How often can a person donate blood? According to the American Red Cross, it depends on what type of donation you are making.
If you are donating whole blood, you must wait 56 days between donations. According to the American Red Cross, those who make double red-cell donations must wait 112 days between donations.
You can make platelet donations more frequently than whole blood donations. The American Red Cross says you can make a platelet apheresis donation every seven days, up to 24 times a year.