Chess Clock
Pick a time control and tap your side after each move. Free, no account needed.
How the chess clock works
Each player has their own time bank. When it is your move, your clock counts down. Make your move on the board, then tap your side of the clock: that stops your clock, adds the increment, and starts your opponent. If your time runs out you have flagged, and the game is over.
The second number in a time control is the Fischer increment, the seconds added to your clock after every move. A 5 | 3 game gives each player five minutes plus three seconds a move, which keeps a game from ending on a scramble as often as a plain five minute clock does.
Two players sharing a bank each is what a chess clock is for. Where three or more people are round a table, or where every turn should get the same fixed slot rather than draw from a bank, the board game turn timer loops a set time around the table instead.