Blood Donor Eligibility
Check whether you likely meet the basic requirements to donate blood, based on weight, age, and hemoglobin level.
Formula
Eligible if weight ≥ 50 kg, age 16–70, and hemoglobin ≥ 12.5 g/dL
- Most donor services require a minimum weight of about 50 kg (110 lb) to donate safely.
- Typical age limits run from 16 or 17 up to around 70, often with parental consent for the youngest donors.
- Hemoglobin is usually required to be at least 12.5 g/dL for women and 13.0 g/dL for men; this tool uses 12.5 as a general threshold.
- Meeting these basics does not guarantee eligibility — travel, medications, and health history are also screened at the centre.
- Rules vary by country and organisation, so always confirm with your local blood service.
65 kg, age 25, Hb 13 g/dL
Inputs
- Weight: 65 kg
- Age: 25 yr
- Hemoglobin: 13 g/dL
At 65 kg, age 25, with hemoglobin of 13 g/dL, all three basic criteria are met, so this person appears eligible pending the centre's full screening.
Frequently asked questions
What are the basic requirements to donate blood?
Generally you must weigh at least 50 kg, be within the accepted age range (often 16–70), and have a hemoglobin level of at least 12.5 g/dL.
Why is weight a requirement?
A standard donation is a fixed volume, so a minimum body weight ensures the amount taken is a safe fraction of your total blood volume.
Why does hemoglobin matter?
Donating lowers your iron stores. A minimum hemoglobin level protects you from becoming anemic after giving blood.
Does meeting these criteria guarantee I can donate?
No. Donor centres also screen recent travel, medications, infections, and other factors. This is only a preliminary check.
Do the rules change by country?
Yes. Age limits, hemoglobin cut-offs, and deferral rules differ between organisations, so always confirm with your local blood service.