Cell automatically updating when other cells are filled out

[Em73]

A Hard one to describe really.
I am creating a stock sheet. I have attached a picture of it and happy to send it. What I want is for a particular Cell (K12) to have the running balance. So at the moment it would display 101 as that is the last balance (from cell K19)in there. However once the next balance is update (K20) I want cell K12 to have that in it. I appreciate it is probably an easy formula but out of my league.
Thanks in advance Em

 

[JackDanIce]

Hi welcome to the board

1) In a totally seperate cell enter exactly:

9.99999999999999E+307

2) Name this cell 'BigNum'
3) In K12 enter the formula:

=VLOOKUP(BigNum,$K$13:$K$500,TRUE,TRUE)

Change 500 if you have more than 500 rows

 

[Em73]

Thank you so much. I never in a million years would have worked that out.
Thank you thank you thank you

 

[JackDanIce]

You're welcome