Subnet cheat sheet · CIDR chart
Quick reference for all 33 IPv4 subnet prefixes (/0 through /32). Open any prefix for its dedicated calculator and configuration guide.
| CIDR | Subnet Mask | Wildcard Mask | Total IPs | Usable Hosts | Binary Mask | Typical Usage | Action |
|---|---|---|---|---|---|---|---|
| /0 | 0.0.0.0 | 255.255.255.255 | 4,29,49,67,296 | 4,29,49,67,294 | 00000000.00000000.00000000.00000000 | Default Route / Entire Internet | View /0 |
| /1 | 128.0.0.0 | 127.255.255.255 | 2,14,74,83,648 | 2,14,74,83,646 | 10000000.00000000.00000000.00000000 | Subnet block | View /1 |
| /2 | 192.0.0.0 | 63.255.255.255 | 1,07,37,41,824 | 1,07,37,41,822 | 11000000.00000000.00000000.00000000 | Subnet block | View /2 |
| /3 | 224.0.0.0 | 31.255.255.255 | 53,68,70,912 | 53,68,70,910 | 11100000.00000000.00000000.00000000 | Subnet block | View /3 |
| /4 | 240.0.0.0 | 15.255.255.255 | 26,84,35,456 | 26,84,35,454 | 11110000.00000000.00000000.00000000 | Subnet block | View /4 |
| /5 | 248.0.0.0 | 7.255.255.255 | 13,42,17,728 | 13,42,17,726 | 11111000.00000000.00000000.00000000 | Subnet block | View /5 |
| /6 | 252.0.0.0 | 3.255.255.255 | 6,71,08,864 | 6,71,08,862 | 11111100.00000000.00000000.00000000 | Subnet block | View /6 |
| /7 | 254.0.0.0 | 1.255.255.255 | 3,35,54,432 | 3,35,54,430 | 11111110.00000000.00000000.00000000 | Subnet block | View /7 |
| /8 | 255.0.0.0 | 0.255.255.255 | 1,67,77,216 | 1,67,77,214 | 11111111.00000000.00000000.00000000 | Class A Major Network (16M usable) | View /8 |
| /9 | 255.128.0.0 | 0.127.255.255 | 83,88,608 | 83,88,606 | 11111111.10000000.00000000.00000000 | Subnet block | View /9 |
| /10 | 255.192.0.0 | 0.63.255.255 | 41,94,304 | 41,94,302 | 11111111.11000000.00000000.00000000 | Subnet block | View /10 |
| /11 | 255.224.0.0 | 0.31.255.255 | 20,97,152 | 20,97,150 | 11111111.11100000.00000000.00000000 | Subnet block | View /11 |
| /12 | 255.240.0.0 | 0.15.255.255 | 10,48,576 | 10,48,574 | 11111111.11110000.00000000.00000000 | Subnet block | View /12 |
| /13 | 255.248.0.0 | 0.7.255.255 | 5,24,288 | 5,24,286 | 11111111.11111000.00000000.00000000 | Subnet block | View /13 |
| /14 | 255.252.0.0 | 0.3.255.255 | 2,62,144 | 2,62,142 | 11111111.11111100.00000000.00000000 | Subnet block | View /14 |
| /15 | 255.254.0.0 | 0.1.255.255 | 1,31,072 | 1,31,070 | 11111111.11111110.00000000.00000000 | Subnet block | View /15 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,536 | 65,534 | 11111111.11111111.00000000.00000000 | Class B Enterprise Network (65,534 usable) | View /16 |
| /17 | 255.255.128.0 | 0.0.127.255 | 32,768 | 32,766 | 11111111.11111111.10000000.00000000 | Subnet block | View /17 |
| /18 | 255.255.192.0 | 0.0.63.255 | 16,384 | 16,382 | 11111111.11111111.11000000.00000000 | Subnet block | View /18 |
| /19 | 255.255.224.0 | 0.0.31.255 | 8,192 | 8,190 | 11111111.11111111.11100000.00000000 | Subnet block | View /19 |
| /20 | 255.255.240.0 | 0.0.15.255 | 4,096 | 4,094 | 11111111.11111111.11110000.00000000 | Large Enterprise / Campus (4,094 usable) | View /20 |
| /21 | 255.255.248.0 | 0.0.7.255 | 2,048 | 2,046 | 11111111.11111111.11111000.00000000 | Subnet block | View /21 |
| /22 | 255.255.252.0 | 0.0.3.255 | 1,024 | 1,022 | 11111111.11111111.11111100.00000000 | Enterprise Site (1,022 usable) | View /22 |
| /23 | 255.255.254.0 | 0.0.1.255 | 512 | 510 | 11111111.11111111.11111110.00000000 | Dual Class C (510 usable) | View /23 |
| /24 | 255.255.255.0 | 0.0.0.255 | 256 | 254 | 11111111.11111111.11111111.00000000 | Standard Office / Home LAN (254 usable) | View /24 |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 | 126 | 11111111.11111111.11111111.10000000 | Half Class C (126 usable) | View /25 |
| /26 | 255.255.255.192 | 0.0.0.63 | 64 | 62 | 11111111.11111111.11111111.11000000 | Department Subnet (62 usable) | View /26 |
| /27 | 255.255.255.224 | 0.0.0.31 | 32 | 30 | 11111111.11111111.11111111.11100000 | Medium Department (30 usable) | View /27 |
| /28 | 255.255.255.240 | 0.0.0.15 | 16 | 14 | 11111111.11111111.11111111.11110000 | Small Branch / VLAN (14 usable) | View /28 |
| /29 | 255.255.255.248 | 0.0.0.7 | 8 | 6 | 11111111.11111111.11111111.11111000 | Small Subnet / DMZ (6 usable) | View /29 |
| /30 | 255.255.255.252 | 0.0.0.3 | 4 | 2 | 11111111.11111111.11111111.11111100 | Point-to-Point Link (Traditional) | View /30 |
| /31 | 255.255.255.254 | 0.0.0.1 | 2 | 2 | 11111111.11111111.11111111.11111110 | Point-to-Point Link (RFC 3021) | View /31 |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | 1 | 11111111.11111111.11111111.11111111 | Single Host / Loopback | View /32 |
This CIDR chart converts between subnet mask to CIDR, wildcard masks and host counts. Every row links to a dedicated page. Need to calculate a specific address? Use the IP subnet calculator, or convert in either direction with the subnet mask calculator and CIDR calculator.
New to the topic? Read subnetting explained and the guide to IP address classes.
A CIDR chart (or CIDR table) lists every prefix length from /0 to /32 with its subnet mask, wildcard mask and number of addresses, so you can convert between notations without calculating.
Find the prefix (for example /26) in the first column. The same row gives the dotted subnet mask (255.255.255.192), the total addresses (64) and the usable hosts (62).
Yes. Use the print button below the table or your browser print dialog; the page has a print stylesheet that hides navigation so you can save a clean PDF.