About onetimer

We operate onetimer.app as a small independent publisher. There is no account system and no paid product behind a login wall. The tools are meant to be used immediately in the browser.

Questions about the site, privacy, or these tools: [email protected].

The core modules are an alarm clock (time of day), a duration timer with sound, a date countdown, a stopwatch with laps, a world clock, a Pomodoro cycle, and Tabata/HIIT interval displays. Date calculators sit alongside those modules for day-count questions.

Each module page explains when to use that tool instead of another. If you only need a bell after a fixed length, use Timer. If you need elapsed laps, use Stopwatch. If you need another city's local time, use World Clock.

Settings stay in this browser unless you copy a share URL. Alarm and timer sounds need the tab to stay open; browsers do not let a background page ring as reliably as a phone alarm. Preview a sound with Try Alert before you rely on it.

Guides under /guides cover study sessions, the 20-20-20 eye break, Notion embeds, and PowerPoint countdowns. Those pages are written as how-to instructions for the same tools.

Email [email protected]. We read mail about broken pages, privacy questions, and how the tools behave. We do not offer phone support.