How old do you have to be donate blood?

The minimum age requirement for blood donation in most countries is usually between 17-18 years old. However, it may vary depending on the country and the blood donation organization. Some places might have a minimum age of 16, while others might require donors to be at least 21 years old. It's always best to check with the specific blood donation organization or blood bank in your area to find out the exact minimum age requirement.