How to create an acumulative result

I’m starting a spreadsheet to track my daily Electric meter usage.
I enter the reading in column/cell “C4”.
In column “L” I want the “amt changed” to reflect day to day readings,
as accumulative, that I can track how much energy I use in 30 days or whatever time period I want to continue the readings.
This means that I need to subtract “C4” from every cell following in the “C” column
and then put the results in the “L” column and the corresponding cell, i.e L4, L5, L6, etc.
For example:

Column C Column L


C4 52896 L4 (C4-C4) 0
C5 52996 L4 (C5-C4) 100
C6 53096 L4 (C6-C4) 200
C7 53196 L4 (C7-C4) 300
|
|
|
etc

What function or formula must I use to get the running accumulative result?
I thought it would be simple but in every case, when used =SUM() or =PRODUCT()
or =RAW SUBTRACT() I had to change the cell number operation in the function every time.
This meant a function had to be different in every subsequent cell.
Is there a “automatic” way to do this?
I’m thinking that it’s a simple solution that is right in front of me, but I don’t see it.

Thank you for your help, once again.

Robotics1949

Hallo
Start in L4 with:

=C4-C$4

and pull down.

1 Like

Thank you!! I knew it was something simple, but I couldn’t remember if I ever used it previously.

Thanks again.

Robotics1949