Radiation - Exposure Converter
Radiation exposure measures the ionisation that X-rays or gamma rays produce in air. The SI unit is the coulomb per kilogram (C/kg); the older roentgen equals 2.58 × 10⁻⁴ C/kg.
1 Coulomb/Kilogram = 3,875.968992 Roentgen
How to convert Coulomb/Kilogram to Roentgen
One Coulomb/Kilogram equals 3,875.968992 Roentgen, so multiply any value in C/kg by 3,875.968992 to get R. To convert back, divide by 3,875.968992 — or multiply by 0.000258.
R = C/kg × 3,875.968992
Example: 25 C/kg × 3,875.968992 = 96,899.22481 R.
Coulomb/Kilogram to Roentgen table
| Coulomb/Kilogram (C/kg) | Roentgen (R) |
|---|---|
| 1 | 3,875.968992 |
| 2 | 7,751.937984 |
| 3 | 11,627.90698 |
| 4 | 15,503.87597 |
| 5 | 19,379.84496 |
| 10 | 38,759.68992 |
| 15 | 58,139.53488 |
| 20 | 77,519.37984 |
| 25 | 96,899.22481 |
| 50 | 193,798.4496 |
| 75 | 290,697.6744 |
| 100 | 387,596.8992 |
| 250 | 968,992.2481 |
| 500 | 1,937,984.496 |
| 1,000 | 3,875,968.992 |
Roentgen to Coulomb/Kilogram table
| Roentgen (R) | Coulomb/Kilogram (C/kg) |
|---|---|
| 1 | 0.000258 |
| 2 | 0.000516 |
| 3 | 0.000774 |
| 4 | 0.001032 |
| 5 | 0.00129 |
| 10 | 0.00258 |
| 15 | 0.00387 |
| 20 | 0.00516 |
| 25 | 0.00645 |
| 50 | 0.0129 |
| 75 | 0.01935 |
| 100 | 0.0258 |
| 250 | 0.0645 |
| 500 | 0.129 |
| 1,000 | 0.258 |
Radiation - Exposure units at a glance
All 8 units this converter supports, each expressed in Coulomb/Kilogram (C/kg) and the other way round.
| Unit | Symbol | 1 unit in C/kg | 1 C/kg in unit |
|---|---|---|---|
| Coulomb/Kilogram | C/kg | 1 | 1 |
| Millicoulomb/Kilogram | mC/kg | 0.001 | 1,000 |
| Microcoulomb/Kilogram | µC/kg | 0.000001 | 1,000,000 |
| Roentgen | R | 0.000258 | 3,875.968992 |
| Milliroentgen | mR | 2.58e-7 | 3,875,968.992 |
| Microroentgen | µR | 2.58e-10 | 3,875,968,992 |
| Parker | parker | 0.000258 | 3,875.968992 |
| Rep | rep | 0.000258 | 3,875.968992 |
Where radiation - exposure conversions are used
Calibrating radiation survey meters, and reading older radiology and radiation-protection records.
Frequently asked questions
What is 1 Coulomb/Kilogram in Roentgen?
1 Coulomb/Kilogram (C/kg) is 3,875.968992 Roentgen (R).
What is 1 Roentgen in Coulomb/Kilogram?
1 Roentgen (R) is 0.000258 Coulomb/Kilogram (C/kg).
How do I convert Coulomb/Kilogram to Roentgen?
Multiply the value in Coulomb/Kilogram by 3,875.968992. For example, 5 C/kg × 3,875.968992 = 19,379.84496 R. To go the other way, divide by 3,875.968992.
How many units does the radiation - exposure converter support?
It converts between 8 units: Coulomb/Kilogram, Millicoulomb/Kilogram, Microcoulomb/Kilogram, Roentgen, Milliroentgen, Microroentgen, Parker, Rep.
More Radiology converters
Figures on this page are calculated with the same conversion factors as the converter above and shown to up to 10 significant figures. See our disclaimer before relying on a result in a professional or safety-critical context.