Grams (g) to Milligrams (mg) Converter
Enter a value to instantly convert between weight units.
1 Gram = 1000 Milligram
Key Formulas
Kilogram → Pound
lb = kg × 2.20462Pound → Kilogram
kg = lb × 0.453592Gram → Ounce
oz = g × 0.035274Ounce → Gram
g = oz × 28.3495Formula
mg = g × 1000A milligram is one-thousandth of a gram — small enough to measure pharmaceutical ingredients, chemical reagents, and nutritional supplements accurately. The gram-to-milligram conversion is a simple shift of the decimal point: 1 gram equals 1000 milligrams. This is fundamental in pharmacy, where dosing often happens in milligrams, and in food labeling, where nutrients are listed per gram of the product.
Source: NIST SP 811, Table B.8
Frequently Asked Questions
Real-World Examples
A recipe calling for 5 g of salt converts to 5000 mg — useful for tracking sodium intake when nutrition labels show mg.
5 g = 5000 mg
A supplement capsule contains 500 mg of vitamin C — the label shows 0.5 g of vitamin C per capsule.
0.5 g = 500 mg
A pharmacist compounding a solution uses 2.5 g of active ingredient — 2500 mg for the prescription.
2.5 g = 2500 mg
A coffee shop measuring 250 mg of caffeine per serving needs to express it as 0.25 g for the ingredient list.
0.25 g = 250 mg