your best bet would be to use a patternit depends on what yarn you use.
It truly depends on the yarn you are using and how much you want it feltedDepending on the yarn and how much stitch definition you want it can felt anywhere between 15 and 50%The best thing to do is knit a swatch, measure it, then felt as desired, and measure again to get a reasonable estimate.
yarn/ fabric from cotton milk from cow wool from sheep eggs from chickens juice from fruits dye from various flowers
