Wondering what your TSH result actually means? This free tool — built by a doctor — shows where your thyroid-stimulating hormone (TSH) sits and what it suggests, and gives you the exact questions to bring to your doctor. For a more precise read, add your free T4. It is educational only, and not a diagnosis.
TSH Interpreter
Enter your result to see where it sits — and what to ask your doctor.
Optional. If your report includes free thyroid hormones, add them for a more precise interpretation.
Questions to ask your doctor
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Get the free guide → Read the full TSH guideThis tool is for general education and is not medical advice, a diagnosis, or a substitute for your doctor. Reference ranges vary between laboratories, ages and situations — always read your results against your own lab’s ranges and discuss them with a qualified doctor. If you feel unwell, seek medical care.
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How to read your TSH
TSH (thyroid-stimulating hormone) is your thyroid’s “thermostat”. In most labs, a normal adult TSH is roughly 0.4–4.0 mIU/L, though the exact range varies by laboratory, age and pregnancy. Because the pituitary raises TSH to push a sluggish thyroid, a high TSH usually leans toward an underactive thyroid (hypothyroidism); a low TSH leans toward an overactive thyroid (hyperthyroidism). TSH is best read together with a free T4 test and your symptoms — which is exactly what the tool above helps you do. For the full story, read our complete guide to TSH levels.
Frequently asked questions
What is a normal TSH level?
In most laboratories a normal adult TSH is roughly 0.4–4.0 mIU/L (the same as µIU/mL). The exact range varies by lab, age and pregnancy, so always read your result against your own lab’s reference range.
What does a high TSH mean?
A TSH above the normal range usually points toward an underactive thyroid (hypothyroidism) — the pituitary is working harder to stimulate a sluggish thyroid. A mildly high TSH with a normal free T4 is often called “subclinical”. Only a doctor can confirm it, usually with a free T4 and sometimes antibodies.
What does a low TSH mean?
A TSH below the normal range usually points toward an overactive thyroid (hyperthyroidism), because the pituitary lowers TSH when there is plenty of thyroid hormone. It should be checked alongside free T4 (and sometimes free T3) and your symptoms.
Is a TSH of 5 or 6 too high?
A TSH between about 4 and 10 mIU/L is mildly above the usual range. If free T4 is still normal, this is often “subclinical hypothyroidism”, which may need monitoring or treatment depending on your age, symptoms and pregnancy plans — a conversation to have with your doctor.
Does TSH change during pregnancy?
Yes. In pregnancy the healthy TSH range is different and generally lower, and it shifts by trimester, so the usual adult bands do not apply. Thyroid levels matter for both mother and baby, so discuss them promptly with your doctor or obstetrician.
Can a TSH test alone diagnose a thyroid problem?
No. TSH is a screening number. A full picture needs your symptoms and often free T4, free T3 and thyroid antibodies. Use this tool to understand your result, then confirm it with a doctor.
This tool and page are for general education only and are not medical advice, a diagnosis, or a substitute for your doctor. Prefer it on paper? Get our free Decode Your Labs guide.