Convert Rem to Gray

Enter the number of rem that you want to convert to grays.

1 rem (rem) = 0.01 Gy (grays)

How to Convert Rem to Grays

The rem and gray are both units of radiation dose. By definition, 1 gray equals exactly 100 rem. This means to convert rem to grays, you divide by 100.

Formula

grays = rem ÷ 100

Step-by-Step Example

Convert 5 rem to grays:

1
Convert 5 rem to grays

We need to convert rem to grays

2
Apply the formula

Since 1 Gy = 100 rem, divide by 100

5 ÷ 100 = 0.05

Answer

5 rem = 0.05 Gy

Rem to Gray Conversion Table

Quick reference table for common rem to gray conversions. Click any value for detailed calculation.

Rem (rem) Grays (Gy)
1 rem 0.01 Gy
2 rem 0.02 Gy
5 rem 0.05 Gy
10 rem 0.1 Gy
15 rem 0.15 Gy
20 rem 0.2 Gy
25 rem 0.25 Gy
50 rem 0.5 Gy
100 rem 1 Gy

About These Units

Rem (rem)

The rem (Roentgen Equivalent Man) is the traditional unit of equivalent dose. One sievert = 100 rem exactly. Still used in US nuclear industry and regulations. Annual occupational limit: 5 rem/year. Natural background: 0.3 rem/year. Acute 450 rem ≈ LD50.

Gray (Gy)

The gray (Gy) is the SI unit of absorbed dose: energy deposited per unit mass (1 Gy = 1 J/kg). Named after Louis Harold Gray. For gamma/X-rays and beta particles, 1 Gy ≈ 1 Sv (quality factor Q=1). Radiation therapy total dose: 40-80 Gy.

Frequently Asked Questions

How do I convert rem to grays?

To convert rem to grays, divide the value by 100. For example, 10 rem = 0.1 Gy.

How many grays are in 1 rem?

1 rem equals 0.01 grays.

What is the formula for rem to grays?

The formula is: Gy = rem ÷ 100.