Mass from Volume & Concentration

Calculating Mass from Target Concentration and Volume

What is this Calculator For?

When preparing chemical solutions in the lab, you often know the target volume and molar concentration you want to achieve, but need to know exactly how much dry powder to weigh out on the balance. This calculator instantly converts your desired volume and concentration into the required mass in grams or milligrams.

How It Works

Our tool automates the standard molarity equations. By entering your target concentration, the formula weight (molar mass) of your compound, and the desired final volume, it calculates the exact mass of solute needed. It also handles all unit conversions behind the scenes.

The Formula

To determine the mass needed for a specific volume and concentration, you multiply the three variables together:

Step-by-step Example

Suppose you want to make 50 mL of a 10 mM solution of a compound with a formula weight of 180.16 g/mol. Here is the manual calculation:

1. Convert units to standard molarity and liters: 10 mM = 0.01 mol/L, and 50 mL = 0.05 L.
2. Calculate the moles needed: 0.01 mol/L × 0.05 L = 0.0005 moles.
3. Calculate the mass needed: 0.0005 moles × 180.16 g/mol = 0.09008 grams.

So, you would weigh out exactly 90.08 mg of your compound.

Common Mistakes

• Ignoring Unit Conversions: The formula strictly requires Volume to be in Liters and Concentration in mol/L (Molarity). Using milliliters without converting will give you a result that is off by a factor of 1,000.