Warfarin Dosing Calculator
Clinical Note: Adjustments are based on the Percentage Change Method. For high INRs (>5.0), omit doses and check for signs of occult bleeding (bruising, hematuria, epistaxis).
When using a calculator, clinicians often refer to the following clinical standards (based on the ACCP Guidelines) for non-loading maintenance phases:
| Current INR | Dose Adjustment Recommendation | Action to Take |
| < 1.5 | Increase weekly dose by 15–20% | Consider extra dose (booster) |
| 1.5 – 1.9 | Increase weekly dose by 10–15% | No booster usually needed |
| 2.0 – 3.0 | No Change | Maintain current schedule |
| 3.1 – 3.9 | Decrease weekly dose by 10–15% | Monitor INR in 1 week |
| 4.0 – 4.9 | Hold 1 dose; Decrease weekly dose by 15% | Close monitoring required |
| > 5.0 | Hold dose(s) until INR < 3.0 | Check for bleeding; Contact MD |
