Stock Solution Calculator

Work out stock solution instantly with clear inputs, formula shown and shareable results.

About Stock Solution Calculator

A stock solution is a concentrate, so the working solution is made by pipetting a small measured volume of stock and topping up with diluent. The stock volume is the working concentration times the working volume divided by the stock concentration - a 10 M stock taken to 0.4 M in 250 mL needs 10 mL of stock and 240 mL of diluent, a 25-fold dilution.

Formulas

Volume of stock

V(stock) = C(working) x V(working) / C(stock)

Fold dilution

fold = C(stock) / C(working)

Worked example

With the default values below, Stock Solution Calculator returns Stock To Pipette of 10.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Stock concentrationminimum 0 M: 10 M
Working concentration wantedminimum 0 M: 0.4 M
Working volume neededminimum 0.01 mL: 250 mL

Results

Stock To Pipette: 10.000 mL
Diluent To Add: 240.000 mL
Fold Dilution: 25.00 x
Stock As Share Of Final Volume: 4.00%

Step by step

1Values used
2Volume of stock
3Fold dilution
4Stock To Pipette= 10.000 mL
5Diluent To Add= 240.000 mL
6Fold Dilution= 25.00 x
7Stock As Share Of Final Volume= 4.00

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What if the working concentration is higher than the stock?

It cannot be reached by dilution, so the calculator flags it rather than returning a negative diluent volume.

Why work with fold dilution?

Serial dilution protocols are usually written as folds (1:25 here), so it is the figure you carry to the bench.