Calculate millimolar concentration from grams, molecular weight, and volume, plus solve for mass or volume, run C1V1=C2V2 dilutions, and convert mg/mL to mM.

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Fills in the molecular weight below. You can still edit it.

Uses C1 × V1 = C2 × V2 to dilute a stock solution.

Fills in the molecular weight below. You can still edit it.

Grams to Millimolar Formula

The following formula is used to calculate the millimolarity (mM) from grams of solute (g), molecular weight (MW), and volume of solution (V).

mM = (g / (MW × V)) × 1000

Variables:

  • mM is the millimolarity
  • g is the grams of solute
  • MW is the molecular weight of the solute
  • V is the volume of the solution in liters

To calculate the millimolarity, divide the grams of solute by the product of the molecular weight and the volume of the solution, then multiply the result by 1000 to convert to millimolarity.

Grams to Millimolar Conversion Table (Assumes NaCl, MW = 58.44 g/mol, final volume = 1.000 L)
Grams of NaCl (g) Millimolarity (mM)
0.0010.017
0.0050.086
0.0100.171
0.0250.428
0.0500.856
0.0751.283
0.1001.711
0.1502.567
0.2003.422
0.2504.278
0.5008.556
0.75012.834
1.00017.112
1.50025.667
2.00034.223
2.50042.779
5.00085.558
7.500128.337
10.000171.116
20.000342.231
* Rounded to 3 decimals. Formula: mM = (grams / (MW × volume in L)) × 1000. With NaCl (58.44 g/mol) at 1.000 L: 1 g → 17.112 mM.

What is Millimolarity?

Millimolarity (mM) is a unit of concentration that represents the number of millimoles of a solute per liter of solution. It is commonly used in chemistry and biology to express the concentration of substances in a solution. One millimole is equal to one-thousandth (1/1000) of a mole, which is a standard unit in chemistry representing a specific number of molecules or atoms.

How to Calculate Millimolarity?

The following steps outline how to calculate the millimolarity of a solution.

  1. First, determine the grams of solute (g).
  2. Next, determine the molecular weight of the solute (MW).
  3. Next, determine the volume of the solution (V).
  4. Finally, calculate the millimolarity using the formula mM = (g / (MW * V)) * 1000.
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Grams of solute (g) = 5

Molecular weight of solute (MW) = 180 g/mol

Volume of solution (V) = 2 L