Skip to main content
Calctrove Calctrove

Molarity Calculator

Molarity calculator

Enter mass, molar mass, and volume to get concentration instantly.

InputsSolution mixg + LLive

Molarity

0.2

Study aid only. Verify values before lab preparation.

Live

mol/L

M = m / (MM * V)

Mass

5.844 g

Volume

0.5 L

Moles

0.1

Formula
M = n / V
where n = m / Mr

Symbol legend

Symbol Meaning Unit Copy
M Molarity (solution concentration) mol/L
n Amount of solute mol
V Solution volume L
m Solute mass g
M_r Molar mass of solute g/mol
  • m is solute mass in grams.
  • Mr is molar mass in g/mol.
  • n is moles of solute, and V is volume in liters.
Example

Worked example: NaCl solution

  1. 1 Mass = 5.844 g NaCl
  2. 2 Molar mass = 58.44 g/mol
  3. 3 Volume = 0.500 L
  4. 4 n = 5.844 / 58.44 = 0.10 mol
  5. 5 M = 0.10 / 0.500 = 0.20 mol/L

Molarity is 0.20 M.

How
  1. Enter solute mass and select its mass unit.
  2. Enter molar mass in g/mol.
  3. Enter solution volume, choose volume unit, and read molarity in mol/L.
Avoid
  • Using mL volume without converting to liters.
  • Entering molar mass with the wrong compound value.
  • Ignoring physically impossible inputs such as zero or negative volume.

Ref only. Verify values. Follow lab safety.

FAQ
What unit is molarity reported in?

Molarity is reported in mol/L, often written as M.

Can I enter mass in mg or kg?

Yes, this calculator supports g, mg, and kg and converts internally to grams.

Is this suitable for direct lab preparation?

It is for educational planning. Always verify calculations and follow laboratory safety rules before preparing solutions.

Switch
Switch12