easy question

[cajsoft]

if I have two numbers, a previous number and a current number. What formula would I use to find out the percentage difference between the two numbers.

I did try and use (previous - current) * 100 / previous but it doesn't always work.

any ideas.
this should be easy.

[dimava]

the percentage difference between what numbers?

if the numbers are from 1 to 100 or something then yea, but you cant really take a percentage differnce of 2 numbers unless theres a specific range

[cajsoft]

example.

previous number is 500, current number is 550.
What is the percentage change between these 2 numbers.

[NotLKH]

CN = (CN/PN)*PN

PN = (PN/CN) * CN

So CN = 100*(CN/PN)% of PN
and
PN = 100*(PN/CN)% of CN


Now, with CN = (CN/PN)*PN, I would say that

PN changed by 100*((CN/PN) - 1)% to become CN.

Which can be seen by

PN + change = CN
if we say that change = ((CN/PN)-1)*PN then

PN + ((CN/PN)-1)*PN is indeed = CN

So, PN to CN does indeed change by 100*((CN/PN)-1)% of PN.

-Lou

[cajsoft]

In english please?

[jemidiah]

I didn't check his logic, but I'm sure it's accurate.

100*((CN/PN)-1)% of PN = 100*((Current Number/Previous Number)-1) = The percent the Current Number differs from the Previous Number

[Dreamlax]

Maybe he wants PN as a percentage of CN?

Wouldn't that be a simple (CN / PN) * 100?
If PN = 500, and CN = 550, then CN is 110% of PN.

[jemidiah]

Basically, thats exactly what Lou (NotLKH)'s code does, except it subtacts 1 (100%), making it x percent more than the first number instead of x percent of the first number, although you're exactly right about what you're saying.