Every year, Singapore companies are required to file their Estimated Chargeable Income (ECI) with the Inland Revenue Authority of Singapore (IRAS). Yet for many business owners — especially those running their first company — ECI filing is one of those obligations that quietly slips by, resulting in missed deadlines, unexpected penalties, or the loss of instalment payment arrangements.
This guide explains what ECI is, who needs to file, when the deadline falls, what the exemptions are, and how to approach ECI filing in a way that avoids the common pitfalls. Whether you are a sole director managing a small business or a CFO overseeing a portfolio of Singapore entities, understanding ECI is an essential part of your annual tax compliance cycle.
What Is Estimated Chargeable Income (ECI)?
ECI is an estimate of your company’s taxable income (chargeable income) for a given Year of Assessment (YA), after deducting tax-allowable expenses. It is filed before the full corporate income tax return (Form C-S, Form C-S Lite, or Form C), and its purpose is to give IRAS an early indication of the tax your company expects to pay for that year.
Think of it as a preliminary declaration — you are telling IRAS: “Based on our financial results for the year ended [date], we estimate our taxable income to be approximately $X.” IRAS will then issue a Notice of Assessment based on this estimate, which you pay (with the option of instalments, if you file on time). You later reconcile this when you file the full tax return.
ECI is computed based on your actual financial results for the financial year — not a guess. By the time you file ECI, your accounts should already be substantially finalised, even if the full audit or tax computation is still in progress.
Who Must File ECI?
Generally, all companies carrying on a business in Singapore are required to file ECI with IRAS for each Year of Assessment. This includes:
- Singapore-incorporated private limited companies (Pte. Ltd.)
- Branch offices of foreign companies registered in Singapore
- Any other company with chargeable income or income subject to Singapore tax
However, two categories of companies are exempt from filing ECI:
- Companies whose annual revenue does not exceed S$5 million for the financial year, and whose ECI is nil for that Year of Assessment.
- Foreign ship owners or charterers whose local shipping agent has submitted or will submit a Shipping Return.
The key point to note about the first exemption is that both conditions must be met simultaneously: your revenue must be S$5 million or below, AND your ECI must be nil (i.e., you have no taxable income after deductions). If your revenue is below S$5 million but you have a positive ECI — or if your revenue exceeds S$5 million — you are not exempt and must file.
This is a common source of confusion for small businesses. Having a low-revenue year does not automatically exempt you if you have even a small amount of chargeable income.
When Is the ECI Filing Deadline?
The ECI filing deadline is within 3 months from the end of your company’s financial year end (FYE). Since different companies have different financial year ends, the ECI deadline varies accordingly:
| Financial Year End | ECI Filing Deadline |
|---|---|
| 31 December | 31 March of the following year |
| 31 March | 30 June of the same calendar year |
| 30 June | 30 September of the same calendar year |
| 30 September | 31 December of the same calendar year |
For example, a company with a 31 December 2025 financial year end must file its ECI for YA 2026 by 31 March 2026. A company with a 31 March 2026 financial year end must file by 30 June 2026.
IRAS strictly enforces these deadlines. Since ACRA also tightened enforcement measures beginning January 2026, the compliance landscape for Singapore companies has become less forgiving of missed or late filings. Our article on the true cost of maintaining a Singapore company annually outlines the broader range of filing obligations companies face.
Why Filing ECI on Time Matters: The Instalment Payment Plan
One of the most significant reasons to file your ECI on time is access to the IRAS instalment payment plan. If your company files ECI within the 3-month window, IRAS will issue a Notice of Assessment and offer you the option to pay your corporate income tax in monthly instalments throughout the year, rather than in a single lump sum.
For companies with meaningful tax liabilities, this can be a significant cash flow advantage. The number of instalments you get depends on how early you file:
- The earlier you file, the more instalments you receive (up to 10 monthly instalments).
- Filing at the last moment (just before the deadline) may result in fewer instalments.
If you miss the ECI deadline, IRAS may issue a Notice of Assessment based on its own estimate of your income — which is often higher than your actual income. In that case, the full tax assessed becomes payable within 1 month from the date of the Notice, with no instalment option available. This can create a significant and unexpected cash flow burden.
How to File ECI
ECI is filed electronically through IRAS myTax Portal (mytax.iras.gov.sg). To file:
- Log in to myTax Portal using Corppass.
- Navigate to “Corporate Tax” → “File ECI”.
- Enter the relevant financial year end and the estimated chargeable income figure.
- Review and submit.
The ECI figure you enter should be based on your company’s draft management accounts or finalised financial statements for the year. You do not need to have completed your full tax computation at this stage, but you should have a reasonable and defensible estimate of your taxable income.
Important: You should not include the Corporate Income Tax (CIT) Rebate in your ECI submission. IRAS computes and applies the rebate automatically when processing your return. For YA 2026, Singapore companies benefit from a 40% CIT Rebate (capped at S$30,000) — one of the Budget 2026 measures to support businesses. This rebate will be factored in by IRAS automatically.
What Happens After You File ECI?
Once you submit your ECI, IRAS will issue a Notice of Assessment (NOA) — typically within a few weeks. The NOA will state the tax payable based on your ECI. You should review it carefully to ensure it matches your submission.
If you disagree with the NOA (for instance, if IRAS has made an adjustment), you can object to the assessment within 2 months of the date of the NOA by writing to IRAS through myTax Portal.
Subsequently, you will need to file your full corporate income tax return (Form C-S, Form C-S Lite, or Form C) by 30 November of the Year of Assessment. This is the more detailed filing that includes a full tax computation, financial statements (in XBRL format where required), and supporting schedules. Our guide on financial reporting standards and XBRL filing explains the financial statements submission requirements in more detail.
ECI and the Startup Tax Exemption
If your company is a qualifying new startup, it may be eligible for the Startup Tax Exemption Scheme, which provides a significant tax exemption for the first three Years of Assessment. For eligible companies:
- 75% exemption on the first S$100,000 of chargeable income
- 50% exemption on the next S$100,000 of chargeable income
This scheme applies to Singapore-incorporated companies that are tax resident and have not previously claimed the full tax exemption under the scheme for three years. Investment holding companies and companies whose principal activity is the holding of investments are generally not eligible.
The Startup Tax Exemption is particularly relevant for newly incorporated companies. If you have recently set up your Singapore company, make sure your accountant or tax adviser is factoring this into your ECI computation. For more on setting up a company in Singapore, see our step-by-step incorporation guide.
For companies that have exhausted their three-year startup exemption, the Partial Tax Exemption (PTE) continues to apply:
- 75% exemption on the first S$10,000 of chargeable income
- 50% exemption on the next S$190,000 of chargeable income
GST and Its Interaction with ECI
It is worth noting that ECI relates to corporate income tax — it is entirely separate from GST (Goods and Services Tax). If your company is GST-registered, your GST obligations (filing quarterly or monthly GST F5 returns) continue independently of your ECI and corporate tax filings. If you are approaching the S$1 million taxable turnover threshold for GST registration, you should read our guide on GST registration in Singapore to understand your obligations.
Key Takeaways
To summarise the key points for ECI filing:
- ECI must be filed within 3 months of your company’s financial year end.
- You are exempt only if your revenue is ≤ S$5 million and your ECI is nil.
- Filing on time gives you access to the instalment payment plan, which is a significant cash flow benefit.
- ECI is not your final tax return — you still need to file Form C-S or Form C by 30 November.
- Do not include the CIT Rebate in your ECI — IRAS applies it automatically.
- If your company qualifies for the Startup Tax Exemption, ensure your adviser factors it into the ECI computation.
How Raffles Corporate Services Can Help
Tax compliance in Singapore is manageable when you have the right support. At Raffles Corporate Services, our accounting and tax team handles ECI preparation and submission for clients across a wide range of industries. We work with you to ensure your ECI is accurately computed based on your draft financials, filed within the deadline, and reconciled against your eventual full tax return.
We also help newly incorporated companies understand and claim their startup tax exemptions, advise on optimal financial year end choices, and handle the full suite of IRAS filing obligations — from ECI to Form C-S to GST returns. Reach out to us to find out how we can make your annual tax compliance simpler and more predictable.
— The Editorial Team, Raffles Corporate Services