How do you convert milliliters to liters?

Divide by 1000.

milli is the scientific prefix for 0.001 or one thousandth.

So to convert millgrams to grams you divide by 1000.

To convert millimetres to metre, divide by 1000

To convert millilitres to litres, divide by 1000.

100 mL = 0.1 L (for example).

Similarly, kilo is 1000x so 2 km is 2000 m (now you multiply by 1000)

And extend to the other common prefixes...