Previously, the calculation method was based on manufacturing and import prices for the affected products and services.
The change is effective from September 16, according to a source from Excise Department of Finance Ministry.
Meanwhile, a 2 per cent increase in the excise for sugary drinks has been approved. The excise has been raised from 8.9 per cent. The change will take effect in two years.
The lead-in time is meant to help producers revise their products by reducing the sugar content in their products, the source said.