Gem Carat Weight Calculator

The premium grade gemstone weight calculation tool from the authors of the award-winning Crystal Guide Pocket Edition app. Gem Carat Weight Calculator allows fast, accurate weight calculations to be performed by using a few simple measurements. By combining industry standard formulae with our comprehensive array of gemstones and facets/cuts data, we are able to bring you an app that performs accurate calculations efficiently, right in your pocket! In addition to calculating weights, the app also has a thorough A-Z list of browsable gem data (300+ profiles, each with it's own image and geological profile), including the ability to directly compare gem profiles.


✔ Calculates gemstone carat weight, gram weight and tolerance value ranges.

✔ Contains 300+ gemstones and over 60 facet/cut types.

✔ Browsable A-Z list of crystals, gemstones and minerals, each with its own image and complete geological profile.

✔ Geological reference charts.

✔ Directly compare gemstone profiles.

✔ Full history of calculations for fast consults.

✔ Free database / profile updates.

✔ Supports both phones and tablets.

✔ Supports App2SD and Move To SD (android 2.2+).

✔ No ads, no intrusive permissions, just a clean fast gem weight calculator app.

Ideal for jewellers, pawnbrokers, gem stone and mineral collectors, gem dealers, geologists and rock hounds alike.


Available now for Android devices.


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We provide full support for all of our applications.  If you are having trouble installing or using any of our apps please contact us at This email address is being protected from spambots. You need JavaScript enabled to view it. and we will do our best to assist you.

We also have a range of FAQ's and help guides in our support section.