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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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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
fe8b:2000::/20
First address
fe8b:2000::
Last address
fe8b:2fff: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
fe8b:2000:0000:0000:0000:0000:0000:0000
Type
Link-local fe80::/10
Every IPv6 interface has one; not routed
Reverse DNS zone
2.b.8.e.f.ip6.arpa
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

fe8b:2000::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1fe8b:2000::/28fe8b:200f:ffff:ffff:ffff:ffff:ffff:ffff
2fe8b:2010::/28fe8b:201f:ffff:ffff:ffff:ffff:ffff:ffff
3fe8b:2020::/28fe8b:202f:ffff:ffff:ffff:ffff:ffff:ffff
4fe8b:2030::/28fe8b:203f:ffff:ffff:ffff:ffff:ffff:ffff
5fe8b:2040::/28fe8b:204f:ffff:ffff:ffff:ffff:ffff:ffff
6fe8b:2050::/28fe8b:205f:ffff:ffff:ffff:ffff:ffff:ffff
7fe8b:2060::/28fe8b:206f:ffff:ffff:ffff:ffff:ffff:ffff
8fe8b:2070::/28fe8b:207f:ffff:ffff:ffff:ffff:ffff:ffff
9fe8b:2080::/28fe8b:208f:ffff:ffff:ffff:ffff:ffff:ffff
10fe8b:2090::/28fe8b:209f:ffff:ffff:ffff:ffff:ffff:ffff
11fe8b:20a0::/28fe8b:20af:ffff:ffff:ffff:ffff:ffff:ffff
12fe8b:20b0::/28fe8b:20bf:ffff:ffff:ffff:ffff:ffff:ffff
13fe8b:20c0::/28fe8b:20cf:ffff:ffff:ffff:ffff:ffff:ffff
14fe8b:20d0::/28fe8b:20df:ffff:ffff:ffff:ffff:ffff:ffff
15fe8b:20e0::/28fe8b:20ef:ffff:ffff:ffff:ffff:ffff:ffff
16fe8b:20f0::/28fe8b:20ff:ffff:ffff:ffff:ffff:ffff:ffff
17fe8b:2100::/28fe8b:210f:ffff:ffff:ffff:ffff:ffff:ffff
18fe8b:2110::/28fe8b:211f:ffff:ffff:ffff:ffff:ffff:ffff
19fe8b:2120::/28fe8b:212f:ffff:ffff:ffff:ffff:ffff:ffff
20fe8b:2130::/28fe8b:213f:ffff:ffff:ffff:ffff:ffff:ffff
21fe8b:2140::/28fe8b:214f:ffff:ffff:ffff:ffff:ffff:ffff
22fe8b:2150::/28fe8b:215f:ffff:ffff:ffff:ffff:ffff:ffff
23fe8b:2160::/28fe8b:216f:ffff:ffff:ffff:ffff:ffff:ffff
24fe8b:2170::/28fe8b:217f:ffff:ffff:ffff:ffff:ffff:ffff
25fe8b:2180::/28fe8b:218f:ffff:ffff:ffff:ffff:ffff:ffff
26fe8b:2190::/28fe8b:219f:ffff:ffff:ffff:ffff:ffff:ffff
27fe8b:21a0::/28fe8b:21af:ffff:ffff:ffff:ffff:ffff:ffff
28fe8b:21b0::/28fe8b:21bf:ffff:ffff:ffff:ffff:ffff:ffff
29fe8b:21c0::/28fe8b:21cf:ffff:ffff:ffff:ffff:ffff:ffff
30fe8b:21d0::/28fe8b:21df:ffff:ffff:ffff:ffff:ffff:ffff
31fe8b:21e0::/28fe8b:21ef:ffff:ffff:ffff:ffff:ffff:ffff
32fe8b:21f0::/28fe8b:21ff:ffff:ffff:ffff:ffff:ffff:ffff
33fe8b:2200::/28fe8b:220f:ffff:ffff:ffff:ffff:ffff:ffff
34fe8b:2210::/28fe8b:221f:ffff:ffff:ffff:ffff:ffff:ffff
35fe8b:2220::/28fe8b:222f:ffff:ffff:ffff:ffff:ffff:ffff
36fe8b:2230::/28fe8b:223f:ffff:ffff:ffff:ffff:ffff:ffff
37fe8b:2240::/28fe8b:224f:ffff:ffff:ffff:ffff:ffff:ffff
38fe8b:2250::/28fe8b:225f:ffff:ffff:ffff:ffff:ffff:ffff
39fe8b:2260::/28fe8b:226f:ffff:ffff:ffff:ffff:ffff:ffff
40fe8b:2270::/28fe8b:227f:ffff:ffff:ffff:ffff:ffff:ffff
41fe8b:2280::/28fe8b:228f:ffff:ffff:ffff:ffff:ffff:ffff
42fe8b:2290::/28fe8b:229f:ffff:ffff:ffff:ffff:ffff:ffff
43fe8b:22a0::/28fe8b:22af:ffff:ffff:ffff:ffff:ffff:ffff
44fe8b:22b0::/28fe8b:22bf:ffff:ffff:ffff:ffff:ffff:ffff
45fe8b:22c0::/28fe8b:22cf:ffff:ffff:ffff:ffff:ffff:ffff
46fe8b:22d0::/28fe8b:22df:ffff:ffff:ffff:ffff:ffff:ffff
47fe8b:22e0::/28fe8b:22ef:ffff:ffff:ffff:ffff:ffff:ffff
48fe8b:22f0::/28fe8b:22ff:ffff:ffff:ffff:ffff:ffff:ffff
49fe8b:2300::/28fe8b:230f:ffff:ffff:ffff:ffff:ffff:ffff
50fe8b:2310::/28fe8b:231f:ffff:ffff:ffff:ffff:ffff:ffff
51fe8b:2320::/28fe8b:232f:ffff:ffff:ffff:ffff:ffff:ffff
52fe8b:2330::/28fe8b:233f:ffff:ffff:ffff:ffff:ffff:ffff
53fe8b:2340::/28fe8b:234f:ffff:ffff:ffff:ffff:ffff:ffff
54fe8b:2350::/28fe8b:235f:ffff:ffff:ffff:ffff:ffff:ffff
55fe8b:2360::/28fe8b:236f:ffff:ffff:ffff:ffff:ffff:ffff
56fe8b:2370::/28fe8b:237f:ffff:ffff:ffff:ffff:ffff:ffff
57fe8b:2380::/28fe8b:238f:ffff:ffff:ffff:ffff:ffff:ffff
58fe8b:2390::/28fe8b:239f:ffff:ffff:ffff:ffff:ffff:ffff
59fe8b:23a0::/28fe8b:23af:ffff:ffff:ffff:ffff:ffff:ffff
60fe8b:23b0::/28fe8b:23bf:ffff:ffff:ffff:ffff:ffff:ffff
61fe8b:23c0::/28fe8b:23cf:ffff:ffff:ffff:ffff:ffff:ffff
62fe8b:23d0::/28fe8b:23df:ffff:ffff:ffff:ffff:ffff:ffff
63fe8b:23e0::/28fe8b:23ef:ffff:ffff:ffff:ffff:ffff:ffff
64fe8b:23f0::/28fe8b:23ff:ffff:ffff:ffff:ffff:ffff:ffff
65fe8b:2400::/28fe8b:240f:ffff:ffff:ffff:ffff:ffff:ffff
66fe8b:2410::/28fe8b:241f:ffff:ffff:ffff:ffff:ffff:ffff
67fe8b:2420::/28fe8b:242f:ffff:ffff:ffff:ffff:ffff:ffff
68fe8b:2430::/28fe8b:243f:ffff:ffff:ffff:ffff:ffff:ffff
69fe8b:2440::/28fe8b:244f:ffff:ffff:ffff:ffff:ffff:ffff
70fe8b:2450::/28fe8b:245f:ffff:ffff:ffff:ffff:ffff:ffff
71fe8b:2460::/28fe8b:246f:ffff:ffff:ffff:ffff:ffff:ffff
72fe8b:2470::/28fe8b:247f:ffff:ffff:ffff:ffff:ffff:ffff
73fe8b:2480::/28fe8b:248f:ffff:ffff:ffff:ffff:ffff:ffff
74fe8b:2490::/28fe8b:249f:ffff:ffff:ffff:ffff:ffff:ffff
75fe8b:24a0::/28fe8b:24af:ffff:ffff:ffff:ffff:ffff:ffff
76fe8b:24b0::/28fe8b:24bf:ffff:ffff:ffff:ffff:ffff:ffff
77fe8b:24c0::/28fe8b:24cf:ffff:ffff:ffff:ffff:ffff:ffff
78fe8b:24d0::/28fe8b:24df:ffff:ffff:ffff:ffff:ffff:ffff
79fe8b:24e0::/28fe8b:24ef:ffff:ffff:ffff:ffff:ffff:ffff
80fe8b:24f0::/28fe8b:24ff:ffff:ffff:ffff:ffff:ffff:ffff
81fe8b:2500::/28fe8b:250f:ffff:ffff:ffff:ffff:ffff:ffff
82fe8b:2510::/28fe8b:251f:ffff:ffff:ffff:ffff:ffff:ffff
83fe8b:2520::/28fe8b:252f:ffff:ffff:ffff:ffff:ffff:ffff
84fe8b:2530::/28fe8b:253f:ffff:ffff:ffff:ffff:ffff:ffff
85fe8b:2540::/28fe8b:254f:ffff:ffff:ffff:ffff:ffff:ffff
86fe8b:2550::/28fe8b:255f:ffff:ffff:ffff:ffff:ffff:ffff
87fe8b:2560::/28fe8b:256f:ffff:ffff:ffff:ffff:ffff:ffff
88fe8b:2570::/28fe8b:257f:ffff:ffff:ffff:ffff:ffff:ffff
89fe8b:2580::/28fe8b:258f:ffff:ffff:ffff:ffff:ffff:ffff
90fe8b:2590::/28fe8b:259f:ffff:ffff:ffff:ffff:ffff:ffff
91fe8b:25a0::/28fe8b:25af:ffff:ffff:ffff:ffff:ffff:ffff
92fe8b:25b0::/28fe8b:25bf:ffff:ffff:ffff:ffff:ffff:ffff
93fe8b:25c0::/28fe8b:25cf:ffff:ffff:ffff:ffff:ffff:ffff
94fe8b:25d0::/28fe8b:25df:ffff:ffff:ffff:ffff:ffff:ffff
95fe8b:25e0::/28fe8b:25ef:ffff:ffff:ffff:ffff:ffff:ffff
96fe8b:25f0::/28fe8b:25ff:ffff:ffff:ffff:ffff:ffff:ffff
97fe8b:2600::/28fe8b:260f:ffff:ffff:ffff:ffff:ffff:ffff
98fe8b:2610::/28fe8b:261f:ffff:ffff:ffff:ffff:ffff:ffff
99fe8b:2620::/28fe8b:262f:ffff:ffff:ffff:ffff:ffff:ffff
100fe8b:2630::/28fe8b:263f:ffff:ffff:ffff:ffff:ffff:ffff
101fe8b:2640::/28fe8b:264f:ffff:ffff:ffff:ffff:ffff:ffff
102fe8b:2650::/28fe8b:265f:ffff:ffff:ffff:ffff:ffff:ffff
103fe8b:2660::/28fe8b:266f:ffff:ffff:ffff:ffff:ffff:ffff
104fe8b:2670::/28fe8b:267f:ffff:ffff:ffff:ffff:ffff:ffff
105fe8b:2680::/28fe8b:268f:ffff:ffff:ffff:ffff:ffff:ffff
106fe8b:2690::/28fe8b:269f:ffff:ffff:ffff:ffff:ffff:ffff
107fe8b:26a0::/28fe8b:26af:ffff:ffff:ffff:ffff:ffff:ffff
108fe8b:26b0::/28fe8b:26bf:ffff:ffff:ffff:ffff:ffff:ffff
109fe8b:26c0::/28fe8b:26cf:ffff:ffff:ffff:ffff:ffff:ffff
110fe8b:26d0::/28fe8b:26df:ffff:ffff:ffff:ffff:ffff:ffff
111fe8b:26e0::/28fe8b:26ef:ffff:ffff:ffff:ffff:ffff:ffff
112fe8b:26f0::/28fe8b:26ff:ffff:ffff:ffff:ffff:ffff:ffff
113fe8b:2700::/28fe8b:270f:ffff:ffff:ffff:ffff:ffff:ffff
114fe8b:2710::/28fe8b:271f:ffff:ffff:ffff:ffff:ffff:ffff
115fe8b:2720::/28fe8b:272f:ffff:ffff:ffff:ffff:ffff:ffff
116fe8b:2730::/28fe8b:273f:ffff:ffff:ffff:ffff:ffff:ffff
117fe8b:2740::/28fe8b:274f:ffff:ffff:ffff:ffff:ffff:ffff
118fe8b:2750::/28fe8b:275f:ffff:ffff:ffff:ffff:ffff:ffff
119fe8b:2760::/28fe8b:276f:ffff:ffff:ffff:ffff:ffff:ffff
120fe8b:2770::/28fe8b:277f:ffff:ffff:ffff:ffff:ffff:ffff
121fe8b:2780::/28fe8b:278f:ffff:ffff:ffff:ffff:ffff:ffff
122fe8b:2790::/28fe8b:279f:ffff:ffff:ffff:ffff:ffff:ffff
123fe8b:27a0::/28fe8b:27af:ffff:ffff:ffff:ffff:ffff:ffff
124fe8b:27b0::/28fe8b:27bf:ffff:ffff:ffff:ffff:ffff:ffff
125fe8b:27c0::/28fe8b:27cf:ffff:ffff:ffff:ffff:ffff:ffff
126fe8b:27d0::/28fe8b:27df:ffff:ffff:ffff:ffff:ffff:ffff
127fe8b:27e0::/28fe8b:27ef:ffff:ffff:ffff:ffff:ffff:ffff
128fe8b:27f0::/28fe8b:27ff:ffff:ffff:ffff:ffff:ffff:ffff
129fe8b:2800::/28fe8b:280f:ffff:ffff:ffff:ffff:ffff:ffff
130fe8b:2810::/28fe8b:281f:ffff:ffff:ffff:ffff:ffff:ffff
131fe8b:2820::/28fe8b:282f:ffff:ffff:ffff:ffff:ffff:ffff
132fe8b:2830::/28fe8b:283f:ffff:ffff:ffff:ffff:ffff:ffff
133fe8b:2840::/28fe8b:284f:ffff:ffff:ffff:ffff:ffff:ffff
134fe8b:2850::/28fe8b:285f:ffff:ffff:ffff:ffff:ffff:ffff
135fe8b:2860::/28fe8b:286f:ffff:ffff:ffff:ffff:ffff:ffff
136fe8b:2870::/28fe8b:287f:ffff:ffff:ffff:ffff:ffff:ffff
137fe8b:2880::/28fe8b:288f:ffff:ffff:ffff:ffff:ffff:ffff
138fe8b:2890::/28fe8b:289f:ffff:ffff:ffff:ffff:ffff:ffff
139fe8b:28a0::/28fe8b:28af:ffff:ffff:ffff:ffff:ffff:ffff
140fe8b:28b0::/28fe8b:28bf:ffff:ffff:ffff:ffff:ffff:ffff
141fe8b:28c0::/28fe8b:28cf:ffff:ffff:ffff:ffff:ffff:ffff
142fe8b:28d0::/28fe8b:28df:ffff:ffff:ffff:ffff:ffff:ffff
143fe8b:28e0::/28fe8b:28ef:ffff:ffff:ffff:ffff:ffff:ffff
144fe8b:28f0::/28fe8b:28ff:ffff:ffff:ffff:ffff:ffff:ffff
145fe8b:2900::/28fe8b:290f:ffff:ffff:ffff:ffff:ffff:ffff
146fe8b:2910::/28fe8b:291f:ffff:ffff:ffff:ffff:ffff:ffff
147fe8b:2920::/28fe8b:292f:ffff:ffff:ffff:ffff:ffff:ffff
148fe8b:2930::/28fe8b:293f:ffff:ffff:ffff:ffff:ffff:ffff
149fe8b:2940::/28fe8b:294f:ffff:ffff:ffff:ffff:ffff:ffff
150fe8b:2950::/28fe8b:295f:ffff:ffff:ffff:ffff:ffff:ffff
151fe8b:2960::/28fe8b:296f:ffff:ffff:ffff:ffff:ffff:ffff
152fe8b:2970::/28fe8b:297f:ffff:ffff:ffff:ffff:ffff:ffff
153fe8b:2980::/28fe8b:298f:ffff:ffff:ffff:ffff:ffff:ffff
154fe8b:2990::/28fe8b:299f:ffff:ffff:ffff:ffff:ffff:ffff
155fe8b:29a0::/28fe8b:29af:ffff:ffff:ffff:ffff:ffff:ffff
156fe8b:29b0::/28fe8b:29bf:ffff:ffff:ffff:ffff:ffff:ffff
157fe8b:29c0::/28fe8b:29cf:ffff:ffff:ffff:ffff:ffff:ffff
158fe8b:29d0::/28fe8b:29df:ffff:ffff:ffff:ffff:ffff:ffff
159fe8b:29e0::/28fe8b:29ef:ffff:ffff:ffff:ffff:ffff:ffff
160fe8b:29f0::/28fe8b:29ff:ffff:ffff:ffff:ffff:ffff:ffff
161fe8b:2a00::/28fe8b:2a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fe8b:2a10::/28fe8b:2a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fe8b:2a20::/28fe8b:2a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fe8b:2a30::/28fe8b:2a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fe8b:2a40::/28fe8b:2a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fe8b:2a50::/28fe8b:2a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fe8b:2a60::/28fe8b:2a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fe8b:2a70::/28fe8b:2a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fe8b:2a80::/28fe8b:2a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fe8b:2a90::/28fe8b:2a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fe8b:2aa0::/28fe8b:2aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fe8b:2ab0::/28fe8b:2abf:ffff:ffff:ffff:ffff:ffff:ffff
173fe8b:2ac0::/28fe8b:2acf:ffff:ffff:ffff:ffff:ffff:ffff
174fe8b:2ad0::/28fe8b:2adf:ffff:ffff:ffff:ffff:ffff:ffff
175fe8b:2ae0::/28fe8b:2aef:ffff:ffff:ffff:ffff:ffff:ffff
176fe8b:2af0::/28fe8b:2aff:ffff:ffff:ffff:ffff:ffff:ffff
177fe8b:2b00::/28fe8b:2b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fe8b:2b10::/28fe8b:2b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fe8b:2b20::/28fe8b:2b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fe8b:2b30::/28fe8b:2b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fe8b:2b40::/28fe8b:2b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fe8b:2b50::/28fe8b:2b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fe8b:2b60::/28fe8b:2b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fe8b:2b70::/28fe8b:2b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fe8b:2b80::/28fe8b:2b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fe8b:2b90::/28fe8b:2b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fe8b:2ba0::/28fe8b:2baf:ffff:ffff:ffff:ffff:ffff:ffff
188fe8b:2bb0::/28fe8b:2bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fe8b:2bc0::/28fe8b:2bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fe8b:2bd0::/28fe8b:2bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fe8b:2be0::/28fe8b:2bef:ffff:ffff:ffff:ffff:ffff:ffff
192fe8b:2bf0::/28fe8b:2bff:ffff:ffff:ffff:ffff:ffff:ffff
193fe8b:2c00::/28fe8b:2c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fe8b:2c10::/28fe8b:2c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fe8b:2c20::/28fe8b:2c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fe8b:2c30::/28fe8b:2c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fe8b:2c40::/28fe8b:2c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fe8b:2c50::/28fe8b:2c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fe8b:2c60::/28fe8b:2c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fe8b:2c70::/28fe8b:2c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fe8b:2c80::/28fe8b:2c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fe8b:2c90::/28fe8b:2c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fe8b:2ca0::/28fe8b:2caf:ffff:ffff:ffff:ffff:ffff:ffff
204fe8b:2cb0::/28fe8b:2cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fe8b:2cc0::/28fe8b:2ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fe8b:2cd0::/28fe8b:2cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fe8b:2ce0::/28fe8b:2cef:ffff:ffff:ffff:ffff:ffff:ffff
208fe8b:2cf0::/28fe8b:2cff:ffff:ffff:ffff:ffff:ffff:ffff
209fe8b:2d00::/28fe8b:2d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fe8b:2d10::/28fe8b:2d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fe8b:2d20::/28fe8b:2d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fe8b:2d30::/28fe8b:2d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fe8b:2d40::/28fe8b:2d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fe8b:2d50::/28fe8b:2d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fe8b:2d60::/28fe8b:2d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fe8b:2d70::/28fe8b:2d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fe8b:2d80::/28fe8b:2d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fe8b:2d90::/28fe8b:2d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fe8b:2da0::/28fe8b:2daf:ffff:ffff:ffff:ffff:ffff:ffff
220fe8b:2db0::/28fe8b:2dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fe8b:2dc0::/28fe8b:2dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fe8b:2dd0::/28fe8b:2ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fe8b:2de0::/28fe8b:2def:ffff:ffff:ffff:ffff:ffff:ffff
224fe8b:2df0::/28fe8b:2dff:ffff:ffff:ffff:ffff:ffff:ffff
225fe8b:2e00::/28fe8b:2e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fe8b:2e10::/28fe8b:2e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fe8b:2e20::/28fe8b:2e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fe8b:2e30::/28fe8b:2e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fe8b:2e40::/28fe8b:2e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fe8b:2e50::/28fe8b:2e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fe8b:2e60::/28fe8b:2e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fe8b:2e70::/28fe8b:2e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fe8b:2e80::/28fe8b:2e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fe8b:2e90::/28fe8b:2e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fe8b:2ea0::/28fe8b:2eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fe8b:2eb0::/28fe8b:2ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fe8b:2ec0::/28fe8b:2ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fe8b:2ed0::/28fe8b:2edf:ffff:ffff:ffff:ffff:ffff:ffff
239fe8b:2ee0::/28fe8b:2eef:ffff:ffff:ffff:ffff:ffff:ffff
240fe8b:2ef0::/28fe8b:2eff:ffff:ffff:ffff:ffff:ffff:ffff
241fe8b:2f00::/28fe8b:2f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fe8b:2f10::/28fe8b:2f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fe8b:2f20::/28fe8b:2f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fe8b:2f30::/28fe8b:2f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fe8b:2f40::/28fe8b:2f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fe8b:2f50::/28fe8b:2f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fe8b:2f60::/28fe8b:2f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fe8b:2f70::/28fe8b:2f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fe8b:2f80::/28fe8b:2f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fe8b:2f90::/28fe8b:2f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fe8b:2fa0::/28fe8b:2faf:ffff:ffff:ffff:ffff:ffff:ffff
252fe8b:2fb0::/28fe8b:2fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fe8b:2fc0::/28fe8b:2fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fe8b:2fd0::/28fe8b:2fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fe8b:2fe0::/28fe8b:2fef:ffff:ffff:ffff:ffff:ffff:ffff
256fe8b:2ff0::/28fe8b:2fff: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.