SERVICE · SINGAPORE
Corporate tax done properly, with nothing left on the table.
Estimated Chargeable Income filed on time, an annual return that claims every exemption and relief you qualify for, and a named accountant who signs off before anything goes to IRAS. Our agents build the computation from your closed accounts; your accountant reviews it, decides the judgement calls, and files once you approve.
Facts checked on 12 September 2026
WHAT THIS COVERS
The work, in plain terms.
Singapore taxes company profits at a headline rate of 17%. Sitting on top of that flat rate are two exemption schemes that change what actually gets taxed: the partial tax exemption, which every company can claim regardless of age, exempts a slice of chargeable income outright, and the start-up tax exemption, available only to a qualifying new company in its first three years of assessment, exempts a larger slice again. Neither is automatic — both have to be claimed correctly on the tax computation, and a computation that skips them gets taxed on the full amount.
Every company files two things a year. The Estimated Chargeable Income, a provisional figure due within three months of the financial year end, lets IRAS set up an instalment plan for the tax that will eventually fall due — and filing is waived entirely if revenue is S$5 million or less and the ECI itself is nil. The annual return itself — Form C-S, Form C-S (Lite) or Form C, depending on the company's revenue and circumstances — is due by 30 November and is where the full computation, the exemptions and any reliefs are set out and assessed.
None of this can be produced from a bank statement. The computation starts from the company's profit and loss account, adds back expenses that tax law does not allow as deductions, works out capital allowances and any reliefs the company is entitled to, and applies the exemptions to arrive at chargeable income. If the underlying accounts are wrong — a private expense booked as a business cost, a renovation never capitalised — the computation built on them is wrong too, no matter how carefully the exemptions themselves are applied.
WHO IT'S FOR
Built for SMEs like these.
A new company in its first three years
You have just incorporated, or you are a year or two in, and you want the start-up tax exemption claimed correctly from your very first return — which means the shareholder structure and the computation both need to support it, not just the intention.
An established SME that has been filing late
Returns have slipped past deadlines, or you have been paying estimated assessments instead of a properly worked-out figure, and you want someone to get the filing history current, stop the estimated assessments, and keep it on schedule going forward.
A company with reliefs it isn't claiming
You suspect capital allowances on equipment, or the renovation and refurbishment deduction on fit-out costs, have never been claimed, and you want a computation that actually finds and uses every relief you are entitled to.
THE SINGAPORE RULES
What the regulator expects.
These are the figures and deadlines IRAS applies to every Singapore company's income tax: the rate itself, the two exemption schemes that reduce what is actually taxed, the two annual filings and their deadlines, and the consequences of missing either one.
The exemptions are where the amount actually taxed drops well below the headline rate. The partial exemption is available to every company every year; the start-up exemption is larger but only available to a qualifying new company, and only for its first three years of assessment. Both are set out below with the exact tiers and, for the start-up exemption, the conditions a company has to meet.
| Requirement | What applies |
|---|---|
| Headline rate | The standard corporate tax rate is 17% of a company's chargeable income for the year of assessment, applied after the partial and, where it qualifies, the start-up exemption have reduced what is actually taxed. |
| Partial tax exemption | Available to every company regardless of how long it has been trading: 75% of the first S$10,000 of chargeable income is exempt, and 50% of the next S$190,000 is exempt, before the 17% rate is applied to what remains. |
| Start-up tax exemption | For a qualifying new company's first three years of assessment: 75% of the first S$100,000 of chargeable income is exempt, and 50% of the next S$100,000 is exempt — a larger relief than the partial exemption while the company still qualifies. |
| Start-up exemption conditions | To qualify, the company must have no more than 20 shareholders, at least one individual shareholder holding at least 10% of the shares, and must not be an investment holding company or one engaged in property development. |
| ECI | Estimated Chargeable Income must be filed within three months of the financial year end. Filing is waived if annual revenue is S$5 million or less and the ECI itself would be nil. |
| Form C-S | The simplified annual return, available where revenue is S$5 million or less, all income is taxed at the 17% rate, and the company is not claiming group relief, a carry-back of losses, or a foreign tax credit. |
| Form C-S (Lite) | A further-simplified version of Form C-S for companies with revenue of S$200,000 or less, requiring less detail than the standard Form C-S while covering the same filing. |
| Form C | Required for every company that does not qualify for Form C-S or Form C-S (Lite), filed together with full financial statements and a detailed tax computation attached to the return. |
| Filing deadline | Form C-S, Form C-S (Lite) or Form C is due by 30 November each year of assessment, whatever date the company's own financial year happens to end on. |
| Basis period | The year of assessment is based on the financial year ending in the calendar year immediately before it — the accounts for that earlier financial year are what gets assessed. |
| Late filing | IRAS can raise an estimated Notice of Assessment based on its own figures, impose composition fees for the missed deadline, and pursue prosecution against the company. |
| Late payment | A 5% penalty is added to unpaid tax as soon as it is overdue, followed by a further 1% for every month it stays outstanding, up to an additional 12% on top of the tax itself. |
| Records | Accounting records, the tax computation and every supporting schedule behind it must be kept for five years and produced if IRAS asks to see them. |
Instalment plans are more generous the earlier ECI is filed, so filing promptly rather than at the three-month deadline is worth doing even when the figure is only an estimate. Corporate tax rebates vary by year of assessment and, when they apply, are applied by IRAS automatically — there is nothing separate to claim.
HOW WE HANDLE IT
Step by step, every period.
- 01
Year-end accounts close
The tax computation starts only once the financial year's accounts are closed and reconciled — every account coded correctly, fixed assets recorded, accruals and prepayments in place. This is the same closed set of accounts your management accounts and ACRA filing are built from, produced once and used everywhere.
- 02
Tax computation
The agent builds the tax computation from the closed accounts: add-backs for non-deductible expenses, capital allowances on qualifying assets, and the partial and, where the company qualifies, start-up exemption applied to the resulting chargeable income, with the schedules behind every figure kept alongside it.
- 03
Accountant review
Your accountant works through the computation, deciding what is genuinely deductible, confirming every capital allowance and relief the company is entitled to has actually been claimed, and checking the exemption applied is the correct one for the company's age and shareholding.
- 04
ECI filed
The Estimated Chargeable Income is filed within three months of the financial year end, or the waiver applied where revenue and a nil ECI both qualify, so any instalment plan starts as early as possible.
- 05
Form C-S / C filed
The annual return — Form C-S, Form C-S (Lite) or Form C, whichever fits the company — is filed by 30 November, a payment plan is arranged for anything due, and any IRAS query on the filing is handled by your accountant directly.
AGENTS + ACCOUNTANT
Who does what.
A tax computation is a large, mechanical exercise built from a fixed set of rules — add back this expense, claim capital allowances on that asset, apply the exemption tiers in the right order — which is exactly the kind of repeatable, rule-based work an AI agent does quickly and consistently. Deciding whether an expense is genuinely deductible, whether a company still qualifies for the start-up exemption, or how to respond to an IRAS query calls for judgement and accountability that only an experienced, named accountant can provide. Keeping that split means the computation is built efficiently and every figure in it has been reviewed by someone who will stand behind it.
- Prepare the tax computation from your year-end accounts
- Draft ECI and Form C-S / C schedules
- Track IRAS deadlines from your financial year end
- Reviews the computation, claims and reliefs
- Files with IRAS once you approve, and handles any queries
WHAT GOES WRONG WITHOUT IT
The expensive mistakes.
Missing ECI
A company that skips or forgets its ECI loses access to instalment payments and can find IRAS issuing an estimated assessment instead, based on figures the company had no say in — a harder outcome to unwind than simply filing on time.
Claiming non-deductible expenses
Private motor vehicle costs, fines and penalties, and spending that is not genuinely for the business are not deductible and have to be added back in the computation. Leaving them in understates chargeable income, and a computation built that way gets corrected — with penalties — if IRAS reviews it.
Not claiming capital allowances or the renovation deduction
Equipment, fixtures and fit-out costs can qualify for capital allowances or the renovation and refurbishment deduction, but only if someone identifies them and includes them in the computation. Left out, the company simply pays more tax than it needs to, year after year.
Filing the wrong form
Filing Form C when the company actually qualifies for Form C-S, or the reverse — claiming the simplified form's conditions when the company has group relief, a carry-back claim or a foreign tax credit that disqualifies it — creates a return that has to be corrected or is rejected outright.
Paying an estimated assessment
Once a return is late enough, IRAS assesses tax on its own estimate rather than the company's real figures — usually higher than the true liability — and that estimate stands, with the tax due against it, until the actual return is filed and processed.
WHAT YOU RECEIVE
Corporate tax filed correctly, with the reliefs you're entitled to.
- A tax computation with full supporting schedules for every add-back, allowance and exemption
- Estimated Chargeable Income filed within three months of your financial year end
- Form C-S, Form C-S (Lite) or Form C filed by 30 November
- Every exemption and relief you're entitled to identified and claimed
- An instalment plan arranged for tax that falls due
- IRAS correspondence and queries on your filing handled by your accountant
- Five years of working papers kept behind every computation filed
INCLUDED IN YOUR PACKAGE
Included from the Essentials package.
For smaller SMEs that need their books and filings handled properly. Every package is a fixed monthly fee with a named accountant on your file — see what each one includes and choose the right starting point.
Common questions.
Do I have to file ECI?
Yes, unless you qualify for the waiver: revenue of S$5 million or less and an Estimated Chargeable Income that comes to nil. Otherwise ECI is due within three months of your financial year end. Filing it, even as an estimate, is what lets IRAS set up an instalment plan for the tax that will eventually be assessed, so filing on time is worth doing even when the figure is not final.
What's the difference between Form C-S, C-S (Lite) and Form C?
Form C-S is the simplified return for companies with revenue of S$5 million or less that are taxed only at the 17% rate and are not claiming group relief, a carry-back or a foreign tax credit. Form C-S (Lite) simplifies it further for companies with revenue of S$200,000 or less. Form C is required for everyone else, filed with full financial statements and a detailed tax computation attached.
What can I deduct?
Expenses genuinely incurred in producing your income are generally deductible; private costs, fines and non-business spending are not, and have to be added back in the computation. Beyond ordinary deductions, capital allowances on qualifying assets and the renovation and refurbishment deduction on fit-out costs can reduce chargeable income further — both need to be identified and included, not assumed.
Does my new company qualify for the start-up exemption?
Only in its first three years of assessment, and only if it has no more than 20 shareholders, at least one individual shareholder holding at least 10% of the shares, and is not an investment holding company or one engaged in property development. If it qualifies, 75% of the first S$100,000 of chargeable income and 50% of the next S$100,000 are exempt.
When do I pay?
Tax follows from the annual return, due by 30 November, though ECI filed earlier can already have an instalment plan running against it. Paying late attracts a 5% penalty immediately, then a further 1% for every month the tax remains outstanding, up to an additional 12% — on top of the tax itself.
What if I've missed previous years?
We work through the outstanding years, rebuild the computations from your accounts, and file them to replace any estimated assessments IRAS has raised in the meantime. The sooner this happens the less the estimated figures and any composition fees compound, so it's worth starting even if several years have built up.
Do you handle IRAS queries and audits?
Yes. If IRAS queries a filing or selects the company for review, your accountant handles the correspondence directly, drawing on the working papers kept behind every computation — the add-backs, the capital allowances, the exemption applied — so the answer is backed by the same records the original filing was built on.
RELATED GUIDES
Read up before you decide.
Corporate tax guide
Singapore Corporate Tax Filing Guide for SMEs
Understand ECI, Form C-S, filing deadlines, tax adjustments and the records your company should prepare.
Corporate tax guide
ECI Filing in Singapore: SME Guide
When Estimated Chargeable Income is due, who qualifies for the waiver, and what records to prepare before the 3-month deadline.
Corporate tax comparison
Form C-S vs Form C-S (Lite) vs Form C
Use the eligibility checklist and comparison table to identify the corporate income tax return your Singapore company should prepare.
Corporate tax guide
Start-Up Tax Exemption vs Partial Tax Exemption in Singapore
Which corporate tax exemption applies to your company, what each is worth at the 17% rate, and how the enhanced YA 2026 CIT rebate stacks on top.
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