Radiological Unit Converter
A free, fast radiological unit conversion calculator for nuclear compliance professionals and radioactive material shippers. All conversions are performed client-side — no data is sent to any server. Select a category, enter a value, and get instant results in all related units.
Conversion Reference
Activity
Activity measures the rate of radioactive decay — how many nuclear transformations occur per unit time. The SI unit is the becquerel (Bq), equal to one disintegration per second. The older conventional unit is the curie (Ci), originally defined as the activity of 1 gram of Ra-226.
| Unit | Symbol | Equivalent |
|---|---|---|
| Becquerel | Bq | 1 disintegration per second (dps) |
| Kilobecquerel | kBq | 1,000 Bq |
| Megabecquerel | MBq | 1,000,000 Bq |
| Gigabecquerel | GBq | 1 × 109 Bq |
| Terabecquerel | TBq | 1 × 1012 Bq |
| Curie | Ci | 3.7 × 1010 Bq |
| Millicurie | mCi | 3.7 × 107 Bq |
| Microcurie | µCi | 3.7 × 104 Bq |
| Nanocurie | nCi | 37 Bq |
| Picocurie | pCi | 0.037 Bq |
| Disintegrations per minute | dpm | 1/60 Bq |
| Disintegrations per second | dps | 1 Bq |
Dose Equivalent
Dose equivalent accounts for the biological effectiveness of different radiation types. The SI unit is the sievert (Sv). The conventional unit is the rem (roentgen equivalent man). For gamma and beta radiation, 1 Sv = 1 Gy numerically (quality factor = 1).
| Unit | Symbol | Equivalent |
|---|---|---|
| Sievert | Sv | 100 rem |
| Millisievert | mSv | 0.1 rem |
| Microsievert | µSv | 0.1 mrem |
| Nanosievert | nSv | 1 × 10-7 rem |
| Rem | rem | 0.01 Sv |
| Millirem | mrem | 10 µSv |
| Microrem | µrem | 0.01 µSv |
Absorbed Dose
Absorbed dose measures the energy deposited per unit mass of tissue by ionizing radiation. The SI unit is the gray (Gy). The conventional unit is the rad (radiation absorbed dose).
| Unit | Symbol | Equivalent |
|---|---|---|
| Gray | Gy | 100 rad |
| Milligray | mGy | 0.1 rad |
| Microgray | µGy | 0.1 mrad |
| Rad | rad | 0.01 Gy |
| Millirad | mrad | 10 µGy |
Dose Rate
Dose rate is the dose delivered per unit time — critical for determining exposure duration limits and shielding requirements under 10 CFR 20.
| Unit | Symbol | Equivalent |
|---|---|---|
| Sievert per hour | Sv/hr | 100 rem/hr |
| Millisievert per hour | mSv/hr | 100 mrem/hr |
| Microsievert per hour | µSv/hr | 0.1 mrem/hr |
| Rem per hour | rem/hr | 0.01 Sv/hr |
| Millirem per hour | mrem/hr | 10 µSv/hr |
| Microrem per hour | µrem/hr | 0.01 µSv/hr |
| Roentgen per hour | R/hr | ~0.00877 Gy/hr (in air) |
| Milliroentgen per hour | mR/hr | ~8.77 µGy/hr (in air) |
| Microroentgen per hour | µR/hr | ~8.77 nGy/hr (in air) |
Transport / Shipping
These conversions are used daily by radioactive material shippers and compliance professionals for contamination surveys, air monitoring, and DOT/NRC transport documentation.
| Conversion | Factor |
|---|---|
| µCi/mL → pCi/L | Multiply by 1,000,000 (106) |
| dpm/100cm² → Bq/cm² | Divide by 6,000 (60 dpm/Bq × 100 cm²) |
| Bq/m³ → pCi/L | Divide by 37 (1 pCi = 0.037 Bq, 1 m³ = 1000 L) |
Disclaimer: This calculator is a reference tool for unit conversions only. It does not account for radiation quality factors, tissue weighting factors, or geometry-specific corrections. Always verify critical calculations against authoritative sources and facility-specific procedures. For dose assessment, consult a qualified health physicist.