Red Cell Distribution Width— Normal Range & What Your Result Means

Cell size variation

Normal Red Cell Distribution Width range (RDW, %)

  • Adults11.5–14.5 %

Ranges are typical adult values and vary between labs. Use the range on your own report.

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What is Red Cell Distribution Width (RDW)?

Red Cell Distribution Width is measured as part of a complete blood count (cbc) panel. Your red blood cells are consistent in size — normal variation.

What does a high Red Cell Distribution Width mean?

Your red blood cells vary significantly in size (high RDW). This can be an early sign of nutritional deficiencies (iron, B12, folate) or mixed anemia. It helps doctors pinpoint the cause of anemia.

What does a low Red Cell Distribution Width mean?

Your RDW is below normal — red blood cells are very uniform in size. This is rarely a concern.

Understand your whole report, not just one number

A single value rarely tells the full story — Red Cell Distribution Width is best read alongside the rest of your panel. Paste your values or upload your report and get a plain-English explanation of every marker, with the important results flagged.

Red Cell Distribution Width: frequently asked questions

What is a normal Red Cell Distribution Width level?

A normal Red Cell Distribution Width (RDW) level is 11.5–14.5 % for adults. Reference ranges vary slightly between laboratories, so always compare against the range printed on your own report.

What does a high Red Cell Distribution Width mean?

Your red blood cells vary significantly in size (high RDW). This can be an early sign of nutritional deficiencies (iron, B12, folate) or mixed anemia. It helps doctors pinpoint the cause of anemia.

What does a low Red Cell Distribution Width mean?

Your RDW is below normal — red blood cells are very uniform in size. This is rarely a concern.

Related Complete Blood Count (CBC) tests