If the towels are the larger size, then 4.5-5 inches would be about right for the design and the letters will look nicer too. I think that is about the size of most designs intended for towels. Bigger can be better when it comes to someones name. Print it out on paper and cut it out. pin it to the towel and hang it up -- then walk away a bit and look at it. I hope this helps...I am not a towel monogram pro. So I hope other Cuties reply too.