Mass and Weight · Unit Converter

Convert Atomic Mass Unit to Femtogram

Convert atomic mass unit to femtograms instantly. 1 atomic mass unit = 1.66054e-9 femtogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Femtogram to Atomic Mass Unit converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Dr. Ashok Kumar K, Ph.D.
Mass and Weight category 2 min read Published Last reviewed Updated

Units explained

Scientific / Atomic

Atomic Mass Unit

What is a atomic mass unit?

One unified atomic mass unit (u) is defined as 1/12 the mass of a carbon-12 atom, about 1.6605E-27 kg.

Origin of the atomic mass unit

Introduced to give atomic and molecular masses convenient numerical values.

Where it is used

Atomic, molecular, and nuclear physics and chemistry.

When and where it was developed

The unified (carbon-12) scale was adopted by IUPAC and IUPAP in 1960-1961.

Metric / SI

Femtogram

What is a femtogram?

A femtogram (fg) equals 10^-18 kilogram.

Origin of the femtogram

From the SI prefix 'femto-' (from Danish/Norwegian 'femten', fifteen).

Where it is used

Nanotechnology and high-sensitivity mass spectrometry.

When and where it was developed

The femto- prefix was adopted by the CGPM in 1975.

Atomic Mass Unit to Femtogram conversion formula

The relationship between atomic mass unit and femtograms:

1 u = 1.66054e-9 fg
1 fg = 6.022137e+8 u

To convert atomic mass unit to femtograms, multiply the value in atomic mass unit by 1.66054e-9. To reverse, multiply femtograms by 6.022137e+8.

How to use this converter

Type a value into the calculator. The result in femtograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Femtogram to Atomic Mass Unit converter for the reverse direction.

Step-by-step: convert atomic mass unit to femtograms

  1. Write down the value in atomic mass unit (u).
  2. Multiply that value by the factor 1.66054e-9.
  3. The product is the equivalent value in femtograms (fg).
  4. To reverse, multiply the femtogram value by 6.022137e+8.

Worked examples

Example 1 — Convert 1 u to fg:
1 × 1.66054e-9 = 1.66054e-9 fg

Example 2 — Convert 100 u to fg:
100 × 1.66054e-9 = 1.66054e-7 fg

Real-world example — Wavelengths across the spectrum

Optical and atomic-scale phenomena are routinely cross-converted between sub-micron units. A photon of wavelength 800 atomic mass unit can be re-expressed in femtograms for direct comparison with another instrument's calibration data sheet.

800 u × 1.66054e-9 = 1.328432e-6 fg

Real-world example — Molecular dimensions

The diameter of small molecular structures (around 2 atomic mass unit) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.

2 u × 1.66054e-9 = 3.32108e-9 fg

Atomic Mass Unit to Femtogram conversion table

Standard reference values for converting atomic mass unit to femtograms:

Atomic Mass Unit [u]Femtogram [fg]
0.011.66054e-11
0.11.66054e-10
11.66054e-9
23.32108e-9
34.981621e-9
46.642161e-9
58.302701e-9
101.66054e-8
203.32108e-8
304.981621e-8
406.642161e-8
508.302701e-8
1001.66054e-7
5008.302701e-7
10001.66054e-6

Frequently asked questions

How many femtograms is 1 atomic mass unit?
1 atomic mass unit equals 1.66054e-9 femtogram.
How do I convert atomic mass unit to femtograms?
Multiply the value in atomic mass unit by 1.66054e-9 to get femtograms.
How do I convert femtograms back to atomic mass unit?
Multiply the value in femtograms by 6.022137e+8, or use the Femtogram to Atomic Mass Unit converter.
How many femtograms is 100 atomic mass unit?
100 atomic mass unit equals 1.66054e-7 femtograms, because 100 × 1.66054e-9 = 1.66054e-7.

Convert Atomic Mass Unit to other weight units

Show all Atomic Mass Unit conversions
Metric / SI (18 units)
Avoirdupois (15 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (8 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Force / Engineering (5 units)

Sources & references

Conversion factor (1 u = 1.66054e-9 fg) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.