There are approximately 29.5735 milliliters (mL) in 1 fluid ounce (fl oz).

It's important to note that this conversion can vary slightly depending on the type of ounce being used.

* US fluid ounce (US fl oz): 29.5735 mL

* Imperial fluid ounce (Imp fl oz): 28.4131 mL

So, for most purposes, it's safe to assume that 1 ounce = 30 milliliters is a close enough approximation.