How much to put away for taxes?

I recently opened my own renovation business and have read some things about how much to put away for taxes and I'm wondering if it is 15% or 25% of my overall earnings. I understand writing things off and all of that but just want to know what to multiply my income by to put away for taxes. The way I have been doing it is dividing 0.75 from my income which covers my taxes and gives my business some overhead.

Any suggestions or help would be awesome.

Thanks