TSAT Calculator – Transferrin Saturation
Calculate your transferrin saturation (TSAT) using your serum iron and TIBC or transferrin values.
Calculate TSAT
Estimated TSAT
How to Get an Accurate TSAT Result
Here are a few quick checks to run before and after using the TSAT calculator, so your transferrin saturation result comes out accurate and easy to interpret.
Pick the Right Calculation Method
Use Serum Iron + TIBC if your lab report includes both values. If you only have transferrin instead of TIBC, use the Serum Iron + Transferrin option — the calculator applies the correct conversion either way.
Double-Check Your Units
Serum iron can be entered in μg/dL or μmol/L, and transferrin in mg/dL or g/L. Mixing these up is the most common reason a TSAT result looks wrong — confirm both before calculating.
Select Gender
Normal TSAT ranges shift slightly between men and women, particularly at the lower end. Adding gender is optional, but it helps put your specific result in better context.
Know What a Normal Range Looks Like
Most adults fall between 20% and 50% TSAT. A result below 20% may point to low iron availability, while above 50% may suggest iron overload — either end is worth discussing with a doctor.
Don’t Interpret TSAT on Its Own
TSAT is almost always reviewed alongside ferritin and other iron studies, not as a standalone result, since other conditions can affect it independently of iron status.
Use the Result to Guide Next Steps
A low or high TSAT is a starting point for further testing or treatment planning, not a diagnosis by itself — bring it to your doctor for interpretation.
What Is Transferrin Saturation (TSAT)?
Transferrin saturation (TSAT) is the percentage of transferrin’s iron-binding capacity that is occupied by iron. It indicates how much circulating iron is available for delivery to tissues.
TSAT is calculated from serum iron and total iron-binding capacity (TIBC), or estimated from serum iron and transferrin concentration. Because it is a calculated value, changes in either serum iron or the iron-binding measurement affect the result.
If your lab report gives UIBC instead of TIBC, use our UIBC Calculator to derive TIBC first.
Transferrin Saturation Formula
TSAT is calculated by dividing serum iron by TIBC and multiplying by 100. When transferrin is used instead of TIBC, a unit-specific conversion factor (≈70.9) is applied.
| Calculation method | Formula |
| Serum Iron + TIBC | |
| Serum Iron + Transferrin | TSAT (%) = (Serum Iron ÷ Transferrin) × 70.9 |
Calculation Example
Suppose a lab report shows:
- Serum Iron = 120 μg/dL
- TIBC = 300 μg/dL
TSAT = (120 ÷ 300) × 100 = 40.0%
Serum iron represents the amount of iron circulating in the blood, while TIBC reflects the blood’s capacity to bind iron through transferrin. TSAT combines these measurements into a percentage, providing a measure of the proportion of available iron-binding capacity that is occupied by iron.
Typical Reference Values for Iron Studies
Iron studies are commonly evaluated together because each measurement provides different information about iron status. The panel may include serum iron, TIBC, transferrin, ferritin, and transferrin saturation. TIBC reflects the capacity of transferrin to bind iron, while ferritin is used as an indicator of iron stores.
| Test | Value |
| Serum iron — men | 75–150 mcg/dL (13–27 micromol/L) |
| Serum iron — women | 60–140 mcg/dL (11–25 micromol/L) |
| Total iron-binding capacity (TIBC) | 250–450 mcg/dL (45–81 micromol/L) |
| Ferritin | 30–300 ng/mL (67.4 to 674.1 pmol/L) |
| Transferrin saturation (TSAT) | 20–50% |
Source: Merck Manual Professional Edition.
Once you’ve confirmed low TSAT, use the Iron Deficit Calculator to estimate your total iron replacement dose.
A TSAT below 20% may indicate reduced iron availability, depending on the clinical context. Low TSAT is commonly considered alongside ferritin and other iron studies when evaluating possible iron deficiency. A TSAT result should not be interpreted in isolation because iron markers can be affected by underlying disease and other factors.
Iron studies typically include serum iron, TIBC, transferrin, and transferrin saturation when evaluating suspected iron deficiency, iron overload, or other disorders of iron metabolism.
Need to estimate iron replacement?
How TSAT Fits With Ferritin and Other Iron Tests
TSAT is generally interpreted together with ferritin and other iron studies because each test provides different information about iron status.
| Test | What it tells you |
| Transferrin Saturation (TSAT) | How much of transferrin’s iron-binding capacity is occupied by iron |
| Serum iron | Amount of iron circulating in the blood |
| Total Iron Binding Capacity (TIBC) | The blood’s total capacity to bind iron |
| Transferrin | The main protein that transports iron |
| Ferritin | An indicator of stored iron |
TSAT is generally interpreted together with ferritin and other iron studies because the tests provide different information about iron status.
Related Iron Panel Calculators:
- Iron Deficit Calculator: — Calculate total iron replacement dose using the Ganzoni formula.
- UIBC Calculator: — Calculate UIBC and derive TIBC if your lab report only gives serum iron.
Frequently Asked Questions
How do you calculate transferrin saturation?
Divide serum iron by TIBC and multiply by 100. If you only have serum transferrin, divide serum iron by transferrin and multiply by 70.9. Use consistent units or let this calculator convert them for you.
What is transferrin saturation (TSAT)?
Transferrin saturation (TSAT) is the percentage of transferrin’s iron-binding capacity occupied by iron. It is calculated from serum iron and TIBC, or from serum iron and transferrin, and is generally interpreted alongside ferritin and other iron studies.
What is a good TSAT level?
For most adults, a TSAT between 20% and 50% is considered normal. Adult females may have a slightly lower lower limit (around 15%). Values below 20% suggest iron deficiency, while values above 50% may indicate iron overload. TSAT should always be interpreted alongside ferritin and clinical context.
How do I calculate iron saturation percentage?
Iron saturation percentage is another name for transferrin saturation. Use the formula (Serum Iron ÷ TIBC) × 100, or use this calculator to get the result instantly.
Transferrin vs transferrin saturation
Transferrin is the iron-transport protein itself, measured as a concentration (e.g., mg/dL). Transferrin saturation is a percentage showing how much of that protein is loaded with iron. Both are useful, but they describe different things.
References
- Fairbanks VF, Beutler E. Iron deficiency. In: Williams Hematology. McGraw-Hill.
- World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. 2020.
- National Institutes of Health, Office of Dietary Supplements. Iron — Fact Sheet for Health Professionals. ods.nih.gov
- MedlinePlus. Transferrin Saturation Test. MedlinePlus
- Faruqi A, Zubair M, Mukkamalla SKR. Iron-Binding Capacity. StatPearls. NCBI Bookshelf. Updated May 2, 2024.
- McDonagh T, et al. Iron deficiency in chronic heart failure: case for intravenous iron therapy. European Journal of Heart Failure.
- Merck Manual Professional Edition. Typical Normal Serum Values for Iron, Iron-Binding Capacity, Ferritin, and Transferrin Saturation.
Disclaimer: We are developers and health information researchers, not medical professionals. Our calculators are educational tools built from published formulas, not a substitute for clinical assessment or confirmation of a medication dose. Always consult a qualified healthcare provider for medical advice, diagnosis, or treatment.