Dilution Calculator - Calculate M₁V₁ = M₂V₂ | Free Online Tool

A dilution calculator (also called a dilution factor calculator or solution dilution tool) is an online utility that solves the fundamental chemistry equation M₁V₁ = M₂V₂. This equation describes how to dilute a concentrated solution (stock) to a desired lower concentration (working solution). The formula is derived from the conservation of moles: the amount of solute before dilution equals the amount after dilution. Whether you are a chemistry student, laboratory technician, biologist, or researcher, dilution calculations are an essential daily task.

In a typical laboratory, chemicals are purchased and stored as stock solutions at high concentrations. To perform experiments, you need to prepare working solutions at much lower concentrations. The dilution equation M₁V₁ = M₂V₂ tells you exactly how much stock solution to use and how much solvent (usually water) to add. For example, if you have a 2 M HCl stock and need 500 mL of 0.1 M HCl, you would calculate: V₁ = (0.1 M × 500 mL) / 2 M = 25 mL. You then measure 25 mL of the 2 M stock and add water to bring the total volume to 500 mL.

This free online dilution calculator lets you solve for any of the four variables (M₁, V₁, M₂, V₂) in the M₁V₁ = M₂V₂ formula. It supports multiple concentration units (M, mM, μM, nM) and volume units (L, mL, μL, nL), making it versatile for any lab situation. All calculations happen locally in your browser - no data is sent to any server, ensuring your privacy and enabling offline use. Whether you are a student doing homework, a technician preparing buffers, or a researcher designing an assay, this tool is your go‑to solution for dilution problems.

Using this M1V1 M2V2 calculator is simple. Follow these steps to solve any dilution problem instantly:

1. Enter any three values. Fill in the concentrations and volumes you know. Leave the fourth field empty - the calculator will solve for it.
2. Select the concentration unit. Choose from M (molar), mM (millimolar), μM (micromolar), or nM (nanomolar). Units are automatically converted before calculation.
3. Select the volume unit. Choose from L (liters), mL (milliliters), μL (microliters), or nL (nanoliters). All units are converted to liters internally.
4. View the result. The missing value is calculated instantly and displayed in the output panel. You can copy the result to your clipboard with a single click.
5. Enter all four values to verify. If you enter all four values, the calculator will check whether they satisfy the equation and show "Equation satisfied" if they do.
6. Use the Clear button to reset all fields and start a new calculation.

The calculator works automatically as you type - you don't need to click a separate calculate button. Your recent selections are saved locally for up to 30 days.

Our dilution factor calculator supports four concentration units and four volume units. Below are complete reference tables with conversion factors.

The dilution equation M₁V₁ = M₂V₂ is based on the conservation of moles: the amount of solute before dilution equals the amount after dilution. Since the number of moles is calculated as concentration × volume, we set the initial product equal to the final product.

The equation can be rearranged to solve for any missing variable:

• To find initial concentration: M₁ = (M₂V₂) / V₁
• To find initial volume: V₁ = (M₂V₂) / M₁
• To find final concentration: M₂ = (M₁V₁) / V₂
• To find final volume: V₂ = (M₁V₁) / M₂

The dilution factor (DF) is another useful concept:

• DF = M₁ / M₂ = V₂ / V₁
• A 10× dilution means the final concentration is one‑tenth of the initial, and the final volume is ten times the aliquot volume.
• The dilution factor for a 1:10 dilution is 10; for a 1:100 dilution, it's 100; and so on.

Practical example: You have a 5 M NaCl stock solution and need to prepare 200 mL of 0.5 M NaCl. Solve for V₁:

You would measure 20 mL of the 5 M stock and add water to bring the total volume to 200 mL. (Note: Add the stock to a volumetric flask, then add solvent up to the mark - not simply add 180 mL of water, because volumes are not always perfectly additive.)

Dilution calculations using the M₁V₁ = M₂V₂ formula are essential in many real‑world settings:

A serial dilution is a sequence of dilutions created using the same dilution factor for each step. Each dilution step uses the previous tube as the source. Serial dilutions are commonly used for:

• Producing a range of concentrations for standard curves
• Determining microorganism concentration (CFU count)
• Antibiotic susceptibility testing (MIC)
• Dose‑response curves in pharmacology (IC₅₀)

For a serial dilution with constant dilution factor D (e.g., D = 10 for a 1:10 dilution):

• Concentration at step n: Cₙ = C₀ / Dⁿ
• Volume transferred from each tube: V₁ = V₂ / D
• The final dilution factor after n steps is Dⁿ

While this calculator focuses on single dilutions, the same M₁V₁ = M₂V₂ equation applies to each step of a serial dilution. Many laboratory protocols require both single‑step and serial dilution calculations.

• Completely free, no registration. Unlimited dilution calculations with no hidden costs.
• Privacy‑first design. All calculations happen locally in your browser. Your data never leaves your device.
• Supports 4 concentration units and 4 volume units- from nanomolar/nanoliter to molar/liter.
• Solves for any variable (M₁, V₁, M₂, V₂). Leave the unknown field blank, and the calculator does the rest.
• Equation verification mode - enter all four values to check if they satisfy M₁V₁ = M₂V₂.
• High precision with results to 6 decimal places, suitable for laboratory and educational use.
• Works offline after initial page load.
• Fully responsive design with resizable panels on desktop for custom workflow.