Ferritin Unit Converter
Ferritin Unit Converter
Convert serum ferritin between ng/mL, µg/L, µg/dL, nmol/L and pmol/L, and see instantly whether the value sits inside the reference interval.
Ferritin converter
Mass ⇄ molarFerritin 18 ng/mL
Formula and conversion factor
ng/mL = pmol/L ÷ 2.247
- 2.247
- conversion factor derived from an apoferritin molecular weight of ≈445,000 Da
- ng/mL
- identical in magnitude to µg/L — no arithmetic needed between them
- µg/dL
- ng/mL ÷ 10
Worked example
Ferritin 18 ng/mL
18 × 2.247 = 40.4 pmol/L
18 ng/mL = 18 µg/L = 1.80 µg/dL = 0.040 nmol/L
Reference ranges
| Group | ng/mL (µg/L) | pmol/L |
|---|---|---|
| Men, adult | 24 – 336 | 54 – 755 |
| Women, adult | 11 – 307 | 25 – 690 |
| Iron deficiency, likely | < 30 | < 67 |
| Iron deficiency with inflammation | < 100 | < 225 |
What ferritin measures
Ferritin is the body’s iron-storage protein, and the small fraction that circulates in serum is proportional to total body iron stores. That proportionality is what makes it the single most useful first-line test for iron deficiency: a low ferritin is the earliest laboratory abnormality in iron depletion, appearing well before haemoglobin falls or red cell indices change.
The interpretation is asymmetric. A low ferritin is close to diagnostic of iron deficiency and is rarely caused by anything else. A normal or raised ferritin does not exclude it, because ferritin is an acute-phase reactant — infection, chronic inflammation, liver disease, malignancy and heavy alcohol use all push it up independently of iron stores. This is why guidelines raise the diagnostic threshold to roughly 100 µg/L when C-reactive protein is elevated, and why ferritin is usually read alongside transferrin saturation rather than alone.
Very high ferritin has its own differential: haemochromatosis and iron overload, but also adult-onset Still’s disease, haemophagocytic lymphohistiocytosis and severe hepatocellular injury, where values in the thousands are common without any excess iron at all.
Frequently asked questions
Is ng/mL the same as µg/L for ferritin?
Yes — they are numerically identical, so a report of 18 ng/mL and one of 18 µg/L mean exactly the same thing. Laboratories in the United States tend to report ng/mL, while most of Europe and the SI convention use µg/L.
How do I convert ferritin to pmol/L?
Multiply the ng/mL value by 2.247. The factor comes from ferritin’s molecular weight of about 445,000 Da; because iron content varies the molecular weight is not perfectly fixed, so molar reporting of ferritin is uncommon in routine practice.
What ferritin level means iron deficiency?
Below 30 µg/L is generally accepted as iron deficiency in an otherwise well adult, and below 15 µg/L is close to specific for absent iron stores. If inflammation is present the threshold rises to around 100 µg/L, and transferrin saturation below 20% supports the diagnosis.
Can ferritin be high without iron overload?
Frequently. Ferritin rises in any inflammatory state, in liver disease, after alcohol, in malignancy and dramatically in haemophagocytic syndromes. A raised ferritin should prompt a transferrin saturation before iron overload is assumed.
Related calculators
References
- WHO. Serum ferritin concentrations for the assessment of iron status and iron deficiency in populations. Geneva, 2020.
- Camaschella C. Iron deficiency. Blood. 2019;133(1):30–39.
- Assay package insert — ferritin immunoassay, molecular weight and unit conversion.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.