Molarity Calculator – Moles, Volume, Mass And Dilution
This Molarity Calculator is designed for lab work, homework and exam preparation. It lets you calculate solution molarity from moles and volume, solve for moles or volume from a known molarity, convert mass and molar mass into molarity, and perform standard dilution calculations using the C₁V₁ = C₂V₂ relationship.
Molarity Basics – M = n ÷ V
Molarity is one of the most common ways to express concentration in chemistry. It is defined as moles of solute per liter of solution. In symbols:
M = n ÷ V
Here, M is molarity in mol/L (often written as M), n is the amount of solute in moles, and V is the total volume of the solution in liters. The first tab of this calculator applies this relationship directly. You can enter moles and volume in liters or milliliters, and the tool converts to base units before computing the concentration.
Finding Moles Or Volume From Molarity
The same equation can be rearranged when you want to prepare a solution with a specific concentration:
n = M × V
V = n ÷ M
The second tab uses n = M × V to find the amount of solute required for a given molarity and volume. This is helpful when you want to know how many moles of solute you need before converting that amount to mass. The third tab uses V = n ÷ M to calculate what total solution volume is needed to reach a particular concentration when you already know how many moles of solute you have available.
Molarity From Mass And Molar Mass
In practice, most solutions are prepared by weighing out a certain mass of solute. To connect mass with molarity, you first convert mass to moles using the molar mass of the solute:
n = mass ÷ molar mass
Once you know the moles, you can divide by volume to get molarity. The mass tab combines these steps. You enter the mass (in grams or milligrams), the molar mass in g/mol, and the final solution volume in liters or milliliters. The calculator reports both the number of moles and the resulting molarity in mol/L.
Dilution Calculations – C₁V₁ = C₂V₂
Diluting a stock solution to make a weaker solution is another common laboratory task. For this, the standard relationship is:
C₁V₁ = C₂V₂
C₁ and V₁ describe the initial (stock) solution, while C₂ and V₂ describe the final, diluted solution. As long as concentration is in mol/L and volume is in any consistent unit, this equality holds. The dilution tab lets you choose which variable you want to solve for and then enters the other three. It handles liter and milliliter volumes by converting everything to liters internally before applying the relationship.
Units And Significant Figures
The calculator keeps concentration values in mol/L and uses liters as the base volume unit, while still allowing convenient input in milliliters or milligrams. Results are formatted to a reasonable number of decimal places for readability. In a real laboratory report or exam, you should still round to an appropriate number of significant figures based on the precision of your measurements.
Using The Molarity Calculator In Study And Lab Work
This Molarity Calculator can be used to check hand calculations, design solution preparations and quickly test what-if scenarios. Students can use it to understand how moles, molarity, mass and volume are related. Instructors may find it useful as a demonstration or as a way to provide practice problems that learners can verify for themselves.
On the same site, other science and math tools work alongside this page so you can handle related topics such as unit conversions and percentage calculations without leaving the overall calculator environment.
Formula Summary
- Molarity: M = n ÷ V
- Moles: n = M × V
- Volume: V = n ÷ M
- Moles from mass: n = mass ÷ molar mass
- Dilution: C₁V₁ = C₂V₂
Molarity Calculator
Frequently Asked Questions
Quick answers about molarity, dilution formulas, molar mass and unit conversions for chemistry calculations.
Molarity is a concentration unit that describes how many moles of solute are dissolved in one liter of solution. It is written as mol/L or simply “M,” such as 0.10 M NaCl. Molarity is widely used in chemistry, labs and stoichiometric calculations.
Yes. The calculator accepts both liters and milliliters. Any value entered in milliliters is converted internally to liters so that molarity remains in mol/L. This makes it convenient for preparing solutions using typical lab glassware.
Molar mass (g/mol) is the mass of one mole of a substance. You can determine it using a periodic table by adding the atomic masses of all elements in the compound. Many chemistry textbooks and lab handbooks also include molar mass tables for common reagents.
The dilution equation C₁V₁ = C₂V₂ only applies when the same solute is present before and after dilution. If you are mixing solutions with different solutes, you must treat each solute independently and apply the equation separately for each one.
The formulas used here follow standard chemistry principles, but you should always follow your instructor’s guidance for rounding rules, significant figures and preferred units. This calculator is best used as a learning tool and a way to check your work, not as a substitute for understanding the theory.