1,500 milliliters converts to 1.5 liters.
Use the King Henry's Math Conversion Chart to answer this for yourself!
King Henry's Math Conversion Chart:
Kilo, Hecto, Deka, Unit, Deci, Centi, Milli.
The saying: "King Henry Died Unexpectedly Drinking Chocolate Milk"
"Unit" is the base unit (liter, meter, etc. depending on what question you are using)
Anyways, the answer to your question is 1.5 liters! Hope this helped.