	10.3.129.1 – 10.3.129.6	10.3.129.7
34	10.3.129.8/29	10.3.129.9 – 10.3.129.14	10.3.129.15
35	10.3.129.16/29	10.3.129.17 – 10.3.129.22	10.3.129.23
36	10.3.129.24/29	10.3.129.25 – 10.3.129.30	10.3.129.31
37	10.3.129.32/29	10.3.129.33 – 10.3.129.38	10.3.129.39
38	10.3.129.40/29	10.3.129.41 – 10.3.129.46	10.3.129.47
39	10.3.129.48/29	10.3.129.49 – 10.3.129.54	10.3.129.55
40	10.3.129.56/29	10.3.129.57 – 10.3.129.62	10.3.129.63
41	10.3.129.64/29	10.3.129.65 – 10.3.129.70	10.3.129.71
42	10.3.129.72/29	10.3.129.73 – 10.3.129.78	10.3.129.79
43	10.3.129.80/29	10.3.129.81 – 10.3.129.86	10.3.129.87
44	10.3.129.88/29	10.3.129.89 – 10.3.129.94	10.3.129.95
45	10.3.129.96/29	10.3.129.97 – 10.3.129.102	10.3.129.103
46	10.3.129.104/29	10.3.129.105 – 10.3.129.110	10.3.129.111
47	10.3.129.112/29	10.3.129.113 – 10.3.129.118	10.3.129.119
48	10.3.129.120/29	10.3.129.121 – 10.3.129.126	10.3.129.127
49	10.3.129.128/29	10.3.129.129 – 10.3.129.134	10.3.129.135
50	10.3.129.136/29	10.3.129.137 – 10.3.129.142	10.3.129.143
51	10.3.129.144/29	10.3.129.145 – 10.3.129.150	10.3.129.151
52	10.3.129.152/29	10.3.129.153 – 10.3.129.158	10.3.129.159
53	10.3.129.160/29	10.3.129.161 – 10.3.129.166	10.3.129.167
54	10.3.129.168/29	10.3.129.169 – 10.3.129.174	10.3.129.175
55	10.3.129.176/29	10.3.129.177 – 10.3.129.182	10.3.129.183
56	10.3.129.184/29	10.3.129.185 – 10.3.129.190	10.3.129.191
57	10.3.129.192/29	10.3.129.193 – 10.3.129.198	10.3.129.199
58	10.3.129.200/29	10.3.129.201 – 10.3.129.206	10.3.129.207
59	10.3.129.208/29	10.3.129.209 – 10.3.129.214	10.3.129.215
60	10.3.129.216/29	10.3.129.217 – 10.3.129.222	10.3.129.223
61	10.3.129.224/29	10.3.129.225 – 10.3.129.230	10.3.129.231
62	10.3.129.232/29	10.3.129.233 – 10.3.129.238	10.3.129.239
63	10.3.129.240/29	10.3.129.241 – 10.3.129.246	10.3.129.247
64	10.3.129.248/29	10.3.129.249 – 10.3.129.254	10.3.129.255
65	10.3.130.0/29	10.3.130.1 – 10.3.130.6	10.3.130.7
66	10.3.130.8/29	10.3.130.9 – 10.3.130.14	10.3.130.15
67	10.3.130.16/29	10.3.130.17 – 10.3.130.22	10.3.130.23
68	10.3.130.24/29	10.3.130.25 – 10.3.130.30	10.3.130.31
69	10.3.130.32/29	10.3.130.33 – 10.3.130.38	10.3.130.39
70	10.3.130.40/29	10.3.130.41 – 10.3.130.46	10.3.130.47
71	10.3.130.48/29	10.3.130.49 – 10.3.130.54	10.3.130.55
72	10.3.130.56/29	10.3.130.57 – 10.3.130.62	10.3.130.63
73	10.3.130.64/29	10.3.130.65 – 10.3.130.70	10.3.130.71
74	10.3.130.72/29	10.3.130.73 – 10.3.130.78	10.3.130.79
75	10.3.130.80/29	10.3.130.81 – 10.3.130.86	10.3.130.87
76	10.3.130.88/29	10.3.130.89 – 10.3.130.94	10.3.130.95
77	10.3.130.96/29	10.3.130.97 – 10.3.130.102	10.3.130.103
78	10.3.130.104/29	10.3.130.105 – 10.3.130.110	10.3.130.111
79	10.3.130.112/29	10.3.130.113 – 10.3.130.118	10.3.130.119
80	10.3.130.120/29	10.3.130.121 – 10.3.130.126	10.3.130.127
81	10.3.130.128/29	10.3.130.129 – 10.3.130.134	10.3.130.135
82	10.3.130.136/29	10.3.130.137 – 10.3.130.142	10.3.130.143
83	10.3.130.144/29	10.3.130.145 – 10.3.130.150	10.3.130.151
84	10.3.130.152/29	10.3.130.153 – 10.3.130.158	10.3.130.159
85	10.3.130.160/29	10.3.130.161 – 10.3.130.166	10.3.130.167
86	10.3.130.168/29	10.3.130.169 – 10.3.130.174	10.3.130.175
87	10.3.130.176/29	10.3.130.177 – 10.3.130.182	10.3.130.183
88	10.3.130.184/29	10.3.130.185 – 10.3.130.190	10.3.130.191
89	10.3.130.192/29	10.3.130.193 – 10.3.130.198	10.3.130.199
90	10.3.130.200/29	10.3.130.201 – 10.3.130.206	10.3.130.207
91	10.3.130.208/29	10.3.130.209 – 10.3.130.214	10.3.130.215
92	10.3.130.216/29	10.3.130.217 – 10.3.130.222	10.3.130.223
93	10.3.130.224/29	10.3.130.225 – 10.3.130.230	10.3.130.231
94	10.3.130.232/29	10.3.130.233 – 10.3.130.238	10.3.130.239
95	10.3.130.240/29	10.3.130.241 – 10.3.130.246	10.3.130.247
96	10.3.130.248/29	10.3.130.249 – 10.3.130.254	10.3.130.255
97	10.3.131.0/29	10.3.131.1 – 10.3.131.6	10.3.131.7
98	10.3.131.8/29	10.3.131.9 – 10.3.131.14	10.3.131.15
99	10.3.131.16/29	10.3.131.17 – 10.3.131.22	10.3.131.23
100	10.3.131.24/29	10.3.131.25 – 10.3.131.30	10.3.131.31
101	10.3.131.32/29	10.3.131.33 – 10.3.131.38	10.3.131.39
102	10.3.131.40/29	10.3.131.41 – 10.3.131.46	10.3.131.47
103	10.3.131.48/29	10.3.131.49 – 10.3.131.54	10.3.131.55
104	10.3.131.56/29	10.3.131.57 – 10.3.131.62	10.3.131.63
105	10.3.131.64/29	10.3.131.65 – 10.3.131.70	10.3.131.71
106	10.3.131.72/29	10.3.131.73 – 10.3.131.78	10.3.131.79
107	10.3.131.80/29	10.3.131.81 – 10.3.131.86	10.3.131.87
108	10.3.131.88/29	10.3.131.89 – 10.3.131.94	10.3.131.95
109	10.3.131.96/29	10.3.131.97 – 10.3.131.102	10.3.131.103
110	10.3.131.104/29	10.3.131.105 – 10.3.131.110	10.3.131.111
111	10.3.131.112/29	10.3.131.113 – 10.3.131.118	10.3.131.119
112	10.3.131.120/29	10.3.131.121 – 10.3.131.126	10.3.131.127
113	10.3.131.128/29	10.3.131.129 – 10.3.131.134	10.3.131.135
114	10.3.131.136/29	10.3.131.137 – 10.3.131.142	10.3.131.143
115	10.3.131.144/29	10.3.131.145 – 10.3.131.150	10.3.131.151
116	10.3.131.152/29	10.3.131.153 – 10.3.131.158	10.3.131.159
117	10.3.131.160/29	10.3.131.161 – 10.3.131.166	10.3.131.167
118	10.3.131.168/29	10.3.131.169 – 10.3.131.174	10.3.131.175
119	10.3.131.176/29	10.3.131.177 – 10.3.131.182	10.3.131.183
120	10.3.131.184/29	10.3.131.185 – 10.3.131.190	10.3.131.191
121	10.3.131.192/29	10.3.131.193 – 10.3.131.198	10.3.131.199
122	10.3.131.200/29	10.3.131.201 – 10.3.131.206	10.3.131.207
123	10.3.131.208/29	10.3.131.209 – 10.3.131.214	10.3.131.215
124	10.3.131.216/29	10.3.131.217 – 10.3.131.222	10.3.131.223
125	10.3.131.224/29	10.3.131.225 – 10.3.131.230	10.3.131.231
126	10.3.131.232/29	10.3.131.233 – 10.3.131.238	10.3.131.239
127	10.3.131.240/29	10.3.131.241 – 10.3.131.246	10.3.131.247
128	10.3.131.248/29	10.3.131.249 – 10.3.131.254	10.3.131.255
129	10.3.132.0/29	10.3.132.1 – 10.3.132.6	10.3.132.7
130	10.3.132.8/29	10.3.132.9 – 10.3.132.14	10.3.132.15
131	10.3.132.16/29	10.3.132.17 – 10.3.132.22	10.3.132.23
132	10.3.132.24/29	10.3.132.25 – 10.3.132.30	10.3.132.31
133	10.3.132.32/29	10.3.132.33 – 10.3.132.38	10.3.132.39
134	10.3.132.40/29	10.3.132.41 – 10.3.132.46	10.3.132.47
135	10.3.132.48/29	10.3.132.49 – 10.3.132.54	10.3.132.55
136	10.3.132.56/29	10.3.132.57 – 10.3.132.62	10.3.132.63
137	10.3.132.64/29	10.3.132.65 – 10.3.132.70	10.3.132.71
138	10.3.132.72/29	10.3.132.73 – 10.3.132.78	10.3.132.79
139	10.3.132.80/29	10.3.132.81 – 10.3.132.86	10.3.132.87
140	10.3.132.88/29	10.3.132.89 – 10.3.132.94	10.3.132.95
141	10.3.132.96/29	10.3.132.97 – 10.3.132.102	10.3.132.103
142	10.3.132.104/29	10.3.132.105 – 10.3.132.110	10.3.132.111
143	10.3.132.112/29	10.3.132.113 – 10.3.132.118	10.3.132.119
144	10.3.132.120/29	10.3.132.121 – 10.3.132.126	10.3.132.127
145	10.3.132.128/29	10.3.132.129 – 10.3.132.134	10.3.132.135
146	10.3.132.136/29	10.3.132.137 – 10.3.132.142	10.3.132.143
147	10.3.132.144/29	10.3.132.145 – 10.3.132.150	10.3.132.151
148	10.3.132.152/29	10.3.132.153 – 10.3.132.158	10.3.132.159
149	10.3.132.160/29	10.3.132.161 – 10.3.132.166	10.3.132.167
150	10.3.132.168/29	10.3.132.169 – 10.3.132.174	10.3.132.175
151	10.3.132.176/29	10.3.132.177 – 10.3.132.182	10.3.132.183
152	10.3.132.184/29	10.3.132.185 – 10.3.132.190	10.3.132.191
153	10.3.132.192/29	10.3.132.193 – 10.3.132.198	10.3.132.199
154	10.3.132.200/29	10.3.132.201 – 10.3.132.206	10.3.132.207
155	10.3.132.208/29	10.3.132.209 – 10.3.132.214	10.3.132.215
156	10.3.132.216/29	10.3.132.217 – 10.3.132.222	10.3.132.223
157	10.3.132.224/29	10.3.132.225 – 10.3.132.230	10.3.132.231
158	10.3.132.232/29	10.3.132.233 – 10.3.132.238	10.3.132.239
159	10.3.132.240/29	10.3.132.241 – 10.3.132.246	10.3.132.247
160	10.3.132.248/29	10.3.132.249 – 10.3.132.254	10.3.132.255
161	10.3.133.0/29	10.3.133.1 – 10.3.133.6	10.3.133.7
162	10.3.133.8/29	10.3.133.9 – 10.3.133.14	10.3.133.15
163	10.3.133.16/29	10.3.133.17 – 10.3.133.22	10.3.133.23
164	10.3.133.24/29	10.3.133.25 – 10.3.133.30	10.3.133.31
165	10.3.133.32/29	10.3.133.33 – 10.3.133.38	10.3.133.39
166	10.3.133.40/29	10.3.133.41 – 10.3.133.46	10.3.133.47
167	10.3.133.48/29	10.3.133.49 – 10.3.133.54	10.3.133.55
168	10.3.133.56/29	10.3.133.57 – 10.3.133.62	10.3.133.63
169	10.3.133.64/29	10.3.133.65 – 10.3.133.70	10.3.133.71
170	10.3.133.72/29	10.3.133.73 – 10.3.133.78	10.3.133.79
171	10.3.133.80/29	10.3.133.81 – 10.3.133.86	10.3.133.87
172	10.3.133.88/29	10.3.133.89 – 10.3.133.94	10.3.133.95
173	10.3.133.96/29	10.3.133.97 – 10.3.133.102	10.3.133.103
174	10.3.133.104/29	10.3.133.105 – 10.3.133.110	10.3.133.111
175	10.3.133.112/29	10.3.133.113 – 10.3.133.118	10.3.133.119
176	10.3.133.120/29	10.3.133.121 – 10.3.133.126	10.3.133.127
177	10.3.133.128/29	10.3.133.129 – 10.3.133.134	10.3.133.135
178	10.3.133.136/29	10.3.133.137 – 10.3.133.142	10.3.133.143
179	10.3.133.144/29	10.3.133.145 – 10.3.133.150	10.3.133.151
180	10.3.133.152/29	10.3.133.153 – 10.3.133.158	10.3.133.159
181	10.3.133.160/29	10.3.133.161 – 10.3.133.166	10.3.133.167
182	10.3.133.168/29	10.3.133.169 – 10.3.133.174	10.3.133.175
183	10.3.133.176/29	10.3.133.177 – 10.3.133.182	10.3.133.183
184	10.3.133.184/29	10.3.133.185 – 10.3.133.190	10.3.133.191
185	10.3.133.192/29	10.3.133.193 – 10.3.133.198	10.3.133.199
186	10.3.133.200/29	10.3.133.201 – 10.3.133.206	10.3.133.207
187	10.3.133.208/29	10.3.133.209 – 10.3.133.214	10.3.133.215
188	10.3.133.216/29	10.3.133.217 – 10.3.133.222	10.3.133.223
189	10.3.133.224/29	10.3.133.225 – 10.3.133.230	10.3.133.231
190	10.3.133.232/29	10.3.133.233 – 10.3.133.238	10.3.133.239
191	10.3.133.240/29	10.3.133.241 – 10.3.133.246	10.3.133.247
192	10.3.133.248/29	10.3.133.249 – 10.3.133.254	10.3.133.255
193	10.3.134.0/29	10.3.134.1 – 10.3.134.6	10.3.134.7
194	10.3.134.8/29	10.3.134.9 – 10.3.134.14	10.3.134.15
195	10.3.134.16/29	10.3.134.17 – 10.3.134.22	10.3.134.23
196	10.3.134.24/29	10.3.134.25 – 10.3.134.30	10.3.134.31
197	10.3.134.32/29	10.3.134.33 – 10.3.134.38	10.3.134.39
198	10.3.134.40/29	10.3.134.41 – 10.3.134.46	10.3.134.47
199	10.3.134.48/29	10.3.134.49 – 10.3.134.54	10.3.134.55
200	10.3.134.56/29	10.3.134.57 – 10.3.134.62	10.3.134.63
201	10.3.134.64/29	10.3.134.65 – 10.3.134.70	10.3.134.71
202	10.3.134.72/29	10.3.134.73 – 10.3.134.78	10.3.134.79
203	10.3.134.80/29	10.3.134.81 – 10.3.134.86	10.3.134.87
204	10.3.134.88/29	10.3.134.89 – 10.3.134.94	10.3.134.95
205	10.3.134.96/29	10.3.134.97 – 10.3.134.102	10.3.134.103
206	10.3.134.104/29	10.3.134.105 – 10.3.134.110	10.3.134.111
207	10.3.134.112/29	10.3.134.113 – 10.3.134.118	10.3.134.119
208	10.3.134.120/29	10.3.134.121 – 10.3.134.126	10.3.134.127
209	10.3.134.128/29	10.3.134.129 – 10.3.134.134	10.3.134.135
210	10.3.134.136/29	10.3.134.137 – 10.3.134.142	10.3.134.143
211	10.3.134.144/29	10.3.134.145 – 10.3.134.150	10.3.134.151
212	10.3.134.152/29	10.3.134.153 – 10.3.134.158	10.3.134.159
213	10.3.134.160/29	10.3.134.161 – 10.3.134.166	10.3.134.167
214	10.3.134.168/29	10.3.134.169 – 10.3.134.174	10.3.134.175
215	10.3.134.176/29	10.3.134.177 – 10.3.134.182	10.3.134.183
216	10.3.134.184/29	10.3.134.185 – 10.3.134.190	10.3.134.191
217	10.3.134.192/29	10.3.134.193 – 10.3.134.198	10.3.134.199
218	10.3.134.200/29	10.3.134.201 – 10.3.134.206	10.3.134.207
219	10.3.134.208/29	10.3.134.209 – 10.3.134.214	10.3.134.215
220	10.3.134.216/29	10.3.134.217 – 10.3.134.222	10.3.134.223
221	10.3.134.224/29	10.3.134.225 – 10.3.134.230	10.3.134.231
222	10.3.134.232/29	10.3.134.233 – 10.3.134.238	10.3.134.239
223	10.3.134.240/29	10.3.134.241 – 10.3.134.246	10.3.134.247
224	10.3.134.248/29	10.3.134.249 – 10.3.134.254	10.3.134.255
225	10.3.135.0/29	10.3.135.1 – 10.3.135.6	10.3.135.7
226	10.3.135.8/29	10.3.135.9 – 10.3.135.14	10.3.135.15
227	10.3.135.16/29	10.3.135.17 – 10.3.135.22	10.3.135.23
228	10.3.135.24/29	10.3.135.25 – 10.3.135.30	10.3.135.31
229	10.3.135.32/29	10.3.135.33 – 10.3.135.38	10.3.135.39
230	10.3.135.40/29	10.3.135.41 – 10.3.135.46	10.3.135.47
231	10.3.135.48/29	10.3.135.49 – 10.3.135.54	10.3.135.55
232	10.3.135.56/29	10.3.135.57 – 10.3.135.62	10.3.135.63
233	10.3.135.64/29	10.3.135.65 – 10.3.135.70	10.3.135.71
234	10.3.135.72/29	10.3.135.73 – 10.3.135.78	10.3.135.79
235	10.3.135.80/29	10.3.135.81 – 10.3.135.86	10.3.135.87
236	10.3.135.88/29	10.3.135.89 – 10.3.135.94	10.3.135.95
237	10.3.135.96/29	10.3.135.97 – 10.3.135.102	10.3.135.103
238	10.3.135.104/29	10.3.135.105 – 10.3.135.110	10.3.135.111
239	10.3.135.112/29	10.3.135.113 – 10.3.135.118	10.3.135.119
240	10.3.135.120/29	10.3.135.121 – 10.3.135.126	10.3.135.127
241	10.3.135.128/29	10.3.135.129 – 10.3.135.134	10.3.135.135
242	10.3.135.136/29	10.3.135.137 – 10.3.135.142	10.3.135.143
243	10.3.135.144/29	10.3.135.145 – 10.3.135.150	10.3.135.151
244	10.3.135.152/29	10.3.135.153 – 10.3.135.158	10.3.135.159
245	10.3.135.160/29	10.3.135.161 – 10.3.135.166	10.3.135.167
246	10.3.135.168/29	10.3.135.169 – 10.3.135.174	10.3.135.175
247	10.3.135.176/29	10.3.135.177 – 10.3.135.182	10.3.135.183
248	10.3.135.184/29	10.3.135.185 – 10.3.135.190	10.3.135.191
249	10.3.135.192/29	10.3.135.193 – 10.3.135.198	10.3.135.199
250	10.3.135.200/29	10.3.135.201 – 10.3.135.206	10.3.135.207
251	10.3.135.208/29	10.3.135.209 – 10.3.135.214	10.3.135.215
252	10.3.135.216/29	10.3.135.217 – 10.3.135.222	10.3.135.223
253	10.3.135.224/29	10.3.135.225 – 10.3.135.230	10.3.135.231
254	10.3.135.232/29	10.3.135.233 – 10.3.135.238	10.3.135.239
255	10.3.135.240/29	10.3.135.241 – 10.3.135.246	10.3.135.247
256	10.3.135.248/29	10.3.135.249 – 10.3.135.254	10.3.135.255

01 / table

IPv4 CIDR prefix table.

Click a prefix longer than your network to split it into subnets.

prefix	subnet mask	addresses	hosts	in your /21
/0	0.0.0.0	4,294,967,296	4,294,967,294	-
/1	128.0.0.0	2,147,483,648	2,147,483,646	-
/2	192.0.0.0	1,073,741,824	1,073,741,822	-
/3	224.0.0.0	536,870,912	536,870,910	-
/4	240.0.0.0	268,435,456	268,435,454	-
/5	248.0.0.0	134,217,728	134,217,726	-
/6	252.0.0.0	67,108,864	67,108,862	-
/7	254.0.0.0	33,554,432	33,554,430	-
/8	255.0.0.0	16,777,216	16,777,214	-
/9	255.128.0.0	8,388,608	8,388,606	-
/10	255.192.0.0	4,194,304	4,194,302	-
/11	255.224.0.0	2,097,152	2,097,150	-
/12	255.240.0.0	1,048,576	1,048,574	-
/13	255.248.0.0	524,288	524,286	-
/14	255.252.0.0	262,144	262,142	-
/15	255.254.0.0	131,072	131,070	-
/16	255.255.0.0	65,536	65,534	-
/17	255.255.128.0	32,768	32,766	-
/18	255.255.192.0	16,384	16,382	-
/19	255.255.224.0	8,192	8,190	-
/20	255.255.240.0	4,096	4,094	-
/21	255.255.248.0	2,048	2,046	1
/22	255.255.252.0	1,024	1,022	2 split →
/23	255.255.254.0	512	510	4 split →
/24	255.255.255.0	256	254	8 split →
/25	255.255.255.128	128	126	16 split →
/26	255.255.255.192	64	62	32 split →
/27	255.255.255.224	32	30	64 split →
/28	255.255.255.240	16	14	128 split →
/29	255.255.255.248	8	6	256 split →
/30	255.255.255.252	4	2	512 split →
/31	255.255.255.254	2	2	1,024 split →
/32	255.255.255.255	1	1	2,048 split →

02 / faq

About this calculator.

How do I use this subnet calculator?

▼

Type an IP address followed by a prefix, like 192.168.1.10/24, or by a subnet mask, like 192.168.1.10 255.255.255.0. Without a prefix it uses /24. Click a row in the table to split the network into smaller subnets.

Why are usable hosts always 2 fewer?

▼

The first address in a subnet is the network address and the last is the broadcast address, so neither can go to a device. The exceptions are /31 (point-to-point links, RFC 3021) and /32 (a single address), which use every address.

Can I use it from a terminal?

▼

Yes. curl 'ipku.in/en/tools/ipv4-subnet-calculator?q=192.168.1.10/24' returns the result as plain text.

Learn how to work it out →