roentgen to milliroentgen converter

Convert roentgen to milliroentgen in the Radiation exposure family. See a sample calculation, unit definitions, and the interactive converter.

Example conversion: 1 R

1000 milliroentgen

This example is calculated from the same unit registry used by the interactive converter.

Formula and unit definitions

Convert exposure units for ionizing radiation in air, including roentgen.

target value = source value × source factor ÷ target factor

Source unit: roentgen (R), factor 0.000258, offset 0.

Target unit: milliroentgen (mR), factor 2.58e-07, offset 0.

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Important note

The calculation is performed locally from the listed unit definitions. Display results are rounded for readability; high-precision and regulated work should use the governing standard and appropriate significant figures.

For high-precision, regulated or safety-critical use, check the underlying standard and its required precision. Historical and approximate units are identified in their names or family descriptions.

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