Beverage Magnesium Serving Calculator

Use the right amount and basis

This worksheet supports magnesium beverage formulation. Ingredient grams per serving and elemental magnesium milligrams per liter are different quantities. It also shows ingredient milligrams per liter, clearly labeled, to help prepare a bench trial.

Ingredient grams = magnesium mg ÷ (assay % ÷ 100) ÷ 1,000. Elemental magnesium mg/L = magnesium mg × 1,000 ÷ volume mL. Ingredient mg/L = ingredient grams × 1,000,000 ÷ volume mL. At 84 mg magnesium, 8% assay and 355 mL, the ingredient input is 1.05 g per serving and the elemental magnesium concentration is about 236.62 mg/L.

Use an as-is assay directly. If the document reports a dry-basis assay, reconcile it with the specified water method before entering an effective as-is value. Do not subtract water twice. This calculator does not add overage, model losses, predict magnesium beverage turbidity or establish shelf life.

What the two label estimates mean

The Daily Value used here is 420 mg for adults and children aged 4 years and older under 21 CFR 101.9(c)(8)(iv). Other intended groups have different values. The %DV comparison assumes that the input represents all magnesium in the finished serving. If the water or other ingredients also supply magnesium, total those contributions separately before evaluating the label.

Nutrition Facts uses the nearest 2-percentage-point increment through 10% DV, the nearest 5 above 10% through 50%, and the nearest 10 above 50%, under 21 CFR 101.9(c)(8)(iii). Below 2% DV, 21 CFR 101.9(c)(8)(iii) allows the nutrient to be omitted, declared as 0%, or marked with an asterisk that refers to the footnote "Contains less than 2 percent of the Daily Value of this (these) nutrient (nutrients)" (or the "Contains <2 percent…" form). A standalone "<2%" in the %DV column is not one of those options. This tool does not choose the complete panel format or whether declaration is required in a specific case.

Supplement Facts uses the unrounded magnesium amount to calculate %DV and rounds to the nearest whole percent under 21 CFR 101.36(b)(2)(iii)(B)–(C). Under paragraph (b)(2)(i), a mineral such as magnesium present below 2% DV is not declared. The "Less than 1%" or "<1%" wording in paragraph (b)(2)(iii)(C) applies to dietary ingredients with Daily Reference Values (for example total carbohydrate), not to magnesium. At exactly 2%, the tool displays 2%. The different rules matter: 50 mg magnesium calculates to about 11.90% DV, shown here as 10% for Nutrition Facts and 12% for Supplement Facts.

The tool rounds exact halfway values upward for this arithmetic estimate. The output covers %DV only, not the full quantitative-mg declaration, required source names, panel layout, serving-size rules, claims or compliance tolerances. These results are arithmetic estimates only. Confirm final label values with finished-product analysis. Verify the formula, analytical results and applicable label requirements with your regulatory team.

The panel choice follows the product classification, not whichever rounded number looks better. FDA's 2014 guidance distinguishes liquid dietary supplements from conventional beverages. Use the two estimates to understand the arithmetic, not to choose a classification.

Related technical guides

• Elemental magnesium and ingredient weight
• Magnesium glycinate beverage feasibility
• Existing elemental magnesium calculator with assay-basis adjustment

Public sources

• 21 CFR 101.9(c)(8)(iii)–(iv)
• 21 CFR 101.36(b)(2)(i) and (iii)
• FDA liquid product classification guidance