Convert Milligram to Gram
Convert milligrams to grams instantly. 1 milligram = 0.001 gram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Gram to Milligram converter for the reverse conversion.
Units explained
Milligram
A milligram (mg) equals one-millionth of a kilogram, or 0.001 gram.
From the SI prefix 'milli-' (from Latin 'mille', thousand).
Standard for medicine dosing, nutrition labels, and fine jewelry.
Part of the original metric system of 1795.
Gram
The gram (g) equals one-thousandth of a kilogram.
From Late Latin 'gramma', a small weight or scruple.
The everyday metric unit for food, medicine, and small objects.
Defined in 1795 as the mass of one cubic centimeter of water at melting point.
Milligram to Gram conversion formula
The relationship between milligrams and grams:
To convert milligrams to grams, multiply the value in milligrams by 0.001. To reverse, multiply grams by 1000.
How to use this converter
Type a value into the calculator. The result in grams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Gram to Milligram converter for the reverse direction.
Step-by-step: convert milligrams to grams
- Write down the value in milligrams (mg).
- Multiply that value by the factor 0.001.
- The product is the equivalent value in grams (g).
- To reverse, multiply the gram value by 1000.
Worked examples
Example 1 — Convert 1 mg to g:
1 × 0.001 = 0.001 g
Example 2 — Convert 100 mg to g:
100 × 0.001 = 0.1 g
Real-world example — Packaging gauge
A 4-milligram plastic bag thickness is a common spec for grocery and freezer bags. Converting from milligrams to grams is what packaging buyers do whenever they bridge US and metric supplier quotes.
4 mg × 0.001 = 0.004 g
Real-world example — Plastic film and laminate thickness
A 500-milligram sheet is a typical spec for ID-card laminates and film overlays. Converting to grams aligns the value with the unit most CAD systems and material datasheets prefer.
500 mg × 0.001 = 0.5 g
Milligram to Gram conversion table
Standard reference values for converting milligrams to grams:
| Milligram [mg] | Gram [g] |
|---|---|
| 0.01 | 1e-5 |
| 0.1 | 0.0001 |
| 1 | 0.001 |
| 2 | 0.002 |
| 3 | 0.003 |
| 4 | 0.004 |
| 5 | 0.005 |
| 10 | 0.01 |
| 20 | 0.02 |
| 30 | 0.03 |
| 40 | 0.04 |
| 50 | 0.05 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1000 | 1 |
Frequently asked questions
How many grams is 1 milligram?
How do I convert milligrams to grams?
How do I convert grams back to milligrams?
How many grams is 100 milligrams?
Popular weight unit conversions
Convert Milligram to other weight units
Show all Milligram conversions
Metric / SI (17 units)
Avoirdupois (15 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 mg = 0.001 g) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.