<prompt> Half-life of factor VIII2-4 hours8-12 hours6 minutest60 days  <response>: Factor VIII 8 Dosage Calculated on the basis that 1 unitkg of factor VIII leads to a rise in plasma factor VIII of approximately 2. EXAMPLE: 50 unitskg will increase factor VIII level by 100. Doses are rounded UP to the nearest l size. The half-life of factor VIII is 8-12 hours. Refer also to RCH Clinical Practice Guideline Haemophilia. 