microgram (µg)
1 microgram = 1.000000e-09 kilograms
What is microgram?
A microgram is a metric unit of mass equal to one millionth of a gram. It is used in analytical chemistry, toxicology, pharmacology, and measuring trace amounts of substances in laboratory settings.
Notes: Metric unit
Real-world uses
Micrograms are used for precise pharmaceutical dosages (e.g., 25 µg levothyroxine), trace element measurements in blood tests, and contaminant detection in water and food safety testing. Vitamin D and B12 are commonly dosed in micrograms.
History
The microgram became important with the development of analytical chemistry and pharmacology in the 20th century. The prefix "micro-" comes from the Greek "mikros" meaning small. It was formalized as an SI prefix in 1960.
Common mistakes
Misreading "µg" as "mg," leading to a 1000-fold dosing error—a potentially lethal mistake in medicine. Some prescribing guidelines mandate writing "microgram" in full to prevent this confusion.
When is this conversion used?
Body weight, grocery items, and luggage limits are commonly expressed in kilograms in most countries and pounds in the US and UK, making this one of the most frequently needed mass conversions.
How to convert microgram to kilogram
To convert microgram to kilogram, multiply the value by 1.000000e-09.
Conversion formula (from base unit)
x * 1e-9
Measurement standards
The kilogram is defined by fixing the Planck constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds, as established at the 26th General Conference on Weights and Measures in 2018. This ended the last SI definition based on a physical artefact.
Did you know?
The International Prototype of the Kilogram, a platinum-iridium cylinder stored near Paris since 1889, was found to have drifted by about 50 micrograms relative to its copies over a century — roughly the mass of a fingerprint.
| micrograms | kilograms |
|---|---|
| 0.1 | 1.000000e-10 |
| 0.5 | 5.000000e-10 |
| 1 | 1.000000e-09 |
| 2 | 2.000000e-09 |
| 5 | 5.000000e-09 |
| 10 | 1.000000e-08 |
| 25 | 2.500000e-08 |
| 50 | 5.000000e-08 |
| 100 | 1.000000e-07 |
| 250 | 2.500000e-07 |
| 500 | 5.000000e-07 |
| 1,000 | 0.000001 |
Common values
| micrograms | kilograms | |
|---|---|---|
| A paperclip | 1,000,000 micrograms | 0.001 kilograms |
| A smartphone | 175,000,000 micrograms | 0.175 kilograms |
| A bag of sugar | 999,999,999.99999988 micrograms | 1 kilogram |
| Average adult human | 7.000000e+10 micrograms | 70 kilograms |
| A small car | 1.200000e+12 micrograms | 1,200 kilograms |
Full microgram conversion table
| Unit | Value | Factor |
|---|---|---|
| kilogram | 1 µg = 1.000000e-09 kg | × 1.000000e-09 |
| gram | 1 µg = 0.000001 g | × 0.000001 |
| pound | 1 µg = 2.204623e-09 lb | × 2.204623e-09 |
| ounce | 1 µg = 3.527396e-08 oz | × 3.527396e-08 |
| tonne | 1 µg = 1.000000e-12 t | × 1.000000e-12 |
| milligram | 1 µg = 0.001 mg | × 0.001 |
| stone | 1 µg = 1.574730e-10 st | × 1.574730e-10 |
| short ton (US) | 1 µg = 1.102311e-12 short ton | × 1.102311e-12 |
| long ton (UK) | 1 µg = 9.842065e-13 long ton | × 9.842065e-13 |