mg to mL Calculator
The mg to mL calculator helps you convert the weight of a liquid that has the density of water to a volume — a conversion from units of milligrams to units of milliliters. As well as a mg to mL conversion, you can also use the calculator backward to perform a mL to mg conversion.
Read on to learn about the historical relationship between the units of milligrams and milliliters.
How many mg in a mL?
So exactly how many milligrams are there in a milliliter? The first step to answering this question is to understand what the letter 'm' means when applied to units. It means onethousandth (1/1000) of the original unit. Therefore we're asking how many thousandths of a gram are there in a thousandth of a liter. Recall that a gram is onethousandth of a kilogram. If you need help converting weight from a different unit to mg, our weight converter can help.
Now that we've sorted that out, the question is now "What is the relationship between kilograms and liters?"
The kilogram was originally defined in 1795 as equal to one liter of water at the temperature of melting ice (0 °C / 32 °F). That's not entirely true in the present day, as the kilogram and meter (a liter is the volume of onethousandths of a cubic meter) have been redefined, but it's very close indeed (0.9998 kg is a more precise figure).
So, a milligram is a thousandth of a thousandth of a kilogram, and a milliliter is a thousandth of a liter. Notice there is an extra thousandth on the weight unit. Therefore, there must be 1,000 milligrams in a milliliter, making the formula for mg to ml conversion:
mL = mg / 1000
.
Check out our volume conversion tool if you need to convert volume units from mL to a different unit.
mL to mg conversion — ml to mg calculator
To perform the reverse conversion, i.e., how many mg in ml, we rearrange the above equation in terms of mg, which gives:
mg = 1000 × mL
Notice that the ml to mg calculator works in both directions. Just enter the value you know, and the other will appear in no time!
How to use this mg to mL conversion calculator?
The mg to ml calculator is straightforward to use, as you need to provide only one value. If you're still not sure how to use it, here's a short set of instructions:

First, select the substance you are converting, either a type of medication (along with its concentration), water, milk, etc. If you are converting another type of liquid, select "Other" and enter its density.

To perform mg to mL conversion, enter the number of milligrams into the first row of the calculator.

There is also the option of using other weight units by clicking on the units dropdown menu.

We will then display the number of milliliters. Again, you can also express the quantity of liquid in terms of other units.

To perform the reverse mL to mg conversion, enter the number of milliliters first.
Example of mg to mL conversion
Let's say you have 5 grams of water, which is 5,000 mg. Dividing by 1,000, as shown in the mg to mL formula, gives an answer of 5 mL.
Liquid concentrations — how many milligrams in a milliliter?
Closely related to liquid density is liquid concentration. You will often see on the packet of medicine in liquid form that the concentration is given in mg/mL. If you set the "Conversion for" setting to Other
, you will see that the default unit for the liquid density is mg/mL. Change the value to match the medicine.
For example, let's say it's 20 mg/mL, so you enter that into the calculator. If you then want to know the volume of liquid that contains 50 mg of medicine, enter 50 mg into the first row of the calculator, and you'll find that the answer is 2.5 mL.
Our density calculator can help you with density calculations.
FAQ
How can I convert milligrams to milliliters?
To convert milligrams to milliliters:
 Find the density of the substance in mg/mL. For water, it is 1000 mg/mL.
 Divide the amount in milligrams by the density, and you have your amount in milliliters.
 Enjoy working in volume.
How can I convert ml to mg?
To convert any amount from ml (milliliter) to mg (milligram), follow the given steps:
 Note down the density of the substance you want to convert. For example, the density of water is 1000 mg/ml, and that of cooking oil is 0.916 mg/ml.
 Multiply the density by the amount you want to convert from ml.
 The result is the amount converted to mg.
Keep in mind that, when converting from weight to volume or vice versa, the density of the substance is of vital importance.
What is 100 mg converted to ml?
100 mg converted to ml is 0.1 ml.
This result is accurate for any substance with 1000 mg/ml density (the same as water).
If you want to convert any substance from mg to ml or vice versa, please use the following formula:
volume = weight / density
How much is 25 ml of cooking oil converted to mg?
25 ml of cooking oil converted to milligrams is 22,900 mg.
The density of cooking oil is 0.916 mg/ml, which is the basis for this conversion.
You may use the following formula to determine the conversion from volume (ml) to weight (mg).
weight = volume × density