How many ml juice is there in one lemon?

There is not a fixed amount of juice in one lemon. The amount of juice in a lemon can vary widely, depending on the variety of lemon, its ripeness, size, and growing conditions.

An average-sized lemon may yield around 30 to 50 ml (1 to 1.7 fl oz) of juice, but some varieties can produce up to 60 or even 100 ml (2 or 3.4 fl oz) of juice.