Radiation Converter
Convert radiation dose rate, the energy absorbed per kilogram per second, between gray per second, milligray and microgray per second, rad per second, watt per kilogram and more. Equivalent dose rate units (Sv/s, rem/s) are kept in their own family.
Select two units to see the conversion factor.
This tool converts dose rates (dose per second). Absorbed dose rate (Gy/s family) and equivalent dose rate (Sv/s family) are not interchangeable: crossing between them needs a radiation weighting factor, so the tool will not do it for you. It is a unit converter, not a safety or medical assessment.
Absorbed Dose Rate Formula
Each unit is a fixed multiple of the reference unit of its family: the gray per second (Gy/s) for absorbed dose rate and the sievert per second (Sv/s) for equivalent dose rate. Within a family, multiply the value by the size of the source unit and divide by the size of the target unit. The relationships are exact: 1 Gy/s = 1 J/(kg·s) = 1 W/kg, 1 rad = 0.01 Gy, 1 rem = 0.01 Sv, and each SI prefix is a power of ten.
What Is Radiation Dose Rate?
Absorbed dose measures the energy that ionizing radiation deposits in a material per unit of mass, in gray (1 Gy = 1 joule per kilogram). Dose rate is how fast that dose builds up: the absorbed dose divided by the time, so its SI unit is the gray per second (Gy/s). Because one joule per second is one watt, a dose rate of 1 Gy/s is the same as 1 W/kg, which is why watt per kilogram appears in the list.
Everyday dose rates are tiny when written in Gy/s, so prefixes such as milligray (mGy/s), microgray (µGy/s) and nanogray per second (nGy/s) are common. The older CGS unit is the rad per second, where 1 rad = 0.01 Gy, so 1 rad/s = 0.01 Gy/s = 10 mGy/s. Radiation instruments often display dose rates per hour, which you can obtain from per-second values by multiplying by 3,600.
Two families, not one. The gray measures energy absorbed by any material. The sievert (Sv), and its older partner the rem (1 rem = 0.01 Sv), measure the biological effect and are used for equivalent dose, which equals the absorbed dose multiplied by a radiation weighting factor wR. That factor is 1 for photons (X-rays and gamma rays) and electrons, but about 20 for alpha particles, and it is larger than 1 for neutrons and protons. A value in Sv/s therefore cannot be turned into Gy/s, or the reverse, without knowing the type of radiation. This converter converts within each family only.
Dose rate also differs from activity (decays per second, becquerel) and from exposure (ionization in air, coulomb per kilogram). The same source can produce very different dose rates depending on the distance, shielding and material, so activity cannot be converted into dose rate without that information.
Supported Units
This converter supports the following 22 dose rate units in two families. Absorbed dose rate: gray per second with every SI prefix from exa to atto, rad per second, joule per kilogram per second and watt per kilogram. Equivalent dose rate: sievert per second and rem per second. The last column gives the size of each unit in the reference unit of its family (Gy/s or Sv/s).
| Unit | Symbol | Family | Size in SI units of its family |
|---|---|---|---|
| Gray per second | Gy/s | Absorbed dose rate (Gy/s family) | 1 |
| Exagray per second | EGy/s | Absorbed dose rate (Gy/s family) | 1e+18 |
| Petagray per second | PGy/s | Absorbed dose rate (Gy/s family) | 1e+15 |
| Teragray per second | TGy/s | Absorbed dose rate (Gy/s family) | 1e+12 |
| Gigagray per second | GGy/s | Absorbed dose rate (Gy/s family) | 1,000,000,000 |
| Megagray per second | MGy/s | Absorbed dose rate (Gy/s family) | 1,000,000 |
| Kilogray per second | kGy/s | Absorbed dose rate (Gy/s family) | 1,000 |
| Hectogray per second | hGy/s | Absorbed dose rate (Gy/s family) | 100 |
| Dekagray per second | daGy/s | Absorbed dose rate (Gy/s family) | 10 |
| Decigray per second | dGy/s | Absorbed dose rate (Gy/s family) | 0.1 |
| Centigray per second | cGy/s | Absorbed dose rate (Gy/s family) | 0.01 |
| Milligray per second | mGy/s | Absorbed dose rate (Gy/s family) | 0.001 |
| Microgray per second | µGy/s | Absorbed dose rate (Gy/s family) | 1e-6 |
| Nanogray per second | nGy/s | Absorbed dose rate (Gy/s family) | 1e-9 |
| Picogray per second | pGy/s | Absorbed dose rate (Gy/s family) | 1e-12 |
| Femtogray per second | fGy/s | Absorbed dose rate (Gy/s family) | 1e-15 |
| Attogray per second | aGy/s | Absorbed dose rate (Gy/s family) | 1e-18 |
| Rad per second | rad/s | Absorbed dose rate (Gy/s family) | 0.01 |
| Joule per kilogram per second | J/(kg·s) | Absorbed dose rate (Gy/s family) | 1 |
| Watt per kilogram | W/kg | Absorbed dose rate (Gy/s family) | 1 |
| Sievert per second (equivalent dose rate) | Sv/s | Equivalent dose rate (Sv/s family) | 1 |
| Rem per second (equivalent dose rate) | rem/s | Equivalent dose rate (Sv/s family) | 0.01 |
How to Use the Radiation Converter
- Type the dose rate in the value box. Decimals and scientific notation such as 0.0025 or 2.5e-3 are accepted.
- Choose the From unit and the To unit.
- The result appears instantly, or press Convert Now. Very large or very small results are shown in scientific notation.
- Use Swap Units to reverse the conversion, Copy Result to copy the answer, open Show this value in all units for a full list, and Clear to start again.
Step-by-step by hand
- Find the size of each unit in the common base unit (Gy/s): 1 rad/s = 0.01 Gy/s and 1 mGy/s = 0.001 Gy/s.
- Divide the source size by the target size to get the conversion factor: 0.01 ÷ 0.001 = 10, so 1 rad/s = 10 mGy/s.
- Multiply by your value: 0.5 rad/s × 10 = 5 mGy/s.
Dose rates cannot be negative, so only zero and positive numbers are accepted. If you pick a Gy-family unit and an Sv-family unit, the tool explains why they cannot be converted and asks you to choose two units from the same family.
Common Dose Rate Conversions
- CGS to SI: 0.5 rad/s equals 5 mGy/s and 0.005 Gy/s.
- Small dose rate: 250 nGy/s equals 0.25 µGy/s.
- Power-density form: 0.002 W/kg equals 2 mGy/s.
- Centigray: 3 cGy/s equals 3 rad/s, because 1 cGy equals 1 rad.
- Equivalent dose rate: 5 rem/s equals 0.05 Sv/s.
- Per hour by hand: 2 µGy/s multiplied by 3,600 is 7,200 µGy/h, or 7.2 mGy/h.
Rad per Second Conversion – Common Values
Quick reference for frequently used values
| Rad/second | Gray/second | Centigray/second | Milligray/second | Watt/kilogram |
|---|---|---|---|---|
| 0.0001 | 1e-6 | 0.0001 | 0.001 | 1e-6 |
| 0.001 | 1e-5 | 0.001 | 0.01 | 1e-5 |
| 0.01 | 0.0001 | 0.01 | 0.1 | 0.0001 |
| 0.1 | 0.001 | 0.1 | 1 | 0.001 |
| 1 | 0.01 | 1 | 10 | 0.01 |
| 5 | 0.05 | 5 | 50 | 0.05 |
| 10 | 0.1 | 10 | 100 | 0.1 |
| 100 | 1 | 100 | 1,000 | 1 |
Where and Why This Conversion Is Used
- Radiotherapy and medical physics: machine output and beam dose rates are specified in Gy per minute or per second, while older charts use rad.
- Radiation protection and monitoring: survey meters and area monitors report dose rates in µGy/h or nGy/s, and manuals may use older units.
- Industrial irradiation: sterilization and materials-processing facilities specify dose rate in kGy per hour or Gy per second.
- Research and education: experiments and textbooks mix SI and CGS dose-rate units.
- Space and detector physics: shielding studies quote very small dose rates in nGy or pGy per second.
Important Differences Between Related Radiation Measurements
- Activity (Bq, Ci): how many nuclei decay per second. It describes the source, not the energy absorbed.
- Exposure (C/kg, R): ionization produced in air by X-rays or gamma rays.
- Absorbed dose (Gy, rad): energy absorbed per kilogram of material. Dose rate is this per unit time.
- Equivalent and effective dose (Sv, rem): absorbed dose weighted for the type of radiation, and for effective dose also for the sensitivity of different tissues.
See the Radiation-Absorbed Dose Converter for dose without time, the Radiation-Activity Converter for becquerel and curie, and the Radiation-Exposure Converter for roentgen and C/kg.
Educational disclaimer: this page converts units of measurement only. The results are not a radiation-safety assessment, a dose estimate for a person or a medical opinion, and they should not replace advice from a qualified radiation-safety officer, medical physicist or physician.