How to Use the Total T3 Unit Conversion Calculator
Choose the conversion direction, enter the Total T3 value from your lab report, and read the result instantly. The calculator supports both ng/dL to nmol/L and nmol/L to ng/dL.
This page is focused on Total T3, also called total triiodothyronine. It is not the same as Free T3, which measures only the unbound active fraction of T3. If your report lists Free T3 instead, use the Free T3 Unit Conversion Calculator.
Total T3 Conversion Formula
Total T3 may be reported in ng/dL in conventional lab reports and in nmol/L in many SI-style or international reports. The conversion uses the molecular weight of triiodothyronine, about 650.98 g/mol.
Total T3 nmol/L = Total T3 ng/dL ÷ 65.10 Total T3 ng/dL = Total T3 nmol/L × 65.10 The same relationship can also be written as nmol/L = ng/dL × 10 ÷ 650.98.
Example Total T3 Conversion
If your Total T3 result is 100 ng/dL, divide by 65.10:
100 ÷ 65.10 = 1.54 nmol/L For the reverse direction, multiply by 65.10. A Total T3 value of 2.0 nmol/L is about 130.2 ng/dL.
Total T3 ng/dL to nmol/L Chart
Use this chart to compare common Total T3 values between ng/dL and nmol/L. Reference ranges vary by lab and assay.
| Total T3 ng/dL | Total T3 nmol/L | Note |
|---|---|---|
| 50 ng/dL | 0.77 nmol/L | Often below many adult reference ranges |
| 80 ng/dL | 1.23 nmol/L | Lower end in many adult reports |
| 100 ng/dL | 1.54 nmol/L | Common Total T3 comparison value |
| 120 ng/dL | 1.84 nmol/L | Common normal-area value |
| 150 ng/dL | 2.30 nmol/L | Common normal-area value |
| 180 ng/dL | 2.76 nmol/L | Upper area in many adult reports |
| 200 ng/dL | 3.07 nmol/L | Often above many adult reference ranges |
| 250 ng/dL | 3.84 nmol/L | Elevated in many clinical contexts |
| 300 ng/dL | 4.61 nmol/L | Markedly elevated in many reports |
nmol/L to ng/dL Reverse Chart
If your thyroid report uses nmol/L and you want the conventional ng/dL value, use this reverse chart.
| Total T3 nmol/L | Total T3 ng/dL |
|---|---|
| 0.8 nmol/L | 52.1 ng/dL |
| 1.0 nmol/L | 65.1 ng/dL |
| 1.2 nmol/L | 78.1 ng/dL |
| 1.5 nmol/L | 97.6 ng/dL |
| 2.0 nmol/L | 130.2 ng/dL |
| 2.5 nmol/L | 162.7 ng/dL |
| 3.0 nmol/L | 195.3 ng/dL |
| 4.0 nmol/L | 260.4 ng/dL |
| 5.0 nmol/L | 325.5 ng/dL |
Total T3 vs Free T3
Total T3 measures both protein-bound and unbound T3 in the blood. Free T3 measures only the unbound fraction. The molecules have the same molecular weight, but the tests answer different clinical questions and use different reference ranges.
For Free T3 unit conversion, use the dedicated Free T3 Unit Conversion Calculator. Do not compare a Total T3 result directly with a Free T3 reference range.
Total T3 in a Thyroid Panel
Total T3 is usually interpreted with other thyroid tests such as TSH, Free T4, and sometimes Free T3. If you also need those units, the TSH Unit Conversion Calculator and Free T4 Unit Conversion Calculator can help keep the full thyroid panel in the same reporting style. Total T3 may be reviewed when hyperthyroidism, T3-predominant thyrotoxicosis, thyroid medication effects, or binding protein changes are being considered.
Unit conversion helps compare reports, but it does not determine whether a thyroid result is normal or abnormal. Use the reference range printed on the same lab report whenever possible.
Common Mistakes to Avoid
Do not use the Free T3 pg/mL conversion factor for Total T3 ng/dL. Total T3 and Free T3 may involve the same hormone molecule, but they are often reported in different units and reference ranges.
Do not mix Total T3 and Total T4 conversions. T3 and T4 have different molecular weights, so their conversion factors are different. For thyroxine results, use the Total T4 Unit Conversion Calculator instead.
Frequently Asked Questions
How do you convert Total T3 ng/dL to nmol/L?
Divide the Total T3 value in ng/dL by 65.10. For example, 100 ng/dL is about 1.54 nmol/L.
How do you convert Total T3 nmol/L to ng/dL?
Multiply the nmol/L value by 65.10. For example, 2.0 nmol/L is about 130.2 ng/dL.
What is 150 ng/dL Total T3 in nmol/L?
150 ng/dL Total T3 equals approximately 2.30 nmol/L.
Is Total T3 the same as Free T3?
No. Total T3 includes bound and unbound hormone, while Free T3 measures only the unbound fraction. They require different reference ranges.
Can this calculator diagnose thyroid disease?
No. This tool only converts units. Thyroid interpretation requires clinical context and usually includes TSH, Free T4, symptoms, medication history, and other clinical details.
Conclusion
This Total T3 unit conversion calculator helps you compare thyroid lab results across ng/dL and nmol/L reporting systems. Use it for accurate unit conversion, then compare the converted value with the reference range from your own report.
For clinical interpretation, Total T3 should be reviewed with TSH, Free T4, symptoms, medications, and guidance from a qualified healthcare professional.