Convert Watts/Kilogram to Rems/Second
Watt/Kilogram (W/kg) to Rem/Second (rem/s) radiation dose rate conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 W/kg = 100 rem/s
1 Watt/Kilogram = 100 Rems/Second
1 Rem/Second = 0.01 Watts/Kilogram
1 W/kg in every supported unit
Conversion chart: Watt/Kilogram to Rems/Second
Conversion table
| Watt/Kilogram (W/kg) | Rem/Second (rem/s) |
|---|---|
| 0.01 W/kg | 1 rem/s |
| 0.1 W/kg | 10 rem/s |
| 1 W/kg | 100 rem/s |
| 2 W/kg | 200 rem/s |
| 3 W/kg | 300 rem/s |
| 5 W/kg | 500 rem/s |
| 10 W/kg | 1000 rem/s |
| 20 W/kg | 2000 rem/s |
| 50 W/kg | 5000 rem/s |
| 100 W/kg | 10000 rem/s |
| 1000 W/kg | 100000 rem/s |
Watt/Kilogram (W/kg)
Definition: Dimensionally identical to the gray/second, since a watt is one joule per second and dividing that power by the irradiated mass gives exactly the same absorbed-dose-rate quantity, just labeled in power-per-mass terms instead.
History: It reflects the fact that absorbed dose rate is, physically, specific power — power delivered per unit mass — a framing more familiar to engineers working from energy-deposition or heating-rate calculations than from dosimetry conventions.
Current use: Occasionally used in radiation-shielding and material-heating calculations where the absorbed energy is being tracked as a power flux into the material rather than a dosimetric quantity.
Rem/Second (rem/s)
Definition: The older CGS-derived dose-equivalent-rate unit, equal to 0.01 sievert per second — one rem ("roentgen equivalent man") delivered every second.
History: The rem was the standard US unit for biologically-weighted dose rate for decades before the sievert became the international SI standard, paralleling how the rad preceded the gray for absorbed dose.
Current use: Still appears in US occupational radiation-safety regulations and older personnel dosimetry records, listed here at the same numeric value as rad/second since both apply the same weighting-factor-of-1 assumption for common radiation types.
Supported Units
| Unit | Symbol | In Gy/s |
|---|---|---|
| Exagray/Second | EGy/s | 1E+18 Gy/s |
| Petagray/Second | PGy/s | 1E+15 Gy/s |
| Teragray/Second | TGy/s | 1E+12 Gy/s |
| Gigagray/Second | GGy/s | 1E+09 Gy/s |
| Megagray/Second | MGy/s | 1000000 Gy/s |
| Kilogray/Second | kGy/s | 1000 Gy/s |
| Hectogray/Second | hGy/s | 100 Gy/s |
| Dekagray/Second | daGy/s | 10 Gy/s |
| Gray/Second | Gy/s | 1 Gy/s |
| Decigray/Second | dGy/s | 0.1 Gy/s |
| Centigray/Second | cGy/s | 0.01 Gy/s |
| Milligray/Second | mGy/s | 0.001 Gy/s |
| Microgray/Second | µGy/s | 1E-06 Gy/s |
| Nanogray/Second | nGy/s | 1E-09 Gy/s |
| Picogray/Second | pGy/s | 1E-12 Gy/s |
| Femtogray/Second | fGy/s | 1E-15 Gy/s |
| Attogray/Second | aGy/s | 1E-18 Gy/s |
| Rad/Second | rd/s | 0.01 Gy/s |
| Joule/Kilogram/Second | J/(kg·s) | 1 Gy/s |
| Watt/Kilogram | W/kg | 1 Gy/s |
| Sievert/Second | Sv/s | 1 Gy/s |
| Rem/Second | rem/s | 0.01 Gy/s |
About These Parameters
- Value
- The dose rate reading you want to convert, expressed in the "From" unit. Accepts decimals, and can represent anything from a faint background reading in nanogray/second to a therapeutic radiotherapy beam's centigray/second delivery rate.
- From Unit
- The unit your dose-rate reading is currently measured in — a dosimeter's microgray/second display, an older instrument's rad/second scale, or a radiotherapy machine's centigray/second output.
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly, which is handy when translating an older rad/second or rem/second reading into the modern SI gray/second or sievert/second.
How Radiation Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to gray per second. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Watt/Kilogram → Rem/Second: multiply by 100. For example, 1 W/kg × 100 = 100 rem/s.
Dose Rate vs. Dose, Activity, and Exposure
A radiation monitor's alarm threshold is set in dose rate, not total dose, because rate is what determines whether it's safe to keep standing where you are right now. A source's activity in becquerel or curie tells you how radioactive the material is, but says nothing about the dose rate someone actually receives from it — that depends on distance, shielding, and the type of radiation emitted. Exposure in roentgen or coulomb/kilogram measures ionization specifically in air from X-rays and gamma rays, a narrower and historically older quantity than the general absorbed-dose-rate concept gray/second represents. Keeping these four quantities straight is essential in radiation safety work, since mixing up a source's activity with the dose rate it delivers at a given distance is a genuinely dangerous error.
Why Gray/Second and Watt/Kilogram Are the Same Thing
A watt is defined as one joule per second, so dividing a power reading in watts by the mass being irradiated, in kilograms, gives exactly the same number as a gray/second dose rate — both are "energy per time per mass," just framed differently. Engineers doing radiation-shielding or material-heating calculations often think in terms of power flux into a material (watts per kilogram), while dosimetrists and health physicists think in terms of a live dose-rate reading (gray per second); the two communities are describing the identical physical quantity through different professional habits.
Example
A dose rate of 1 W/kg equals 100 rem/s. For scale, natural background radiation delivers roughly 100-300 nanogray per second at ground level, a typical diagnostic X-ray delivers on the order of a few milligray/second during the brief exposure, and a therapeutic radiotherapy beam commonly runs at several centigray per second while actively treating a tumor.
Frequently Asked Questions
How many Rems/Second are in 1 Watt/Kilogram?
1 Watt/Kilogram (W/kg) equals exactly 100 Rems/Second (rem/s).
What's the difference between gray/second and gray?
Gray/second is a rate — how much dose is being delivered right now, per second. Gray alone (covered by the separate Radiation-Absorbed-Dose Converter) is a cumulative total with no time component. Multiplying a gray/second dose rate by the number of seconds of exposure gives you the total absorbed dose in gray.
Why are sievert/second and gray/second numerically equal here?
Sievert applies a biological weighting factor to the raw absorbed-energy rate that gray measures, to account for how damaging different radiation types are to tissue. For X-rays, gamma rays, and beta radiation that weighting factor equals exactly 1, so the two units read the same number for those common radiation types — but they remain conceptually different quantities (physical dose vs. biologically weighted dose), which is why sievert is used for radiation-protection limits rather than gray.
Is rad/second the same thing as gray/second?
No — one rad/second equals 0.01 gray/second, since the rad is the older, smaller CGS-derived unit that the gray replaced in 1975. A dose rate of 1 gray/second is the same as 100 rad/second.
Does dose rate tell me how radioactive a source is?
No — that's activity (becquerel or curie), measured by the separate Radiation-Activity Converter. Dose rate tells you how much energy is being absorbed per second by something near the source, which depends on the source's activity but also on distance, shielding, and radiation type. A highly active source far away or well-shielded can deliver a low dose rate, while a much less active source held close can deliver a higher one.