My Calculator Stack · Time formulas
Time formulas
One printable sheet for 2 Time tools — formulas collected from each calculator’s How it works.
Exam Timer
Open tool →
\[ t_{\mathrm{left}} = T - t_{\mathrm{elapsed}} \]
Remaining time is the configured duration minus the time that has actually run (pauses are skipped).
\[ p = t_{\mathrm{left}} / T \]
The progress bar is remaining divided by the original duration: full at start, empty at zero. Reset returns to the configured duration and clears the start time.
Stopwatch
Open tool →
\[ \Delta t = t_{1} - t_{0} \]
Elapsed time is the difference between the current clock reading and the start reading (plus any time already accumulated before a pause).
Keep going
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