Femtogray is 1e-15 gray units.
Femtograys to Kilograys Converter — fGy to kGy
Convert Femtogray (fGy) to Kilogray (kGy) using the exact conversion factor (1 femtogray = 1e-18 kilogray). See the formula, worked examples, and conversion table.
Femtograys to Kilograys 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.
Kilogray is 1000 gray units.
Result = input x 1e-15 / 1000.
Absorbed Dose units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Femtograys to Kilograys
Femtogray and Kilogray 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: Femtogray is 1e-15 gray units, and kilogray is 1000 gray units.
Formula
kilograys = femtograys × 1e-18
This factor comes from each unit's defined relationship to the category's base unit: 1 femtogray equals 1e-15 base units, and 1 kilogray equals 1000 base units, so dividing one by the other gives the direct femtogray-to-kilogray factor of 1e-18.
Simple example
1 fGy × 1e-18 = 1e-18 kGy
1 femtogray = 1e-18 kilograys.
Real-world example
10 fGy × 1e-18 = 1e-17 kGy
10 femtograys = 1e-17 kilograys.
Conversion table
| Femtogray (fGy) | Kilogray (kGy) |
|---|---|
| 0.001 fGy | 1e-21 kGy |
| 0.01 fGy | 1e-20 kGy |
| 0.1 fGy | 1e-19 kGy |
| 1 fGy | 1e-18 kGy |
| 10 fGy | 1e-17 kGy |
| 100 fGy | 1e-16 kGy |
Reverse conversion: Kilogray to Femtogray
1e-18 kGy × 1e+18 = 1 fGy
1e-18 kilograys = 1 femtogray.
femtograys = kilograys × 1e+18
For a page dedicated to this direction, see Kilogray to Femtogray.
Understanding the Femtogray (fGy)
Femtogray is 1e-15 gray units.
Understanding the Kilogray (kGy)
Kilogray is 1000 gray units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilograys are in 1 femtogray?
1 femtogray equals 1e-18 kilograys, using the exact defined conversion factor rather than an estimate.
How do I convert femtogray to kilogray?
Multiply the femtogray value by 1e-18. The converter above does this instantly to whatever precision you set.
How do I convert kilogray back to femtogray?
Use the reverse factor: 1 kilogray equals 1e+18 femtograys. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtogray?
Femtogray (fGy) is a unit of radiation.
What is a kilogray?
Kilogray (kGy) is a unit of radiation.
Is the femtogray to kilogray conversion exact?
Yes. Both femtogray and kilogray are defined by fixed standards rather than physical artifacts, so the factor of 1e-18 used above is exact to as many digits as you choose to display.
What's the difference between absorbed dose, equivalent dose, and activity?
Absorbed dose (gray, rad) measures the energy radiation deposits in matter. Equivalent dose (sievert, rem) adjusts that figure for how harmful different types of radiation are to biological tissue. Activity (becquerel, curie) measures how often a radioactive source decays, independent of how much dose a person actually receives from it.