---
title: "Transferrin Saturation Calculator (Iron ÷ TIBC)"
type: tool
url: "https://www.test-well.com/tools/transferrin-saturation-calculator"
date_published: 2026-10-12
free: true
---

# Transferrin Saturation Calculator (Iron ÷ TIBC)

> Divide serum iron by total iron-binding capacity and multiply by 100 to get transferrin saturation — the share of iron-carrying capacity actually loaded with iron. About 20–45% is usual; under 16% is the iron-deficient pattern (or iron locked away by inflammation when ferritin is normal), and 45% or more is the screening threshold for iron overload that prompts a repeat fasting test and HFE gene testing.

## Key facts

| Fact | Value |
| --- | --- |
| Inputs | Serum iron · TIBC |
| Usual | ≈ 20–45% |
| Overload screen | ≥ 45% → repeat + HFE |
| Cost | Free |

## For agents

See https://www.test-well.com/developers for the agent endpoints.

## Frequently asked questions

### What is a normal transferrin saturation?

Roughly 20–45% in adults; laboratories print ranges such as 15–50% or 20–50%. Because serum iron varies by the hour and with meals, a value is best read from a morning fasting draw and together with ferritin, which reflects the iron stores themselves.

### What does a low transferrin saturation mean?

Under about 16% there is too little iron for the carrying capacity. With a low ferritin that is iron deficiency — from periods, blood loss in the gut, low intake or malabsorption — and the cause is worth finding, not just the iron replacing. With a normal or high ferritin it is usually the anemia of chronic inflammation, where iron is present but sequestered.

### When does a high saturation suggest hemochromatosis?

The ACG and AASLD guidelines use a fasting transferrin saturation of 45% or more, usually with an elevated ferritin, as the trigger to repeat the test and order HFE genotyping. Iron supplements, a recent transfusion, hemolysis and liver disease also raise saturation, so a single value on supplements is repeated after stopping them.

### My report shows transferrin, not TIBC — can I still use this?

Yes. TIBC can be estimated from transferrin: multiply transferrin in mg/dL by about 1.39 (some laboratories use 1.42) to get TIBC in µg/dL, then enter that value. The estimate differs slightly from a measured TIBC, which the limits section notes.

## Related

- [iron](https://www.test-well.com/biomarkers/iron)
- [tibc](https://www.test-well.com/biomarkers/tibc)
- [iron saturation](https://www.test-well.com/biomarkers/iron-saturation)
- [ferritin](https://www.test-well.com/biomarkers/ferritin)
- [transferrin](https://www.test-well.com/biomarkers/transferrin)
- [iron panel complete](https://www.test-well.com/tests/iron-panel-complete)
- [ferritin](https://www.test-well.com/tests/ferritin)
- [anemia panel](https://www.test-well.com/tests/anemia-panel)
- [cbc with differential](https://www.test-well.com/tests/cbc-with-differential)

---

Canonical page: https://www.test-well.com/tools/transferrin-saturation-calculator
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.