Grams to Milligrams Converter (g to mg)
1 g = 1,000 mg exactly. Convert grams to milligrams for medicine doses, coins and small kitchen or lab amounts, with g to mg and mg to g charts.
Milligram (mg) = Gram (g) × 1000
Gram (g): The gram is one thousandth of a kilogram, the SI base unit of mass. It is used worldwide for food, postage and small quantities of almost anything.
Milligram (mg): A milligram is one thousandth of a gram, or one millionth of a kilogram. There are 1,000 micrograms in one milligram.
| Gram (g) | Milligram (mg) |
|---|---|
| 1 | 1000 |
| 5 | 5000 |
| 10 | 10000 |
| 25 | 25000 |
| 50 | 50000 |
| 100 | 100000 |
Grams become awkward once amounts fall below one: a 0.5 g tablet, a 0.25 g dose of powder or a 0.05 g sample is easier to read, write and check as 500 mg, 250 mg or 50 mg. Multiplying grams by 1,000 gives milligrams with no rounding involved, because the milligram is defined as exactly one thousandth of a gram.
This is the direction used to turn a prescription written in grams into the milligram strength printed on a box, or to read a jeweler's or laboratory balance. A pocket scale that reads to 0.01 g is in effect weighing in 10 mg steps, and a laboratory balance that reads to 0.001 g resolves single milligrams.
How to use this tool
- Type a value in the Gram box to see it in milligrams, or type in the Milligram box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Weight & Mass converter.
Formula
Milligram (mg) = Gram (g) × 1000
Gram (g) = Milligram (mg) × 0.001
Both factors come from exact definitions: 1 milligram = 0.001 grams and 1 gram = 1000 milligrams (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
0.5 g × 1000 = 500 mg
750 mg × 0.001 = 0.75 g
Gram to Milligram chart
Common values from grams to milligrams, rounded to four decimal places.
| Gram (g) | Milligram (mg) |
|---|---|
| 0.001 | 1 |
| 0.005 | 5 |
| 0.01 | 10 |
| 0.02 | 20 |
| 0.025 | 25 |
| 0.05 | 50 |
| 0.075 | 75 |
| 0.1 | 100 |
| 0.125 | 125 |
| 0.15 | 150 |
| 0.2 | 200 |
| 0.3 | 300 |
| 0.4 | 400 |
| 0.5 | 500 |
| 0.6 | 600 |
| 0.75 | 750 |
| 0.8 | 800 |
| 1 | 1,000 |
| 1.2 | 1,200 |
| 1.5 | 1,500 |
| 2 | 2,000 |
| 3 | 3,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 20 | 20,000 |
Milligram to Gram chart
The reverse direction for values people often look up.
| Milligram (mg) | Gram (g) |
|---|---|
| 15 | 0.015 |
| 40 | 0.04 |
| 75 | 0.075 |
| 120 | 0.12 |
| 150 | 0.15 |
| 300 | 0.3 |
| 450 | 0.45 |
| 600 | 0.6 |
| 800 | 0.8 |
| 1,200 | 1.2 |
| 1,800 | 1.8 |
| 3,500 | 3.5 |
Small things weighed in grams
| Item | Gram (g) | Milligram (mg) |
|---|---|---|
| Paracetamol tablet, standard UK strength | 0.5 | 500 |
| US dime | 2.268 | 2,268 |
| US penny, copper-plated zinc | 2.5 | 2,500 |
| US nickel | 5 | 5,000 |
| Daily salt limit the WHO advises (stay under) | 5 | 5,000 |
| US quarter | 5.67 | 5,670 |
| US half dollar | 11.34 | 11,340 |
Quick mental estimate
Shift the digits three places to the right, filling with zeros: 0.25 g becomes 250 mg and 5.67 g becomes 5,670 mg. Nothing is rounded, because milli- means exactly one thousandth.
Use the converter or the charts when the exact figure matters.
The two units
Gram (g): The gram is one thousandth of a kilogram, the SI base unit of mass. It is used worldwide for food, postage and small quantities of almost anything.
Milligram (mg): A milligram is one thousandth of a gram, or one millionth of a kilogram. There are 1,000 micrograms in one milligram.
Frequently asked questions
How many milligrams is half a gram?
500 mg. A quarter of a gram is 250 mg, a tenth of a gram is 100 mg and a twentieth is 50 mg, strengths printed on many tablets and capsules.
Can a kitchen scale weigh milligrams?
Usually not. Most kitchen scales step in whole grams, which is 1,000 mg at a time. Pocket or jewelry scales commonly read to 0.01 g (10 mg), and analytical balances in laboratories read to 0.0001 g (0.1 mg) or finer.
Why do prescriptions say 500 mg rather than 0.5 g?
Whole numbers are harder to misread. Medication-safety guidance warns against writing a dose without a leading zero (.5 g can be read as 5 g) or with a trailing zero (5.0 mg can be read as 50 mg), so doses are usually written in a unit that avoids decimals.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/gram-to-milligram-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Grams to Milligrams Converter (g to mg). https://kakao.mobile/tools/gram-to-milligram-converter/
“Grams to Milligrams Converter (g to mg).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/gram-to-milligram-converter/.
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