INR: normal range and what it means
Short answer: The normal INR range is 0.8 – 1.2 for adults. Labs differ a little, so also check the range printed on your report.
Check your value
Where does your INR sit?
Your result
Type the number from your lab report to see where it sits.
Upload your whole lab report and see every marker, with this value already in. Free, no account.
Add the rest of your reportWorked out in your browser. Nothing you type is sent or saved.
Information, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.
A standardized clotting ratio (key if on blood thinners).
Normal range
Adult reference range.
- Low< 0.8 ratio
- Normal0.8 – 1.2 ratio
- High≥ 1.2 ratio
What it measures
Prothrombin time expressed on a standard scale, so a result means the same thing in any lab. It exists mainly so warfarin can be dosed consistently.
What moves it
A standardised version of prothrombin time. Driven by warfarin dose, vitamin K in the diet, and liver function.
How to bring it into range
If you take warfarin, keep vitamin K intake steady rather than avoiding it. Swings in leafy greens are what move this number.
How fast it responds
Two to five days after a dose change.
Also reported as: international normalized ratio
See where your own value lands
Upload a lab report and HealthOS reads all 88 markers, personalises every range to your sex and age, and tells you which ones actually need attention. Free, no account needed.
Check my blood testGet this marker explained for your own numbers
We’ll send you a short guide to reading this marker in context — what to check alongside it, and when a value is worth acting on.
One email about this marker. No spam, unsubscribe anytime.
We handle your details as described in our Privacy Policy.
Common questions
- What is the normal INR range?
- The normal INR range is 0.8 – 1.2 for adults. Labs differ a little, so also check the range printed on your report.
- What does a high INR mean?
- A value above the reference band means INR is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my INR?
- If you take warfarin, keep vitamin K intake steady rather than avoiding it. Swings in leafy greens are what move this number.
Related markers
More in Coagulation
Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.