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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/20
Addresses2^108
/64 networks2^44
Network
fc65::/20
First address
fc65::
Last address
fc65:fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
fc65:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
0.5.6.c.f.ip6.arpa
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

fc65::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1fc65::/28fc65:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc65:10::/28fc65:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc65:20::/28fc65:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc65:30::/28fc65:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc65:40::/28fc65:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc65:50::/28fc65:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc65:60::/28fc65:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc65:70::/28fc65:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc65:80::/28fc65:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc65:90::/28fc65:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc65:a0::/28fc65:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc65:b0::/28fc65:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc65:c0::/28fc65:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc65:d0::/28fc65:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc65:e0::/28fc65:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc65:f0::/28fc65:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc65:100::/28fc65:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc65:110::/28fc65:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc65:120::/28fc65:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc65:130::/28fc65:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc65:140::/28fc65:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc65:150::/28fc65:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc65:160::/28fc65:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc65:170::/28fc65:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc65:180::/28fc65:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc65:190::/28fc65:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc65:1a0::/28fc65:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc65:1b0::/28fc65:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc65:1c0::/28fc65:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc65:1d0::/28fc65:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc65:1e0::/28fc65:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc65:1f0::/28fc65:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc65:200::/28fc65:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc65:210::/28fc65:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc65:220::/28fc65:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc65:230::/28fc65:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc65:240::/28fc65:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc65:250::/28fc65:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc65:260::/28fc65:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc65:270::/28fc65:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc65:280::/28fc65:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc65:290::/28fc65:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc65:2a0::/28fc65:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc65:2b0::/28fc65:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc65:2c0::/28fc65:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc65:2d0::/28fc65:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc65:2e0::/28fc65:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc65:2f0::/28fc65:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc65:300::/28fc65:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc65:310::/28fc65:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc65:320::/28fc65:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc65:330::/28fc65:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc65:340::/28fc65:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc65:350::/28fc65:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc65:360::/28fc65:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc65:370::/28fc65:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc65:380::/28fc65:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc65:390::/28fc65:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc65:3a0::/28fc65:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc65:3b0::/28fc65:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc65:3c0::/28fc65:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc65:3d0::/28fc65:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc65:3e0::/28fc65:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc65:3f0::/28fc65:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc65:400::/28fc65:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc65:410::/28fc65:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc65:420::/28fc65:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc65:430::/28fc65:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc65:440::/28fc65:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc65:450::/28fc65:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc65:460::/28fc65:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc65:470::/28fc65:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc65:480::/28fc65:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc65:490::/28fc65:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc65:4a0::/28fc65:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc65:4b0::/28fc65:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc65:4c0::/28fc65:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc65:4d0::/28fc65:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc65:4e0::/28fc65:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc65:4f0::/28fc65:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc65:500::/28fc65:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc65:510::/28fc65:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc65:520::/28fc65:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc65:530::/28fc65:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc65:540::/28fc65:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc65:550::/28fc65:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc65:560::/28fc65:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc65:570::/28fc65:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc65:580::/28fc65:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc65:590::/28fc65:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc65:5a0::/28fc65:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc65:5b0::/28fc65:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc65:5c0::/28fc65:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc65:5d0::/28fc65:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc65:5e0::/28fc65:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc65:5f0::/28fc65:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc65:600::/28fc65:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc65:610::/28fc65:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc65:620::/28fc65:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc65:630::/28fc65:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc65:640::/28fc65:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc65:650::/28fc65:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc65:660::/28fc65:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc65:670::/28fc65:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc65:680::/28fc65:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc65:690::/28fc65:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc65:6a0::/28fc65:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc65:6b0::/28fc65:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc65:6c0::/28fc65:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc65:6d0::/28fc65:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc65:6e0::/28fc65:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc65:6f0::/28fc65:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc65:700::/28fc65:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc65:710::/28fc65:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc65:720::/28fc65:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc65:730::/28fc65:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc65:740::/28fc65:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc65:750::/28fc65:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc65:760::/28fc65:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc65:770::/28fc65:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc65:780::/28fc65:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc65:790::/28fc65:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc65:7a0::/28fc65:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc65:7b0::/28fc65:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc65:7c0::/28fc65:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc65:7d0::/28fc65:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc65:7e0::/28fc65:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc65:7f0::/28fc65:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc65:800::/28fc65:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc65:810::/28fc65:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc65:820::/28fc65:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc65:830::/28fc65:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc65:840::/28fc65:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc65:850::/28fc65:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc65:860::/28fc65:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc65:870::/28fc65:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc65:880::/28fc65:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc65:890::/28fc65:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc65:8a0::/28fc65:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc65:8b0::/28fc65:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc65:8c0::/28fc65:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc65:8d0::/28fc65:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc65:8e0::/28fc65:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc65:8f0::/28fc65:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc65:900::/28fc65:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc65:910::/28fc65:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc65:920::/28fc65:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc65:930::/28fc65:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc65:940::/28fc65:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc65:950::/28fc65:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc65:960::/28fc65:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc65:970::/28fc65:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc65:980::/28fc65:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc65:990::/28fc65:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc65:9a0::/28fc65:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc65:9b0::/28fc65:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc65:9c0::/28fc65:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc65:9d0::/28fc65:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc65:9e0::/28fc65:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc65:9f0::/28fc65:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc65:a00::/28fc65:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc65:a10::/28fc65:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc65:a20::/28fc65:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc65:a30::/28fc65:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc65:a40::/28fc65:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc65:a50::/28fc65:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc65:a60::/28fc65:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc65:a70::/28fc65:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc65:a80::/28fc65:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc65:a90::/28fc65:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc65:aa0::/28fc65:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc65:ab0::/28fc65:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc65:ac0::/28fc65:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc65:ad0::/28fc65:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc65:ae0::/28fc65:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc65:af0::/28fc65:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc65:b00::/28fc65:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc65:b10::/28fc65:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc65:b20::/28fc65:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc65:b30::/28fc65:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc65:b40::/28fc65:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc65:b50::/28fc65:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc65:b60::/28fc65:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc65:b70::/28fc65:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc65:b80::/28fc65:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc65:b90::/28fc65:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc65:ba0::/28fc65:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc65:bb0::/28fc65:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc65:bc0::/28fc65:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc65:bd0::/28fc65:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc65:be0::/28fc65:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc65:bf0::/28fc65:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc65:c00::/28fc65:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc65:c10::/28fc65:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc65:c20::/28fc65:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc65:c30::/28fc65:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc65:c40::/28fc65:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc65:c50::/28fc65:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc65:c60::/28fc65:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc65:c70::/28fc65:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc65:c80::/28fc65:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc65:c90::/28fc65:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc65:ca0::/28fc65:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc65:cb0::/28fc65:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc65:cc0::/28fc65:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc65:cd0::/28fc65:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc65:ce0::/28fc65:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc65:cf0::/28fc65:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc65:d00::/28fc65:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc65:d10::/28fc65:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc65:d20::/28fc65:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc65:d30::/28fc65:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc65:d40::/28fc65:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc65:d50::/28fc65:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc65:d60::/28fc65:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc65:d70::/28fc65:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc65:d80::/28fc65:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc65:d90::/28fc65:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc65:da0::/28fc65:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc65:db0::/28fc65:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc65:dc0::/28fc65:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc65:dd0::/28fc65:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc65:de0::/28fc65:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc65:df0::/28fc65:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc65:e00::/28fc65:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc65:e10::/28fc65:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc65:e20::/28fc65:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc65:e30::/28fc65:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc65:e40::/28fc65:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc65:e50::/28fc65:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc65:e60::/28fc65:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc65:e70::/28fc65:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc65:e80::/28fc65:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc65:e90::/28fc65:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc65:ea0::/28fc65:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc65:eb0::/28fc65:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc65:ec0::/28fc65:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc65:ed0::/28fc65:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc65:ee0::/28fc65:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc65:ef0::/28fc65:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc65:f00::/28fc65:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc65:f10::/28fc65:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc65:f20::/28fc65:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc65:f30::/28fc65:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc65:f40::/28fc65:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc65:f50::/28fc65:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc65:f60::/28fc65:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc65:f70::/28fc65:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc65:f80::/28fc65:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc65:f90::/28fc65:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc65:fa0::/28fc65:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc65:fb0::/28fc65:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc65:fc0::/28fc65:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc65:fd0::/28fc65:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc65:fe0::/28fc65:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc65:ff0::/28fc65: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.