Blood count

Red cell distribution width (RDW) unit converter

Variation in red blood cell size (anisocytosis)

Converter

Enter a value in any unit and all other units fill in.

fraction %

Worked example

12 % (middle of the reference range) = 0.12 fraction

Conversion formulas

fraction	fraction = % × 0.01	% = fraction × 100

Good to know

Red cell distribution width (RDW) is reported in % or fraction. The page converts between the units only.

fraction × 100 = % (exact factor 100).
The range shown is a guide from the named source; targets and reference ranges differ between laboratories, methods and indications, so compare with the range on your own report.

Reference range

Unit	Adults
fraction	0.1 – 0.14
%	10 – 14

Source: Newcastle Hospitals Laboratories: Red Cell Distribution Width (part of FBC) · Last reviewed: 2026-10-19

Note from the source: 10.0-14.0 % (Newcastle Hospitals Laboratories)

Frequently asked questions

How do I convert Red cell distribution width (RDW) from % to fraction?

fraction = % × 0.01. In the other direction: % = fraction × 100.

What is the reference range of Red cell distribution width (RDW)?

For adults the range is 10 – 14 % (Newcastle Hospitals Laboratories: Red Cell Distribution Width (part of FBC)). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for Red cell distribution width (RDW)?

Common units are fraction, %.