Instantly Convert Grams ↔ Milligrams — Both Directions
Convert grams to milligrams (g → mg) or milligrams to grams (mg → g) instantly. Get the exact conversion with formula breakdown, reference table, and real-world examples — all free, no sign-up needed.
The gram and milligram are both metric units of mass within the International System of Units (SI). Converting between them is simple — 1 gram equals exactly 1,000 milligrams. Our converter handles both directions instantly and accurately.
The gram (g) is a metric unit of mass equal to one thousandth of a kilogram — the SI base unit of mass. The gram is used worldwide for everyday measurements such as food portions, ingredients in recipes, body weight supplements, and product labels. One gram is defined as exactly 1/1,000 of a kilogram, or equivalently 1,000 milligrams. It is the standard unit on kitchen scales and nutritional information panels globally.
The milligram (mg) is one thousandth of a gram and one millionth of a kilogram. It is used to measure very small masses — particularly in medicine, pharmaceuticals, chemistry, and nutrition. Drug dosages, vitamin supplements, and micronutrients are almost universally expressed in milligrams. For example, a standard aspirin tablet contains 500 mg (= 0.5 g), and the recommended daily intake of Vitamin C is approximately 1,000 mg (= 1 g).
The exact conversion factor is 1 gram = 1,000 milligrams — this is an exact metric relationship, not an approximation. The prefix "milli-" means one thousandth (10⁻³), so 1 milligram = 0.001 grams by definition. For the reverse: 1 milligram = 0.001 grams. All conversions on this page use these exact values with no rounding errors.
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Figure: Metric mass scale showing the relationship between kilograms, grams, and milligrams
The conversion between grams and milligrams is one of the simplest in the metric system — it is based on a pure power of ten. The prefix "milli" means 10⁻³, so 1 milligram is exactly one thousandth of a gram. This relationship is exact and universal across all fields of science, medicine, and everyday use. For more metric conversions, visit our full converter collection.
The table below lists commonly needed gram-to-milligram conversions used in medicine, nutrition, cooking, and science. All values use the exact factor of 1 g = 1,000 mg. For milligrams to grams, simply divide the mg value by 1,000 or use the converter above.
| Grams (g) | Milligrams (mg) | Micrograms (µg) | Kilograms (kg) | Common Context |
|---|---|---|---|---|
| 0.001 g | 1 mg | 1,000 µg | 0.000001 kg | Small drug trace amount |
| 0.005 g | 5 mg | 5,000 µg | 0.000005 kg | Low-dose vitamin tablet |
| 0.01 g | 10 mg | 10,000 µg | 0.00001 kg | Small medication dose |
| 0.05 g | 50 mg | 50,000 µg | 0.00005 kg | Common tablet dose |
| 0.1 g | 100 mg | 100,000 µg | 0.0001 kg | Standard supplement dose |
| 0.2 g | 200 mg | 200,000 µg | 0.0002 kg | Ibuprofen tablet |
| 0.25 g | 250 mg | 250,000 µg | 0.00025 kg | Half an aspirin (500 mg) |
| 0.5 g | 500 mg | 500,000 µg | 0.0005 kg | Standard aspirin tablet |
| 1 g | 1,000 mg | 1,000,000 µg | 0.001 kg | 1,000 mg Vitamin C dose |
| 2 g | 2,000 mg | 2,000,000 µg | 0.002 kg | Antibiotic daily dose (approx.) |
| 5 g | 5,000 mg | 5,000,000 µg | 0.005 kg | Creatine supplement serving |
| 10 g | 10,000 mg | 10,000,000 µg | 0.01 kg | Small seasoning portion |
| 50 g | 50,000 mg | 50,000,000 µg | 0.05 kg | Small chocolate bar |
| 100 g | 100,000 mg | 100,000,000 µg | 0.1 kg | Standard food portion |
The table below shows common milligram values converted to grams. All values use the exact factor of 1 mg = 0.001 g. This is particularly useful in pharmaceutical and medical settings where dosages in milligrams need to be weighed on gram-based scales.
| Milligrams (mg) | Grams (g) | Kilograms (kg) | Micrograms (µg) |
|---|---|---|---|
| 1 mg | 0.001 g | 0.000001 kg | 1,000 µg |
| 5 mg | 0.005 g | 0.000005 kg | 5,000 µg |
| 10 mg | 0.01 g | 0.00001 kg | 10,000 µg |
| 50 mg | 0.05 g | 0.00005 kg | 50,000 µg |
| 100 mg | 0.1 g | 0.0001 kg | 100,000 µg |
| 200 mg | 0.2 g | 0.0002 kg | 200,000 µg |
| 250 mg | 0.25 g | 0.00025 kg | 250,000 µg |
| 500 mg | 0.5 g | 0.0005 kg | 500,000 µg |
| 1,000 mg | 1 g | 0.001 kg | 1,000,000 µg |
| 2,500 mg | 2.5 g | 0.0025 kg | 2,500,000 µg |
| 5,000 mg | 5 g | 0.005 kg | 5,000,000 µg |
| 10,000 mg | 10 g | 0.01 kg | 10,000,000 µg |
| 100,000 mg | 100 g | 0.1 kg | 100,000,000 µg |
The grams-to-milligrams conversion is one of the most frequently needed metric conversions in everyday life — from reading medicine labels and following recipes to conducting scientific experiments and tracking nutrition.
Drug dosages are almost always expressed in milligrams on packaging — a standard paracetamol tablet is 500 mg = 0.5 g, and a common ibuprofen tablet is 200 mg = 0.2 g. Pharmacists and healthcare professionals regularly convert between grams and milligrams when calculating dosages, compounding medications, or interpreting prescriptions written in different units.
Nutritional labels list vitamins and minerals in milligrams or micrograms, while food portions are measured in grams. The recommended daily intake of Vitamin C is 1,000 mg = 1 g; iron is about 18 mg = 0.018 g. Athletes, dietitians, and health-conscious individuals routinely convert between these units when planning supplement intake or reading food labels.
Laboratory measurements, chemical reagents, and sample weights in chemistry and biology are often expressed in milligrams for precision. When preparing solutions, a chemist might weigh 2.5 g = 2,500 mg of a compound, then dissolve it in a known volume of solvent. Converting between grams (scale readout) and milligrams (protocol specification) is a fundamental lab skill as of 2026.
Precision cooking and baking — especially for spices, food additives, and specialty ingredients — often requires milligram-level accuracy. A recipe might call for 500 mg of saffron = 0.5 g, or 2,000 mg of baking powder = 2 g. Home bakers and professional chefs using digital scales frequently need to switch between grams and milligrams for accurate results.
While jewellers typically use carats (1 carat = 0.2 g = 200 mg), milligrams are used for extremely fine measurements of precious metals and gemstone powder. Converting between grams and milligrams is essential when working with gold, silver, and precious stones at the sub-gram level, particularly in hallmarking, assaying, and gemological certification.
Students studying chemistry, biology, physics, and pharmacology routinely work with gram and milligram measurements in lab sessions and problem sets. Converting between these units is a core metric literacy skill taught from secondary school onwards. The relationship of 1 g = 1,000 mg is one of the first metric conversions students learn and one of the most frequently applied throughout their scientific education.
The Bureau International des Poids et Mesures (BIPM) is the international body responsible for defining SI units including the gram and kilogram. Their resources cover official mass definitions and the 2019 SI revision that redefined the kilogram via the Planck constant.
Visit BIPM →The World Health Organization (WHO) publishes international pharmaceutical standards where drug dosages and active ingredients are expressed in milligrams and grams. Their essential medicines list is a key reference for gram/milligram conversions in healthcare.
Visit WHO →The National Institute of Standards and Technology (NIST) provides authoritative guidance on metric units including grams and milligrams, and their relationship to US customary units — essential for science, industry, and trade.
Visit NIST →The USDA FoodData Central database lists all nutritional values in grams and milligrams — making it an essential reference for anyone converting between these units in a dietary or food science context.
Visit USDA →