SECOND function: extract seconds (0-59) and compute total duration in seconds

SECOND extracts only the 0-59 clock component

SECOND(serial_number) returns an integer from 0 to 59 representing the seconds portion of a time value—not the entire duration converted to seconds. For a 4-minute 38-second call (TIME(0, 4, 38)), SECOND returns 38.

To convert the full hh:mm:ss duration into total elapsed seconds, combine HOUR(t)*3600 + MINUTE(t)*60 + SECOND(t) (or ROUND(t * 86400, 0)).

The HOUR/MINUTE/SECOND combination covers only the time-of-day part and wraps after 24 hours. For a numeric duration that includes whole days, use ROUND(duration*86400,0). For two date-time stamps, use ROUND((end-start)*86400,0); do not multiply an absolute timestamp to obtain an elapsed duration.

Total duration in seconds formula

Weighting hours by 3,600 and minutes by 60 avoids floating-point rounding drift when billing per-second telephony or telemetry intervals.

=HOUR(A2) * 3600 + MINUTE(A2) * 60 + SECOND(A2)

Automatic rollover above 59 seconds inside TIME

Passing 75 seconds to TIME(0, 0, 75) carries 60 seconds into 1 minute and leaves 15 seconds, so SECOND(TIME(0, 0, 75)) returns 15.

=SECOND(TIME(0, 0, 75))

Further reading

• Microsoft Support — SECOND function