Low decimals incorrect in simple formula

**kretzen** · 11-05-2012, 08:32 AM

I get a weird result to these formulas when looking at many decimal places, anyone knows why? Especially weird that I dont get it on all of them?

=94%-1 ==> -6,00000000000001000000%
=8%+1 ==> 8,00000000000001000000%
=15%-1 ==> -85,00000000000000000000%

Best Regards
Rasmus

**sidd.iths** · 11-05-2012, 08:42 AM

hi kretzen,

in the above formula, '1' would relate to 100%. hence the results.

however, "=8%+1", should have given you 108%.

**kretzen** · 11-05-2012, 08:45 AM

Hi.

My question is not on how % work (although, you are correct, I missed the first two digits on the 1+8%).

My question is why excel would invent the "1" in the 13:th decimal place?

**zbor** · 11-05-2012, 08:54 AM

Numbers are stored in a computer in the binary number system.
Conversion from base 10 to base 16, base 8, or base 2 will almost always introduce error since the computer is using a fixed amount of memory to store this new representation of the data.

that's why you can have this error.