Reconstitution Calculator
Use this calculator to determine the volume of a concentrated stock solution needed to achieve a desired final concentration and volume. It also calculates the amount of diluent required.
Understanding Reconstitution and Dilution
Reconstitution, often synonymous with dilution, is the process of preparing a solution of a specific concentration from a more concentrated stock solution or a solid substance. This is a fundamental technique in various fields, including chemistry, biology, pharmacy, cooking, and even everyday household tasks.
The core principle behind dilution calculations is the conservation of solute. When you dilute a solution, you are adding more solvent (like water), but the amount of the original solute remains the same. This relationship is expressed by the formula:
C1V1 = C2V2
- C1: The initial concentration of your stock solution.
- V1: The initial volume of the stock solution you need to take.
- C2: The desired final concentration of your new solution.
- V2: The desired final volume of your new solution.
This calculator helps you solve for V1 (the volume of stock solution needed) and then determines the volume of diluent required to reach your desired final volume.
How to Use the Reconstitution Calculator
- Stock Solution Concentration: Enter the concentration of your starting material. This could be in percentages (e.g., 70%), molarity (e.g., 2 M), or mass/volume (e.g., 100 mg/mL).
- Desired Final Concentration: Input the target concentration you want your final solution to have. It is crucial that this unit matches the unit of your stock solution concentration.
- Desired Final Volume: Specify the total volume of the final solution you wish to prepare. This could be in milliliters (mL), liters (L), or any other volume unit.
- Calculate: Click the "Calculate Reconstitution" button to get your results.
Example Usage
Let's say you have a 70% alcohol stock solution and you need to prepare 500 mL of a 35% alcohol solution for a specific application.
- Stock Solution Concentration: 70
- Desired Final Concentration: 35
- Desired Final Volume: 500
Using the calculator:
Volume of Stock Needed = (35 * 500) / 70 = 250 mL
Volume of Diluent to Add = 500 mL (Desired Final Volume) - 250 mL (Volume of Stock Needed) = 250 mL
So, you would take 250 mL of your 70% alcohol stock solution and add 250 mL of diluent (e.g., water) to achieve 500 mL of a 35% alcohol solution.
Important Considerations
- Unit Consistency: Always ensure that your concentration units (e.g., %, mg/mL, M) are consistent with each other, and your volume units (e.g., mL, L) are consistent. The calculator performs the mathematical operation; it does not convert units.
- Accuracy: For precise results, use appropriate laboratory equipment like graduated cylinders, pipettes, or volumetric flasks for measuring volumes.
- Safety: Always follow proper safety protocols when handling chemicals. Wear appropriate personal protective equipment (PPE) and work in a well-ventilated area if necessary.
- Temperature: For some solutions, temperature can affect density and thus concentration. For most routine dilutions, this effect is negligible, but it's a factor in highly precise work.
- Mixing: Ensure thorough mixing of the stock solution and diluent to achieve a homogeneous final solution.