Chess Clock

A two-player alternating countdown clock — the same style used for chess, but works for any turn-based game or timed debate.

The chess clock is a much newer invention than the game it's associated with — chess itself is centuries old, but timed chess only became standard in the mid-1800s, after tournament games without a clock had a habit of dragging on for many hours or even being abandoned entirely when a player refused to move. The solution, a clock that only runs for whichever player's turn it currently is, has barely changed in concept since then, even as the physical mechanism evolved from wind-up dual clocks to today's digital versions.

What makes a chess clock structurally different from every other timer on this site is that it's built around exactly two competing countdowns that hand control back and forth — only one side's clock ever runs at a time, and pressing your side after a move is what starts your opponent's clock instead. That alternating mechanic is what actually defines the tool; the fact that it originated in chess is almost incidental; the same mechanic works identically for any turn-based activity where you want to enforce a time budget per side, from formal debates to two-player board games that don't come with a built-in clock.

This version keeps the core mechanic intentionally simple — set a starting time per side, tap to pass the turn, and see a clear alert the moment either side runs out — without adding the increment or delay rules that competitive tournament chess clocks use, since those add complexity that most casual uses of a chess clock don't actually need.

1. Set the minutes per side.
2. Press Start.
3. Tap a player's clock after their turn to pass time to the other player. When a clock hits zero, that player is out of time.