Income Tax Glossary

Glossary of terms relating to individual income tax such as Year of Assessment, Notice of Assessment, and Assessable Income.

Year of Assessment

'Year of Assessment' (YA) refers to the year in which income tax is calculated and charged. The assessment is for the income earned in the preceding year, starting on 1 Jan and ending on 31 Dec.

Example: For YA 2018, the assessment is for income earned from Jan to Dec 2017.

Basis period

'Basis period' refers to the period of income relevant to the YA. The basis period for a YA is the year preceding that YA.
Example: The basis period for YA 2018 is 1 Jan 2017 to 31 Dec 2017.
If you receive business income , the basis period may be different if your accounts are made up to a date other than 31 Dec.

Example 1: Employment Income

Mr Tan has employment income from 1 Jan to 31 Dec 2017. This income is earned in the basis period from 1 Jan to 31 Dec 2017 and hence, it will be assessed in the Year of Assessment (YA) 2018.

Example 2: Business Income

Mr Lee is a sole-proprietor. His financial year ends on 31 Mar 2017. His business income is earned in the basis period from 1 Apr 2016 to 31 Mar 2017 and hence, it will be assessed in the YA 2018.

Notice of Assessment (NOA)

'Notice of Assessment' refers to your tax bill. It shows the types of income and amount of income subject to tax, calculates the tax amount you need to pay, the deductions (e.g. reliefs, expenses, donations) given, as well as the credit balance to be refunded to you.

Find out more about how to read your tax bill.

Assessable income

Assessable income

'Assessable income' is your total income after deducting allowable expenses and approved donations. Total income includes:

  1. trade income for the accounting year;
  2. employment income and; or
  3. other income such as rental income.


'Employment' income shown is the net amount after deducting your employment expenses. 
'Property' income shown is the net rental income after deducting your rental expenses.

Personal reliefs

Personal reliefs

'Personal reliefs' are the deductions which help you to save tax. Tax reliefs and rebates are allowable if:

• You are a Singapore tax resident; and
• You meet the qualifying conditions.

Find out more about reliefs.


Chargeable income

'Chargeable income' is your 'assessable income' after deducting 'personal reliefs'. A typical tax computation looks like this:

Income Tax Glossary YA 2018

Singapore's personal income tax rates for resident taxpayers are progressive. This means that the higher the earnings, the higher the marginal tax rate. Please refer to the links below for more information:

Resident Tax Rates

How to Calculate Your Tax



  • Strongly Disagree
  • Strongly Agree

Information is easy to understand.

Information is useful.

Information is easy to find.

Please email us if you would like us to respond to your enquiries.