The share of each province, city and municipality is computed based on the following factors:
Population - 50%
Land Area - 25%
Equal Share - 25%

The IRA share based on population is computed using the population data from a census of population conducted by the NSO every 10 years as contained in a Presidential Proclamation Order. The IRA share based on land area is computed using the consolidated masterlist of land area prepared by the Land Management Bureau (LMB) of the Department of Environment and Natural Resources (DENR) every three (3) years.
The allocation of the individual share in the case of barangays, shall be P80,000.00 for each barangay with a population of not less than 100 inhabitants. The balance to be distributed shall be based on population (60%) and equal sharing (40%).

Source: Office of the Local Budget Officer, Tayabas