Roughly one in five women of reproductive age has iron-deficiency anemia. Men are affected less often but, when they are, the cause is usually more serious. Fatigue, pale skin, and breathlessness are the leading clues — and early detection prevents complications.
This guide shows how to quantify your anemia risk — by checking your hemoglobin against WHO cutoffs and scoring 10 typical clinical signs.
What is anemia?
Anemia means a reduced hemoglobin level in your blood. Hemoglobin is the red protein that carries oxygen from the lungs to every tissue. When it falls, oxygen delivery drops everywhere — and that is why the symptoms are so varied.
The WHO estimates that more than 1.6 billion people worldwide are anemic. Iron deficiency is by far the most common cause, followed by vitamin B12 and folate deficiency, chronic disease, and blood loss.
WHO hemoglobin cutoffs
| Severity | Women | Men |
|---|---|---|
| No anemia | ≥ 12.0 g/dL | ≥ 13.0 g/dL |
| Mild | 11.0–11.9 g/dL | 11.0–12.9 g/dL |
| Moderate | 8.0–10.9 g/dL | 8.0–10.9 g/dL |
| Severe | < 8.0 g/dL | < 8.0 g/dL |
Pregnancy uses a lower cutoff (11.0 g/dL); childhood values are age-specific (11.0–12.0 g/dL). Hemoglobin under 7 g/dL is a transfusion threshold and a medical emergency.
The 10 clinical symptoms in our score
Our calculator weights ten typical signs based on guideline descriptions:
| Symptom | Points | Meaning |
|---|---|---|
| Fatigue | 1 | Most common, but unspecific |
| Pale skin | 1 | Inner eyelids, nail beds, lips |
| Shortness of breath | 2 | Reduced oxygen-carrying capacity |
| Lightheadedness | 1 | Orthostatic or on exertion |
| Cold hands/feet | 1 | Peripheral vasoconstriction to protect core organs |
| Headache | 1 | Cortical hypoxia |
| Palpitations | 2 | Tachycardia as compensation |
| Brittle nails / hair loss | 1 | Specific for iron deficiency |
| Restless legs | 1 | Highly specific for iron deficiency |
| Pica (ice/dirt cravings) | 2 | Red flag — almost always iron deficiency |
Pica and restless legs are particularly informative: both are highly specific for iron deficiency, even when hemoglobin is still normal but ferritin is low (latent iron deficiency).
Calculate your anemia risk now
Hemoglobin, sex, and 10 clinical symptoms — instant severity grading and clinical guidance. Anonymous, no sign-up.
Run the free check →Common causes of anemia
- Iron deficiency (50–80 % of all anemias): Heavy menstruation, vegan diet, peptic ulcer, colorectal tumors, frequent blood donation.
- Vitamin B12 deficiency: Vegans, atrophic gastritis, gastric surgery, long-term metformin.
- Folate deficiency: Alcohol overuse, pregnancy, certain anticonvulsants.
- Renal anemia: Chronic kidney disease leads to low erythropoietin.
- Anemia of chronic disease: Cancer, autoimmune disease, chronic infection.
How anemia is treated
Treatment depends on cause and severity:
- Iron deficiency: Oral iron (60–120 mg elemental iron/day) for at least 3 months, ideally on an empty stomach with vitamin C, separated from coffee/tea. IV iron if oral therapy fails or deficiency is severe.
- B12 deficiency: Intramuscular injections or high-dose oral.
- Severe symptomatic anemia (Hb < 7–8 g/dL): Consider transfusion.
- Underlying disease: Always treat alongside — iron alone will not fix anemia driven by GI bleeding or cancer.
Related calculators
Anemia often comes with quantifiable companion symptoms. For exertional fatigue, the cardiovascular risk calculator is helpful for assessing cardiac reserve. For low energy that may be diet-driven, see the BMR calculator to separate nutritional from disease-driven fatigue. If thyroid problems may be contributing, the thyroid function calculator will help interpret TSH, T3, and T4.
Summary
Anemia is common, easy to screen for, and very treatable — once recognized. With our anemia risk calculator you can spot a likely problem in seconds. Hemoglobin below the WHO cutoff or several matching symptoms warrants a complete blood count plus iron, B12, and folate testing.