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Ferritin & Hemoglobin Checker: Normal, Low or Iron-Deficiency Anemia?

Enter your ferritin and hemoglobin to see if your iron stores are normal, low or deficient — and whether you meet the WHO anemia threshold. Ferritin under 30 ng/mL means low iron. Includes a full reference chart.

🗓️ Updated June 2026 Reviewed by Martín Rodríguez

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Reviewed by: Martín Rodríguez (editorial policy ) · Last reviewed: Jun 20, 2026

Hemoglobin (g/dL)*

Ferritin (ng/mL)*

Sex*

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Iron-deficiency anemia is the most common nutritional deficiency worldwide, affecting over 1.2 billion people according to the WHO. The two key lab tests are hemoglobin (which detects existing anemia) and ferritin (which detects depleted iron stores before anemia develops). This calculator applies the reference thresholds used by the WHO and the U.S. National Institutes of Health to your own values and tells you where you stand.

When to use this calculator

Interpreting a blood test result at home before your follow-up appointment
Tracking iron stores during pregnancy, when requirements nearly double
Athletes monitoring iron status, which can fall due to high training loads (footstrike hemolysis, sweat losses)
Vegetarians and vegans checking whether their iron intake is keeping stores replete

Combined Iron Status: Ferritin + Hemoglobin Interpretation

Ferritin (ng/mL)	Hemoglobin vs. threshold	Iron status	What it means
≥ 30	Above threshold	Normal	Iron stores adequate; no anemia
15–29	Above threshold	Low stores — pre-latent/latent deficiency	Borderline iron; anemia not yet present
< 15	Above threshold	Iron deficiency without anemia	Stores empty; hemoglobin still compensated
< 30	Below threshold	Iron-deficiency anemia	Stores depleted and anemia confirmed
≥ 300	Above or below threshold	High ferritin — possible overload or inflammation	May mask true deficiency; clinical context required

Fuente: WHO Haemoglobin Concentrations for the Diagnosis of Anaemia (2011) & NIH Office of Dietary Supplements — Iron Fact Sheet for Health Professionals. Hemoglobin thresholds: men < 13.0 g/dL, non-pregnant women < 12.0 g/dL, pregnant women < 11.0 g/dL.

How it works

Quick Reference: Ferritin & Hemoglobin at a Glance

Use these two numbers from your blood test to know where you stand. Ferritin shows your iron stores (drops first); hemoglobin shows whether anemia has set in (drops later).

Ferritin (ng/mL)	What it means
< 15	Iron deficiency (stores empty)
15–29	Low — borderline, depleting
30–299	Normal
≥ 300	High — possible overload or inflammation

Hemoglobin anemia threshold	Value
Adult men	< 13.0 g/dL
Adult women (non-pregnant)	< 12.0 g/dL
Pregnant women	< 11.0 g/dL

The key rule: ferritin under 30 ng/mL means low iron stores even if your hemoglobin is still normal. Catching it at this stage — before anemia develops — is the whole point of checking ferritin.

How Iron and Ferritin Relate

Your body processes iron in two measurable stages:

1. Iron depletion (early stage): Iron stores are depleted but the bone marrow still has enough to produce red blood cells. Ferritin falls below 30 ng/mL while hemoglobin remains normal. You may feel slightly fatigued but a standard CBC may look fine.
2. Iron-deficiency anemia (late stage): Stores are exhausted and red blood cell production is affected. Hemoglobin drops below the sex-specific threshold.

How This Calculator Works

Step 1 — Anemia classification (WHO criteria)

The WHO defines anemia based on hemoglobin measured at sea level:

Group	Anemia threshold (Hb)
Adult men (≥15 y)	< 13.0 g/dL
Adult women (≥15 y, non-pregnant)	< 12.0 g/dL
Pregnant women	< 11.0 g/dL

This calculator uses the adult thresholds (13.0 for males, 12.0 for females).

Step 2 — Iron stores classification (ferritin)

Ferritin is the primary marker for iron storage. The ranges used here follow the NIH Office of Dietary Supplements and clinical guidelines:

Ferritin level	Classification
< 15 ng/mL	Very low — iron deficiency
15–29 ng/mL	Low — borderline stores
30–299 ng/mL	Normal
≥ 300 ng/mL	High — possible overload or inflammation

Important note on ferritin as an acute-phase reactant: ferritin is also elevated during infection, inflammation, or liver disease. A high ferritin level therefore does not always mean iron overload — it can mask underlying deficiency. Always interpret in clinical context.

Step 3 — Treatment suggestion

If ferritin < 30 ng/mL: oral iron supplementation (typically 100–200 mg elemental iron per day for adults) combined with vitamin C is the standard first-line approach, with a follow-up blood test at 3 months.

If ferritin ≥ 30 ng/mL: no iron supplementation is indicated based on the values entered.

Disclaimer

This tool is an educational reference, not a diagnostic instrument. Lab values must be interpreted by a qualified healthcare professional alongside your symptoms, medical history, and a full blood count (CBC). Do not self-prescribe iron supplements at high doses without medical supervision — iron overload (hemochromatosis) is also a serious condition.

Real worked example — pre-menopausal woman

Sex: Female | Hemoglobin: 11.4 g/dL | Ferritin: 8 ng/mL

WHO anemia threshold for non-pregnant women: Hb < 12 g/dL → 11.4 is BELOW threshold → Anemia: Yes

Ferritin < 15 ng/mL → Iron reserves: Very low (deficiency)

Both hemoglobin and ferritin are below cutoffs → classic iron-deficiency anemia pattern

Anemia: Yes | Iron Reserves: Very low (deficiency) | Suggested Treatment: Supplement oral iron + vitamin C. Follow up in 3 months.

Frequently asked questions

What is the normal ferritin range for adults?

Typical reference ranges are 20–250 ng/mL for adult men and 10–120 ng/mL for adult women (values vary slightly by laboratory). However, functional iron deficiency — where stores are too low to support optimal red blood cell production — can occur at ferritin levels below 30 ng/mL even within the 'normal' range of some labs. The NIH recommends at least 30 ng/mL as adequate.

Can I have iron deficiency without anemia?

Yes, and it is very common. Iron depletion (ferritin < 30 ng/mL) precedes anemia by weeks to months. During this stage hemoglobin is still normal, but you may experience fatigue, difficulty concentrating, cold hands, or reduced exercise tolerance. This calculator will flag low ferritin even when hemoglobin is above the anemia threshold.

Why is the hemoglobin cutoff different for men and women?

Men naturally have higher hemoglobin due to testosterone-driven erythropoiesis (the production of red blood cells). The WHO sets the anemia threshold at 13.0 g/dL for adult men and 12.0 g/dL for adult women. Pregnant women have a lower cutoff (11.0 g/dL) because plasma volume expands during pregnancy, diluting hemoglobin even without true anemia.

What symptoms suggest iron-deficiency anemia?

Classic symptoms include fatigue and weakness, pale skin and mucous membranes, shortness of breath on exertion, rapid or irregular heartbeat, headaches, dizziness, cold hands and feet, brittle nails, an inflamed or sore tongue, and unusual cravings for non-food items (pica, such as ice or dirt). Not everyone has all symptoms — some people are asymptomatic until hemoglobin is quite low.

How long does it take for ferritin to recover with iron supplements?

Hemoglobin typically begins to rise within 4–6 weeks of starting oral iron. However, restoring ferritin stores to normal takes considerably longer — usually 3 to 6 months of continued supplementation after hemoglobin normalises. This is why doctors usually continue iron therapy for several months after the CBC looks normal.

What can cause elevated ferritin that is NOT iron overload?

Ferritin is an acute-phase protein — it rises in response to infection, inflammation, autoimmune diseases (such as rheumatoid arthritis), liver disease, and some cancers. A high ferritin reading therefore does not automatically mean you have too much iron. If ferritin is elevated and you feel unwell, your doctor will look at other markers such as transferrin saturation, serum iron, and the full clinical picture.

Should I take iron supplements if my ferritin is low but hemoglobin is normal?

Many clinicians recommend iron supplementation when ferritin is below 30 ng/mL — especially in women of reproductive age, pregnant women, athletes, and vegetarians — even when hemoglobin has not yet fallen. However, the decision to supplement depends on symptoms, dietary intake, and the cause of depletion. Always discuss with your doctor before starting supplementation, as too much iron is also harmful.

Why is vitamin C recommended alongside iron supplements?

Vitamin C (ascorbic acid) converts dietary iron from the less-absorbable ferric form (Fe³⁺) to the more-absorbable ferrous form (Fe²⁺), and prevents it from forming insoluble complexes in the gut. Taking 200–500 mg of vitamin C with an iron supplement can increase absorption by up to 67% according to studies. Conversely, tea, coffee, calcium, and antacids taken at the same time reduce iron absorption.

What are the main causes of iron deficiency?

The most common causes include: (1) inadequate dietary intake — heme iron from red meat is absorbed more efficiently than non-heme iron from plants; (2) increased requirements — pregnancy and infancy demand far more iron; (3) blood loss — heavy menstrual periods, gastrointestinal bleeding (ulcers, colorectal cancer), or frequent blood donation; (4) malabsorption — coeliac disease, Crohn's disease, gastric bypass surgery, and low stomach acid impair iron absorption.

Are altitude and dehydration relevant to these thresholds?

Yes. At high altitudes (> 1000 m above sea level) hemoglobin thresholds for anemia should be adjusted upward because lower oxygen pressure stimulates the body to produce more red blood cells. The WHO provides altitude-adjustment tables. Dehydration can artificially raise hemoglobin by reducing plasma volume. This calculator uses sea-level thresholds; consult your doctor if either factor applies to you.

Sources & references

Methodology & trust

Editorial

Calculadora de salud revisada por el equipo editorial de Hacé Cuentas, contrastada con WHO — Haemoglobin Concentrations for the Diagnosis of Anaemia (2011), según nuestra política editorial y metodología.

Updates

Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). Ferritin & Hemoglobin Checker: Normal, Low or Iron-Deficiency Anemia?. Hacé Cuentas. https://hacecuentas.com/iron-ferritin-anemia

Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.

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