Transferrin Saturation Calculator
Calculate transferrin saturation (TSAT) from a serum iron and total iron-binding capacity (TIBC). TSAT is the percentage of transferrin’s iron-carrying capacity that is filled, and it is a core part of iron studies — low values point to iron deficiency and high values to iron overload. Enter serum iron and TIBC in the same units to get the saturation and its band.
About transferrin saturation
Transferrin saturation shows how much of the blood’s iron-carrying capacity is in use, complementing ferritin in the assessment of iron deficiency and overload. It is interpreted alongside the rest of the iron studies and the clinical context, not on its own. This is an educational reference, not medical advice.
Frequently asked questions
What is the transferrin saturation formula?
Transferrin saturation (TSAT) = serum iron ÷ total iron-binding capacity (TIBC) × 100, expressed as a percentage. Serum iron and TIBC must be in the same units (both µg/dL or both µmol/L); the ratio is unitless so the percentage is the same either way. For example, a serum iron of 60 µg/dL with a TIBC of 300 µg/dL gives a TSAT of 20%.
What is a normal transferrin saturation?
A typical reference range is roughly 20–50%, though laboratories vary and it is a little lower in women. A TSAT below about 20% suggests iron deficiency (not enough iron for the binding capacity available), while a value above about 45–50% suggests iron overload and is used as a screening threshold for conditions such as hereditary haemochromatosis. Always compare against the range on your own report.
How does TSAT fit with ferritin and TIBC?
Iron studies are read together. In iron deficiency, serum iron is low, TIBC is high and TSAT is low, usually with a low ferritin. In iron overload, serum iron and TSAT are high. Ferritin is also an acute-phase reactant that rises with inflammation, so TSAT can help interpret a ferritin that is confusing on its own. No single number is diagnostic in isolation.
What can make TSAT misleading?
Serum iron varies through the day and rises after iron-containing food or supplements, so samples are often taken fasting in the morning. Acute inflammation lowers serum iron and can lower TSAT independently of iron stores. Recent transfusion or iron infusion raises it. Because of this variability, TSAT is interpreted alongside ferritin and the clinical picture rather than from one measurement.
Is this calculator a diagnosis?
No. It computes the saturation and shows a general band, but diagnosing iron deficiency or overload depends on the full iron panel, ferritin, symptoms and history. This is an educational reference, not medical advice — discuss your results with a healthcare professional.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
More medical calculators
eGFRCreatinine ClearanceBody Surface AreaCorrected CalciumAnion GapA1C to eAGHOMA-IRQUICKIGMICholesterol RatioMean Arterial PressureQTcWaist-to-Hip RatioWaist-to-Height RatioLean Body MassPack-YearVO₂ MaxMELD ScoreFramingham RiskASCVD RiskCHA₂DS₂-VAScHAS-BLEDWells DVTWells PEMELD 3.0PREVENT RiskCHA₂DS₂-VAGeneva ScorePERC RuleChild-PughCURB-65Glasgow Coma (GCS)FIB-4 IndexCorrected SodiumSerum OsmolalityAPRIFatty Liver IndexNAFLD Fibrosis ScoreCentor ScoreFeNaqSOFALVH (ECG)ESR (VSH)Thymol TurbidityMaddrey's DFA-a GradientNEWS2ANCWinters' FormulaShock IndexAlvarado ScoreReticulocyte IndexFree Water DeficitPadua ScoreGlasgow-BlatchfordCIWA-ArMMEMaintenance FluidsBishop ScoreVancomycinSteroid ConversionHEART ScorePediatric DoseSOFA ScoreSF Syncope RuleParkland FormulaInsulin CorrectionCaprini ScoreNIHSSPSI / PORT Lab unit converters →