Interim dividends are paid from undistributed profits that have been brought forward. Interim dividends may be paid quarterly or every six months depending on the reserves of the company holds.
Final Dividends will be paid at the end of the Financial year. Since final dividends will be paid out once the company's end of the year financial statements have been prepared and audited, the decisions regarding final dividend payments will be fuelled by more insights and information on the company's financial health.
The main difference b/w Interim dividend and final dividend are the time period in which dividend payments are made.