Is there a formula or algorithm...

[Nove]

for converting decimals to fractions? For instance, some way in VB6 I could convert something like .678584 to the most simplified fraction? If there is, how many places past the decimal point is this reliable? Thanks.

[NotLKH]

Will you need a method for repeating decimals, ie .765765765765...?

If Not, if they always terminate, then multiply it by (10^n) to get a whole integral value.

Then find the GCD between it and 10^n. Divide both by this GCD.

You'll end up with a usable set of (numerator, denominator) for your fraction.

[Nove]

sounds good, i'll try to work it out in code and come back if I have any problem. Thanks.

[NotLKH]

If you do have a repeating decimal type, then, by example, this is how you'd deal with it:

Say you had .1234123412341234...
Thus:
X=.12341234...
10000X=1234.12341234...
10000X-X=1234.12341234... - .12341234....
9999X=1234
X=(1234/9999)
So, now just reduce the fraction .