There is no backend, login or telemetry in the project. Calculations happen on your device.
Free · Private · Browser-based
Small admin tools that get out of your way.
Calculate IPv4 subnets, build Linux permissions, generate standard cron expressions and convert Unix timestamps. Everything runs locally in your browser.
$ cidr 192.168.10.20/27
network 192.168.10.0/27
hosts 30 usable
$ chmod rwxr-xr-x
mode 755
$ cron "weekdays 08:00"
schedule 0 8 * * 1-5
Choose a tool
Useful answers in a few clicks
No account, API key, backend or network scan. Your input stays in the current browser tab.
CIDR Calculator
Find network, broadcast, host range, mask, wildcard and address counts for an IPv4 prefix.
Calculate a subnet →chmod Calculator
Convert visual read, write and execute permissions into symbolic and numeric Linux modes.
Build permissions →Cron Generator
Create common standard five-field Unix cron schedules without memorising every field.
Generate a schedule →Unix Timestamp
Convert dates to Unix seconds or milliseconds and turn timestamps back into readable dates.
Convert time →After the first successful visit, the installable web app can keep the core tools available without a connection.
The complete HTML, CSS and JavaScript source is available on GitHub under the MIT License.
Built by Wojciech Lepczyński
Hardware, Linux, cloud and practical experiments
Admin Toolkit grew out of my ESP32 Pocket Admin Toolkit project. Read more practical articles on my blog, watch hardware and cloud experiments on YouTube, or inspect the source code.