Convert Roentgen to Rad

Input the number of roentgens you want to convert to rads.

1 R (roentgens) = 0.877 rad (rads)

How to Convert Roentgens to Rads

The roentgen and rad are both units of radiation dose. 1 rad equals 1.1402508552 roentgens. This means to convert roentgens to rads, you divide by 1.1402508552.

Formula

rads = roentgens ÷ 1.1402508552

Step-by-Step Example

Convert 5 R to rads:

1
Convert 5 R to rads

We need to convert roentgens to rads

2
Apply the formula

Since 1 rad = 1.1402508552 R, divide by 1.1402508552

5 ÷ 1.1402508552 = 4.385

Answer

5 R = 4.385 rad

Roentgen to Rad Conversion Table

Quick reference table for common roentgen to rad conversions. Click any value for detailed calculation.

Roentgens (R) Rads (rad)
1 R 0.877 rad
2 R 1.754 rad
5 R 4.385 rad
10 R 8.77 rad
15 R 13.155 rad
20 R 17.54 rad
25 R 21.925 rad
50 R 43.85 rad
100 R 87.7 rad

About These Units

Roentgen (R)

The roentgen (R) measures ionization produced by X-rays or gamma rays in air. One roentgen produces 2.58×10⁻⁴ C/kg of ionization. Approximately: 1 R ≈ 8.77 mGy or 0.877 rad in soft tissue. Named after Wilhelm Röntgen, discoverer of X-rays.

Rad (rad)

The rad (Radiation Absorbed Dose) is the traditional unit of absorbed dose. One gray = 100 rads exactly. One rad = 100 ergs/gram = 0.01 J/kg. Still used in US medical and nuclear industries. One rad = one centigray = one rem for gamma/X-rays.

Frequently Asked Questions

How do I convert roentgens to rads?

To convert roentgens to rads, divide the value by 1.1402508552. For example, 10 R = 8.77 rad.

How many rads are in 1 roentgen?

1 roentgen equals 0.877 rads.

What is the formula for roentgens to rads?

The formula is: rad = R ÷ 1.1402508552.