Excel SECOND Function: Syntax, Examples and Tips

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The Excel SECOND function returns the seconds component of a time as a whole number from 0 to 59. It reads the time fraction of a serial number, so it works on time cells, full timestamps, decimal fractions of a day and time text such as “9:30:45 AM”. SECOND is used with HOUR and MINUTE to split times into parts, to strip or round seconds, and to convert clock times into total seconds for timing calculations.

Table of Contents

Syntax

=SECOND(serial_number)

Arguments

Argument	Required / Optional	Meaning
serial_number	Required	The time to read: a time or date-time cell, a decimal such as 0.5, a TIME or NOW result, or recognisable time text.

How SECOND works

Excel stores a time as a fraction of a day, so one second is 1/86400. SECOND converts the fraction to hours, minutes and seconds and returns only the seconds. =SECOND("9:30:45 AM") returns 45, =SECOND("2026-09-04 14:05:07") returns 7 and =SECOND(0.5) returns 0. Fractions of a second are rounded to the nearest whole second. The date part is ignored, and values above one day wrap, so a duration of 25:00:30 returns 30. Text that is not a valid time gives #VALUE!, negative numbers give #NUM!.

Step-by-step example: lap times in total seconds

Column A holds lap times such as 0:01:42.
In B2 enter =SECOND(A2) and fill down to see the seconds part (42).
In C2 enter =HOUR(A2)*3600+MINUTE(A2)*60+SECOND(A2). For 0:01:42 the result is 102 seconds.
Fill down and use =MIN(C2:C20) to find the fastest lap. Convert back with =MIN(C2:C20)/86400 formatted as mm:ss.

Practical use cases

1. Total seconds in a time

=A2*86400

Equivalent to the HOUR, MINUTE and SECOND combination but also correct for durations over 24 hours.

2. Remove seconds from timestamps

=A2-SECOND(A2)/86400

3. Round a time to the nearest minute

=IF(SECOND(A2)>=30,A2+(60-SECOND(A2))/86400,A2-SECOND(A2)/86400)

MROUND(A2,”0:01″) does the same in one step.

4. Check that log entries are exactly on the minute

=SECOND(A2)=0

5. Build a time label with two-digit seconds

=TEXT(HOUR(A2),"00")&":"&TEXT(MINUTE(A2),"00")&":"&TEXT(SECOND(A2),"00")

Common mistakes and tips

Using SECOND for durations: a stopwatch reading of 1:30 (one minute thirty) returns 30, not 90. Multiply by 86400 for total seconds.
Hidden seconds: a cell formatted h:mm still stores seconds. SECOND reveals them, which explains why two times that look identical compare as different.
Rounding surprises: 0.4 seconds rounds down and 0.5 rounds up; Excel time formats can show a different rounding.
Result displayed as a time: a cell in time format shows 45 as a date. Set it to General.
#VALUE! error: the text cannot be read as a time. Check separators and AM/PM spelling.

SECOND compared with HOUR, MINUTE, TEXT and multiplication

SECOND, MINUTE and HOUR return one component each and TIME reassembles them, so together they handle any clock manipulation within a 24-hour day. When the goal is an amount of time rather than a clock reading, arithmetic is simpler and safer: multiply a time difference by 24 for hours, 1440 for minutes or 86400 for seconds, and the result is correct for any duration, including days. TEXT(A2,”ss”) returns the seconds as two-digit text for display only. In Excel 365 and Google Sheets the behaviour of SECOND is identical, and in both the seconds portion is often the culprit when timestamps that appear equal fail to match in VLOOKUP or MATCH; stripping seconds with the formula above fixes that.