Convert Gigameter to Attometer
Convert gigameters to attometers instantly. 1 gigameter = 1e+27 attometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Attometer to Gigameter converter for the reverse conversion.
Units explained
Gigameter
A gigameter is a metric unit of length equal to one billion meters (1×10⁹ m). It is most often used in astronomy and astrophysics when expressing distances within the inner solar system.
The gigameter uses the SI prefix giga- (from Greek gigas, giant), adopted by the CGPM in 1960 to denote multiplication by one billion (10⁹).
Gigameters are used to express distances such as the Sun's diameter (~1.39 Gm), the Earth–Moon distance (~0.384 Gm), and similar inner-solar-system scales. Astronomical units and light-seconds are also common for these distances.
SI prefix giga- adopted in 1960; the gigameter became standard in astronomy for sub-AU distances by the late 20th century.
Attometer
An attometer is a metric unit of length equal to one quintillionth of a meter (1×10⁻¹⁸ m). It is among the smallest length units in the SI system and is used almost exclusively in particle physics and theoretical work involving sub-nuclear dimensions.
The attometer was defined using the SI prefix atto- (from Danish atten, meaning eighteen), adopted by the Conférence Générale des Poids et Mesures (CGPM) in 1964 to denote one quintillionth (10⁻¹⁸).
Attometers appear in particle physics literature when describing distances comparable to or smaller than nuclear dimensions, including the range of weak nuclear interactions and theoretical Planck-scale ratios. They are rarely encountered outside specialised scientific work.
SI prefix atto- adopted in 1964; the attometer became the standard unit for sub-femtometer measurements in high-energy physics from the late 20th century onward.
Gigameter to Attometer conversion formula
The relationship between gigameters and attometers:
To convert gigameters to attometers, multiply the value in gigameters by 1e+27. To reverse, multiply attometers by 1e-27.
How to use this converter
Type a value into the calculator. The result in attometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Attometer to Gigameter converter for the reverse direction.
Step-by-step: convert gigameters to attometers
- Write down the value in gigameters (Gm).
- Multiply that value by the factor 1e+27.
- The product is the equivalent value in attometers (am).
- To reverse, multiply the attometer value by 1e-27.
Worked examples
Example 1 — Convert 1 Gm to am:
1 × 1e+27 = 1e+27 am
Example 2 — Convert 100 Gm to am:
100 × 1e+27 = 1e+29 am
Gigameter to Attometer conversion table
Standard reference values for converting gigameters to attometers:
| Gigameter [Gm] | Attometer [am] |
|---|---|
| 0.01 | 1e+25 |
| 0.1 | 1e+26 |
| 1 | 1e+27 |
| 2 | 2e+27 |
| 3 | 3e+27 |
| 4 | 4e+27 |
| 5 | 5e+27 |
| 10 | 1e+28 |
| 20 | 2e+28 |
| 30 | 3e+28 |
| 40 | 4e+28 |
| 50 | 5e+28 |
| 100 | 1e+29 |
| 500 | 5e+29 |
| 1000 | 1e+30 |
Frequently asked questions
How many attometers is 1 gigameter?
How do I convert gigameters to attometers?
How do I convert attometers back to gigameters?
How many attometers is 100 gigameters?
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Sources & references
Conversion factor (1 Gm = 1e+27 am) 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.