A chronograph is a stopwatch on your wrist
The watch continues to show the time while a separate mechanism measures an interval. Most models use a start/stop pusher near 2 o’clock and a reset pusher near 4 o’clock, but layouts and functions vary.
Identify the hands first
The long center seconds hand may be the chronograph seconds hand, while normal running seconds appear on a subdial. Other subdials may total elapsed minutes or hours. Some quartz chronographs include fractions of a second. Check the manual before assuming what each register measures.
The basic sequence
Press the start/stop pusher once to begin timing. Press it again to stop. Read the elapsed seconds and any minute or hour totalizers. Then press reset to return the chronograph hands to zero. On most standard chronographs, reset should be used only after timing has stopped.
Do not force or improvise
A pusher that feels blocked or abnormal needs inspection. Do not repeatedly reset a running chronograph unless the movement is specifically designed as a flyback. Do not use pushers underwater unless the manufacturer expressly approves underwater operation.
What a tachymeter does
A tachymeter scale can estimate average speed over a known distance. Start timing at the beginning of one mile or kilometer and stop at the end; the chronograph seconds hand points to the approximate units per hour. The scale assumes constant distance and is not a substitute for precision instrumentation.
Quartz hand alignment
After battery work or a strong impact, a quartz chronograph hand may no longer rest exactly at zero. Many models allow electronic re-centering through a specific crown-and-pusher sequence. Because sequences differ, use the model manual rather than a generic procedure.