Hectogray is 100 gray units.
Hectograys to Grays Converter — hGy to Gy
Convert Hectogray (hGy) to Gray (Gy) using the exact conversion factor (1 hectogray = 100 gray). See the formula, worked examples, conversion table, history, and common uses.
Hectograys to Grays converter
Converter
Radiation Converter
Convert radioactivity, absorbed dose, and equivalent dose units by compatible radiation family.
Context values
Some unit families need one extra value for a physically accurate result.
Gray is absorbed dose in joules per kilogram.
Result = input x 100 / 1.
Absorbed Dose units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Hectograys to Grays
Hectogray and Gray both belong to the radiation-measurement family, though radiation quantities fall into genuinely distinct categories: absorbed dose (gray, rad) measures energy deposited in matter, equivalent dose (sievert, rem) weights that for biological harm, and activity (becquerel, curie) measures how often a radioactive source decays — this page only converts between units of the same kind. Specifically: Hectogray is 100 gray units, and gray is absorbed dose in joules per kilogram.
Formula
grays = hectograys × 100
This factor comes from each unit's defined relationship to the category's base unit: 1 hectogray equals 100 base units, and 1 gray equals 1 base unit, so dividing one by the other gives the direct hectogray-to-gray factor of 100.
Simple example
1 hGy × 100 = 100 Gy
1 hectogray = 100 grays.
Real-world example
10 hGy × 100 = 1,000 Gy
10 hectograys = 1,000 grays.
Conversion table
| Hectogray (hGy) | Gray (Gy) |
|---|---|
| 0.001 hGy | 0.1 Gy |
| 0.01 hGy | 1 Gy |
| 0.1 hGy | 10 Gy |
| 1 hGy | 100 Gy |
| 10 hGy | 1,000 Gy |
| 100 hGy | 10,000 Gy |
Reverse conversion: Gray to Hectogray
100 Gy × 0.01 = 1 hGy
100 grays = 1 hectogray.
hectograys = grays × 0.01
For a page dedicated to this direction, see Gray to Hectogray.
Understanding the Hectogray (hGy)
Hectogray is 100 gray units.
Understanding the Gray
Gray (Gy) measures absorbed radiation dose. The SI derived unit of absorbed radiation dose, equal to one joule of radiation energy absorbed per kilogram of matter. It is classified as a SI derived unit.
Where it's used: Universal — SI derived unit used worldwide in medicine and radiation protection
Gray vs. sievert. The gray measures physically absorbed energy; the sievert measures equivalent dose, which weights the gray value for how biologically damaging a given type of radiation is. The same absorbed dose in gray can correspond to different sievert values depending on the radiation type.
Uses of the Gray today
- Radiation therapy dose prescriptions in medicine
- Radiation safety and occupational dose monitoring
- Nuclear and radiological research
History of the Gray
The gray is named after Louis Harold Gray (1905–1965), a British physicist who pioneered the physics of radiation dosimetry and its biological effects, and was adopted by the CGPM as an SI derived unit in 1975.
Historical origin. Gray was not the invention of a single named person; it developed through the process described above.
Gray — sources
- BIPM SI Brochure, 9th edition — Official definition of the gray as an SI derived unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grays are in 1 hectogray?
1 hectogray equals 100 grays, using the exact defined conversion factor rather than an estimate.
How do I convert hectogray to gray?
Multiply the hectogray value by 100. The converter above does this instantly to whatever precision you set.
How do I convert gray back to hectogray?
Use the reverse factor: 1 gray equals 0.01 hectograys. You can also use the swap control in the converter above to flip the direction instantly.
What is a hectogray?
Hectogray (hGy) is a unit of radiation.
What is a gray?
Gray (Gy) measures absorbed radiation dose. The SI derived unit of absorbed radiation dose, equal to one joule of radiation energy absorbed per kilogram of matter. It is classified as a SI derived unit.
Is the hectogray to gray conversion exact?
Yes. Both hectogray and gray are defined by fixed standards rather than physical artifacts, so the factor of 100 used above is exact to as many digits as you choose to display.
What is the difference between gray vs. sievert?
The gray measures physically absorbed energy; the sievert measures equivalent dose, which weights the gray value for how biologically damaging a given type of radiation is. The same absorbed dose in gray can correspond to different sievert values depending on the radiation type.