Milligrams to Kilograms
Convert milligrams (mg) to kilograms (kg). Both measure mass and weight, and the conversion comes up in cooking, shipping, fitness work.
The Formula
``
kilograms = milligrams × 0.000001
milligrams = kilograms × 1000000
`
One milligram is 1.0000e-6 kilograms, and one kilogram is 1,000,000 milligrams.
Conversion Table
| Milligrams | Kilograms |
|---|---|
| 1 mg | 1.0000e-6 kg |
| 2 mg | 2.0000e-6 kg |
| 5 mg | 5.0000e-6 kg |
| 10 mg | 1.0000e-5 kg |
| 25 mg | 2.5000e-5 kg |
| 50 mg | 5.0000e-5 kg |
| 100 mg | 1.0000e-4 kg |
| 500 mg | 5.0000e-4 kg |
| 1,000 mg | 0.001 kg |
The Other Direction
| Kilograms | Milligrams |
|---|---|
| 1 kg | 1,000,000 mg |
| 2 kg | 2,000,000 mg |
| 5 kg | 5,000,000 mg |
| 10 kg | 10,000,000 mg |
| 25 kg | 25,000,000 mg |
| 50 kg | 50,000,000 mg |
| 100 kg | 100,000,000 mg |
| 500 kg | 500,000,000 mg |
| 1,000 kg | 1,000,000,000 mg |
What Each Unit Is
Milligrams (mg) — one thousandth of a gram. The metric unit for doses and trace quantities.
Kilograms (kg) — defined since 2019 by fixing the Planck constant — the SI base unit of mass. Originally the mass of a litre of water, then a platinum-iridium cylinder near Paris until 2019.
A Sense of Scale
A grain of sand is about 1 mg- An aspirin tablet is 300–500 mg
- Nutrition labels use mg for sodium
- A litre of water is 1 kg
- A laptop is 1.5–2 kg
- Checked baggage allowance is often 23 kg
Precision
The factor 0.000001 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
In Code
`javascript
const milligramToKilogram = (value) => value * 0.000001;
``
Where This Conversion Comes Up
- Cooking
- Shipping
- Fitness
- Medicine
- Manufacturing
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 mg with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 mg becomes | Error |
|---|---|---|---|
| 0 | 0 | 0 | 100.0000% |
| 1 | 0 | 0 | 100.0000% |
| 2 | 0 | 0 | 100.0000% |
| 3 | 0 | 0 | 100.0000% |
| 4 | 0 | 0 | 100.0000% |
The right number of significant figures is set by your input, not by the converter. If you measured milligrams to three significant figures, the answer in kilograms is only good to three — writing more digits claims precision the measurement never had.