Medical disclaimer

Gravis Labs provides general educational information and calculation tools. Results may be estimates and are not a medical diagnosis or a substitute for professional medical advice, clinical examination, clinical judgment, or treatment.

Nothing on this site creates a clinician–patient relationship. We do not know your medical history, your medications, your symptoms, or anything else a clinician would take into account, and no page here can take those things into account on your behalf.

Every calculator on this site:

• applies a published equation to the numbers you enter,
• states which equation it used and where that equation comes from,
• places the result against a published range, and names the body that publishes it,
• lists the limitations that apply to that result.

No calculator on this site:

• diagnoses any condition,
• tells you whether you are healthy, or unhealthy,
• recommends or adjusts any treatment or medication,
• replaces a test, an examination, or a conversation with a clinician.

A calculated result is an estimate derived from the values you entered. If those values are mistyped, in the wrong units, or from a test taken in circumstances that affect it, the result will be wrong in ways this site cannot detect.

Several tools show which published range a value falls into — for example a blood pressure category or an HbA1c screening range. These ranges exist to indicate when further assessment may be worthwhile. They are not diagnoses, and a value near a threshold is not meaningfully different from one just the other side of it.

Guidelines also differ by country. Where that is the case we say so and, where practical, let you choose which guideline to apply.

Gravis Labs is an information and calculation service. It is not a medical device, and it is not registered, approved, certified or cleared by any medical regulator or health authority in any country. It has not been submitted for such approval. Nothing here should be read as implying that a regulator has assessed, endorsed or validated this site or anything on it.

We also hold no clinical authority of our own. Every equation on this site belongs to the organization that published it, and that organization is named on the page. Implementing a published equation faithfully — which is what we do, and what our tests check — is not the same as being an authority on how it should be applied to a person.

The practical consequence is simple. A result here is a starting point for a conversation with a qualified clinician, and never a substitute for one. Anything that matters — what a result means for you, whether to act on it, whether to seek care — needs the opinion of a professional who can examine you and see your full history.

Every formula, threshold and category on this site is taken from a named clinical guideline, government health agency, professional society, or peer-reviewed publication, and cited on the page where it is used with the date we last reviewed it.

Medical knowledge changes. We review content on a schedule, but a page may not reflect the most recent guidance at the moment you read it. Where a specific decision matters, check with a clinician rather than relying on this site.

Articles carry a byline naming who wrote them. Where a page has been reviewed by a qualified clinician, that reviewer is named with their credentials and the date of review. Where no reviewer is named, no clinician review has taken place — we do not imply review that has not happened.

Always seek the advice of a physician or other qualified health provider with any questions you have about a medical condition or a health measurement. Never disregard professional medical advice, or delay seeking it, because of something you read here.

Never start, stop, or change any medication or treatment on the basis of a result from this site.