Your tax bill for this year is settled, or at least scheduled. Now is the ideal time to look ahead. The income you are earning right now will be taxed next year, and the easiest way to avoid a nasty surprise is to estimate that bill early. The IRAS tax calculator lets you do just that, using your own figures, so you can set aside money month by month instead of scrambling when the Notice of Assessment (NOA) arrives.
This guide focuses on using the calculator as a budgeting tool: what to put in, how to test different scenarios, and how to turn the result into a savings plan. It does not explain tax rates in detail; for that, see our guide on Singapore income tax rates. It is general information, not financial advice, and the Inland Revenue Authority of Singapore (IRAS) remains the authority on current rules.
Understanding Which Year You Are Estimating
Singapore uses the idea of a Year of Assessment (YA). Each YA taxes the income you earned in the previous calendar year. So the salary, bonus, rental and freelance income you receive this calendar year will be assessed in next year’s YA.
When you open the calculator, make sure you pick the version for the right YA. IRAS publishes calculators for different assessment years, and rates or reliefs can differ between them. If the calculator for the coming YA is not yet available, use the latest one as a reasonable estimate and update it when the new version appears.
Where to Find the Calculator
IRAS provides tax calculators on its website for different types of taxpayers, including resident individuals and non-residents. They are typically downloadable spreadsheets or online tools. Search the IRAS website for the individual income tax calculators and choose:
- The resident version if you are a tax resident for the year.
- The non-resident version if you are not.
Download a fresh copy each year rather than reusing an old file, since rates and relief caps may have changed.
Gathering Your Inputs
The estimate is only as good as the numbers you feed it. Before you start, collect:
- Employment income so far this year, from your payslips, plus expected income for the remaining months.
- Expected bonus, based on past years or your company’s practice. If uncertain, use a conservative figure and a higher one as a second scenario.
- Other income, such as rental, freelance or commission. Remember to estimate allowable expenses for rental and trade income. Our guide on reporting freelance income explains what counts.
- Reliefs you expect to claim, such as CPF relief, parent relief, child-related reliefs, course fees or voluntary CPF top ups. Check the eligibility conditions on IRAS before including them.
- Donations to approved institutions, which may qualify for tax deductions.
Running Scenarios Instead of One Number
The real value of the calculator is testing “what if” situations. Run at least three versions and compare them.
| Scenario | What to change in the calculator | Why it helps |
|---|---|---|
| Baseline | Current salary for the full year, usual bonus, usual reliefs | Gives your most likely bill |
| Higher income | Add a larger bonus, a pay rise or new side income | Shows the bill if the year goes well |
| Lower income | Remove the bonus or assume a gap between jobs | Helps you avoid oversaving if income drops |
| Extra reliefs | Add a planned CPF top up or course fees | Shows how much a relief may reduce the bill |
Note how the bill changes in each case. Because Singapore uses progressive rates, an extra dollar of income near a band boundary may be taxed at a higher rate than your average. The calculator handles this for you, which is exactly why it is more reliable than a rough percentage.
Turning the Estimate Into a Monthly Budget
Once you have a likely figure, convert it into a regular saving.
- Pick the scenario to plan around. Many people choose the baseline, or a figure between baseline and higher income, to build in a buffer.
- Count the months until the bill is due. The NOA usually arrives during the following year, and payment is due within a set period after it. If you plan to use GIRO instalments, the payments will be spread further.
- Divide the estimate by the months available. That is your monthly tax set aside.
- Automate it. Set up a standing instruction to move that amount into a separate savings account each payday. Keeping it apart from daily spending makes it less tempting to use.
If you are on GIRO instalments, you could still save ahead. Having the full amount ready gives you flexibility if your income changes unexpectedly.
Using the Estimate to Make Decisions
A forecast does more than prevent surprises. It can also inform decisions you make during the year, within the rules.
- Reliefs and top ups. If you were already considering a voluntary CPF top up for yourself or a family member, the calculator shows how the related relief may affect your bill. IRAS and the CPF Board set the conditions and caps, so check them first. Our guide to income tax reliefs covers the main types.
- Side income. If you are starting freelance work or renting out a room, the calculator shows how much of the extra income may go to tax, which helps you price your time realistically.
- Major life changes. Marriage, a new child, caring for parents or a job change can all affect reliefs and income. Rerun the calculator when these happen.
Avoid making decisions purely to reduce tax. Reliefs exist to support specific goals such as retirement savings or caring for family, and the money you commit to them may be locked up. Make sure the underlying decision makes sense for you first.
Common Estimating Mistakes
- Using last year’s calculator with outdated rates or reliefs.
- Forgetting the bonus, or counting it in the wrong year.
- Ignoring rental or side income because no tax is deducted at source.
- Claiming reliefs you may not qualify for, such as parent relief when a sibling is also claiming.
- Mixing up residency status. Tax residency affects how your income is taxed, so confirm yours before choosing the calculator.
- Treating the estimate as final. It is only a guide. The actual bill comes from IRAS after you file.
Make It a Yearly Habit
A useful rhythm is to run the calculator twice a year: once soon after you receive your NOA, to set this year’s savings target, and again mid-year, once you know your bonus or any big changes. Pair it with a broader review of your finances; our guide on planning your next five years is a good companion.
Estimating early turns income tax from an annual shock into a predictable monthly line in your budget. Use the IRAS tax calculator, test a few scenarios, set the savings aside automatically, and check IRAS for any updates to rates and reliefs before you rely on your figures.
Official sources: IRAS
Further reading: Checking Your Pre-Filled Income on myTax Portal Before You File · How to Get a Certificate of Residence From IRAS for Tax Treaty Claims · What Changes in Your Income Tax After You Marry in Singapore