Vitamins & Minerals

MG to ML Converter Dosage Chart

Converting milligrams (mg) to milliliters (mL) requires knowing the density of the liquid. For water-based solutions, 1 mL ≈ 1,000 mg (since water density = 1 g/mL). For supplement liquids like magnesium citrate, melatonin drops, and liquid vitamins, the concentration on the label (mg/mL) is the key conversion factor.

5 age groups4 cautions2 cited sources

Not medical advice. Dosage information on this page is for educational reference only and is sourced from published guidelines. Individual needs vary based on health status, medications, and goals. Consult a healthcare provider — physician, pharmacist, or registered dietitian — before starting or adjusting any supplement.

MG to ML Converter Dosage by Age Group

Age GroupAge RangeDose RangeNotes
Water-based solution (reference)N/A1000 mg1 mL water = 1,000 mg (density 1 g/mL)
Magnesium citrate liquidAdults170–175 mgPer mL; typical 10 fl oz bottle = 1,700 mg Mg citrate
Liquid melatonin (typical)Adults1–10 mg1–10 mg per mL varies greatly by product
Liquid vitamin D3 (typical)Adults1000–2000 IUIU per drop or per mL; read label carefully
Syrup / suspension (general)Adults0 mgVaries by product; always check mg/mL on label

MG to ML Converter

Convert milligrams to milliliters for liquid supplements. Select the liquid type or enter a custom mg/mL concentration from your supplement label.

Common Liquid Supplement Concentrations

SupplementConcentrationExample: 500 mg =
Water / water-based solution1,000 mg/mL0.5 mL
Magnesium citrate (OTC laxative)~170 mg/mL~2.9 mL
Liquid vitamin C (250 mg/5 mL)50 mg/mL10 mL
Melatonin drops (1 mg/mL)1 mg/mL500 mL (too high)
Pediatric ibuprofen (100 mg/5mL)20 mg/mL25 mL

Safety Cautions

  • Never assume 1 mg = 1 mL or 1 mL = 1 mg for supplements — this conversion only applies to pure water at standard conditions.
  • Always read the 'concentration per mL' on your supplement label before calculating doses.
  • Oral syringes are more accurate than teaspoons for liquid supplement dosing — 5 mL ≈ 1 teaspoon but household spoons vary by 20%.
  • For pediatric liquid medications, only use the measuring device provided with the product.

Frequently Asked Questions

How do I convert mg to ml for liquid supplements?

Divide the milligram dose by the concentration (mg/mL) listed on the label. If your supplement contains 200 mg per 5 mL (40 mg/mL) and you need 100 mg, calculate: 100 mg ÷ 40 mg/mL = 2.5 mL. Always check the label for concentration — it varies by product.

Is 1 mg the same as 1 ml?

No. 1 mg (milligram) is a unit of mass; 1 mL (milliliter) is a unit of volume. They are only numerically equal for pure water, where 1 mL weighs approximately 1,000 mg (or 1 gram). For most liquid supplements, the conversion factor is different — it depends on the solution's concentration and density.

How many ml is 500 mg?

It depends on the liquid concentration. For pure water: 500 mg = 0.5 mL. For a 250 mg/5 mL syrup (50 mg/mL): 500 mg ÷ 50 mg/mL = 10 mL. For a 100 mg/mL solution: 500 mg ÷ 100 mg/mL = 5 mL. Always check the concentration on your specific product label.

Sources & References

  1. NIST Handbook of Mathematical Functions
  2. USP Compounding Standards — Concentration notation