Generally, you may claim tax deductions on expenses "wholly and exclusively" incurred in earning your income. Find out more about deductions for the different types of expenses (e.g. employment expenses, business expenses). 

To simplify the tax filing for rental expenses, you may opt to claim the rental expenses based on 15% of the gross rental income derived from the tenanted residential property, instead of the actual amount of deductible expenses incurred. In addition to the 15%, you may claim a deduction on interest paid on the loan taken to purchase the property. You may use the Rental Calculator (XSLM, 146KB) to decide if it is beneficial to claim 15% deemed rental expenses or to claim based on actual rental expenses incurred. Find out more about the Simplification of Claim of Rental Expenses for Individuals.

This information is sourced from IRAS.