Dilution Calculator

1. Enter any three of initial concentration, initial volume, final concentration and final volume.
2. Use the same concentration unit on both sides and the same volume unit on both sides.
3. Leave the one you want to find blank.
4. Read the result and how much solvent to add.

Here is what each result means:

Dilution is the process of making a solution weaker by adding more solvent, usually water. The amount of solute stays the same, but it is spread through a larger volume, so the concentration falls. Diluting is one of the most common tasks in a chemistry lab, from preparing working solutions to setting up a titration.

The key idea is that the moles of solute before and after dilution are equal. Since concentration times volume gives the amount of solute, the initial concentration times the initial volume must equal the final concentration times the final volume. This gives the simple and powerful dilution equation, C1 V1 equals C2 V2.

In practice you usually know the stock concentration you are starting from and the final concentration and volume you want. The equation then tells you exactly how much stock to measure out, and the rest of the final volume is made up with solvent. This calculator does that rearrangement for whichever value you leave blank.

It rearranges the dilution equation to solve for whichever value you leave blank.

1. For a concentration, multiply the other side and divide by the matching volume.
2. For a volume, multiply the other side and divide by the matching concentration.
3. The solvent to add is the final volume minus the initial volume.

Dilution builds on concentration; see the molarity calculator and proportion calculator.

Dilute a 2 molar stock to 0.5 molar, making 1 liter of final solution.

Calculation: V1 = (0.5 x 1) / 2 = 0.25 liters of stock. Then add water up to 1 liter, so you add 1 minus 0.25, which is 0.75 liters of solvent.

One equation, rearranged for whatever you need to find.

All four come from C1 V1 equals C2 V2, so any three of the values give the fourth. Because both sides equal the same amount of solute, the equation works with any concentration unit as long as both sides match.

There are two ways to reach a target concentration, and they use different tools.

Dilution is quicker when you already have a stock solution, since you just measure and top up. Making a solution from a solid needs the molarity and moles relationships instead, so the two approaches suit different starting points in the lab.

The Dilution Factor

The ratio of final to initial volume sets how much weaker the solution becomes. A tenfold volume gives a tenfold dilution.

The Stock Concentration

A more concentrated stock means you need less of it to reach the same final concentration.

The Final Volume

A larger final volume needs more stock to keep the same final concentration.

Chemistry Homework

Solve for any concentration or volume in a dilution problem.

Preparing Working Solutions

Work out how much stock to dilute to reach a target concentration.

Titrations and Assays

Make accurate dilutions from a concentrated standard.

1. Mismatched Concentration Units

Use the same unit on both sides, such as molar on both. Mixing units breaks the equation.

2. Mismatched Volume Units

Both volumes must be in the same unit, both liters or both milliliters.

3. Adding to the Initial Volume

The final volume is the total, not the extra solvent. Solvent to add is final minus initial.

4. Using It for a Solid

The dilution equation needs a stock solution. To start from a solid, use the molarity relationships.

5. Zero Volume or Concentration

Solving for a value cannot divide by a matching zero volume or concentration.

The relation is exact; only the displayed decimals are rounded, and very large or small results are shown in scientific notation.

The dilution equation is C1 V1 = C2 V2, where C is concentration and V is volume, before and after dilution. It says the amount of solute stays the same as solvent is added.

Rearrange C1 V1 = C2 V2 for the unknown. To find the stock volume, multiply the final concentration by the final volume and divide by the stock concentration.

Multiply the final concentration by the final volume, then divide by the stock concentration. For a 2 molar stock to make 1 liter of 0.5 molar, you need 0.25 liters.

Subtract the initial volume from the final volume. If you use 0.25 liters of stock to make 1 liter, you add 0.75 liters of solvent.

Any, as long as both concentrations share a unit and both volumes share a unit. Molar with liters, or the same unit throughout, all work because they cancel.

Because concentration times volume gives the amount of solute, and dilution does not change that amount. So the product is the same before and after adding solvent.

No. The dilution equation needs a starting solution. To dissolve a solid, use the molarity relationship, moles divided by volume, instead.

The dilution factor is the ratio of final volume to initial volume, or equivalently initial to final concentration. A tenfold dilution has a dilution factor of 10.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Dilution (equation) (Wikipedia).
• Molar concentration (Wikipedia).
• Concentration (Maths Is Fun).