A stock solution is a known concentrated solution that is often times diluted to some lower concentration for laboratory use. Using a stock solution has several advantages, these include:

• Reduced storage space: a single stock solution can be prepared and stored rather than storing several vials of working solutions
• Reduced preparation time: working solutions can be prepared by diluting a stock solution
• Greater stability: Because stock solutions do not support bacterial growth they are more stable than working solutions.
• Conserves precious materials
• Improves the accuracy of experiments