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How to Get the Sum of Rounded Numbers “correct”?

Märt Parker — Mon, 14 Dec 2009 07:32:04 +0000

It’s quite common that the calculation adds precise numbers which are formatted to be less precise. It might also happen that due to rounding, the formatted result seems mathematically incorrect on screen.

Example:

	Cell value	Cell value formatted with 1 decimal
A	12,75	12,8
B	12,75	12,8
SUM A+B	25,5	25,5

The last red number seems incorrect, because 12,8 + 12,8 = 25,6

Usually this is OK, as from the source data point of view, this is mathematically correct. But on some rare cases you want to add up numbers as they are displayed and you want the result to be 25,6. To let Excel do the math at the displayed precision level go to:

On Excel 2007: Excel Options > Advanced, scroll down to When calculating this workbook

On Excel Mac 2008: Excel -> Preferences -> Calculation

And check the field ‘Set precision as displayed‘

This should be used with caution as Excel changes the numbers in cells permanently.

Small Excel Chart Inside the Cell

Märt Parker — Tue, 08 Dec 2009 11:30:21 +0000

Here is one tip for improving the readability of larger data tables – use in-cell graphics. This is based on using ordinary characters as graphic elements. It is possible to repeat the characters using Excel REPT() function.

Below is a statistical table from Eurostat that is tuned with in-cell graphics.

Tip 1: You can apply calculations to second parameter to fit the result into desired space (in this case, the numerical value is divided by 10)

Tip 2: Try experimenting with different characters for the repetition, like “-”, “o” as the first parameter for the function. You can also apply some other character at the end of the formula with “&”+[end character]

Tip 3: Changing fonts and font sizes of the cell can result in creative outcomes

Excel in-cell graphics for improved readability

Subtotal function in Excel Formulas Helps to Stay Organized

Märt Parker — Fri, 04 Dec 2009 11:23:37 +0000

Large Excel spreadsheets are very vulnerable to mistakes in formulas. To reduce the probability of errors, good organization and structuring of data is a must.

Subtotal() function is one of the features that can help you to organize the spreadsheets better and prevent messy calculation logics. Novice Excel users often use SUM() function in places where SUBTOTAL() would be more appropriate. For large tables this practice can produce unmanagable files and hard to find calculation errors.

SUBTOTAL is meant to calculate subtotals or summary rows in the middle of the data table. The important distinction between Subtotal and Sum is that Subtotal does not sum cells which contain another use of Subtotal. This prevents multiple sums.

Bad practice

Better solution

*Subtotals of categories are calculated with SUBTOTAL as well

Using Subtotal instead of Sum() in formulas has the advantage, if you need to calculate over large number of subtotals and the table is long.

Be careful – if somebody else modifies the table and accidentally adds a row with SUM() function into the range that you sum with subtotal, then the result will be wrong.