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.
Grams to Millimolar Formula
The following formula calculates millimolar concentration (mM, or mmol/L) from solute mass in grams (g), molar mass in g/mol (MW), and final solution volume in liters (V).
Variables:
- mM is the millimolarity
- g is the grams of solute
- MW is the molar mass of the exact solute form in g/mol
- V is the final solution volume in liters, not the volume of solvent added
Divide grams of solute by its molar mass in g/mol to obtain moles, divide by final solution volume in liters, then multiply by 1000 to convert mol/L to mmol/L (mM). Match the molar mass to the chemical form actually weighed, including any salt form or water of crystallization in a hydrate. A hydrate and its anhydrous form have different molar masses.
| Grams of NaCl (g) | Millimolarity (mM) |
|---|---|
| 0.001 | 0.017 |
| 0.005 | 0.086 |
| 0.010 | 0.171 |
| 0.025 | 0.428 |
| 0.050 | 0.856 |
| 0.075 | 1.283 |
| 0.100 | 1.711 |
| 0.150 | 2.567 |
| 0.200 | 3.422 |
| 0.250 | 4.278 |
| 0.500 | 8.556 |
| 0.750 | 12.834 |
| 1.000 | 17.112 |
| 1.500 | 25.667 |
| 2.000 | 34.223 |
| 2.500 | 42.779 |
| 5.000 | 85.558 |
| 7.500 | 128.337 |
| 10.000 | 171.116 |
| 20.000 | 342.231 |
| * 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.
- First, determine the grams of solute (g).
- Next, determine the molar mass of the exact solute form in g/mol (MW).
- Next, determine the final solution volume in liters (V), after the solute has dissolved.
- Finally, calculate the millimolarity using the formula mM = (g / (MW * V)) * 1000.
- 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
Molar mass of solute (MW) = 180 g/mol
Final volume of solution (V) = 2 L
