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IPv4 Wildcard Mask Calculator
Calculate an IPv4 wildcard mask from a subnet mask or CIDR prefix. View the network and broadcast addresses, binary representations, and sample Cisco ACL and OSPF configuration statements.
Calculate a Wildcard Mask
Enter an IPv4 address and either a CIDR prefix (/24) or a dotted subnet mask (255.255.255.0).
Request Diagnostics
These details help determine whether the server received your form submission. Avoid leaving diagnostic information publicly enabled.
| Check | Value |
|---|---|
| PHP version | 8.2.34 |
| Request method | GET |
| Request path | /wildcard-mask-calculator |
| POST received | No |
| POST IP field | Missing |
| POST mask field | Missing |
| Calculation result | Not submitted |
Common Wildcard Mask Examples
| CIDR | Subnet mask | Wildcard mask | Total addresses |
|---|---|---|---|
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,216 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,536 |
| /24 | 255.255.255.0 | 0.0.0.255 | 256 |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 |
| /26 | 255.255.255.192 | 0.0.0.63 | 64 |
| /27 | 255.255.255.224 | 0.0.0.31 | 32 |
| /30 | 255.255.255.252 | 0.0.0.3 | 4 |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 |
Frequently Asked Questions
What is a wildcard mask?
A wildcard mask identifies which IPv4 address bits a networking configuration should match. It is commonly used in Cisco ACLs and routing protocol network statements.
What is the wildcard mask for /24?
The wildcard mask is 0.0.0.255, corresponding to
subnet mask 255.255.255.0.
Can I enter a dotted subnet mask?
Yes. Enter a mask such as 255.255.255.192 or a
CIDR prefix such as /26.
Why are there 256 addresses in a /24?
An IPv4 /24 leaves eight host bits. There are 28 = 256 total addresses in that block.