Convert Attogram to Carat (metric)
Convert attograms to carats (metric) instantly. 1 attogram = 5e-18 carat (metric) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Carat (metric) to Attogram converter for the reverse conversion.
Units explained
Attogram
An attogram (ag) equals 10^-21 kilogram.
From the SI prefix 'atto-' (from Danish 'atten', eighteen).
Frontier nanoscience and single-molecule mass detection.
The atto- prefix was adopted by the CGPM in 1975.
Carat (metric)
The metric carat (ct) equals exactly 200 milligrams (0.0002 kg).
From Arabic 'qirat' and Greek 'keration', the carob seed once used as a counterweight.
The worldwide standard for gemstone and diamond mass.
The metric carat was fixed at 200 mg internationally in 1907.
Attogram to Carat (metric) conversion formula
The relationship between attograms and carats (metric):
To convert attograms to carats (metric), multiply the value in attograms by 5e-18. To reverse, multiply carats (metric) by 2e+17.
How to use this converter
Type a value into the calculator. The result in carats (metric) updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Carat (metric) to Attogram converter for the reverse direction.
Step-by-step: convert attograms to carats (metric)
- Write down the value in attograms (ag).
- Multiply that value by the factor 5e-18.
- The product is the equivalent value in carats (metric) (ct).
- To reverse, multiply the carat (metric) value by 2e+17.
Worked examples
Example 1 — Convert 1 ag to ct:
1 × 5e-18 = 5e-18 ct
Example 2 — Convert 100 ag to ct:
100 × 5e-18 = 5e-16 ct
Real-world example — Sub-visible-light wavelength
500 attograms (the green-yellow visible band) equals 0.5 carats (metric) — the canonical conversion in optics between wavelength specifications and micron-scale lens-coating thicknesses.
500 ag × 5e-18 = 2.5e-15 ct
Real-world example — Spanning sub-micron to micron scale
Crossing from attograms to carats (metric) is the everyday workflow of microscopy and semiconductor engineering — a measurement of 1000 attograms translates to a much more compact value in carats (metric) that fits the scale of biological cells and process nodes.
1000 ag × 5e-18 = 5e-15 ct
Attogram to Carat (metric) conversion table
Standard reference values for converting attograms to carats (metric):
| Attogram [ag] | Carat (metric) [ct] |
|---|---|
| 0.01 | 5e-20 |
| 0.1 | 5e-19 |
| 1 | 5e-18 |
| 2 | 1e-17 |
| 3 | 1.5e-17 |
| 4 | 2e-17 |
| 5 | 2.5e-17 |
| 10 | 5e-17 |
| 20 | 1e-16 |
| 30 | 1.5e-16 |
| 40 | 2e-16 |
| 50 | 2.5e-16 |
| 100 | 5e-16 |
| 500 | 2.5e-15 |
| 1000 | 5e-15 |
Frequently asked questions
How many carats (metric) is 1 attogram?
How do I convert attograms to carats (metric)?
How do I convert carats (metric) back to attograms?
How many carats (metric) is 100 attograms?
Popular weight unit conversions
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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 ag = 5e-18 ct) 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 Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.