It’s confusing, but there are two different units: “oz” (ounces) and “fl oz” (fluid ounces). Ounces are a unit of weight and fluid ounces are a unit of volume. But it’s not always written explicitly as “fl oz”, sometimes it’s shortened to just “oz” and you get from context they mean the fluid ones.
So 16 oz in that context means 16 fl oz, which is about 473 ml.
For water, they’re actually equivalent, just like grams and milliliters. As the old saying goes, “a pint’s a pound the world around, but mainly in the U.S. and Liberia.”
It’s confusing, but there are two different units: “oz” (ounces) and “fl oz” (fluid ounces). Ounces are a unit of weight and fluid ounces are a unit of volume. But it’s not always written explicitly as “fl oz”, sometimes it’s shortened to just “oz” and you get from context they mean the fluid ones.
So 16 oz in that context means 16 fl oz, which is about 473 ml.
So “about 500ml” like OP stated
For water, they’re actually equivalent, just like grams and milliliters. As the old saying goes, “a pint’s a pound the world around, but mainly in the U.S. and Liberia.”
And not in the UK