A complete radiation conversion calculator for all absorbed dose units — gray to rad conversion, rad to gray conversion, millisieverts to rads, milligray, centigray, kilogray, J/kg, and all gray SI-prefix multiples.
For a gray to rad conversion, multiply the gray value by 100. This is the most common radiation unit conversion in medical physics and radiation therapy planning. The gray to rad formula is exact: rad = Gy × 100. For example, 2.5 Gy = 250 rad. This gray to rad conversion is used when referencing older radiation therapy records or US regulatory documents still expressed in rad.
Gy → rad: multiply by 100 | 1 Gy = 100 rad | 5 Gy = 500 rad
For a rad to gray conversion, divide by 100 (or multiply by 0.01). The rad to gray formula: Gy = rad ÷ 100. For example, 5,000 rad ÷ 100 = 50 Gy. This rad to gray conversion is essential when updating historical radiotherapy records (written in rad) into modern SI units (gray) for treatment comparison or research.
rad → Gy: divide by 100 | 1 rad = 0.01 Gy | 500 rad = 5 Gy
To convert millisieverts to rads, divide mSv by 10 (for radiation with quality factor = 1, such as X-rays, gamma rays, and beta particles). The millisieverts to rads formula: rad = mSv ÷ 10. For example, 50 mSv = 5 rad = 0.05 Gy. This millisieverts to rads conversion links effective dose (Sv) to absorbed dose (rad) and is frequently needed when comparing occupational exposure limits expressed in different unit systems.
mSv → rad: divide by 10 (QF=1) | 10 mSv = 1 rad | 1 mSv = 0.1 rad
This radiation conversion calculator supports 23 units. Every key pair is covered below with exact formulas for both directions, making this the most comprehensive radiation unit conversion calculator for absorbed dose on the web.
Gray to milligray: multiply by 1,000. Milligray to gray: divide by 1,000. The Gy to mGy conversion is the standard for diagnostic imaging — chest X-ray doses (0.01–0.1 mGy) and CT scans (10–20 mGy) are always expressed in milligray.
1 Gy = 1,000 mGy | 1 mGy = 0.001 Gy
Gray to centigray: multiply by 100. Centigray to gray: divide by 100. Note that 1 cGy = 1 rad, so the gray to centigray conversion is identical to the gray to rad conversion. Centigray (cGy) is the preferred unit in radiation oncology fractionated therapy.
1 Gy = 100 cGy | 1 cGy = 1 rad = 0.01 Gy
Gray to microgray: multiply by 1,000,000. Microgray to gray: multiply by 10⁻⁶. Used for very low-dose measurements such as natural background radiation (~2,000 µGy/year) and neonatal medical imaging.
1 Gy = 1,000,000 µGy | 1 µGy = 10⁻⁶ Gy
Gray to kilogray: divide by 1,000. Kilogray to gray: multiply by 1,000. The kGy range is used for industrial applications: food sterilization (1–10 kGy), medical device sterilization (25 kGy), and polymer cross-linking.
1 kGy = 1,000 Gy | 1 Gy = 0.001 kGy
Gray to joule per kilogram: the conversion factor is exactly 1. J/kg to gray is also 1:1. Gray is defined as 1 joule of energy absorbed per kilogram of matter, so 1 Gy = 1 J/kg by definition. This is fundamental to all radiation measurement units conversion.
1 Gy = 1 J/kg | 1 J/kg = 1 Gy (exact)
Gray to joule/gram: divide by 1,000 (since 1 kg = 1,000 g). Joule/gram to gray: multiply by 1,000. For example, 1 J/g = 1,000 Gy — an extremely high dose used in materials science research.
1 Gy = 0.001 J/g | 1 J/g = 1,000 Gy
Rad to millirad: multiply by 1,000. Millirad to rad: divide by 1,000. Millirad is used for very low absorbed dose levels in environmental radiation monitoring and in expressing occupational background exposures in legacy US systems.
1 rad = 1,000 mrad | 1 mrad = 0.001 rad = 0.01 mGy
Rad to milligray: multiply by 10. Milligray to rad: divide by 10. Since 1 rad = 0.01 Gy = 10 mGy, the rad to mGy conversion is important in diagnostic radiology where doses are measured in mGy but older equipment reports in rad.
1 rad = 10 mGy | 1 mGy = 0.1 rad
Rad to joule/kilogram: multiply by 0.01 (same as rad to gray). J/kg to rad: multiply by 100. Since 1 Gy = 1 J/kg = 100 rad, this three-way rad gray conversion is fundamental to all dosimetry.
1 rad = 0.01 J/kg | 1 J/kg = 100 rad
Rad to centigray: 1 rad = 1 cGy (exact). Centigray to rad: also 1:1. This is because both units equal 0.01 gray. The rad/cGy equivalence is why radiation oncologists often express therapy doses interchangeably in rad and cGy.
1 rad = 1 cGy | 1 cGy = 1 rad (exact)
Rad to microgray: multiply by 10,000. Microgray to rad: divide by 10,000. Used when converting legacy environmental dose reports (in rad) to modern SI microgray values.
1 rad = 10,000 µGy | 1 µGy = 0.0001 rad
Milligray to centigray: divide by 10. Centigray to milligray: multiply by 10. For example, 1 cGy = 10 mGy. This radiation unit conversion is common when switching between imaging-dose scale (mGy) and therapy-dose scale (cGy).
1 cGy = 10 mGy | 1 mGy = 0.1 cGy
Milligray to microgray: multiply by 1,000. Microgray to milligray: divide by 1,000. Natural background radiation (~2 mGy/year = 2,000 µGy/year) is a common real-world example of this radiation measurement units conversion.
1 mGy = 1,000 µGy | 1 µGy = 0.001 mGy
Gray to decigray: multiply by 10. Decigray to gray: divide by 10. The decigray is used in some European radiation therapy systems as an intermediate scale between gray and centigray.
1 Gy = 10 dGy | 1 dGy = 0.1 Gy
Gray to megagray: divide by 1,000,000. Megagray to gray: multiply by 1,000,000. The megagray is used in extreme radiation environments: nuclear reactor cores, particle accelerator beam targets, and space satellite shielding research.
1 MGy = 1,000,000 Gy | 1 Gy = 10⁻⁶ MGy
Large gray multiples used in nuclear physics research and astrophysics: gray to teragray: ÷ 10¹². Gray to gigagray: ÷ 10⁹. Gray to petagray: ÷ 10¹⁵. Gray to exagray: ÷ 10¹⁸. These large-scale radiation unit conversion values appear in nuclear engineering simulations and accelerator physics calculations.
1 TGy = 10¹² Gy | 1 GGy = 10⁹ Gy | 1 EGy = 10¹⁸ Gy
Extremely small gray multiples for ultra-low dose research: gray to nanogray: × 10⁹. Gray to picogray: × 10¹². Gray to femtogray: × 10¹⁵. Gray to attogray: × 10¹⁸. These sub-milligray radiation measurement units conversion values are used in radiation detector research, single-cell dosimetry, and ultra-low background physics.
1 Gy = 10⁹ nGy = 10¹² pGy = 10¹⁵ fGy = 10¹⁸ aGy
Gray to joule/centigram: multiply by 0.00001 (since 1 cg = 10⁻⁵ kg). Gray to joule/milligram: multiply by 10⁻⁶. These conversion of radiation units to J/cg and J/mg appear in small-sample materials science dosimetry where milligram or centigram quantities are irradiated.
1 Gy = 10⁻⁵ J/cg | 1 Gy = 10⁻⁶ J/mg
Kilogray to megagray: divide by 1,000. Megagray to kilogray: multiply by 1,000. Industrial sterilization uses kGy (25 kGy for medical devices), while the MGy range is reserved for extreme radiation processing research.
1 MGy = 1,000 kGy | 1 kGy = 0.001 MGy
Millirad to milligray: divide by 100 (since 1 rad = 0.01 Gy, so 1 mrad = 0.01 mGy). Milligray to millirad: multiply by 100. Used in radiation conversion calculator scenarios involving very low occupational or environmental doses expressed in legacy US units.
1 mrad = 0.01 mGy | 1 mGy = 100 mrad
All key conversions in this radiation unit conversion calculator, sorted from gray as the base unit.
| From | To | Multiply By | Example |
|---|---|---|---|
| Gray (Gy) | Rad | 100 | 1 Gy = 100 rad |
| Rad | Gray (Gy) | 0.01 | 100 rad = 1 Gy |
| Gray (Gy) | Centigray (cGy) | 100 | 1 Gy = 100 cGy |
| Gray (Gy) | Milligray (mGy) | 1,000 | 1 Gy = 1,000 mGy |
| Gray (Gy) | Microgray (µGy) | 1,000,000 | 1 Gy = 10⁶ µGy |
| Gray (Gy) | Nanogray (nGy) | 10⁹ | 1 Gy = 10⁹ nGy |
| Gray (Gy) | J/kg | 1 | 1 Gy = 1 J/kg |
| Gray (Gy) | J/g | 0.001 | 1 Gy = 0.001 J/g |
| Gray (Gy) | Kilogray (kGy) | 0.001 | 1,000 Gy = 1 kGy |
| Gray (Gy) | Megagray (MGy) | 10⁻⁶ | 10⁶ Gy = 1 MGy |
| Gray (Gy) | Decigray (dGy) | 10 | 1 Gy = 10 dGy |
| Gray (Gy) | Dekagray (daGy) | 0.1 | 10 Gy = 1 daGy |
| Gray (Gy) | Hectogray (hGy) | 0.01 | 100 Gy = 1 hGy |
| Rad | Centigray (cGy) | 1 | 1 rad = 1 cGy |
| Rad | Milligray (mGy) | 10 | 1 rad = 10 mGy |
| Rad | Millirad (mrad) | 1,000 | 1 rad = 1,000 mrad |
| Rad | J/kg | 0.01 | 1 rad = 0.01 J/kg |
| mSv | Rad | 0.1 (QF=1) | 10 mSv = 1 rad |
| mSv | mGy | 1 (QF=1) | 1 mSv = 1 mGy |
| cGy | mGy | 10 | 1 cGy = 10 mGy |
| mGy | µGy | 1,000 | 1 mGy = 1,000 µGy |
| kGy | MGy | 0.001 | 1,000 kGy = 1 MGy |
| mrad | mGy | 0.01 | 1 mrad = 0.01 mGy |
The gray is the SI unit of absorbed radiation dose: 1 joule of energy deposited per kilogram of matter. 1 Gy = 100 rad = 1 J/kg. Named after physicist Louis Harold Gray. The gray to rad conversion factor (×100) and the rad to gray conversion factor (÷100) are the most fundamental formulas in this radiation conversion calculator.
1 rad = 0.01 Gy = 1 cGy = 10 mGy. The rad was the standard unit before the gray was adopted internationally. The rad gray conversion is exact. Still found in US NRC regulations, older medical equipment, and historical dosimetry data. For radiation measurement units conversion from legacy records, rad to Gy is always the first step.
1 cGy = 0.01 Gy = 1 rad. Centigray is the preferred unit in radiation oncology because it is numerically equal to rad — making historical comparison easy. A typical radiotherapy fraction is 180–200 cGy. The gray to centigray conversion (×100) is identical to the gray to rad conversion.
1 mGy = 0.001 Gy = 0.1 rad = 1 mSv (for QF=1). The milligray is the standard unit for diagnostic imaging doses. Chest X-ray: 0.01–0.1 mGy; CT head: 50–80 mGy. The millisieverts to rads conversion passes through milligray: 1 mSv = 1 mGy = 0.1 rad.
1 J/kg = 1 Gy exactly. The gray is dimensionally identical to J/kg. This makes gray to joule/kilogram a trivial 1:1 conversion, and is the physical basis of all conversion of radiation units in absorbed dose dosimetry.
1 kGy = 1,000 Gy. Used in industrial radiation processing: food irradiation (1–10 kGy), sterilization of medical devices (25 kGy), and polymer modification. The kilogray to gray and gray to megagray conversions are covered in this radiation unit conversion calculator.
For gray to rad conversion, multiply the gray value by 100. For example, 5 Gy × 100 = 500 rad. The gray to rad formula is exact: rad = Gy × 100. This gray to rad conversion applies because 1 Gy = 1 J/kg and 1 rad = 0.01 J/kg, making the rad gray conversion factor exactly 100.
For rad to gray conversion, divide by 100. For example, 250 rad ÷ 100 = 2.5 Gy. The rad to gray formula: Gy = rad × 0.01. This rad to gray conversion is used when reconciling older US dosimetry records (rad) with modern SI records (Gy). The rad to gray conversion is the inverse of the gray to rad conversion.
To convert millisieverts to rads, divide mSv by 10 (for quality factor QF = 1, valid for X-rays, gamma, and beta radiation). For example, 50 mSv ÷ 10 = 5 rad. The full millisieverts to rads pathway: mSv ÷ 1,000 = Sv → Sv = Gy (QF=1) → Gy × 100 = rad. So the shortcut for millisieverts to rads is simply ÷ 10.
The rad gray conversion factor is: 1 Gy = 100 rad (or equivalently, 1 rad = 0.01 Gy). This means for gray to rad conversion, multiply by 100; for rad to gray conversion, multiply by 0.01. The rad gray conversion is the most important formula in this radiation conversion calculator.
Gray to milligray: multiply by 1,000. For example, 0.05 Gy = 50 mGy. Milligray to gray: divide by 1,000. This radiation unit conversion is the most common in diagnostic imaging, where CT doses (10–20 mGy) and X-ray doses (0.01–0.1 mGy) are expressed in milligray.
Gray to centigray: multiply by 100. For example, 2 Gy = 200 cGy. Centigray to gray: divide by 100. Note that the gray to centigray conversion is numerically the same as the gray to rad conversion, because 1 cGy = 1 rad exactly. Radiation oncologists use cGy and rad interchangeably.
Gray to J/kg: the conversion factor is exactly 1 (they are identical). J/kg to gray is also 1:1. The gray is defined as 1 joule of energy absorbed per kilogram, making this the only radiation unit conversion with a factor of exactly 1.
A radiation conversion calculator for absorbed dose converts between units that measure energy deposited per unit mass of matter. This radiation unit conversion calculator supports 23 units: gray, rad, milligray, centigray, microgray, kilogray, megagray, J/kg, J/g, J/cg, J/mg, millirad, and all gray SI prefixes from attogray to exagray. It handles everything from gray to rad conversion to millisieverts to rads, covering all conversion of radiation units needed in medical physics, radiation therapy, and radiation safety.
Radiation unit conversion (or radiation measurement units conversion) refers to converting values between different units of the same radiation quantity. For absorbed dose, this means gray to rad conversion, rad to gray conversion, milligray, centigray, etc. For other quantities, conversion of radiation units may involve activity (Bq/Ci), exposure (C/kg/R), or effective dose (Sv/rem). This page is a radiation unit conversion calculator specifically for absorbed dose units.