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NETWORK DESK
Convert a subnet mask in dotted-decimal form to a CIDR prefix length, or vice versa.
WHAT THIS DOES
Runs entirely in your browser.
/tools/subnet-calculatorsubnet-calcv4.0.0LOCAL · LOCAL RUNIMPLEMENTED — This workbench is functional in the current release.Presets for this workbench
No preset yet. A preset stores the values in this form — never the result — and only for workbenches that run entirely in your browser.
Collections
Saved on this device only. Turn on sync to carry them to another device.
BATCH / ONE VALUE PER LINE
Up to 200 lines, one at a time, in this browser. Each line takes the place of value and everything else stays as you set it. Nothing is uploaded, and the row limit is not exceeded silently.
METHOD / LOCAL RUN
Dotted → CIDR: count contiguous 1 bits in the 32-bit mask. CIDR → Dotted: shift 1s into the upper bits and format.
Boundary: Valid contiguous masks only. Non-contiguous (CIDR-invalid) masks are rejected.
The calculation or transformation runs in your browser using the values entered above. No input is sent to UtilityForge for this tool.
EXAMPLES / LOCAL RUN FIXTURES
FAQ
No. The subnet mask calculator runs entirely in your browser.
The workbench states the exact method behind every result — the formula or procedure this page runs — so you can verify the computation instead of trusting a black box.
No. This workbench runs in the page: Mode, Subnet mask or prefix are read by the code your browser already downloaded, and UtilityForge receives neither the values nor the result.
Valid contiguous masks only. Non-contiguous (CIDR-invalid) masks are rejected.
RELATED TOOLS
LOCAL — Runs entirely in your browser.
COMMON USE CASES / SOURCE NOTE
Last reviewed:
Source information: Local bit math; no remote call.