Introduction
Total Iron Binding Capacity (TIBC) shows how much iron your blood can carry. Iron travels through your blood on a protein called transferrin. TIBC tells you how much room that protein has for iron. When your body is low on iron, it makes more transferrin, so TIBC goes up. When you have too much iron, or you have swelling and illness inside the body, TIBC goes down.
This TIBC calculator works in two ways. You can enter your serum iron and your UIBC (unsaturated iron binding capacity), and it adds them together. Or you can enter your serum iron and your transferrin level, and it changes transferrin into TIBC for you. Either way, you get your TIBC, your transferrin saturation percent, and your UIBC.
You can type your numbers in µg/dL, µmol/L, mg/dL, or g/L, and the calculator converts between them. It then shows your results on a simple color bar, tells you if each value is low, normal, or high, and walks you through each step of the math. Charts show how much of your iron binding capacity is full and how much is still free.
Doctors use TIBC and transferrin saturation together to help spot iron deficiency anemia, iron overload, and other iron problems. This calculator is a learning and checking tool. It does not replace a doctor. Always go over your lab results with your health care provider.
How to use our TIBC Calculator
Enter your blood test numbers, and this TIBC calculator gives you your total iron binding capacity, transferrin saturation, UIBC, and a color bar showing where your results fall.
Choose Input Method: Pick the UIBC Method tab if your lab report lists UIBC. Pick the Transferrin Method tab if it lists transferrin instead.
Serum Iron: Type the serum iron value from your blood test. Then pick the unit that matches your report, either µg/dL or µmol/L.
Unsaturated Iron Binding Capacity (UIBC): In the UIBC tab, type your UIBC value and pick its unit. This is the iron space on transferrin that is still empty.
Transferrin Level: In the Transferrin tab, type your transferrin value and pick the unit: mg/dL, g/L, or µmol/L.
Transferrin → TIBC Factor: Pick 1.25 or 1.43. Labs use different factors to change transferrin into TIBC. Use 1.25 if you are not sure.
Display iron / TIBC / UIBC in: Choose µg/dL (conventional) or µmol/L (SI) for your results. This only changes how the answers are shown.
Calculate: Click Calculate to see your TIBC, transferrin saturation, UIBC, and step-by-step math. Click Reset to start over with the sample values.
What Is TIBC (Total Iron Binding Capacity)?
TIBC is a blood test that shows how much iron your blood can carry. Iron does not float freely in the blood. It rides on a protein called transferrin. TIBC measures how much room all that transferrin has for iron. Think of transferrin as a bus and iron as the riders. TIBC is the total number of seats on the bus.
How TIBC Is Found
Labs get TIBC in two main ways:
- Serum iron + UIBC. UIBC (unsaturated iron binding capacity) is the empty seats. Add the filled seats (serum iron) to the empty seats and you get the total.
- From transferrin. Labs multiply the transferrin level by about 1.25 (some labs use 1.43) to estimate TIBC. This number changes a bit by lab and test method.
Transferrin Saturation (TSAT)
Transferrin saturation tells you what share of the seats are full. You divide serum iron by TIBC, then multiply by 100. Most healthy adults sit between 20% and 50%. A low number means little iron is moving to the bone marrow, where red blood cells are made.
Normal TIBC Ranges
Most labs use about 240 to 450 µg/dL (roughly 43 to 81 µmol/L) as normal for adults. Ranges differ a little from lab to lab, so always check the range printed on your own report.
What High and Low TIBC Mean
- High TIBC: The body makes extra transferrin when iron is short. This is seen in iron deficiency anemia, pregnancy, and slow blood loss.
- Low TIBC: Seen with long-term inflammation, liver disease, poor nutrition, and iron overload such as hemochromatosis.
Common Iron Test Patterns
- High TIBC + low saturation: classic iron deficiency.
- Low TIBC + low saturation: more like anemia of chronic disease or inflammation.
- Low TIBC + high saturation: points toward iron overload.
Things That Can Change Results
Iron levels swing during the day and are usually highest in the morning, so many labs ask for a fasting morning draw. Iron pills, birth control pills, pregnancy, infection, and liver problems can all shift TIBC and saturation.
Reading Your Results
TIBC is rarely read alone. Doctors look at it next to serum iron, ferritin, and sometimes CRP to see the full iron picture. These numbers are for learning only. Talk with your doctor about what your own lab report means and what to do next.