Are you looking for gram equivalent?
it's 1 mole of Ca2+ per mole of CaCl2, and 3 moles per mole of citrate.
But that's not the big issue. Big issue is solubility. in water, cacl2 is highly soluble, and citrate is highly insoluble. Citrate is something like .001 gram per ml, whereas cacl2 is something like .7 grams per ml.
If you're using citrate for leuconostoc food or to increase diacetyl, the potassium or sodium salts are a better choice.