# Radiation Dose Converter (Gy, Sv, rad, rem)

URL: https://speedycalculator.com/calculators/health/radiation-dose/
Last updated: 2026-10-30

> The radiation dose converter turns absorbed dose (gray, rad) into equivalent dose (sievert, rem) with the radiation weighting factor, and converts between SI and older units.

## Inputs

- Absorbed dose (Gy, mGy, rad)
- Radiation type

## Results

- Equivalent dose
- Absorbed dose in rad

## Formula

```
Equivalent dose (Sv) = absorbed dose (Gy) × radiation weighting factor (wR)
1 Gy = 100 rad · 1 Sv = 100 rem
wR: photons and electrons 1, protons 2, alpha particles 20, neutrons 2.5–20
```

## Explanation

Gray measures energy absorbed per kilogram; sievert adjusts for how damaging each type of radiation is. Alpha particles deposit their energy densely and are about 20 times more harmful per gray than X-rays.

### How to use the Radiation Dose Converter

- **Absorbed dose**
- **Radiation type**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the absorbed dose and choose the radiation type.

### Tips

- Keep a record of your imaging and its doses.
- Ask whether an ultrasound or MRI could answer the question without radiation.
- Tell staff if you might be pregnant.
- Background radiation varies by altitude and region.

### Common mistakes to avoid

- Comparing mSv (effective dose) with mGy (absorbed dose).
- Assuming every scan of the same type gives the same dose.
- Ignoring cumulative dose from repeated scans.

### Inputs explained

FieldWhat to enterAbsorbed doseUnits: Gy, mGy, radRadiation typeChoose one: X-rays, gamma rays, electrons (wR 1), Protons (wR 2), Neutrons, typical (wR 10), Alpha particles (wR 20)

### What each result means

- **Equivalent dose** = [Absorbed dose]×[Radiation type]
- **Absorbed dose in rad** = [Absorbed dose]×100

### Example values

How the main result changes when **Absorbed dose** changes and everything else stays at the example values above:

Absorbed dose (Gy)Equivalent dose (mSv)0.00550.00757.50.01100.012512.50.015150.0220
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Absorbed dose: 0.01 Gy; Radiation type: X-rays, gamma rays, electrons (wR 1).

Results — **Equivalent dose = 10 mSv**; Absorbed dose in rad = 1.

## Key terms

- **wR**: Radiation weighting factor.

## FAQ

**What is the difference between gray and sievert?**
Gray is absorbed energy; sievert reflects biological harm.

**How much radiation causes sickness?**
Acute doses above about 1 Gy to the whole body can cause radiation sickness.

**What is the annual limit for radiation workers?**
20 mSv a year averaged over 5 years (ICRP).


## Sources

- [ICRP Publication 103 – The 2007 recommendations of the ICRP](https://www.icrp.org/publication.asp?id=ICRP%20Publication%20103)