Convert Grams to Milligrams
1 gram (g) equals 1000 milligrams (mg).
1 g = 1000 mg
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk gram to milligram converter to paste a column from Excel.
How to Convert Gram to Milligram
- 1 g = 1000 mg
- 1 mg = 0.001 g
- Example: convert 15 g to mg: 15 g = 15 × 1000 mg = 15000 mg
Formula
mg = g × 1000
Derivation from SI units:
- 1 g = 10⁻³ kg
- 1 mg = 10⁻⁶ kg = 10⁻³ g
- 1 g = 0.001 kg ÷ 0.000001 kg per mg = 1000 mg
Both units are defined exactly, so the factor is exact. Gram definition: gram; Milligram definition: milligram.
Worked examples
- 0.5 g of powder is 500 mg.
0.5 g × 1000 = 500 mg - 1.2 g of salt contains about 470 mg of sodium; the salt itself is 1200 mg.
1.2 g × 1000 = 1200 mg
Gram to Milligram conversion table
| Grams (g) | Milligrams (mg) |
|---|---|
| 0.1 g | 100 mg |
| 0.5 g | 500 mg |
| 1 g | 1000 mg |
| 2 g | 2000 mg |
| 5 g | 5000 mg |
| 10 g | 10000 mg |
| 14 g | 14000 mg |
| 20 g | 20000 mg |
| 25 g | 25000 mg |
| 28.35 g | 28350 mg |
| 30 g | 30000 mg |
| 50 g | 50000 mg |
| 75 g | 75000 mg |
| 100 g | 100000 mg |
| 113 g | 113000 mg |
| 125 g | 125000 mg |
| 150 g | 150000 mg |
| 200 g | 200000 mg |
| 250 g | 250000 mg |
| 300 g | 300000 mg |
| 454 g | 454000 mg |
| 500 g | 500000 mg |
| 750 g | 750000 mg |
| 1000 g | 1000000 mg |
Where it's used
Gram quantities are converted to milligrams for dosing, supplements and analytical work. Multiply by 1000.
Gram to other weight and mass units
| Conversion | 1 g equals |
|---|---|
| gram to kilogram | 0.001 kg |
| gram to milligram | 1000 mg |
| gram to microgram | 1000000 µg |
| gram to metric ton | 0.000001 t |
| gram to pound | 0.002204622622 lb |
| gram to ounce | 0.03527396195 oz |
| gram to stone | 0.0001574730444 st |
| gram to short ton | 0.000001102311311 ton (US) |
| gram to long ton | 9.842065276 × 10⁻⁷ ton (UK) |
| gram to grain | 15.43235835 gr |
| gram to troy ounce | 0.03215074657 oz t |
| gram to carat | 5 ct |
Frequently asked questions
How do I convert g to mg?
Multiply by 1000: 0.25 g = 250 mg.
How many milligrams are in 1 gram?
1 g = 1000 mg.
How do I convert grams to milligrams?
Multiply the value in g by 1000. For example, 15 g × 1000 = 15000 mg.
Is the g to mg conversion exact?
Yes. Both units are defined exactly, and 1 g is exactly 1000 mg.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Grams to Milligrams. Retrieved October 17, 2026, from https://scientificconverters.com/mass/grams-to-milligrams/
IEEE
Scientific Converters, "Convert Grams to Milligrams," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/mass/grams-to-milligrams/