Solution Dilution Calculator

Choose the task that matches your solution preparation. Open a dedicated calculator with worked examples, or use it here. All five tools support molarity and % v/v without converting between those concentration categories.

What are you trying to do?

Prepare from stockMake a new solution at a desired concentration. Solve for any one concentration or volume.Example: Prepare 100 mL of 1 M solution from 10 M stock.Open C1V1 = C2V2 Dilution Calculator →

Add to an existing solutionAdd concentrated stock to an existing sample to reach a target concentration.Example: Add 5 M NaCl stock to reach 150 mM NaCl.Open Solution Spiking Calculator →

Dilute an existing solutionLower a concentration or add a specified fraction of diluent.Example: Add water so it is 10% of the final mixture volume.Open Dilute Back Down Calculator →

Reach an exact volumeTop up to a final volume, with or without a concentration target.Example: Bring 500 µL of sample to a final volume of 2 mL.Open Dilute to Exact Final Volume Calculator →

Mix two solutionsCombine known volumes at different concentrations and find the result.Example: Mix equal volumes of 1 M and 3 M NaCl.Open Mix Two Solutions Calculator →

Prepare from stock

Make a new working solution from a stock. Enter any three values and choose the unknown.

C₁ × V₁ = C₂ × V₂

Try an example

Solve for:

C₁ — Stock concentration

V₁ — Volume of stock

C₂ — Desired concentration

V₂ — Final total volume

Concentration basis: Use molarity (M, mM, µM, nM, pM) or % v/v throughout a calculation. % v/v is the volume of a liquid component per 100 volume units of final solution; it is not % w/v or % w/w. These tools do not convert between concentration categories or percentage bases. Solute must be conserved. Calculated added volumes and mixture concentrations assume additive solution volumes; measure the final volume for precise preparation.

Which dilution calculator should I use?

Start by deciding whether you are preparing a new solution, changing an existing sample, or combining two solutions. The quantity you need to find determines the workflow.

C1V1 = C2V2: prepare from stock or solve for any one of the two concentrations and two volumes.
Solution spiking: raise concentration by adding stock to a sample that already has a known volume and concentration. The spike increases the total volume.
Dilute back down: lower the concentration of a solution you already have, or specify added diluent as a percentage of starting or final volume.
Dilute to exact final volume: top up an existing sample, or calculate a stock aliquot and bring it to a measured final volume.
Mix two solutions: calculate the final concentration from two known concentrations and volumes of the same solute.

A final volume includes the stock or starting sample. “Bring to 100 mL” means adjust the total solution to 100 mL; it does not mean add 100 mL of diluent. Each dedicated page explains its equation, assumptions, and preparation steps.