You can donate whole blood approximately every 8 weeks (56 days) in the United States, allowing up to 6 donations per year for men and slightly less frequent for women due to iron level considerations

. In the UK and Australia, the recommended interval is generally every 12 weeks for men and every 16 weeks for women, with men allowed up to 4 donations per year and women fewer, reflecting differences in iron recovery times

. For other types of donations:

• Platelet donors can give every 7 to 14 days, up to 24 times per year

• Plasma donors may donate as often as every 2 to 4 weeks depending on the program

• Double red cell donations require a longer wait, typically 112 days or more between donations

These intervals ensure the body has enough time to replenish blood cells and iron, maintaining donor health. Specific guidelines can vary by country and donation center, so it is advisable to check with local blood services for exact requirements