Convert Femtogram to Kilogram
Convert femtograms to kilograms instantly. 1 femtogram = 1e-18 kilogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilogram to Femtogram converter for the reverse conversion.
Units explained
Femtogram
A femtogram (fg) equals 10^-18 kilogram.
From the SI prefix 'femto-' (from Danish/Norwegian 'femten', fifteen).
Nanotechnology and high-sensitivity mass spectrometry.
The femto- prefix was adopted by the CGPM in 1975.
Kilogram
The kilogram (kg) is the SI base unit of mass, defined by fixing the Planck constant h at 6.62607015E-34 J s.
From Greek 'khilioi' (thousand) plus 'gramma' (small weight).
The worldwide base unit of mass in science, commerce, and everyday life.
Adopted in 1795; redefined through the Planck constant on 20 May 2019.
Femtogram to Kilogram conversion formula
The relationship between femtograms and kilograms:
To convert femtograms to kilograms, multiply the value in femtograms by 1e-18. To reverse, multiply kilograms by 1e+18.
How to use this converter
Type a value into the calculator. The result in kilograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilogram to Femtogram converter for the reverse direction.
Step-by-step: convert femtograms to kilograms
- Write down the value in femtograms (fg).
- Multiply that value by the factor 1e-18.
- The product is the equivalent value in kilograms (kg).
- To reverse, multiply the kilogram value by 1e+18.
Worked examples
Example 1 — Convert 1 fg to kg:
1 × 1e-18 = 1e-18 kg
Example 2 — Convert 100 fg to kg:
100 × 1e-18 = 1e-16 kg
Real-world example — Bridging nine orders of magnitude
500 million femtograms equals a value comfortably in the human-scale kilograms range. Physics problems that span this gap are common when comparing the wavelength of light to the path length of an experiment.
5e+8 fg × 1e-18 = 5e-10 kg
Real-world example — From sub-micron to human scale
One billion femtograms equals one kilogram — the conversion that drives home the gulf between atomic-scale features and everyday objects in physics curricula.
1e+9 fg × 1e-18 = 1e-9 kg
Femtogram to Kilogram conversion table
Standard reference values for converting femtograms to kilograms:
| Femtogram [fg] | Kilogram [kg] |
|---|---|
| 0.01 | 1e-20 |
| 0.1 | 1e-19 |
| 1 | 1e-18 |
| 2 | 2e-18 |
| 3 | 3e-18 |
| 4 | 4e-18 |
| 5 | 5e-18 |
| 10 | 1e-17 |
| 20 | 2e-17 |
| 30 | 3e-17 |
| 40 | 4e-17 |
| 50 | 5e-17 |
| 100 | 1e-16 |
| 500 | 5e-16 |
| 1000 | 1e-15 |
Frequently asked questions
How many kilograms is 1 femtogram?
How do I convert femtograms to kilograms?
How do I convert kilograms back to femtograms?
How many kilograms is 100 femtograms?
Popular weight unit conversions
Convert Femtogram to other weight units
Show all Femtogram 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 fg = 1e-18 kg) 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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.