Filing your ECI is one of the most important annual tax obligations for Singapore companies, yet many business owners are still unsure about what ECI is, when to file it, and how it affects their tax payments. Understanding ECI early can save you from unnecessary penalties, help you manage cash flow better, and ensure smooth corporate tax compliance. Whether you qualify for an ECI waiver or need to submit your figures within the required timeline, knowing how ECI works will make the process far simpler and more predictable.
Do You Need to File ECI?
The Estimated Chargeable Income (ECI) is an estimate of your company’s taxable profits for a Year of Assessment (YA), calculated after deducting tax-allowable expenses. Most companies need to file ECI within three months of their Financial Year-End (FYE), but there’s an important waiver that could save you time.
The ECI Filing Waiver
Your company doesn’t need to file ECI if both of these conditions are met:
- Your annual revenue is $5 million or below
- Your ECI is nil (zero).
When to File Your ECI
You need to file within three months from the end of your financial year. IRAS will send you a notification in the last month of your financial year, but even if you don’t receive one and you’re not exempt, you still need to file on time.
For example, If your FYE ends on:
- On 31 March 2025 → file by 30 June 2025.
- On 30 June 2025 → file by 30 September 2025
- On 31 December 2024 → file by 31 March 2025.
Why Filing Early Matters
The earlier you file your ECI, the more payment flexibility you get. If you’re a Singapore-registered company on GIRO, you can enjoy instalment payments. Note that you must sign up for GIRO at least three weeks before filing your ECI. If your GIRO arrangement isn’t approved before the payment due date (which is one month from your Notice of Assessment), you’ll lose the instalment benefit and need to pay in full.
How to Calculate Your ECI
Calculating your ECI follows a straightforward process, though the details can get nuanced depending on your business situation. Check how here.
*Don’t deduct tax exemptions when calculating your ECI. IRAS will automatically apply the partial tax exemption or the new start-up tax exemption when they process your filing. Your ECI figure should be before these exemptions.
If Your Actual Profit Differs
Sometimes your final taxable income (when you file Form C-S / Form C later) can differ from what you estimated in your ECI. If you end up with less chargeable income than you declared, IRAS will refund the excess tax automatically. If it’s more than reported, you’ll need to pay the additional tax within one month of receiving the updated Notice of Assessment.
Making Corrections
Mistakes happen, and you can revise your ECI if you need to. IRAS provides detailed user guides if you need step-by-step assistance with the revision process.
The revision process is straightforward for simple errors, but if IRAS has concerns about significant changes, they may ask for supporting documentation or clarification.
What If I Don’t File?
Missing your ECI filing deadline has real consequences. IRAS may issue an estimated Notice of Assessment based on your company’s past income or other information they have on file. When this happens, you must pay the full tax amount within one month.
You still need to make payment based on this estimated assessment even if you file an objection. If the assessment is later revised in your favor, IRAS will refund any overpayment. But if you don’t pay on time, late payment penalties kick in, and IRAS may take enforcement action.
If you disagree with an estimated assessment, you can file an objection within two months from the date of the Notice of Assessment and explain why you were late or failed to file your ECI and provide the revised ECI amount you believe is correct.
Important Reminders
Filing your ECI on time protects you from estimated assessments and gives you access to instalment payments if you’re on GIRO. Keep proper records throughout the year of your income and expenses. It makes the calculation much easier when filing time comes around.
Always declare your company’s revenue when filing, even if you’re reporting nil ECI. If you’ve changed your financial year, you may need to file for multiple YA so plan accordingly. Don’t try to factor in tax exemptions when calculating your ECI. IRAS handles those automatically.
Need help with your ECI filing? Our team at Verti specializes in corporate tax compliance for Singapore businesses. We’ll handle calculations, ensure you’re claiming all eligible deductions, and file everything on time so you can focus on running your business. Reach out to contactus@verti.sg or +65 6909 5691.
All information accurate as of 9 December 2025