Build multi-step intervals for fitness, study, focused work, and more
Interval training works by alternating between periods of effort and recovery on a fixed schedule. Whether you are running Tabata circuits, pacing a deep-work session, or timing a coaching drill, the key is keeping the schedule consistent and hands-free. Timer Composer lets you name each phase, assign it a color, and set precise durations so the segmented bar tells you at a glance where you are in the full routine.
The countdown runs in a dedicated background thread that anchors to an absolute end timestamp rather than counting down from a stored number. This means switching tabs, dimming your screen, or a brief CPU spike will never cause the timer to run slow. The worker fires every 200 ms and posts the remaining milliseconds directly to the display.
Each step gets its own color, which appears in the segmented progress bar and on the live clock readout. The bar is proportional to each step's share of the total session time, so a 60-second warm-up alongside a 20-second work interval will look exactly as wide as their durations imply. The cursor and shaded fill move together in real time.
Saved presets are stored in your browser's local storage and reload instantly by name. The Share button encodes your entire current routine, including step names, durations, colors, and chime preference, into a single URL parameter using Base64. Anyone who opens that link will see the exact same configuration loaded and ready to run, on any device.