Network Mask Calculator
The subnet mask from a prefix Enter your values, click Calculate, and get the full result with its breakdown — everything is processed on your device, nothing is sent to a server.
or press Ctrl+Enter
Result
Fill the fields and click Calculate — the result appears here.
All calculations run in your browser. Your data is never sent to our servers.
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Example
Example Input
/26
Example Output
255.255.255.192
How to Use
- 1Fill in each input field with the values you want to compute.
- 2If there are choices (units, mode, operation), pick what you need.
- 3Click the Calculate button (or press Ctrl+Enter).
- 4The main result and its breakdown appear in the Result area. Click Copy to copy it.
About the Network Mask Calculator
The Network Mask Calculator computes the subnet mask from a prefix from an IPv4 address and its prefix. Enter IP/CIDR or set the prefix separately.
Computed natively with 32-bit bit operations, 100% in the browser.
FAQ
Is this Network Mask Calculator accurate?
Yes. It uses standard formulas and runs directly in your browser at full JavaScript precision (plus BigInt/decimal.js for large numbers where needed).
Is my data sent to a server?
No. All calculations happen entirely on your device. No values are sent to or stored on our servers.