问题
I had an application for returning closest matches to certain values in a large cluster of values( as in my earlier question) and I chose a VBA solution. While in the course of using the said application, I observed that the results for the value of 0.5 were not correct. I had been using the VBA Round function which I found to be returning 0 for 0.5 rounded to integer whereas the worksheet round function returns 1. Strangely, the VBA round function returns 2 for 1.5. I had to substitute the worksheet function in place of the VBA one.
Am I missing something?
回答1:
It's a known issue. The VBA Round() function uses Banker's rounding while the spreadsheet cell function uses arithmetic rounding. Check the details here:
PRB: Round Function different in VBA 6 and Excel Spreadsheet
The workaround proposed by Microsoft is to write a custom function to get the desired results.
Banker's rounding always rounds 0.5 to the nearest even number and is standard in accounting, which is why Excel works that way. Arithmetic rounding rounds 0.5 up to the next number.
回答2:
You can blame Microsoft for this one: http://support.microsoft.com/kb/194983
Here is a list of ways around it: http://www.excelforum.com/excel-programming/401104-worksheet-rounding-vs-vba-rounding.html
回答3:
Question answered completely here and copied here (by permission of the author :):
Be careful, the VBA Round function uses Banker's rounding, where it rounds .5 to an even number, like so:
Round (12.55, 1) would return 12.6 (rounds up)
Round (12.65, 1) would return 12.6 (rounds down)
Round (12.75, 1) would return 12.8 (rounds up)
Whereas the Excel Worksheet Function Round, always rounds .5 up.
I've done some tests and it looks like .5 up rounding (symmetric rounding) is also used by cell formatting, and also for Column Width rounding (when using the General Number format). The 'Precision as displayed' flag doesn't appear to do any rounding itself, it just uses the rounded result of the cell format.
I tried to implement the SymArith function from Microsoft in VBA for my rounding, but found that Fix has an error when you try to give it a number like 58.55; the function giving a result of 58.5 instead of 58.6. I then finally discovered that you can use the Excel Worksheet Round function, like so:
Application.Round(58.55, 1)
This will allow you to do normal rounding in VBA, though it may not be as quick as some custom function. I realize that this has come full circle from the question, but wanted to include it for completeness.
来源：https://stackoverflow.com/questions/265926/round-function-in-excel-worksheet-function-vs-vba