Blood Donation Eligibility Calculator
Donate now or wait days from donor rules.
What it does
Blood drives turn away willing donors daily on four predictable rules: too young, too light, too soon, or too low on iron. Checking all four at home saves the trip and plans the return.
The tool above takes age, weight, days since the last gift, and hemoglobin. It returns eligible now, wait days, or the blocking rule.
The default 30 year old at 150 lb, 60 days out with 14 hemoglobin, passes all four. The 30 day case waits 26 more days under the 56 day whole blood rule.
Red Cross eligibility pages publish the 17 plus age with 16 consent paths, the 110 lb floor, 56 day intervals, and 12.5 hemoglobin screening. AABB standards hold member centers to matching safety floors.
Deferrals protect both sides: low iron donors feel faint while frequent draws thin red cells. Eat iron rich meals, hydrate, and book when the tool reads green.
How to use
- Type age.
- Type weight.
- Type days since last gift.
- Type hemoglobin if known.
- Read eligible or wait first.
- Read which rule decides beside it.
Formula
- age
- Years; 16 needs parent consent.
- weight
- Pounds; 110 minimum.
- interval
- Days since last whole blood gift.
- hgb
- Finger stick g/dL; 12.5 minimum.
Red Cross donation guidance publishes the 17 plus age, 110 lb weight, 56 day whole blood interval, and hemoglobin screening behind every drive. AABB donor standards mirror the same safety floors for member centers. Rules shift by donation type and state consent law, so drives confirm edge cases.
Worked example
Example: routine returning donor
Defaults: 30, 150 lb, 60 days, 14 g/dL.
- Donor: 30 years, 150 lb, 60 days out, 14 hemoglobin.
- Age: 30 clears 17 freely.
- Weight: 150 clears the 110 lb floor.
- Interval: 60 clears the 56 day whole blood rule.
- Hemoglobin: 14 clears 12.5 g/dL.
- Tool shows Eligible to donate, Eligible now, 4 checks pass.
Reference table
| Check | Rule | Default |
|---|---|---|
| Age | 17+, 16 with consent | 30, pass |
| Weight | 110 lb minimum | 150, pass |
| Interval | 56 days | 60, pass |
| Hemoglobin | 12.5 g/dL | 14, pass |
Limits
- Big four screen only.
- State consent ages vary.
- Types differ: plasma, platelets, Power Red.
- Staff questionnaire rules all.
Common mistakes
- Driving over at day 40.
- Guessing weight over the floor.
- Skipping iron meals before drives.
- Donating through colds and antibiotics.
- Ignoring travel deferrals.
Try it yourself
Quick checks. Answers sit tucked under each question.
25, 150 lb, 30 days, 14?
56 minus 30 = 26 days to wait, interval rule.
25, 100 lb, 60 days, 14?
Under the 110 lb floor: not eligible by weight rule.
16, 130 lb, 60 days, 13.5?
Passes all four with parent consent noted for age 16.
Questions
Age rules?
17 plus, or 16 with parent consent in most states. Under 16 waits.
Weight floor?
110 lb minimum for whole blood, guarding safe draw volume.
How often?
56 days between whole blood gifts, 112 for Power Red, 7 for platelets.
Hemoglobin cutoff?
12.5 g/dL minimum at the finger stick. Iron rich meals help next visits.
Other deferrals?
Cold, flu, antibiotics, pregnancy windows, and travel exposures each defer. Ask the drive staff.
Full screening?
No, this screens the big four. Medications and history need the staff questionnaire.