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
30 Ratings

30 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.

hkgamer ,

A nice start!

I can see this becoming a very useful tool in the lab. How about adding a molecular weight calculator that takes a molecular formula and returns the MW? I've always wanted one of those.


2.1 MB

Requires iOS 3.0 or later. Compatible with iPhone, iPad, and iPod touch.



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  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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