How stop counting if met requirements

[Kemark16]

Dear all,
Could you please advice how in a quick way put correct formula, I am novice and struggling already a lot of time without result
A4 start date
B4 stop date
C4 days - here I would like to have number of days (so B4 - A4), but if I will fill the "stop date", so B4 - it should stop counting and be marked as green - automatically.
Can you please help?

 

[PeteWright]

I think you made a mistake.

If A4 is filled with a start date and C4 contains a formula (B4-A4), then how can B4 be empty at all?

Could you revise your data please.

 

[Kemark16]

I think you made a mistake.

If A4 is filled with a start date and C4 contains a formula (B4-A4), then how can B4 be empty at all?

Could you revise your data please.

I assume that we need to combine these two visible formulas on the picture uploaded.
I would like to have first formula (red C4) to be blocked when I put formula to (B4) cell.
Any ideas?

 

[PeteWright]

There's a problem with your formula, the formula uses it's own cell as reference:

So B4 = DAYS(B4; A4) is a recursion and therefore not working.

Could you please check your formula again.

 

[Kemark16]

There's a problem with your formula, the formula uses it's own cell as reference:

So B4 = DAYS(B4; A4) is a recursion and therefore not working.

Could you please check your formula again.

formula = DAYS(B4; A4) is correct "no date (data) in cell B4"
My thought is:
Two formulas in one cell, so that the formula =days(today();A4) works until the date is entered in B4
That is:
=days(today(),A4) =days(B4,A4) these two formulas are supposed to run in cell C4

 

[PeteWright]

formula = DAYS(B4; A4) is correct "no date (data) in cell B4"
My thought is:
Two formulas in one cell, so that the formula =days(today();A4) works until the date is entered in B4
That is:
=days(today(),A4) =days(B4,A4) these two formulas are supposed to run in cell C4

Well, two formulas at the same time in a single cell, that is not possible.

You should overthink your calculations and decide which formula you want to run in cell C4. Until then, I'm afraid I can't help.

 

[kevin9999]

Like @PeteWright I'm a bit confused about your intention, but is this what you meant?

Book1
	A	B	C
3	Data Start	Data stop	Days
4	01.11.2023		12
Sheet1

Cell Formulas
Range	Formula
C4	C4	=IF(B4="",TODAY()-A4,B4-A4)

Book1
	A	B	C
3	Data Start	Data stop	Days
4	01.11.2023	10.11.2023	9
Sheet1

Cell Formulas
Range	Formula
C4	C4	=IF(B4="",TODAY()-A4,B4-A4)