Thyroid TSH Calculator

Thyroid TSH Calculator — evidence-based tool to check your thyroid tsh. Includes formula, tips, and interpretation guide.

Informational only — not a diagnosis. The Thyroid TSH Calculator is an educational tool for a thyroid-stimulating hormone (TSH) result. It does not diagnose, rule out, or treat a condition, and it should not be used to start, stop, or change medicine. For related context, see Creatinine Clearance Calculator and BMI Calculator.

Use the page only with the units and context shown beside each field. TSH in mIU/L and whether the reference context is a non-pregnant adult or a pregnancy trimester are not interchangeable with a different specimen, collection time, assay, device, or population. Preserve the date and original laboratory report, because an apparently precise comparison can still be wrong when a reference interval or method has changed.

TSH is a pituitary signal, not a complete thyroid assessment. Results can be affected by pregnancy, thyroid medicine, biotin, acute illness, age, assay calibration, and local laboratory practice. Interpretation normally considers free T4, symptoms, history, and repeat testing. Pregnancy-specific ranges should come from the laboratory or antenatal team where available. Do not start, stop, or change thyroid medicine from this comparison alone, and mention supplements such as biotin to the clinician. A qualified clinician should interpret an abnormal, unexpected, urgent, or personally concerning result with the symptoms, history, examination, medicines, and the laboratory's own range.

Read the original report and enter the value in the exact unit requested.
Select the reference context that matches the report, including sex, pregnancy, cycle phase, or collection time where the page asks for it.
Check fasting status, medicines, supplements, recent illness, and the laboratory method before comparing the result.
Read the displayed formula and interval as an educational comparison, not as a clinical conclusion.
Save the result with the report date and discuss anything outside the report range or any concerning symptom with a qualified clinician.

Thyroid TSH formula and reference limits

Compare TSH with the selected context-specific interval; free T4 and symptoms are not inferred by this page. The illustrative non-pregnant adult interval is 0.4–4.0 mIU/L. The pregnancy examples are 0.1–2.5, 0.2–3.0, and 0.3–3.0 mIU/L for the first, second, and third trimesters.

Reference intervals describe the population and method used by a laboratory; they are not universal treatment thresholds. The reporting laboratory's interval normally takes priority over an example shown here. Age, sex, pregnancy, cycle phase, collection time, fasting status, assay calibration, medicines, and jurisdiction can all change what a result means.

For the named source behind this page, see MedlinePlus thyroid-stimulating hormone (TSH) test.The sources are provided so the assumptions can be checked, not so a web calculator can replace the ordering clinician or the laboratory report.

How to read your thyroid tsh result

A screening comparison is not a verdict

The result is best treated as a prompt to verify context. A value near a boundary can move between categories because of biological variation, rounding, collection conditions, device or assay differences, and the chosen reference population. Repeat testing, when clinically appropriate, should follow the clinician's instructions rather than an arbitrary schedule.

Pregnancy-specific ranges should come from the laboratory or antenatal team where available. Do not start, stop, or change thyroid medicine from this comparison alone, and mention supplements such as biotin to the clinician. If symptoms are severe, rapidly worsening, or urgent, seek appropriate medical care instead of waiting for a calculator comparison. Do not infer a diagnosis from a normal-looking result, because a calculator cannot see symptoms, examination findings, medication history, or related laboratory values.

Informational only — not a diagnosis. Share the raw value, unit, collection date, reference interval, and relevant context with a qualified clinician. That information is more useful than reporting the category alone.

Health tips and best practices

Use the reference interval printed on the original report whenever it is available.
Keep units, specimen type, collection time, fasting status, and assay method with the result.
Record medicines and supplements that could influence the marker or measurement.
Compare trends only when the testing conditions and laboratory method are reasonably comparable.
Ask a clinician before acting on an abnormal or unexpected result.
Never use an estimate to adjust prescription treatment or delay urgent care.

A reference interval is a statistical description, not a boundary between healthy and ill.
Unit conversions can preserve arithmetic while changing the meaning if the specimen or formula is wrong.
One result is a snapshot; trend, symptoms, and clinical context often matter more than a rounded category.
Different laboratories may use different assays, calibration, populations, and reporting units.

Common mistakes to avoid

Replacing the laboratory's own interval with a generic internet range.
Entering the wrong unit, specimen, collection time, cycle phase, or fasting status.
Treating a screening signal or age estimate as a diagnosis, prognosis, or treatment target.
Ignoring pregnancy, medicines, supplements, acute illness, or recent changes in treatment.
Using a single result to make a consequential decision without qualified clinical interpretation.

Informational only — not a diagnosis. This calculator is general educational information, not medical advice, a laboratory report, a diagnosis, a treatment recommendation, or an emergency service. Reference ranges and clinical practice vary by laboratory, assay, jurisdiction, age, sex, pregnancy, medicines, and patient history. Discuss results and care decisions with a qualified clinician.