Spreadsheet Practice

How to convert an ISO 8601 timestamp to a date and time in Excel

Formula (Excel and Google Sheets)

=DATEVALUE(LEFT(A2,10))+TIMEVALUE(MID(A2,12,8))

Convert the date and time parts and add them: =DATEVALUE(LEFT(A2,10))+TIMEVALUE(MID(A2,12,8)).

Result on the example
one result per row in B2, filled down to B6
Works in
Every current version
Google Sheets
Same formula

See it work

The formula is already in B2, filled down to B6. Change any input and the result updates, or edit the formula to experiment.

How it works

An ISO 8601 timestamp is text: the date in the first 10 characters, a T, then the time. DATEVALUE(LEFT(A2,10)) gives the date, TIMEVALUE(MID(A2,12,8)) gives the time as a fraction of a day, and adding them gives one date-time value. The trailing Z means UTC.

=DATEVALUE(LEFT(A2,10))+TIMEVALUE(MID(A2,12,8))

Result46086.60417

  1. A2"2026-03-05T14:30:00Z"

    The value in A2.

  2. LEFT(A2,10)"2026-03-05"

    LEFT: Characters from the start of text.

    • textA2"2026-03-05T14:30:00Z"
    • num_chars10
  3. DATEVALUE(LEFT(A2,10))3/5/2026 (46086)

    DATEVALUE: Converts date text to a date.

    • date_textLEFT(A2,10)"2026-03-05"
  4. MID(A2,12,8)"14:30:00"

    MID: Characters from the middle of text.

    • textA2"2026-03-05T14:30:00Z"
    • start_num12
    • num_chars8
  5. TIMEVALUE(MID(A2,12,8))0.6041666667

    TIMEVALUE: Converts time text such as "1:30 PM" into a time.

    • time_textMID(A2,12,8)"14:30:00"
  6. DATEVALUE(LEFT(A2,10))+TIMEVALUE(MID(A2,12,8))46086.60417

    The + operator adds.

In Google Sheets

The same formula works in Google Sheets: =DATEVALUE(LEFT(A2,10))+TIMEVALUE(MID(A2,12,8)). We ran it in Google Sheets mode on the same data and it returns the same results.

Other ways to do it

Each one was run on the same example sheet.

FormulaResultWhen to use it
=--SUBSTITUTE(LEFT(A2,19),"T"," ")3/5/2026 14:30:00, 3/5/2026 9:05:12, 11/1/2026 0:00:00…Replaces the T with a space and converts the text in one step.
=DATEVALUE(LEFT(A2,10))3/5/2026 0:00:00, 3/5/2026 0:00:00, 11/1/2026 0:00:00…Different resultThe date only. Drops the time.

Common mistakes

  • A timestamp with an offset like +02:00 is local time. Subtract the offset (add it for a minus sign) to get UTC.
  • Fractional seconds like 14:30:00.123Z make the text longer; MID(A2,12,8) ignores them.

Try it yourself

Same data, empty answer cell. Your formula is graded instantly, then re-checked on changed data, so a typed-in number won't pass.

Convert an ISO 8601 timestamp to a date and time

In B2, convert the ISO 8601 text timestamp to a real date and time, and fill down to B6.

Questions

How do I convert it to my time zone?

Add or subtract hours/24: =B2-5/24 for US Eastern Standard Time.

How do I write a date as ISO 8601 text?

=TEXT(B2,"yyyy-mm-dd")&"T"&TEXT(B2,"hh:mm:ss")&"Z".

Why do I see a number like 46086.60417?

That is the date-time value. Format the cell as a date and time, for example m/d/yyyy h:mm.

Checked by running on 2026-10-30: every formula and result on this page was calculated by the Spreadsheet Practice formula engine, in both Excel and Google Sheets modes.