Blood Type Compatibility Calculator
Show the math
What Your Result Means
- Can Donate To: The blood types that can safely receive your red blood cells. This is determined by whether the recipient's plasma has antibodies that would attack your red cell antigens.
- Can Receive From: The blood types whose red blood cells are compatible with your plasma antibodies. In emergencies, type O- blood is used as the universal donor.
- U.S. & World Population: The approximate share of the U.S. and global population with your blood type. They differ because ABO/Rh frequencies vary by region — e.g. O+ and B+ are more common worldwide, while Rh-negative types are rarer outside North America and Europe. Rarer types may face supply shortages at blood banks.
- Designation: Special labels like "Universal Donor" (O-) or "Universal Recipient" (AB+) based on broad compatibility. These apply to red blood cell transfusions specifically.
How This Calculator Works
You select your ABO/Rh blood type from the eight standard types. The tool looks up your type in a compatibility table based on the ABO/Rh antigen system. It shows which types you can donate to (recipients who lack antibodies against your antigens), which types you can receive from, your U.S. population prevalence, and any special designation. No formula is involved — this is a reference lookup based on established immunology.
Quick Questions
What makes O- the universal donor?
Type O- red blood cells have no A, B, or Rh antigens on their surface, so they won't trigger an immune reaction in any recipient. This makes O- blood safe for emergency transfusions when the patient's blood type is unknown.
Why is AB+ the universal recipient?
People with AB+ blood have all three antigens (A, B, and Rh) on their red cells and produce no antibodies against any of them. They can receive red blood cells from any ABO/Rh type without rejection.
Does this apply to plasma and platelets too?
No — plasma compatibility works in reverse. AB plasma is the universal plasma donor because it contains no anti-A or anti-B antibodies. This calculator covers red blood cell compatibility only.
How do I find out my blood type?
You can find out through a blood donation (the blood bank will tell you), a blood type test kit from a pharmacy, or by asking your doctor to include it in routine blood work. Many people learn their type during pregnancy screening.
Sources
- American Red Cross — Blood Types (compatibility charts and population prevalence data)
- NCBI Bookshelf — Blood Groups and Red Cell Antigens (immunology of ABO/Rh system)
- WorldAtlas — World Population by Percentage of Blood Types (global ABO/Rh distribution)
Method & review
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.