Grams to Milligrams (g to mg) Converter & Formula
1 gram equals 1,000 milligrams — multiply the number of grams by 1,000 to convert to milligrams. A milligram is one-thousandth of a gram, so the conversion is a simple decimal-point shift. ByteTools applies the exact factor as you type.
The formula
To convert grams to milligrams, multiply by 1,000:
mg = g × 1000
For example, 5 grams × 1000 = 5,000 milligrams. To reverse it, divide milligrams by 1,000.
Conversion table
| Grams (g) | Milligrams (mg) |
|---|---|
| 1 | 1000 |
| 2 | 2000 |
| 5 | 5000 |
| 10 | 10000 |
| 25 | 25000 |
| 50 | 50000 |
| 100 | 100000 |
| 500 | 500000 |
| 1000 | 1000000 |
How to convert online
- Type the number of grams into the first box.
- Read the milligrams result instantly in the second box.
- Type a milligram value instead to convert back to grams — it works both ways.
Use the Gram to Milligram Converter — free and instant in your browser.
Where this conversion is used
Grams-to-milligram conversions are essential in medicine and supplement dosing, chemistry, nutrition labels and jewelry, where small masses are measured in milligrams but often quoted in grams. Multiplying by 1,000 keeps dosages and formulas exact.
FAQ
How many milligrams are in a gram?
One gram equals 1,000 milligrams. So 5 grams is 5,000 mg and 100 grams is 100,000 mg.
What is the formula to convert grams to milligrams?
Multiply grams by 1,000: mg = g × 1000. The converter applies this exact factor automatically.
How do I convert milligrams back to grams?
Divide by 1,000, or multiply milligrams by 0.001. For example, 2,500 mg = 2.5 grams.
Is the conversion exact?
Yes. The metric prefix milli- means exactly one-thousandth, so 1 gram is precisely 1,000 mg.
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