Gram to Milligram
Free instant gram to milligram converter. 1 g = 1000 mg.
Common Gram to Milligram values
| Gram (g) | Milligram (mg) |
|---|---|
| 1 | 1000 |
| 5 | 5000 |
| 10 | 10000 |
| 25 | 25000 |
| 50 | 50000 |
| 100 | 100000 |
| 500 | 500000 |
| 1000 | 1000000 |
How does Gram to Milligram conversion work?
Type a value in the Gram (g) field and the equivalent in Milligram (mg) appears instantly to the right. The math uses the exact formula shown above — no rounding errors, no approximations beyond standard floating-point precision. Use the swap button to flip the units and see the inverse conversion.
Gram. One thousandth of a kilogram. About the weight of a paperclip.
Milligram. One thousandth of a gram. Used for medication doses, vitamins, and very fine measurements.
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🎯 Accurate conversions
Conversion factors come from the official standard (NIST, BIPM, ISO definitions where applicable). Values are precise to standard floating-point limits.
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How it works — the formula
value_in_base = value × scale
For mass, scale = kilograms per unit (e.g. 1 lb = 0.45359237 kg exactly)The SI base unit for what laypeople call "weight" is the kilogram, redefined in 2019 in terms of the Planck constant h = 6.62607015 × 10⁻³⁴ J·s exactly (CGPM 26th meeting, Resolution 1). Strictly, weight is a force (mass × g) measured in newtons, but everyday usage and US-customary units treat it as mass. The international avoirdupois pound has been exactly 0.45359237 kg since the 1959 agreement.
Worked examples
- Inputs:
- 150 lb = ? kg
- Output:
- 150 × 0.45359237 = 68.0388555 kg
- Inputs:
- 8 oz = ? g
- Output:
- 8 × 28.349523125 = 226.796185 g (avoirdupois)
- Inputs:
- 1 t (metric) = ? short ton
- Output:
- 1 / 0.90718474 ≈ 1.1023 short tons
Limitations
- Avoirdupois ounce (28.349523125 g) differs from troy ounce (31.1034768 g, used for precious metals) — pick the right unit for context.
- Short ton (US, 2,000 lb), long ton (UK, 2,240 lb), and tonne / metric ton (1,000 kg) all share the spelling "ton" — disambiguate carefully.
- "Weight" on a scale is technically force; readings change by ~0.5% between equator and poles due to gravity, but local scales are calibrated to read mass.
- Pharmaceutical and apothecary scales use yet another set of units (grain, drachm) — not modeled here.
Conversions assume mass; scale readings on Earth approximate mass to within local-gravity precision, which is more than sufficient for everyday use.