Setting percentages straight

[flaviooooo]

Hey,

I'm having some problems with the following:

we have a designcode that consists of several inks. Every ink is defined as to having a certain amount of KG in the design, and then a column percentage is set that shows how much of the design this ink is part of... sounds complicated, but isnt.

For example Design X consists of 20 KG of ink A, and 30 kg of ink B -> ink A is used 40%, ink B 60%

So far so good, but now I see that the percentages aren't always 100%, but 100,01 or so...

An example:

FORMULA_ID CODE KG Percentage
00MR00004 R511-321433A 1,5 7,49 (0,0749)
00MR00004 R513-843775A 0,44 2,20 (0,022)
00MR00004 R517-909587A 0,3 1,50 (0,015)
00MR00004 R519-029382A 17,8 88,82 (0,8882)

Total Percentage = 100,01%

Is there any way I can fix this, so that it always equals 100% in total?

Thanks in advance

 

[dhookom]

I would first confirm the calculations are correct. I expect you are seeing rounding in your numbers. What do
The actual percentages from your numbers are:
[tt][blue]0.074850299
0.021956088
0.01497006
0.888223553[/blue][/tt]



Duane MS Access MVP

 

[substitute]

As dhookum says, the problem is rounding. The results you show are actually correct, but rounding makes them look wrong.

The problem is inevitable. Take a case where you have three inks in proportion 1:1:1. The real proportions are 33.333333333333... percent but rounding to two decimal places you get 33.33% and a total of 99.99%. However many decimal places you include you will always get under 100%. Further, there are no grounds on which you can make one ink 33.34% to make the total correct, all three inks are equivalent.

This happened to me last week on an invoicing issue. I had to give someone a 0.01% discount.

Ian

 

[JerryKlmns]

If you round your calculations to 5 decimals (while formatting them to 4) and round your summing to 4 decimals, you might have less cases of 0.01% error