One milligray is exactly 100 millirads, so converting milligrays to millirads is a single multiplication. Enter any figure and the result appears as you type — the arithmetic runs in your browser, so nothing is sent anywhere.
Millirads appear on older survey meters and in US regulatory limits. One milli gray is one thousandth of a gray (1e-3 grays).
Grays are not sieverts. The gray measures energy deposited per kilogram; the sievert weights that energy by how biologically damaging the particular radiation is. For X-rays and gamma the weighting factor is 1 and the numbers coincide, but for alpha particles it is 20, so converting between them blindly can be wrong by that factor. The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in millirads, so you can sanity-check whether your answer is a plausible size.
The formula
milligrays- The amount you are converting, in milligrays
100- The exact number of millirads in one milligray
millirads- The converted result
How it works, step by step
- Enter the value in milligrays.
- It is multiplied by 100, the exact factor between the two units.
- The answer is shown in millirads, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Head CT scan: 20 mGy in millirads
At 20 mGy (head ct scan), the same quantity in millirads is 20 × 100 = 2000 mrad. One milligray is 100 millirads, so the numbers grow as expected.
Chest X-ray: 0.1 mGy in millirads
At 0.1 mGy (chest x-ray), the same quantity in millirads is 0.1 × 100 = 10 mrad. One milligray is 100 millirads, so the numbers grow as expected.
How to read your score
Frequently asked questions
How many millirads are in one milligray?
Exactly 100. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert milligrays to millirads?
millirads = milligrays × 100. Reversed, milligrays = millirads ÷ 100, which is the same as multiplying by 0.01.
Which is the bigger unit, the milligray or the millirad?
The milligray. One milligray equals 100 millirads.
What does this quantity actually measure?
Both units measure the energy a radiation field deposits per kilogram. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a milligray?
One milli gray is one thousandth of a gray (1e-3 grays).
What is a millirad?
Millirads appear on older survey meters and in US regulatory limits.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Milligrays to millirads reference tables
| Milligrays | Millirads |
|---|---|
| 0.5 mGy | 50 mrad |
| 1 mGy | 100 mrad |
| 2 mGy | 200 mrad |
| 3 mGy | 300 mrad |
| 5 mGy | 500 mrad |
| 10 mGy | 1000 mrad |
| 20 mGy | 2000 mrad |
| 25 mGy | 2500 mrad |
| 50 mGy | 5000 mrad |
| 75 mGy | 7500 mrad |
| 100 mGy | 10,000 mrad |
| 250 mGy | 25,000 mrad |
| 500 mGy | 50,000 mrad |
| 1000 mGy | 100,000 mrad |
| 5000 mGy | 500,000 mrad |
Exact factor: 1 milligray = 100 millirads.
| Quantity | mGy | mrad |
|---|---|---|
| Dental X-ray | 0.005 mGy | 0.5 mrad |
| Chest X-ray | 0.1 mGy | 10 mrad |
| Head CT scan | 20 mGy | 2000 mrad |
| Radiotherapy fraction | 2000 mGy | 2e+05 mrad |
| Full radiotherapy course | 6e+04 mGy | 6e+06 mrad |
| Whole-body dose likely to be fatal | 5000 mGy | 5e+05 mrad |
Published reference values, converted with the same factor this page uses.