I have four fields in Numbers on macOS:

  1. F1: datetime
  2. F2: datetime
  3. F3: duration
  4. F4: number

The dateime-fieds contain only a time, like:

10:00    11:00
11:00    12:30
13:00    13:15

The duration-field is calculated by this formular:

F2 - F1

And shows something like:

1h 30m

This works fine.

Now I want to calculate F4 which is a number representation of the duration-field F3. For the examples above it should result in:


Unfortuanteley I can't find a way to achieve this. How can this be solved?

What I've tried so far:

  • changing the fomatting to number didn't work as it will always reset to duration
  • setting the field F3 to seconds-only and then calculating F3 / 3600, but the result will always be a new duration
  • What have you tried that fails? A formula, or calculation? Just setting the cell format? A combination? Cheers
    – bjbk
    Jan 9 '18 at 15:21
  • @bjbk Good point - I've updated the question. The problem seems that every formular applied to F3 will result in a new duration-value and never in a number.
    – lampshade
    Jan 9 '18 at 15:34
  • Great! I’ll work on it too and see what we can come up with.
    – bjbk
    Jan 9 '18 at 15:35
  • 2
    Did you try googling first? I ask because searching e.g. convert hours and minutes to decimal in numbers gave me the DUR2HOURS() formula. Jan 9 '18 at 16:25

Use the DUR2HOURS() formula.


Pass the duration from F3 to the formula.

Duration to hours example

  • Wow, that's awesome. Didn't know a function like this exists. Thank you very much.
    – lampshade
    Jan 9 '18 at 16:24

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