Decibels conversion into amplitude ratio I want to convert db into amplitude ratio.

I did some research but I only found online convertor, and I don't understand what's on Wikipedia very well...

Here is a little of backstory :
I am a programmer and I have to code an Equalizer; the problem is, I'm new to this DSP world.
I'm using a small documentation that an audio engineer in my company made a while ago and there are stuffs that I don't understand in it. (He's obviously not in the company anymore...)

In his documentation, he writes that the equalization is made step by step with an incrementation of ±0.1 dB.

So here are my questions :


What's the formula to convert dB into a percentage ?
On Wikipedia, there is 10 log10(x), but x is the power ratio, and I don't know how to get that either...
Does processing step by step is the best/only solution ?
Or can I calculate the ratio that I need each time (to limit the number of measures needed) ?


Thanks for you time.
You will want to work with what Wikipedia calls "field quantities."

Your engineer is telling you to work in steps of .1dB, which would be an amplitude ratio of .1=20log10(x).  To get x you do 10^(.1/20) = 1.01158

From x dB to ratio (amplitude):  10^(x/20)

From x ratio (amplitude) to dB:  20Log10(x)

If you can calculate the ratio, then you should be able to calculate the correction needed, round to the next .1dB step, and apply it in one step.