The Molarity App from Sigma-Aldrich(R) is a chemistry calculator tool that generates lab-ready directions describing how to prepare an acid or base solution of a specified molarity or normality from a concentrated acid or base solution. A second tab includes a general molarity function that calculates the mass of any reagent needed to prepare a given volume of solution of desired molarity. A third tab features a stock dilution function that calculates how to dilute a stock solution of any known molarity to your desired volume and molarity.

- Calculates molarity and normality for common commercial acid and base solutions by auto-populating density, formula weight and weight percentage.
- Users may input lot-specific certificate of analysis values for density and weight percentage.
- The Acid and Base instructions link to Sigma-Aldrich website/mobile website to display relevant acid or base products.
- General molarity and solution dilution options feature molar, millimolar, micromolar, picomolar and femtomolar concentration options.
- The iPad version includes option to save and email acid and base solution preparation instructions.

Normality calculations assume reactions based on H+ or OH- ions.
Concentration of 56.6% ammonium hydroxide is equivalent to 28% ammonia (NH3).
Additional calculation details may be found with online web version at

Ratings and Reviews

3.9 out of 5
29 Ratings
29 Ratings
Lenin Dominguez ,

Very good app with room for improvement

I like this app. I am in favor of know and understanding how this calculations are performed. However, there are times when only e result is important. This app does a great job in the latter case.

Adding other chemicals besides acids or bases (think DMSO, DMF, glycerol, etc.) would make it even better and more useful.

labqueen ,

Update for iOS 11

I love this app and use it several times a week for work. I recently updated my phone to ios11, tried to use the app and it’s not compatible. Could you please update? Otherwise, I will be forced to find a new app.

Pinero27 ,

Excellent app

Must have if you are a chem grad student, you avoid the sitting down and calculate concentrations by hand. Although they should include ppm and ppb concentration in the stock dilution section.


2.1 MB
Requires iOS 3.0 or later. Compatible with iPhone, iPad, and iPod touch.
Age Rating
Rated 4+
© 2011 Sigma-Aldrich Co.


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