What is the relationship between rem and sievert?

1 rem = 0.01 sieverts (Sv). The rem is the older customary unit used in the United States; the sievert is the modern SI unit. To convert rem to Sv, divide by 100. To convert Sv to rem, multiply by 100.

Why is a dose factor needed — why can't I convert Ci directly to rem?

Curies measure activity (decays per second). Rem measures biological dose, which depends on how much energy the radiation deposits in tissue and how damaging that energy is. The dose conversion factor (rem/Bq) bridges the two; it differs by radiation type and specific nuclide. This tool uses representative factors for illustration.

What dose conversion factors does this tool use?

Representative effective dose coefficients in rem/Bq: alpha ≈ 2.0 × 10⁻⁵ rem/Bq, beta ≈ 1.0 × 10⁻⁶ rem/Bq, gamma/X-ray ≈ 3.0 × 10⁻⁷ rem/Bq. These equal the Sv/Bq values multiplied by 100 (since 1 Sv = 100 rem). Always consult ICRP Publication 119 or a health physicist for regulatory calculations.

What is 1 curie equal to in becquerels?

1 curie (Ci) = 3.7 × 10¹⁰ becquerels (Bq). The curie was originally defined as the activity of 1 gram of radium-226. The becquerel is the SI unit: 1 Bq = 1 disintegration per second.

Can I use this for regulatory compliance?

No. This tool is educational. Regulatory dose calculations require nuclide-specific dose coefficients, pathway modeling, and verification by a qualified health physicist. Use ICRP, NCRP, or NRC data for any compliance purpose.

Curies to Rem Converter

Convert radioactivity in curies (Ci) to radiation dose in rem via becquerels, with radiation-type dose factors shown step by step.

Input Activity

Activity value

Input unit

Radiation type

Enter a value and select a radiation type, then click Convert.

Note: Dose factors shown are representative effective dose coefficients for ingestion (Sv/Bq × 100). Actual values depend on the specific nuclide and exposure pathway. For regulatory use, consult ICRP Publication 119 or a licensed health physicist.

Summary

The curie (Ci) measures radioactivity — how many atoms decay per second. The rem (roentgen equivalent man) measures biological radiation dose in the older customary unit system, where 1 rem = 0.01 sieverts. Converting curies to rem requires two steps: first multiply curies by 3.7 × 10¹⁰ to get becquerels, then apply a dose conversion factor (rem/Bq) that depends on the radiation type. This tool walks through that chain step by step so you can see exactly where each number comes from.

How it works

Enter an activity value in curies (Ci), millicuries (mCi), or microcuries (µCi).
Select the radiation type: alpha, beta, gamma, or X-ray.
The tool converts your input to becquerels using 1 Ci = 3.7 × 10¹⁰ Bq.
It then applies a representative dose conversion factor (rem/Bq) for the selected radiation type.
Results are shown in rem, millirem, and sieverts (for reference), with each calculation step displayed.

Use cases

Converting legacy curie-based radiation measurements to rem for US regulatory reporting.
Cross-checking radiation safety calculations in labs still using customary units.
Converting historical nuclear data that references both curies and rem.
Teaching the Ci → Bq → rem conversion chain in nuclear physics or health physics courses.
Estimating approximate dose in rem from a known activity source for educational purposes.
Comparing dose across different radiation types for the same activity level in rem units.

Frequently Asked Questions

Last updated: 2026-07-14 · Reviewed by Nham Vu

Curies to Rem Converter

Input Activity

Dose Result

Calculation Chain

Summary

How it works

Use cases

Frequently Asked Questions

Curies to Rem Converter

Use the Curies to Rem Converter

Input Activity

Dose Result

Calculation Chain

Summary

How it works

Use cases

Frequently Asked Questions