Convert Attogram to Gram
Convert attograms to grams instantly. 1 attogram = 1e-18 gram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Gram 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.
Gram
The gram (g) equals one-thousandth of a kilogram.
From Late Latin 'gramma', a small weight or scruple.
The everyday metric unit for food, medicine, and small objects.
Defined in 1795 as the mass of one cubic centimeter of water at melting point.
Attogram to Gram conversion formula
The relationship between attograms and grams:
To convert attograms to grams, multiply the value in attograms by 1e-18. To reverse, multiply grams by 1e+18.
How to use this converter
Type a value into the calculator. The result in grams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Gram to Attogram converter for the reverse direction.
Step-by-step: convert attograms to grams
- Write down the value in attograms (ag).
- Multiply that value by the factor 1e-18.
- The product is the equivalent value in grams (g).
- To reverse, multiply the gram value by 1e+18.
Worked examples
Example 1 — Convert 1 ag to g:
1 × 1e-18 = 1e-18 g
Example 2 — Convert 100 ag to g:
100 × 1e-18 = 1e-16 g
Real-world example — From wavelengths to millimeter-scale objects
A value of one million attograms sounds vast at the atomic scale but converts to a small everyday quantity in grams — useful when relating optical-wavelength specifications to physical mounting hardware.
1000000 ag × 1e-18 = 1e-12 g
Real-world example — Sub-micron to millimeter
500,000 attograms converts to a small everyday quantity in grams — useful when relating optical-wavelength specifications to physical mounting hardware.
500000 ag × 1e-18 = 5e-13 g
Attogram to Gram conversion table
Standard reference values for converting attograms to grams:
| Attogram [ag] | Gram [g] |
|---|---|
| 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 grams is 1 attogram?
How do I convert attograms to grams?
How do I convert grams back to attograms?
How many grams is 100 attograms?
Popular weight unit conversions
Convert Attogram to other weight units
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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 = 1e-18 g) 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.