How many kilograms are in 1 microgram?

1 microgram equals 1e-9 kilograms, using the exact defined conversion factor rather than an estimate.

How do I convert microgram to kilogram?

Multiply the microgram value by 1e-9. The converter above does this instantly to whatever precision you set.

How do I convert kilogram back to microgram?

Use the reverse factor: 1 kilogram equals 1,000,000,000 micrograms. You can also use the swap control in the converter above to flip the direction instantly.

Microgram (ug) is a unit of scientific units.

Is the microgram to kilogram conversion exact?

Yes. Both microgram and kilogram are defined by fixed standards rather than physical artifacts, so the factor of 1e-9 used above is exact to as many digits as you choose to display.

Why does this category span everything from atomic to astronomical scales?

Scientific work spans an enormous range of physical scales, from atomic distances (measured in angstroms or atomic mass units) to interstellar distances (measured in astronomical units or parsecs), so this category groups SI-derived and scale-specific units that researchers commonly need to convert between within their field.

Micrograms to Kilograms Converter

Q: What is a kilogram?

Kilogram (kg) measures mass. The kilogram is the SI base unit of mass; every other SI mass unit is a decimal multiple or fraction of it. It is classified as a SI base unit.

About Converting Micrograms to Kilograms

Microgram and Kilogram are both scientific-measurement units, spanning everything from atomic and laboratory scales to astronomical distances — the kind of conversion that comes up constantly in physics, chemistry, and astronomy when a result needs to move between conventions used in different subfields. Specifically: Microgram is 0.000001 gram units, and kilogram is 1000 gram units.

Formula

kilograms = micrograms × 1e-9

This factor comes from each unit's defined relationship to the category's base unit: 1 microgram equals 1e-9 base units, and 1 kilogram equals 1 base unit, so dividing one by the other gives the direct microgram-to-kilogram factor of 1e-9.

Simple example

1 ug × 1e-9 = 1e-9 kg

1 microgram = 1e-9 kilograms.

Real-world example

10 ug × 1e-9 = 1e-8 kg

10 micrograms = 1e-8 kilograms.

Conversion table

Microgram (ug)	Kilogram (kg)
0.001 ug	1e-12 kg
0.01 ug	1e-11 kg
1 ug	1e-9 kg
10 ug	1e-8 kg
100 ug	1e-7 kg
1,000 ug	0.000001 kg

Reverse conversion: Kilogram to Microgram

1e-9 kg × 1000000000 = 1 ug

1e-9 kilograms = 1 microgram.

micrograms = kilograms × 1000000000

For a page dedicated to this direction, see Kilogram to Microgram.

Understanding the Microgram (ug)

Microgram is 0.000001 gram units.

Understanding the Kilogram

Kilogram (kg) measures mass. The kilogram is the SI base unit of mass; every other SI mass unit is a decimal multiple or fraction of it. It is classified as a SI base unit.

Where it's used: Used as the standard mass unit in nearly every country except the United States and a few others that primarily use the pound.

Uses of the Kilogram today

Pricing and labeling goods sold by weight in retail and commodity trade
Dosing calculations in medicine, especially for pediatric and weight-based prescriptions
Structural and material specification in metric-system engineering
Scientific measurement of mass across chemistry, physics, and materials research

History of the Kilogram

The kilogram's direct predecessor was the 'grave,' defined by the French Academy of Sciences in 1793 as the mass of one cubic decimeter of water at its temperature of maximum density. Because 'grave' echoed the aristocratic title 'graf,' revolutionary France's decree of 18 Germinal, Year III (7 April 1795) renamed the system: the gram became the reference unit, defined as the mass of one cubic centimeter of water at the melting point of ice, and the kilogram — one thousand grams — took over the grave's practical role.

Turning that water-based definition into a physical object required real experimental work: chemist Louis Lefèvre-Gineau was tasked in 1795 with measuring precisely how much a cubic decimeter of water weighed, and former royal jeweller Marc-Étienne Janety then fabricated a platinum cylinder to embody that measured mass. Deposited in the French National Archives in 1799, it became known as the Kilogramme des Archives.

The metric system spread unevenly — Napoleon briefly restricted its use — but France made it compulsory in 1840, and the 1875 Metre Convention (signed by seventeen nations including the US) established the BIPM and a shared international prototype. The platinum-iridium International Prototype of the Kilogram, adopted in 1889 and nicknamed 'Le Grand K,' served as the world's mass reference for over a century.

On 20 May 2019, the kilogram was redefined by fixing the Planck constant at exactly 6.62607015 × 10⁻³⁴ joule-seconds, so it can now be realized in a laboratory (via a Kibble balance) without reference to any physical object.

Historical origin. Kilogram was not the invention of a single named person; it developed through the process described above.

Kilogram — sources

BIPM — The kilogram (SI base unit) — Official definition and history since the 2019 redefinition.
NIST — Kilogram: The Past — History of the kilogram standard from the grave to the International Prototype Kilogram.
SI Brochure, 9th edition (2019), Appendix 2 — BIPM — Official text of the Planck-constant-based definition of the kilogram.

Micrograms to Kilograms Converter — ug to kg

Scientific Units Converter