Hello-
I'll try to explain as simply as I can:
An individual whose blood clots normally and who is not on anticoagulation should have an INR of approximately 1. The higher your INR is, the longer it takes your blood to clot.
As the INR increases above a given level, the risk of bleeding and bleeding-related events increases. On the other hand, as the INR decreases below a given level, the risk of clotting events increases.
The ideal target INR range will vary from person to person depending on a variety of factors such as the reason for taking anticoagulants, other medical conditions, and a number of other issues. Your Dr will determine the appropriate INR range for you. The most common INR target range for someone on warfarin is somewhere between 2.0 and 4.0. INRs of 5 or more typically are avoided because the risk of bleeding increases significantly at INRs above 5.