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Radiation Unit Converter
Convert radiation dose values between Sievert, rem, Gray, and rad, with millisievert and millirem equivalents shown instantly.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
- Sievert
- Millisievert
- Rem
- Millirem
- Gray
- Rad
Sievert/rem measure equivalent dose (biological effect); Gray/rad measure absorbed dose (energy deposited). For X-ray, gamma, and beta radiation the two scales are numerically equivalent (quality factor 1), which this converter assumes.
How it works
- Enter a dose value and its unit.
- See it converted across Sievert, millisievert, rem, millirem, Gray, and rad instantly.
The formula
1 Sievert = 100 rem = 1 Gray (at quality factor 1) = 100 rad
FAQ
What's the difference between Sievert and Gray?
Gray measures absorbed dose — the raw energy deposited per kilogram of tissue. Sievert measures equivalent dose — absorbed dose adjusted for how biologically damaging that type of radiation is. For X-rays, gamma rays, and beta particles, the two are numerically equal.
Why do rem and rad still show up?
They're the older (CGS-based) units still used in some contexts, particularly in the US — 1 Sv = 100 rem, and 1 Gy = 100 rad.
Is this accurate for all radiation types?
This simplified converter assumes a radiation quality factor of 1 (true for X-ray, gamma, and beta). Alpha particles and neutrons have higher quality factors, making Sv and Gy diverge — not modeled here.
How we compare
| Feature | Online Tool Store | Manual unit conversion | Reference tables |
|---|---|---|---|
| All six units shown at once | ✓ | ✗ | ✗ |
| Live, no lookup table needed | ✓ | ✗ | ✓ |
Radiation units mix metric and legacy systems, which is easy to get wrong by hand. Radiation Unit Converter shows every common unit at once.