Grams to Milligrams Converter
Convert Grams (g) to Milligrams (mg) instantly, or use the conversion table below to look up common values.
Grams to Milligrams conversion table
| Grams (g) | Milligrams (mg) |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 4 | 4,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
How to convert Grams to Milligrams
1 g equals 1,000 mg. Use the converter above for any value, or read the table for common conversions.
mg = g × 1000.0000000000001 · g = mg × 0.001Multiply a grams figure by 1,000 to get milligrams, or divide it by 0.001 to go the other way.
Worked examples
- 1 g= 1,000 mg
- 5 g= 5,000 mg
- 10 g= 10,000 mg
- 25 g= 25,000 mg
- 100 g= 100,000 mg
What these units are
Grams (g). A gram is one thousandth of a kilogram. It is used for food portions, recipe ingredients, jewellery and postal items, and it is the unit most kitchen scales show.
Milligrams (mg). A milligram is one thousandth of a gram. It is used for medicine doses, laboratory work, water-quality readings and any measurement of trace amounts.
Metric conversions are exact. Results are displayed rounded, so values at the extreme ends of the scale — milligrams and tonnes — carry fewer significant digits than the middle of the range.
Converting Grams to Milligrams in practice
Working in grams
A gram is one thousandth of a kilogram, and it is defined through the kilogram, the SI base unit of mass. Metric prefixes scale it by powers of ten.
Grams appear on kitchen scales for food portions and recipe ingredients, on postal and courier labels for small packages, and in jewellery listings where the mass of metal or stones is stated.
Converting grams to kilograms or milligrams is a pure decimal shift and is exact. Imperial factors are exact by definition, but results are rounded for display, so a round trip can differ in the last digit.
A frequent error is reading a jewellery weight given in troy ounces as an avoirdupois ounce, since the troy ounce is 31.1035 grams. Grams suit small quantities, while kilograms suit body weight, market produce and freight.
The nearest sibling to a gram is the kilogram, and kitchen and market scales invite a mix-up; 500 grams is 0.5 kilograms, so a thousandfold slip is easy. Use grams for small portions and kilograms for bulk quantities.
Checking a grams to milligrams conversion
Between the metric units a weight conversion is a power of a thousand, so grams to kilograms and kilograms to tonnes are decimal shifts. The imperial units are all defined against the kilogram, which makes every metric-to-imperial pair a multiplication with the same factor at any size.
The dimension where this goes wrong is the ounce, because the same word covers two different weights. An avoirdupois ounce is one sixteenth of a pound and is the one used for food and parcels; a troy ounce is about 10% heavier (31.1035 g) and is used for precious metals. A price per ounce is meaningless until you know which ounce is meant.
To check a weight conversion, convert the result back, or go through the pound or the kilogram as a middle step. The commonest error is converting a figure stated in pounds into kilograms and then comparing it with a figure that was already in kilograms, which doubles or halves nothing and merely hides the mistake.
Tanzania reference points
Real quantities, converted into the units on this page.
The most a packet declared between 500 g and 1 kg may fall short under Tanzanian weights and measures rules
15 g = 15,000 mg
Table IIIC of the 2019 regulations allows an individual deficiency of 1.5%, or 15 g, on a nominal net content between 500 g and 1 kg. Regulation 179 separately requires the average net content of a whole lot to be at least what the packet declares, so the tolerance is on single packets rather than the batch.
Source: The Weights and Measures (General) Regulations, 2019 (GN No. 288) — Weights and Measures Agency · verified 2026-09-14
Related conversions
More weight & mass conversions you can convert instantly.
Related calculators
Try these calculators that use weight & mass measurements.