Concentration Calculator

The Concentration Calculator solves common solution preparation problems in chemistry and biology — converting between mass, volume, molarity, and percentage concentration so you can prepare reagents accurately. Select a calculation type (such as mass from concentration, molarity from mass and volume, or diluting a stock solution), then enter your concentration, volume, molecular weight, and any other required values. You'll get a primary result alongside secondary outputs for molarity, mass required, volume required, and mass percentage.

g/mol
g/mL

Results

Primary Result

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Molarity

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Mass Required

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Volume Required

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Mass Percentage

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Frequently Asked Questions

What is concentration in chemistry?

Concentration describes the amount of solute dissolved in a given amount of solvent or solution. It can be expressed in various units like molarity (moles/liter), mass percentage, or parts per million.

What is molarity and how is it calculated?

Molarity (M) is the number of moles of solute per liter of solution. It's calculated as: Molarity = moles of solute / liters of solution. To find moles, divide the mass by molecular weight.

How do I calculate mass percentage concentration?

Mass percentage is calculated as: (mass of solute / total mass of solution) × 100%. For example, 10g of salt in 100g of water gives (10/110) × 100% = 9.09% concentration.

How do I prepare a dilution from a stock solution?

Use the dilution formula C1V1 = C2V2, where C1 and V1 are the stock concentration and volume needed, and C2 and V2 are the desired concentration and final volume.

How do I convert between molarity and mass percentage?

To convert molarity to mass percentage, you need the molecular weight and solution density. Use: Mass% = (Molarity × MW × 100) / (density × 1000), where MW is molecular weight and density is in g/mL.

What information do I need to calculate molarity?

To calculate molarity, you need the mass of solute (in grams), molecular weight of the compound (g/mol), and the volume of solution (in liters).

Why is molecular weight important in concentration calculations?

Molecular weight allows you to convert between mass and moles of a substance. Since molarity is expressed in moles per liter, you need molecular weight to determine how many moles are in a given mass of compound.

What's the difference between molarity and molality?

Molarity is moles of solute per liter of solution, while molality is moles of solute per kilogram of solvent. Molarity changes with temperature because volume changes, but molality remains constant.