Coulomb per Kilogram (C/kg)
Coulomb per kilogram (C/kg) is the SI unit of exposure — ionization charge produced per unit mass of air.
C/kg is the modern SI replacement for the roentgen in radiation exposure metrology.
Coulomb per Kilogram to Roentgen
Convert coulomb per kilogram to roentgen instantly. Type in either field — results update live.
Instant
Private
Free
radiation-exposure Coulomb per Kilogram Roentgen
1 coulomb per kilogram = 3,875.9689922481 roentgens
Unit
Unit
Conversion table
Selected C/kg values converted to R using the exact factor from this tool.
| C/kg | R |
|---|---|
| 0.01 | 38.7596899225 |
| 0.1 | 387.5968992248 |
| 1 | 3,875.9689922481 |
| 2 | 7,751.9379844961 |
| 3 | 11,627.9069767442 |
| 5 | 19,379.8449612403 |
| 10 | 38,759.6899224806 |
| 20 | 77,519.3798449613 |
| 50 | 193,798.4496124031 |
| 100 | 387,596.8992248062 |
| 1,000 | 3,875,968.9922480625 |
How to convert
Exact conversion factors in both directions, plus a worked example.
1 C/kg = 3875.9689922481 R
1 R = 0.000258 C/kg
To convert coulomb per kilogram to roentgen, multiply by 3875.9689922481.
To convert roentgen to coulomb per kilogram, multiply by 0.000258.
Example: convert 10 C/kg to R
10 × 3875.9689922481 = 38759.6899224806 R
About these units
Short background on the units used in this conversion.
Roentgen (R)
The roentgen (R) equals 0.000258 coulomb per kilogram — the classic unit of photon exposure in air for X-rays and gamma rays.
Roentgens label X-ray tube output, radiographic technique factors, and legacy exposure specifications — the most searched exposure conversion.
Frequently asked questions
How many roentgens are in one coulomb per kilogram?
One coulomb per kilogram equals 3,875.9689922481 roentgens. Multiply your coulomb per kilograms value by 3,875.9689922481 to convert to roentgens.
What is the conversion formula?
R = C/kg × 3,875.9689922481The reverse is
C/kg = R × 0.000258, using the same exact factors as this converter.Is this Coulomb per Kilogram to Roentgen converter private?
Yes. All calculations run locally in your browser. Nothing you type is sent to a server.