I tried but accidentally terminated the post.
Here is part of my sheet:
20/06/2020 17/09/2020 15827 16478 9.2
I've pasted it in and things don't seem to behave when I try to improve the appearance.
The first entry is cell B33, containing the date of the start of the period, entered by hand
Second is C33, containing the formula =TODAY() and so showing the (then) current date
Third is D33, a value that is the reading on the first day of the period (i.e. the reading of the date in B33), entered by hand
Fourth is E33, showing the accumulated total value up to the day before the current date, entered by hand
Fifth is F33 showing the value of the current day, entered by hand. It is this value that I wish to add to E33 automatically so that I no longer have to do the arithmetic and enter the result by hand. Clearly = E33 + F33 will fail.
However, when I first tried this I got the error message about a circular reference but just now Excel inserted 0 into E33. Um