quick excel question

[thubby]

I'm working some lab data for school, and it occurred to me that excel could do a lot of the tedious math for me. my only snag is that i don't know one function.

rather than setting a cell to =sum(x1:x2) is there a way to set it to just sum all entries in a column in perpetuity?

that way it would update the total with every new entry without having to potentially adjust the range.

[ShadowHunter]

All entries in a column? You could just lower the bottom part of the range to some huge number, like 10000 - the blank cells are just 0s

It seems like a weird question; the fact that for some reason you're wanting to continuously update your data and immediately update the sums (rather than just dump all the data and build the sums later) makes me think you're doing something, er, non-optimally.

[Shhalahr Windrider]

=Sum($X) Where X is the column you want should do the whole column. That is, just don’t specify a row number.

Of note, I do believe specifying an entire row or column in this way does slow down Excel’s calculation. But it should only be a problem with larger worksheets.

(On the off-chance I am wrong, the other way to do it is to type "=SUM(" and then click on the column you want to sum, as if you wanted to select the column. Excel will then fill in the appropriate reference. Then type ")" to close it and hit Enter.)

[ShadowHunter]

Yah, you can also do sum(C:C) to do all of C, for example.

The problem with the whole column is that if the sum is in the same column (which it often is) you'll make a circular reference.

[thubby]

All entries in a column? You could just lower the bottom part of the range to some huge number, like 10000 - the blank cells are just 0s

It seems like a weird question; the fact that for some reason you're wanting to continuously update your data and immediately update the sums (rather than just dump all the data and build the sums later) makes me think you're doing something, er, non-optimally.

I knew I could just set a huge range, but that seemed more like a work-around. if what i wanted existed, it would be good to know.

the short version is that my group and I are developing a very simple machine. one of the things that matters is the total development costs and lab hours used.
keeping them low is better for the grade, so having a running total is useful. (and, as mentioned, keeping track of minute sums like the cost of a sheet of paper gets tedious)

edit: btw got it working, ty!

[Brother Oni]

Further to other replies, may I suggest pressing F9 before reading a value from the table?

One thing I've noticed in Excel 2010, is that occasionally the equations don't auto-update when new values are entered. F9 forces all equations to re-calculate.