Loading Calculator...
Please wait a moment
Please wait a moment
Convert Rem to Sieverts (Sv) instantly with our accurate radiation dose equivalent converter
1 Rem = 0.01 Sieverts (Sv)
Formula: Sv = rem ÷ 100
| Rem | Sieverts (Sv) |
|---|---|
| 0.1 | 0.001 |
| 0.5 | 0.005 |
| 1 | 0.01 |
| 2 | 0.02 |
| 5 | 0.05 |
| 10 | 0.1 |
| 25 | 0.25 |
| 50 | 0.5 |
| 100 | 1 |
| 200 | 2 |
| 500 | 5 |
| 1000 | 10 |
Rem (Roentgen Equivalent Man) is a traditional unit of radiation dose equivalent that has been used in the United States for decades to measure the biological effect of ionizing radiation. The rem accounts for both the amount of radiation absorbed and its biological impact on human tissue. While most of the world has transitioned to the SI unit Sievert, the rem remains prevalent in U.S. nuclear regulations, medical radiation documentation, and occupational safety standards. Understanding rem is essential for interpreting American radiation safety literature and regulatory compliance documents.
The Sievert (Sv) is the International System of Units (SI) measure of radiation dose equivalent, representing the stochastic health risk of ionizing radiation on the human body. Named after Swedish medical physicist Rolf Sievert, this unit takes into account the type and energy of radiation as well as the sensitivity of exposed tissues. The Sievert is widely used in international radiation protection guidelines, scientific research, and medical physics. Because 1 Sv represents a substantial radiation dose, practical measurements often use millisieverts (mSv, one-thousandth of a Sievert) or microsieverts (µSv, one-millionth of a Sievert).
Converting Rem to Sieverts is a simple calculation:
Example: Convert 5 rem to Sieverts
5 rem ÷ 100 = 0.05 Sv (or 50 mSv)
Alternative method: Multiply by 0.01
5 rem × 0.01 = 0.05 Sv
Quick reference:
• 1 rem = 10 mSv (millisieverts)
• 100 rem = 1 Sv
• 0.1 rem = 1 mSv
Rem and Sievert conversions are essential in multiple fields:
Context for different radiation dose levels in both units:
| Exposure Source | Dose (rem) | Dose (Sv/mSv) |
|---|---|---|
| Dental X-ray | 0.0005 rem | 0.005 mSv |
| Chest X-ray | 0.01 rem | 0.1 mSv |
| Annual background (U.S.) | 0.31 rem | 3.1 mSv |
| Mammogram | 0.04 rem | 0.4 mSv |
| Head CT scan | 0.2 rem | 2 mSv |
| Chest CT scan | 0.7 rem | 7 mSv |
| Annual occupational limit | 5 rem | 50 mSv |
| Radiation sickness threshold | 100 rem | 1 Sv |
This calculator is for educational purposes only and should not replace professional radiation safety equipment or expertise.
Radiation measurement and protection require specialized training and calibrated instruments. Never attempt to estimate radiation doses without proper dosimetry equipment such as film badges, thermoluminescent dosimeters (TLDs), or electronic personal dosimeters (EPDs).
All radiation work must comply with applicable regulations including:
If you believe you have been exposed to radiation, contact emergency services and radiation safety personnel immediately.
Historical regulations and documentation in the U.S. were established using rem, and changing all regulatory frameworks would be a massive undertaking. Many U.S. agencies are gradually transitioning to SI units, but rem remains common in existing regulations and industry practice. Both units measure the same quantity and are easily convertible.
These are related but different units: Roentgen measures exposure (ionization in air), rad measures absorbed dose (energy deposited), and rem measures dose equivalent (biological effect). For gamma and X-rays in tissue, the numeric values are approximately equal, but they measure different physical quantities. In SI units: rem → Sievert, rad → Gray, roentgen → Coulomb/kilogram.
When reading international scientific papers, comparing U.S. and international regulations, or using equipment from different countries, you may encounter both units. Modern dosimeters often display readings in both rem and Sv. Always verify which unit is being referenced in safety documentation.
Dose equivalent (measured in rem or Sv) applies to a specific organ or tissue. Effective dose accounts for the varying sensitivity of different organs and represents the whole-body risk. Both use the same units (rem or Sv) but effective dose provides a single number representing overall cancer risk from non-uniform exposure.
Yes, radiation dose is cumulative for regulatory and risk assessment purposes. Occupational exposure is tracked over career lifetimes. However, the body can repair some radiation damage, so the timing and rate of exposure matter. Acute high doses are more dangerous than the same total dose spread over years.
The quality factor (Q) or radiation weighting factor accounts for the biological effectiveness of different radiation types. For X-rays, gamma rays, and beta particles, Q=1. For alpha particles, Q=20. For neutrons, Q varies from 5-20 depending on energy. This is why rem (and Sv) differ from rad (and Gray) for non-gamma radiation.
Yes. In the U.S., occupational limits are 5 rem/year (50 mSv/year) for total effective dose and 50 rem/year (500 mSv/year) for individual organs except the lens of the eye. Public exposure limits are 0.1 rem/year (1 mSv/year) above background. Medical exposures are not limited but must be justified and optimized following ALARA principles.