# Countdown Timer & Stopwatch A precise, drift-corrected countdown timer and stopwatch with laps, presets, and a gentle chime when time's up. Runs entirely in your browser — no sign-in, no tracking. ### How it works Naive timers built on `setInterval` drift — the browser never fires them exactly on schedule. This one reads a `performance.now()` timestamp on every animation frame and re-derives the remaining time from real elapsed time, so it stays accurate even in a backgrounded tab. Want to build one? Read the [step-by-step guide](build-countdown-timer.html). --- *Source: [ocxly.com/countdown-timer.html](https://ocxly.com/countdown-timer.html) — OCXLY, free 100% client-side privacy-first tools. A free, accurate online countdown timer and stopwatch with laps, presets, a chime and optional desktop notification. Drift-corrected and runs entirely in your browser.*