One gram is exactly 1,000 milligrams. Multiply grams by 1,000, or move the decimal point three places right. 1.25 g is 1,250 mg; 2.5 g is 2,500 mg; 4.5 g is 4,500 mg.
Why it is exactly 1,000
Milli- means one thousandth, so a milligram is a thousandth of a gram by definition. Like every metric conversion, this is a decimal shift with no rounding — the factor is exact by construction rather than by measurement.
Common values
| Grams | Milligrams |
|---|---|
| 0.1 g | 100 mg |
| 0.25 g | 250 mg |
| 0.5 g | 500 mg |
| 1 g | 1,000 mg |
| 1.25 g | 1,250 mg |
| 2 g | 2,000 mg |
| 2.5 g | 2,500 mg |
| 3 g | 3,000 mg |
| 4.5 g | 4,500 mg |
| 5 g | 5,000 mg |
| 10 g | 10,000 mg |
Where milligrams are used
Almost anywhere the quantity is small enough that grams would need decimals: medicine doses, vitamin and supplement labels, nutrition information for sodium and caffeine, and laboratory measurement.
Nutrition labels are the everyday case. Sodium is listed in milligrams while the food's weight is in grams, so a label reading 2,300 mg of sodium is 2.3 g — and seeing it as 2.3 g often makes the quantity easier to judge than the larger-looking number.
Common mistake
Confusing mg with mcg (micrograms). A microgram is a thousandth of a milligram, so the two differ by a factor of 1,000 — and both appear on supplement labels, sometimes on the same panel. Where a dose matters, check the unit before the number: 500 mcg and 500 mg are not close.
Grams to milligrams is ×1,000: 0.5 g = 500 mg, 2 g = 2,000 mg. Nutrition labels list sodium and cholesterol in mg; kitchen scales read grams — the conversion links the two.
Where you'll meet this conversion
- 2.3 g of sodium is 2,300 mg — the common daily limit.
- A 1 g paracetamol dose is two 500 mg tablets.
- 0.4 g of caffeine (400 mg) is the typical daily ceiling for adults.
Common mistake
Confusing mg with mcg (µg): 1 g = 1,000 mg = 1,000,000 µg. Vitamin doses often use µg.
Quick answer: one gram equals 1,000 milligrams. So to convert grams to milligrams, multiply by 1,000.
How to convert grams to milligrams
milligrams = grams × 1,000
The gram is the metric everyday unit for cooking ingredients, letters and jewelry. Originally defined as the mass of a cubic centimeter of water.
The milligram — one thousandth of a gram — is the unit of medicine dosages and nutrition labels, where tiny quantities matter enormously.
Gram to Milligram conversion table
| Gram (g) | Milligram (mg) |
|---|---|
| 0.01 g | 10 mg |
| 0.1 g | 100 mg |
| 0.25 g | 250 mg |
| 0.4 g | 400 mg |
| 0.75 g | 750 mg |
| 1.25 g | 1,250 mg |
| 1.75 g | 1,750 mg |
| 2.5 g | 2,500 mg |
| 3.5 g | 3,500 mg |
| 4.5 g | 4,500 mg |
| 6 g | 6,000 mg |
| 8 g | 8,000 mg |
| 10 g | 10,000 mg |
| 12 g | 12,000 mg |
| 14 g | 14,000 mg |
| 16 g | 16,000 mg |
| 18 g | 18,000 mg |
| 20 g | 20,000 mg |
| 24 g | 24,000 mg |
| 26 g | 26,000 mg |
| 30 g | 30,000 mg |
| 35 g | 35,000 mg |
| 45 g | 45,000 mg |
| 55 g | 55,000 mg |
| 65 g | 65,000 mg |
| 75 g | 75,000 mg |
| 85 g | 85,000 mg |
| 95 g | 95,000 mg |
| 110 g | 110,000 mg |
| 125 g | 125,000 mg |
| 175 g | 175,000 mg |
| 250 g | 250,000 mg |
| 350 g | 350,000 mg |
| 450 g | 450,000 mg |
| 600 g | 600,000 mg |
| 750 g | 750,000 mg |
| 900 g | 900,000 mg |
| 1,500 g | 1,500,000 mg |
| 2,500 g | 2,500,000 mg |
| 10,000 g | 10,000,000 mg |
Need the opposite direction? Use the Milligram to Gram converter, or read our complete guide to weight conversions for every formula in one place.
Frequently asked questions
How many milligrams are in one gram?
One gram equals 1,000 milligrams. Multiply any gram value by 1,000 to get milligrams.
What is 10 grams in milligrams?
10 grams equal 10,000 milligrams (10 × 1,000).
Is the gram to milligram conversion exact?
The conversion factor used here (1,000) is based on the internationally agreed definitions of both units, so results are exact up to rounding of the final decimal places.
Is my data stored when I use this converter?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is sent to a server, logged or stored.