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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.

Prefix/16
Addresses2^112
/64 networks2^48
Network
fc19::/16
First address
fc19::
Last address
fc19:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
fc19:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
9.1.c.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fc19::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc19::/28fc19:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc19:10::/28fc19:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc19:20::/28fc19:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc19:30::/28fc19:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc19:40::/28fc19:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc19:50::/28fc19:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc19:60::/28fc19:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc19:70::/28fc19:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc19:80::/28fc19:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc19:90::/28fc19:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc19:a0::/28fc19:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc19:b0::/28fc19:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc19:c0::/28fc19:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc19:d0::/28fc19:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc19:e0::/28fc19:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc19:f0::/28fc19:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc19:100::/28fc19:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc19:110::/28fc19:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc19:120::/28fc19:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc19:130::/28fc19:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc19:140::/28fc19:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc19:150::/28fc19:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc19:160::/28fc19:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc19:170::/28fc19:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc19:180::/28fc19:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc19:190::/28fc19:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc19:1a0::/28fc19:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc19:1b0::/28fc19:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc19:1c0::/28fc19:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc19:1d0::/28fc19:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc19:1e0::/28fc19:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc19:1f0::/28fc19:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc19:200::/28fc19:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc19:210::/28fc19:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc19:220::/28fc19:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc19:230::/28fc19:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc19:240::/28fc19:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc19:250::/28fc19:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc19:260::/28fc19:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc19:270::/28fc19:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc19:280::/28fc19:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc19:290::/28fc19:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc19:2a0::/28fc19:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc19:2b0::/28fc19:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc19:2c0::/28fc19:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc19:2d0::/28fc19:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc19:2e0::/28fc19:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc19:2f0::/28fc19:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc19:300::/28fc19:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc19:310::/28fc19:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc19:320::/28fc19:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc19:330::/28fc19:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc19:340::/28fc19:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc19:350::/28fc19:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc19:360::/28fc19:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc19:370::/28fc19:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc19:380::/28fc19:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc19:390::/28fc19:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc19:3a0::/28fc19:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc19:3b0::/28fc19:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc19:3c0::/28fc19:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc19:3d0::/28fc19:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc19:3e0::/28fc19:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc19:3f0::/28fc19:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc19:400::/28fc19:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc19:410::/28fc19:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc19:420::/28fc19:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc19:430::/28fc19:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc19:440::/28fc19:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc19:450::/28fc19:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc19:460::/28fc19:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc19:470::/28fc19:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc19:480::/28fc19:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc19:490::/28fc19:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc19:4a0::/28fc19:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc19:4b0::/28fc19:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc19:4c0::/28fc19:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc19:4d0::/28fc19:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc19:4e0::/28fc19:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc19:4f0::/28fc19:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc19:500::/28fc19:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc19:510::/28fc19:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc19:520::/28fc19:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc19:530::/28fc19:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc19:540::/28fc19:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc19:550::/28fc19:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc19:560::/28fc19:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc19:570::/28fc19:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc19:580::/28fc19:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc19:590::/28fc19:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc19:5a0::/28fc19:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc19:5b0::/28fc19:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc19:5c0::/28fc19:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc19:5d0::/28fc19:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc19:5e0::/28fc19:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc19:5f0::/28fc19:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc19:600::/28fc19:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc19:610::/28fc19:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc19:620::/28fc19:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc19:630::/28fc19:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc19:640::/28fc19:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc19:650::/28fc19:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc19:660::/28fc19:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc19:670::/28fc19:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc19:680::/28fc19:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc19:690::/28fc19:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc19:6a0::/28fc19:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc19:6b0::/28fc19:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc19:6c0::/28fc19:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc19:6d0::/28fc19:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc19:6e0::/28fc19:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc19:6f0::/28fc19:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc19:700::/28fc19:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc19:710::/28fc19:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc19:720::/28fc19:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc19:730::/28fc19:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc19:740::/28fc19:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc19:750::/28fc19:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc19:760::/28fc19:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc19:770::/28fc19:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc19:780::/28fc19:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc19:790::/28fc19:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc19:7a0::/28fc19:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc19:7b0::/28fc19:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc19:7c0::/28fc19:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc19:7d0::/28fc19:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc19:7e0::/28fc19:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc19:7f0::/28fc19:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc19:800::/28fc19:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc19:810::/28fc19:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc19:820::/28fc19:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc19:830::/28fc19:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc19:840::/28fc19:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc19:850::/28fc19:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc19:860::/28fc19:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc19:870::/28fc19:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc19:880::/28fc19:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc19:890::/28fc19:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc19:8a0::/28fc19:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc19:8b0::/28fc19:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc19:8c0::/28fc19:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc19:8d0::/28fc19:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc19:8e0::/28fc19:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc19:8f0::/28fc19:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc19:900::/28fc19:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc19:910::/28fc19:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc19:920::/28fc19:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc19:930::/28fc19:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc19:940::/28fc19:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc19:950::/28fc19:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc19:960::/28fc19:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc19:970::/28fc19:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc19:980::/28fc19:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc19:990::/28fc19:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc19:9a0::/28fc19:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc19:9b0::/28fc19:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc19:9c0::/28fc19:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc19:9d0::/28fc19:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc19:9e0::/28fc19:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc19:9f0::/28fc19:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc19:a00::/28fc19:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc19:a10::/28fc19:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc19:a20::/28fc19:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc19:a30::/28fc19:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc19:a40::/28fc19:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc19:a50::/28fc19:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc19:a60::/28fc19:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc19:a70::/28fc19:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc19:a80::/28fc19:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc19:a90::/28fc19:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc19:aa0::/28fc19:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc19:ab0::/28fc19:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc19:ac0::/28fc19:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc19:ad0::/28fc19:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc19:ae0::/28fc19:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc19:af0::/28fc19:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc19:b00::/28fc19:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc19:b10::/28fc19:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc19:b20::/28fc19:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc19:b30::/28fc19:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc19:b40::/28fc19:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc19:b50::/28fc19:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc19:b60::/28fc19:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc19:b70::/28fc19:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc19:b80::/28fc19:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc19:b90::/28fc19:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc19:ba0::/28fc19:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc19:bb0::/28fc19:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc19:bc0::/28fc19:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc19:bd0::/28fc19:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc19:be0::/28fc19:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc19:bf0::/28fc19:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc19:c00::/28fc19:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc19:c10::/28fc19:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc19:c20::/28fc19:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc19:c30::/28fc19:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc19:c40::/28fc19:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc19:c50::/28fc19:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc19:c60::/28fc19:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc19:c70::/28fc19:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc19:c80::/28fc19:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc19:c90::/28fc19:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc19:ca0::/28fc19:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc19:cb0::/28fc19:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc19:cc0::/28fc19:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc19:cd0::/28fc19:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc19:ce0::/28fc19:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc19:cf0::/28fc19:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc19:d00::/28fc19:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc19:d10::/28fc19:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc19:d20::/28fc19:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc19:d30::/28fc19:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc19:d40::/28fc19:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc19:d50::/28fc19:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc19:d60::/28fc19:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc19:d70::/28fc19:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc19:d80::/28fc19:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc19:d90::/28fc19:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc19:da0::/28fc19:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc19:db0::/28fc19:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc19:dc0::/28fc19:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc19:dd0::/28fc19:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc19:de0::/28fc19:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc19:df0::/28fc19:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc19:e00::/28fc19:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc19:e10::/28fc19:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc19:e20::/28fc19:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc19:e30::/28fc19:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc19:e40::/28fc19:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc19:e50::/28fc19:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc19:e60::/28fc19:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc19:e70::/28fc19:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc19:e80::/28fc19:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc19:e90::/28fc19:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc19:ea0::/28fc19:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc19:eb0::/28fc19:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc19:ec0::/28fc19:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc19:ed0::/28fc19:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc19:ee0::/28fc19:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc19:ef0::/28fc19:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc19:f00::/28fc19:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc19:f10::/28fc19:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc19:f20::/28fc19:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc19:f30::/28fc19:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc19:f40::/28fc19:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc19:f50::/28fc19:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc19:f60::/28fc19:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc19:f70::/28fc19:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc19:f80::/28fc19:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc19:f90::/28fc19:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc19:fa0::/28fc19:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc19:fb0::/28fc19:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc19:fc0::/28fc19:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc19:fd0::/28fc19:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc19:fe0::/28fc19:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc19:ff0::/28fc19:fff:ffff:ffff:ffff:ffff:ffff:ffff

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.