The liter and the milliliter are both key units of volume in the metric system. The method for converting liters to milliliters is demonstrated in this worked example problem.

### How Many Milliliters in a Liter?

The key to working a liter to milliliter problem (or vice versa) is to know the conversion factor. There are 1000 milliliters in each liter. Because this is a factor of 10, you don't actually have to break out the calculator to do a conversion. You can simply move the decimal point. Move it three spaces to the right to convert liters to milliliters (e.g., 5.442 L = 5443 ml) or three spaces to the left to convert milliliters to liters (e.g., 45 ml = 0.045 L).

### Problem

How many milliliters are in a 5.0-liter canister?

### Solution

1 liter = 1000 mL

Set up the conversion so the desired unit will be cancelled out. In this case, we want mL to be the remaining unit.

Volume in mL = (Volume in L) x (1000 mL/1 L)

Volume in mL = 5.0 L x (1000 mL/1 L)

Volume in mL = 5000 mL

### Answer

There are 5000 mL in a 5.0-liter canister.

Check your answer to make sure it makes sense. There are 1000 times more milliliters than liters, so the milliliter number should be much greater than the liter number. Also, since we are multiplying by a factor of 10, the value of the digits won't change. It's only a matter of moving the decimal point.