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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.

Network0.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
0.0.0.0
Broadcast address
3.255.255.255
First usable
0.0.0.1
Last usable
3.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 00000000 · Integer 0 to 67108863
Reverse DNS zones
0.in-addr.arpa
1.in-addr.arpa
2.in-addr.arpa
3.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000000.00000000.00000000.000000000.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network00000000.00000000.00000000.000000000.0.0.0
Broadcast00000011.11111111.11111111.111111113.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

0.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.0.0.0/170.0.0.1 to 0.0.127.2540.0.127.25532,766
20.0.128.0/170.0.128.1 to 0.0.255.2540.0.255.25532,766
30.1.0.0/170.1.0.1 to 0.1.127.2540.1.127.25532,766
40.1.128.0/170.1.128.1 to 0.1.255.2540.1.255.25532,766
50.2.0.0/170.2.0.1 to 0.2.127.2540.2.127.25532,766
60.2.128.0/170.2.128.1 to 0.2.255.2540.2.255.25532,766
70.3.0.0/170.3.0.1 to 0.3.127.2540.3.127.25532,766
80.3.128.0/170.3.128.1 to 0.3.255.2540.3.255.25532,766
90.4.0.0/170.4.0.1 to 0.4.127.2540.4.127.25532,766
100.4.128.0/170.4.128.1 to 0.4.255.2540.4.255.25532,766
110.5.0.0/170.5.0.1 to 0.5.127.2540.5.127.25532,766
120.5.128.0/170.5.128.1 to 0.5.255.2540.5.255.25532,766
130.6.0.0/170.6.0.1 to 0.6.127.2540.6.127.25532,766
140.6.128.0/170.6.128.1 to 0.6.255.2540.6.255.25532,766
150.7.0.0/170.7.0.1 to 0.7.127.2540.7.127.25532,766
160.7.128.0/170.7.128.1 to 0.7.255.2540.7.255.25532,766
170.8.0.0/170.8.0.1 to 0.8.127.2540.8.127.25532,766
180.8.128.0/170.8.128.1 to 0.8.255.2540.8.255.25532,766
190.9.0.0/170.9.0.1 to 0.9.127.2540.9.127.25532,766
200.9.128.0/170.9.128.1 to 0.9.255.2540.9.255.25532,766
210.10.0.0/170.10.0.1 to 0.10.127.2540.10.127.25532,766
220.10.128.0/170.10.128.1 to 0.10.255.2540.10.255.25532,766
230.11.0.0/170.11.0.1 to 0.11.127.2540.11.127.25532,766
240.11.128.0/170.11.128.1 to 0.11.255.2540.11.255.25532,766
250.12.0.0/170.12.0.1 to 0.12.127.2540.12.127.25532,766
260.12.128.0/170.12.128.1 to 0.12.255.2540.12.255.25532,766
270.13.0.0/170.13.0.1 to 0.13.127.2540.13.127.25532,766
280.13.128.0/170.13.128.1 to 0.13.255.2540.13.255.25532,766
290.14.0.0/170.14.0.1 to 0.14.127.2540.14.127.25532,766
300.14.128.0/170.14.128.1 to 0.14.255.2540.14.255.25532,766
310.15.0.0/170.15.0.1 to 0.15.127.2540.15.127.25532,766
320.15.128.0/170.15.128.1 to 0.15.255.2540.15.255.25532,766
330.16.0.0/170.16.0.1 to 0.16.127.2540.16.127.25532,766
340.16.128.0/170.16.128.1 to 0.16.255.2540.16.255.25532,766
350.17.0.0/170.17.0.1 to 0.17.127.2540.17.127.25532,766
360.17.128.0/170.17.128.1 to 0.17.255.2540.17.255.25532,766
370.18.0.0/170.18.0.1 to 0.18.127.2540.18.127.25532,766
380.18.128.0/170.18.128.1 to 0.18.255.2540.18.255.25532,766
390.19.0.0/170.19.0.1 to 0.19.127.2540.19.127.25532,766
400.19.128.0/170.19.128.1 to 0.19.255.2540.19.255.25532,766
410.20.0.0/170.20.0.1 to 0.20.127.2540.20.127.25532,766
420.20.128.0/170.20.128.1 to 0.20.255.2540.20.255.25532,766
430.21.0.0/170.21.0.1 to 0.21.127.2540.21.127.25532,766
440.21.128.0/170.21.128.1 to 0.21.255.2540.21.255.25532,766
450.22.0.0/170.22.0.1 to 0.22.127.2540.22.127.25532,766
460.22.128.0/170.22.128.1 to 0.22.255.2540.22.255.25532,766
470.23.0.0/170.23.0.1 to 0.23.127.2540.23.127.25532,766
480.23.128.0/170.23.128.1 to 0.23.255.2540.23.255.25532,766
490.24.0.0/170.24.0.1 to 0.24.127.2540.24.127.25532,766
500.24.128.0/170.24.128.1 to 0.24.255.2540.24.255.25532,766
510.25.0.0/170.25.0.1 to 0.25.127.2540.25.127.25532,766
520.25.128.0/170.25.128.1 to 0.25.255.2540.25.255.25532,766
530.26.0.0/170.26.0.1 to 0.26.127.2540.26.127.25532,766
540.26.128.0/170.26.128.1 to 0.26.255.2540.26.255.25532,766
550.27.0.0/170.27.0.1 to 0.27.127.2540.27.127.25532,766
560.27.128.0/170.27.128.1 to 0.27.255.2540.27.255.25532,766
570.28.0.0/170.28.0.1 to 0.28.127.2540.28.127.25532,766
580.28.128.0/170.28.128.1 to 0.28.255.2540.28.255.25532,766
590.29.0.0/170.29.0.1 to 0.29.127.2540.29.127.25532,766
600.29.128.0/170.29.128.1 to 0.29.255.2540.29.255.25532,766
610.30.0.0/170.30.0.1 to 0.30.127.2540.30.127.25532,766
620.30.128.0/170.30.128.1 to 0.30.255.2540.30.255.25532,766
630.31.0.0/170.31.0.1 to 0.31.127.2540.31.127.25532,766
640.31.128.0/170.31.128.1 to 0.31.255.2540.31.255.25532,766
650.32.0.0/170.32.0.1 to 0.32.127.2540.32.127.25532,766
660.32.128.0/170.32.128.1 to 0.32.255.2540.32.255.25532,766
670.33.0.0/170.33.0.1 to 0.33.127.2540.33.127.25532,766
680.33.128.0/170.33.128.1 to 0.33.255.2540.33.255.25532,766
690.34.0.0/170.34.0.1 to 0.34.127.2540.34.127.25532,766
700.34.128.0/170.34.128.1 to 0.34.255.2540.34.255.25532,766
710.35.0.0/170.35.0.1 to 0.35.127.2540.35.127.25532,766
720.35.128.0/170.35.128.1 to 0.35.255.2540.35.255.25532,766
730.36.0.0/170.36.0.1 to 0.36.127.2540.36.127.25532,766
740.36.128.0/170.36.128.1 to 0.36.255.2540.36.255.25532,766
750.37.0.0/170.37.0.1 to 0.37.127.2540.37.127.25532,766
760.37.128.0/170.37.128.1 to 0.37.255.2540.37.255.25532,766
770.38.0.0/170.38.0.1 to 0.38.127.2540.38.127.25532,766
780.38.128.0/170.38.128.1 to 0.38.255.2540.38.255.25532,766
790.39.0.0/170.39.0.1 to 0.39.127.2540.39.127.25532,766
800.39.128.0/170.39.128.1 to 0.39.255.2540.39.255.25532,766
810.40.0.0/170.40.0.1 to 0.40.127.2540.40.127.25532,766
820.40.128.0/170.40.128.1 to 0.40.255.2540.40.255.25532,766
830.41.0.0/170.41.0.1 to 0.41.127.2540.41.127.25532,766
840.41.128.0/170.41.128.1 to 0.41.255.2540.41.255.25532,766
850.42.0.0/170.42.0.1 to 0.42.127.2540.42.127.25532,766
860.42.128.0/170.42.128.1 to 0.42.255.2540.42.255.25532,766
870.43.0.0/170.43.0.1 to 0.43.127.2540.43.127.25532,766
880.43.128.0/170.43.128.1 to 0.43.255.2540.43.255.25532,766
890.44.0.0/170.44.0.1 to 0.44.127.2540.44.127.25532,766
900.44.128.0/170.44.128.1 to 0.44.255.2540.44.255.25532,766
910.45.0.0/170.45.0.1 to 0.45.127.2540.45.127.25532,766
920.45.128.0/170.45.128.1 to 0.45.255.2540.45.255.25532,766
930.46.0.0/170.46.0.1 to 0.46.127.2540.46.127.25532,766
940.46.128.0/170.46.128.1 to 0.46.255.2540.46.255.25532,766
950.47.0.0/170.47.0.1 to 0.47.127.2540.47.127.25532,766
960.47.128.0/170.47.128.1 to 0.47.255.2540.47.255.25532,766
970.48.0.0/170.48.0.1 to 0.48.127.2540.48.127.25532,766
980.48.128.0/170.48.128.1 to 0.48.255.2540.48.255.25532,766
990.49.0.0/170.49.0.1 to 0.49.127.2540.49.127.25532,766
1000.49.128.0/170.49.128.1 to 0.49.255.2540.49.255.25532,766
1010.50.0.0/170.50.0.1 to 0.50.127.2540.50.127.25532,766
1020.50.128.0/170.50.128.1 to 0.50.255.2540.50.255.25532,766
1030.51.0.0/170.51.0.1 to 0.51.127.2540.51.127.25532,766
1040.51.128.0/170.51.128.1 to 0.51.255.2540.51.255.25532,766
1050.52.0.0/170.52.0.1 to 0.52.127.2540.52.127.25532,766
1060.52.128.0/170.52.128.1 to 0.52.255.2540.52.255.25532,766
1070.53.0.0/170.53.0.1 to 0.53.127.2540.53.127.25532,766
1080.53.128.0/170.53.128.1 to 0.53.255.2540.53.255.25532,766
1090.54.0.0/170.54.0.1 to 0.54.127.2540.54.127.25532,766
1100.54.128.0/170.54.128.1 to 0.54.255.2540.54.255.25532,766
1110.55.0.0/170.55.0.1 to 0.55.127.2540.55.127.25532,766
1120.55.128.0/170.55.128.1 to 0.55.255.2540.55.255.25532,766
1130.56.0.0/170.56.0.1 to 0.56.127.2540.56.127.25532,766
1140.56.128.0/170.56.128.1 to 0.56.255.2540.56.255.25532,766
1150.57.0.0/170.57.0.1 to 0.57.127.2540.57.127.25532,766
1160.57.128.0/170.57.128.1 to 0.57.255.2540.57.255.25532,766
1170.58.0.0/170.58.0.1 to 0.58.127.2540.58.127.25532,766
1180.58.128.0/170.58.128.1 to 0.58.255.2540.58.255.25532,766
1190.59.0.0/170.59.0.1 to 0.59.127.2540.59.127.25532,766
1200.59.128.0/170.59.128.1 to 0.59.255.2540.59.255.25532,766
1210.60.0.0/170.60.0.1 to 0.60.127.2540.60.127.25532,766
1220.60.128.0/170.60.128.1 to 0.60.255.2540.60.255.25532,766
1230.61.0.0/170.61.0.1 to 0.61.127.2540.61.127.25532,766
1240.61.128.0/170.61.128.1 to 0.61.255.2540.61.255.25532,766
1250.62.0.0/170.62.0.1 to 0.62.127.2540.62.127.25532,766
1260.62.128.0/170.62.128.1 to 0.62.255.2540.62.255.25532,766
1270.63.0.0/170.63.0.1 to 0.63.127.2540.63.127.25532,766
1280.63.128.0/170.63.128.1 to 0.63.255.2540.63.255.25532,766
1290.64.0.0/170.64.0.1 to 0.64.127.2540.64.127.25532,766
1300.64.128.0/170.64.128.1 to 0.64.255.2540.64.255.25532,766
1310.65.0.0/170.65.0.1 to 0.65.127.2540.65.127.25532,766
1320.65.128.0/170.65.128.1 to 0.65.255.2540.65.255.25532,766
1330.66.0.0/170.66.0.1 to 0.66.127.2540.66.127.25532,766
1340.66.128.0/170.66.128.1 to 0.66.255.2540.66.255.25532,766
1350.67.0.0/170.67.0.1 to 0.67.127.2540.67.127.25532,766
1360.67.128.0/170.67.128.1 to 0.67.255.2540.67.255.25532,766
1370.68.0.0/170.68.0.1 to 0.68.127.2540.68.127.25532,766
1380.68.128.0/170.68.128.1 to 0.68.255.2540.68.255.25532,766
1390.69.0.0/170.69.0.1 to 0.69.127.2540.69.127.25532,766
1400.69.128.0/170.69.128.1 to 0.69.255.2540.69.255.25532,766
1410.70.0.0/170.70.0.1 to 0.70.127.2540.70.127.25532,766
1420.70.128.0/170.70.128.1 to 0.70.255.2540.70.255.25532,766
1430.71.0.0/170.71.0.1 to 0.71.127.2540.71.127.25532,766
1440.71.128.0/170.71.128.1 to 0.71.255.2540.71.255.25532,766
1450.72.0.0/170.72.0.1 to 0.72.127.2540.72.127.25532,766
1460.72.128.0/170.72.128.1 to 0.72.255.2540.72.255.25532,766
1470.73.0.0/170.73.0.1 to 0.73.127.2540.73.127.25532,766
1480.73.128.0/170.73.128.1 to 0.73.255.2540.73.255.25532,766
1490.74.0.0/170.74.0.1 to 0.74.127.2540.74.127.25532,766
1500.74.128.0/170.74.128.1 to 0.74.255.2540.74.255.25532,766
1510.75.0.0/170.75.0.1 to 0.75.127.2540.75.127.25532,766
1520.75.128.0/170.75.128.1 to 0.75.255.2540.75.255.25532,766
1530.76.0.0/170.76.0.1 to 0.76.127.2540.76.127.25532,766
1540.76.128.0/170.76.128.1 to 0.76.255.2540.76.255.25532,766
1550.77.0.0/170.77.0.1 to 0.77.127.2540.77.127.25532,766
1560.77.128.0/170.77.128.1 to 0.77.255.2540.77.255.25532,766
1570.78.0.0/170.78.0.1 to 0.78.127.2540.78.127.25532,766
1580.78.128.0/170.78.128.1 to 0.78.255.2540.78.255.25532,766
1590.79.0.0/170.79.0.1 to 0.79.127.2540.79.127.25532,766
1600.79.128.0/170.79.128.1 to 0.79.255.2540.79.255.25532,766
1610.80.0.0/170.80.0.1 to 0.80.127.2540.80.127.25532,766
1620.80.128.0/170.80.128.1 to 0.80.255.2540.80.255.25532,766
1630.81.0.0/170.81.0.1 to 0.81.127.2540.81.127.25532,766
1640.81.128.0/170.81.128.1 to 0.81.255.2540.81.255.25532,766
1650.82.0.0/170.82.0.1 to 0.82.127.2540.82.127.25532,766
1660.82.128.0/170.82.128.1 to 0.82.255.2540.82.255.25532,766
1670.83.0.0/170.83.0.1 to 0.83.127.2540.83.127.25532,766
1680.83.128.0/170.83.128.1 to 0.83.255.2540.83.255.25532,766
1690.84.0.0/170.84.0.1 to 0.84.127.2540.84.127.25532,766
1700.84.128.0/170.84.128.1 to 0.84.255.2540.84.255.25532,766
1710.85.0.0/170.85.0.1 to 0.85.127.2540.85.127.25532,766
1720.85.128.0/170.85.128.1 to 0.85.255.2540.85.255.25532,766
1730.86.0.0/170.86.0.1 to 0.86.127.2540.86.127.25532,766
1740.86.128.0/170.86.128.1 to 0.86.255.2540.86.255.25532,766
1750.87.0.0/170.87.0.1 to 0.87.127.2540.87.127.25532,766
1760.87.128.0/170.87.128.1 to 0.87.255.2540.87.255.25532,766
1770.88.0.0/170.88.0.1 to 0.88.127.2540.88.127.25532,766
1780.88.128.0/170.88.128.1 to 0.88.255.2540.88.255.25532,766
1790.89.0.0/170.89.0.1 to 0.89.127.2540.89.127.25532,766
1800.89.128.0/170.89.128.1 to 0.89.255.2540.89.255.25532,766
1810.90.0.0/170.90.0.1 to 0.90.127.2540.90.127.25532,766
1820.90.128.0/170.90.128.1 to 0.90.255.2540.90.255.25532,766
1830.91.0.0/170.91.0.1 to 0.91.127.2540.91.127.25532,766
1840.91.128.0/170.91.128.1 to 0.91.255.2540.91.255.25532,766
1850.92.0.0/170.92.0.1 to 0.92.127.2540.92.127.25532,766
1860.92.128.0/170.92.128.1 to 0.92.255.2540.92.255.25532,766
1870.93.0.0/170.93.0.1 to 0.93.127.2540.93.127.25532,766
1880.93.128.0/170.93.128.1 to 0.93.255.2540.93.255.25532,766
1890.94.0.0/170.94.0.1 to 0.94.127.2540.94.127.25532,766
1900.94.128.0/170.94.128.1 to 0.94.255.2540.94.255.25532,766
1910.95.0.0/170.95.0.1 to 0.95.127.2540.95.127.25532,766
1920.95.128.0/170.95.128.1 to 0.95.255.2540.95.255.25532,766
1930.96.0.0/170.96.0.1 to 0.96.127.2540.96.127.25532,766
1940.96.128.0/170.96.128.1 to 0.96.255.2540.96.255.25532,766
1950.97.0.0/170.97.0.1 to 0.97.127.2540.97.127.25532,766
1960.97.128.0/170.97.128.1 to 0.97.255.2540.97.255.25532,766
1970.98.0.0/170.98.0.1 to 0.98.127.2540.98.127.25532,766
1980.98.128.0/170.98.128.1 to 0.98.255.2540.98.255.25532,766
1990.99.0.0/170.99.0.1 to 0.99.127.2540.99.127.25532,766
2000.99.128.0/170.99.128.1 to 0.99.255.2540.99.255.25532,766
2010.100.0.0/170.100.0.1 to 0.100.127.2540.100.127.25532,766
2020.100.128.0/170.100.128.1 to 0.100.255.2540.100.255.25532,766
2030.101.0.0/170.101.0.1 to 0.101.127.2540.101.127.25532,766
2040.101.128.0/170.101.128.1 to 0.101.255.2540.101.255.25532,766
2050.102.0.0/170.102.0.1 to 0.102.127.2540.102.127.25532,766
2060.102.128.0/170.102.128.1 to 0.102.255.2540.102.255.25532,766
2070.103.0.0/170.103.0.1 to 0.103.127.2540.103.127.25532,766
2080.103.128.0/170.103.128.1 to 0.103.255.2540.103.255.25532,766
2090.104.0.0/170.104.0.1 to 0.104.127.2540.104.127.25532,766
2100.104.128.0/170.104.128.1 to 0.104.255.2540.104.255.25532,766
2110.105.0.0/170.105.0.1 to 0.105.127.2540.105.127.25532,766
2120.105.128.0/170.105.128.1 to 0.105.255.2540.105.255.25532,766
2130.106.0.0/170.106.0.1 to 0.106.127.2540.106.127.25532,766
2140.106.128.0/170.106.128.1 to 0.106.255.2540.106.255.25532,766
2150.107.0.0/170.107.0.1 to 0.107.127.2540.107.127.25532,766
2160.107.128.0/170.107.128.1 to 0.107.255.2540.107.255.25532,766
2170.108.0.0/170.108.0.1 to 0.108.127.2540.108.127.25532,766
2180.108.128.0/170.108.128.1 to 0.108.255.2540.108.255.25532,766
2190.109.0.0/170.109.0.1 to 0.109.127.2540.109.127.25532,766
2200.109.128.0/170.109.128.1 to 0.109.255.2540.109.255.25532,766
2210.110.0.0/170.110.0.1 to 0.110.127.2540.110.127.25532,766
2220.110.128.0/170.110.128.1 to 0.110.255.2540.110.255.25532,766
2230.111.0.0/170.111.0.1 to 0.111.127.2540.111.127.25532,766
2240.111.128.0/170.111.128.1 to 0.111.255.2540.111.255.25532,766
2250.112.0.0/170.112.0.1 to 0.112.127.2540.112.127.25532,766
2260.112.128.0/170.112.128.1 to 0.112.255.2540.112.255.25532,766
2270.113.0.0/170.113.0.1 to 0.113.127.2540.113.127.25532,766
2280.113.128.0/170.113.128.1 to 0.113.255.2540.113.255.25532,766
2290.114.0.0/170.114.0.1 to 0.114.127.2540.114.127.25532,766
2300.114.128.0/170.114.128.1 to 0.114.255.2540.114.255.25532,766
2310.115.0.0/170.115.0.1 to 0.115.127.2540.115.127.25532,766
2320.115.128.0/170.115.128.1 to 0.115.255.2540.115.255.25532,766
2330.116.0.0/170.116.0.1 to 0.116.127.2540.116.127.25532,766
2340.116.128.0/170.116.128.1 to 0.116.255.2540.116.255.25532,766
2350.117.0.0/170.117.0.1 to 0.117.127.2540.117.127.25532,766
2360.117.128.0/170.117.128.1 to 0.117.255.2540.117.255.25532,766
2370.118.0.0/170.118.0.1 to 0.118.127.2540.118.127.25532,766
2380.118.128.0/170.118.128.1 to 0.118.255.2540.118.255.25532,766
2390.119.0.0/170.119.0.1 to 0.119.127.2540.119.127.25532,766
2400.119.128.0/170.119.128.1 to 0.119.255.2540.119.255.25532,766
2410.120.0.0/170.120.0.1 to 0.120.127.2540.120.127.25532,766
2420.120.128.0/170.120.128.1 to 0.120.255.2540.120.255.25532,766
2430.121.0.0/170.121.0.1 to 0.121.127.2540.121.127.25532,766
2440.121.128.0/170.121.128.1 to 0.121.255.2540.121.255.25532,766
2450.122.0.0/170.122.0.1 to 0.122.127.2540.122.127.25532,766
2460.122.128.0/170.122.128.1 to 0.122.255.2540.122.255.25532,766
2470.123.0.0/170.123.0.1 to 0.123.127.2540.123.127.25532,766
2480.123.128.0/170.123.128.1 to 0.123.255.2540.123.255.25532,766
2490.124.0.0/170.124.0.1 to 0.124.127.2540.124.127.25532,766
2500.124.128.0/170.124.128.1 to 0.124.255.2540.124.255.25532,766
2510.125.0.0/170.125.0.1 to 0.125.127.2540.125.127.25532,766
2520.125.128.0/170.125.128.1 to 0.125.255.2540.125.255.25532,766
2530.126.0.0/170.126.0.1 to 0.126.127.2540.126.127.25532,766
2540.126.128.0/170.126.128.1 to 0.126.255.2540.126.255.25532,766
2550.127.0.0/170.127.0.1 to 0.127.127.2540.127.127.25532,766
2560.127.128.0/170.127.128.1 to 0.127.255.2540.127.255.25532,766

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.