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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
fc55::/16
First address
fc55::
Last address
fc55: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
fc55:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
5.5.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)

fc55::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc55::/28fc55:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc55:10::/28fc55:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc55:20::/28fc55:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc55:30::/28fc55:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc55:40::/28fc55:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc55:50::/28fc55:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc55:60::/28fc55:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc55:70::/28fc55:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc55:80::/28fc55:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc55:90::/28fc55:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc55:a0::/28fc55:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc55:b0::/28fc55:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc55:c0::/28fc55:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc55:d0::/28fc55:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc55:e0::/28fc55:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc55:f0::/28fc55:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc55:100::/28fc55:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc55:110::/28fc55:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc55:120::/28fc55:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc55:130::/28fc55:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc55:140::/28fc55:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc55:150::/28fc55:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc55:160::/28fc55:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc55:170::/28fc55:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc55:180::/28fc55:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc55:190::/28fc55:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc55:1a0::/28fc55:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc55:1b0::/28fc55:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc55:1c0::/28fc55:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc55:1d0::/28fc55:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc55:1e0::/28fc55:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc55:1f0::/28fc55:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc55:200::/28fc55:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc55:210::/28fc55:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc55:220::/28fc55:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc55:230::/28fc55:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc55:240::/28fc55:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc55:250::/28fc55:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc55:260::/28fc55:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc55:270::/28fc55:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc55:280::/28fc55:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc55:290::/28fc55:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc55:2a0::/28fc55:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc55:2b0::/28fc55:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc55:2c0::/28fc55:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc55:2d0::/28fc55:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc55:2e0::/28fc55:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc55:2f0::/28fc55:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc55:300::/28fc55:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc55:310::/28fc55:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc55:320::/28fc55:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc55:330::/28fc55:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc55:340::/28fc55:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc55:350::/28fc55:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc55:360::/28fc55:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc55:370::/28fc55:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc55:380::/28fc55:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc55:390::/28fc55:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc55:3a0::/28fc55:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc55:3b0::/28fc55:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc55:3c0::/28fc55:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc55:3d0::/28fc55:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc55:3e0::/28fc55:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc55:3f0::/28fc55:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc55:400::/28fc55:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc55:410::/28fc55:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc55:420::/28fc55:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc55:430::/28fc55:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc55:440::/28fc55:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc55:450::/28fc55:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc55:460::/28fc55:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc55:470::/28fc55:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc55:480::/28fc55:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc55:490::/28fc55:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc55:4a0::/28fc55:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc55:4b0::/28fc55:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc55:4c0::/28fc55:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc55:4d0::/28fc55:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc55:4e0::/28fc55:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc55:4f0::/28fc55:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc55:500::/28fc55:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc55:510::/28fc55:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc55:520::/28fc55:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc55:530::/28fc55:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc55:540::/28fc55:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc55:550::/28fc55:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc55:560::/28fc55:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc55:570::/28fc55:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc55:580::/28fc55:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc55:590::/28fc55:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc55:5a0::/28fc55:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc55:5b0::/28fc55:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc55:5c0::/28fc55:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc55:5d0::/28fc55:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc55:5e0::/28fc55:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc55:5f0::/28fc55:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc55:600::/28fc55:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc55:610::/28fc55:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc55:620::/28fc55:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc55:630::/28fc55:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc55:640::/28fc55:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc55:650::/28fc55:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc55:660::/28fc55:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc55:670::/28fc55:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc55:680::/28fc55:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc55:690::/28fc55:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc55:6a0::/28fc55:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc55:6b0::/28fc55:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc55:6c0::/28fc55:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc55:6d0::/28fc55:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc55:6e0::/28fc55:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc55:6f0::/28fc55:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc55:700::/28fc55:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc55:710::/28fc55:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc55:720::/28fc55:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc55:730::/28fc55:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc55:740::/28fc55:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc55:750::/28fc55:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc55:760::/28fc55:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc55:770::/28fc55:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc55:780::/28fc55:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc55:790::/28fc55:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc55:7a0::/28fc55:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc55:7b0::/28fc55:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc55:7c0::/28fc55:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc55:7d0::/28fc55:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc55:7e0::/28fc55:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc55:7f0::/28fc55:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc55:800::/28fc55:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc55:810::/28fc55:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc55:820::/28fc55:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc55:830::/28fc55:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc55:840::/28fc55:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc55:850::/28fc55:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc55:860::/28fc55:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc55:870::/28fc55:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc55:880::/28fc55:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc55:890::/28fc55:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc55:8a0::/28fc55:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc55:8b0::/28fc55:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc55:8c0::/28fc55:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc55:8d0::/28fc55:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc55:8e0::/28fc55:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc55:8f0::/28fc55:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc55:900::/28fc55:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc55:910::/28fc55:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc55:920::/28fc55:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc55:930::/28fc55:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc55:940::/28fc55:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc55:950::/28fc55:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc55:960::/28fc55:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc55:970::/28fc55:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc55:980::/28fc55:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc55:990::/28fc55:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc55:9a0::/28fc55:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc55:9b0::/28fc55:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc55:9c0::/28fc55:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc55:9d0::/28fc55:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc55:9e0::/28fc55:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc55:9f0::/28fc55:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc55:a00::/28fc55:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc55:a10::/28fc55:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc55:a20::/28fc55:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc55:a30::/28fc55:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc55:a40::/28fc55:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc55:a50::/28fc55:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc55:a60::/28fc55:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc55:a70::/28fc55:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc55:a80::/28fc55:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc55:a90::/28fc55:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc55:aa0::/28fc55:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc55:ab0::/28fc55:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc55:ac0::/28fc55:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc55:ad0::/28fc55:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc55:ae0::/28fc55:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc55:af0::/28fc55:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc55:b00::/28fc55:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc55:b10::/28fc55:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc55:b20::/28fc55:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc55:b30::/28fc55:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc55:b40::/28fc55:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc55:b50::/28fc55:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc55:b60::/28fc55:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc55:b70::/28fc55:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc55:b80::/28fc55:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc55:b90::/28fc55:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc55:ba0::/28fc55:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc55:bb0::/28fc55:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc55:bc0::/28fc55:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc55:bd0::/28fc55:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc55:be0::/28fc55:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc55:bf0::/28fc55:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc55:c00::/28fc55:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc55:c10::/28fc55:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc55:c20::/28fc55:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc55:c30::/28fc55:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc55:c40::/28fc55:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc55:c50::/28fc55:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc55:c60::/28fc55:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc55:c70::/28fc55:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc55:c80::/28fc55:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc55:c90::/28fc55:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc55:ca0::/28fc55:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc55:cb0::/28fc55:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc55:cc0::/28fc55:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc55:cd0::/28fc55:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc55:ce0::/28fc55:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc55:cf0::/28fc55:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc55:d00::/28fc55:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc55:d10::/28fc55:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc55:d20::/28fc55:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc55:d30::/28fc55:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc55:d40::/28fc55:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc55:d50::/28fc55:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc55:d60::/28fc55:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc55:d70::/28fc55:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc55:d80::/28fc55:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc55:d90::/28fc55:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc55:da0::/28fc55:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc55:db0::/28fc55:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc55:dc0::/28fc55:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc55:dd0::/28fc55:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc55:de0::/28fc55:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc55:df0::/28fc55:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc55:e00::/28fc55:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc55:e10::/28fc55:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc55:e20::/28fc55:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc55:e30::/28fc55:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc55:e40::/28fc55:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc55:e50::/28fc55:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc55:e60::/28fc55:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc55:e70::/28fc55:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc55:e80::/28fc55:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc55:e90::/28fc55:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc55:ea0::/28fc55:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc55:eb0::/28fc55:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc55:ec0::/28fc55:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc55:ed0::/28fc55:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc55:ee0::/28fc55:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc55:ef0::/28fc55:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc55:f00::/28fc55:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc55:f10::/28fc55:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc55:f20::/28fc55:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc55:f30::/28fc55:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc55:f40::/28fc55:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc55:f50::/28fc55:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc55:f60::/28fc55:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc55:f70::/28fc55:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc55:f80::/28fc55:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc55:f90::/28fc55:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc55:fa0::/28fc55:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc55:fb0::/28fc55:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc55:fc0::/28fc55:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc55:fd0::/28fc55:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc55:fe0::/28fc55:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc55:ff0::/28fc55: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.