SaaS free trial impact on conversion rate

I'm curious about the impact of free trials on SaaS subscriptions rates.

Suppose you have a SaaS with a subscription model and a free trial. 4% of your website visitors trial and 4% of your trial users convert. So, .16% of visitors to your site eventually become subscribers. Let's call this your subscription rate.

Now suppose you turn off the free trial. Visitors to your site can either subscribe or not. What impact do you expect on your subscription rate? I suspect it gets is worse. But how much worse?

Anyone have personal experience with this and willing to chime in?