Blood donation is a very important part of healthcare. Doctors around the world use blood transfusions to save lives.

Every year, people donate over 100 million units of blood worldwide.

The amount of blood the United States has in blood banks varies. Each state and region will have different amounts of blood available for treatment.

Some factors that influence how much blood is available include:

  • peak holiday periods
  • illnesses and pandemics, such as COVID-19
  • time of year

It is best to check with local blood blanks to see if they need blood donors.

In this article, learn more about donating blood, including facts, statistics, and what to expect.

A woman talks to a doctor about blood donation facts while donating blood.Share on Pinterest
Around 10% of eligible U.S. donors give blood each year.

According to the American Red Cross, donated blood is useful for a variety of reasons. These include:

  • serious injuries, such as those sustained in vehicle accidents
  • surgical procedures
  • childbirth
  • anemia
  • blood disorders
  • cancer treatments

Blood donors can experience several benefits. These include:

  • Saving lives: A single donation can save up to three lives.
  • Burning calories: According to a 2010 article, giving blood can burn up to 650 calories per donation.
  • Reducing high blood pressure: According to a 2016 study, donating blood can help reduce hypertension.

There are a few different types of blood donation. The sections below will discuss these in more detail.

Whole blood

Doctors can use whole blood donations in many different ways.

For example, it can help people in its original form, or a doctor can separate it into red cells, platelets, and plasma to treat different conditions.

Whole blood can help those who have experienced significant physical trauma and those undergoing surgery.

Platelets and plasma

People can donate platelets and plasma through apheresis. Apheresis allows donors to only donate either plasma or platelets.

Once a health professional has drawn the blood through the needle, a machine will separate out the plasma or platelets, and the rest of the blood will go back to the donor.

Apheresis donation also includes white blood cells.

Power red donation

This sort of donation focuses on red cells. It uses a process that separates red blood cells from the other components of the blood. The plasma and platelets will then go back to the donor.

This type of donation can help those who have experienced trauma, newborn infants, and those who need emergency transfusions after birth. It can also help those with sickle cell anemia.

Compatibility can change depending on which blood component the doctor is using. The sections below will discuss some considerations regarding compatibility in more detail.

Blood type

The table below describes the different blood types and how common they are, according to the American Association of Blood Banks (AABB).

It will also explain which other blood types they are compatible with, according to the National Kidney Foundation.

Blood typeU.S. prevalenceCompatibility


People with type O blood can donate to all blood types, but they can only receive donations of type O blood.


People with type A blood can donate to blood types A and AB, and they can receive donations from types A and O.


People with type B blood can donate to blood types B and AB, and they can receive donations from types B and O.


People with type AB blood can donate to type AB only, but they can receive blood donations from any type.


Plasma compatibility is different from blood type compatibility:

Blood type of the recipientWhich donor blood type is compatible?

all blood types

A and AB blood types

B and AB blood types

AB blood type


According to the American Cancer Society (ACS), doctors often give platelets to people with the same blood type as the donor. However, people can receive platelets of a different blood type than theirs.

If the platelets are the same blood type, it may reduce the risk of side effects.

There are some requirements that a person must meet before donating blood.

The following sections will explore eligibility in more detail.

Who can donate blood?

In order to donate blood, a person:

  • must be at least 16 years old
  • must weigh at least 110 pounds
  • must not currently be ill

Who is unable to donate blood?

The AABB will not allow someone to donate blood if they:

  • have used needles to inject drugs, steroids, or anything else without the permission of a doctor
  • have HIV
  • have ever had sex in return for drugs or money
  • have had babesiosis or Chagas disease
  • have anemia, uncontrolled diabetes, or uncontrolled hypertension
    are pregnant

As a result of the COVID-19 pandemic, the Food and Drug Administration (FDA) made some changes to the current guidelines. Specifically, they have changed the deferral time from 12 months to 3 months for the following groups of people:

  • males who have had sex with males
  • females who have had sex with males who have had sex with other males
  • people who have had recent tattoos and piercings

Previously, a person was not able to donate blood if they are at risk of having Creutzfeldt-Jakob disease or have a blood relative with the condition.

However, the FDA have suggested changes to the previous guidelines. Those who were previously not eligible to donate blood are now able to reapply.

Before donating blood, a person should:

  • try to get a good night’s sleep
  • eat something
  • drink fluids that do not contain alcohol or caffeine
  • prepare a list of medications they currently take and two forms of identification

How much blood can a person donate at once?

People donate around 500 milliliters of whole blood.

The amount of platelets and plasma that people can donate depends on:

  • their height
  • their weight
  • their platelet count

How long does it take?

The time it takes to donate blood varies on the type of donation:

  • Whole blood: This type of donation takes roughly 1 hour.
  • Platelet: This type of donation takes roughly 2.5 to 3 hours.
  • Plasma: This type of donation takes roughly 1 hour and 15 minutes.
  • Power red: This type of donation takes roughly 1.5 hours.

According to the ACS, removing a unit of whole blood usually takes 10–15 minutes.

Although removing whole blood only takes a short amount of time, it takes about 1 hour from registration to post-donation refreshments.

How soon can a person donate again?

According to the AABB, people should wait at least 56 days before donating whole blood again.

Platelet donors may donate sooner, as platelet levels return to normal within around 72 hours of donating.

What are the potential side effects of blood donation?

Some potential side effects of donating blood include:


A person may experience slight bruising. To help prevent this, they can apply ice or cold compresses.


To help prevent fainting, after the donation, a person may need to lie down for a few minutes and eat and drink something.

A person should also avoid caffeine and alcohol for a few hours after the donation.

Blood donation resources

To discover more evidence-based information and resources for donating blood, visit our dedicated hub.

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The following sections provide some facts and statistics about blood donation.

How many people donate blood each year?

According to the AABB, around 8 million people donated blood in the U.S. in 2017. In the same year, people donated 12.2 million units of blood.

Who is the average blood donor?

The AABB state that the average blood donor is a white male who is college-educated and aged 30–50 years.

However, the average blood donor is changing. More females and people of color become blood donors each year.

How many people donate blood?

The AABB state that around 38% of U.S. individuals meet the criteria to donate blood. However, only 10% of people donate annually.

What is the shelf-life of blood?

The table below shows the shelf-life of different components of donated blood:

Blood componentShelf life
Red blood cells42 days
Plasma1 year
Platelet5–7 days
White blood cells24 hours

Red blood cells can last for up to 10 years if frozen.

How long does it take for the blood to replenish?

It takes the body 48 hours to replenish plasma and up to 8 weeks to replace the red blood cells.

Giving blood is a quick and easy way to help people in need. It only takes up to 2 hours and can save multiple lives.

If a person cannot or does not wish to donate blood, blood banks may be looking for volunteers.