Hong Kong Tax Year and Filing Calendar: Basis Periods, Return Dates and Provisional Tax.

How the year of assessment works

The Hong Kong tax year runs from 1 April to 31 March, and the Inland Revenue Department (IRD) calls it the year of assessment. Each one takes its name from the two calendar years it spans, so the year that began on 1 April 2026 is 2026/27 and ends on 31 March 2027. For an employee, that is the whole story: salaries tax is assessed on the actual income of the year of assessment.

Businesses are where the tax period gets less intuitive. A company can close its books on any date it chooses, and its profits tax follows that accounting year. Hong Kong also has no withholding from pay, so the IRD assesses tax after a year ends and collects part of the next year's tax in advance as provisional tax. One year of assessment therefore produces returns, assessments and payments spread across roughly two calendar years.

This guide covers how basis periods map a company's accounting year onto the year of assessment, including the first and last years of a business, then sets out the IRD's filing and payment calendar month by month, with the current 2025/26 and 2026/27 dates.

Hong Kong tax year vs your accounting year: basis periods

The year of assessment is the label. The basis period is the stretch of time whose income or profits are actually taxed under that label.

For salaries tax and property tax the two are identical. The IRD states that the basis period is from 1 April each year to 31 March of the following year, whatever your circumstances.

Profits tax works differently. Under the IRD's rules on the basis period for profits tax, a business that makes up its accounts to 31 March is taxed on the year ended 31 March. A business with any other year-end is taxed on the accounting year that ends within the year of assessment, and accounts kept by lunar year use the lunar year ending in it.

The code in the last column matters later. It decides how much extra time a company with a tax representative gets to file, and the IRD groups profits tax returns by it.

A 31 March year-end keeps the books and the tax year aligned. Any other date is accepted; what changes is how old the profits are by the time the return is due, and which filing deadline applies.

Changing the year-end later is possible, but a change of accounting date brings in special basis period rules of its own. A tax advisor can model the effect before the new date is adopted.

The first and last years of a business

The Inland Revenue Ordinance prescribes special basis periods, in sections 18C to 18E, for a business that starts, stops or changes its accounting date. The IRD's own examples, written for sole proprietorships and partnerships and updated for the current cycle, show how the timing works.

The first year. A business that started on 1 October 2025 and closes its first accounts on 30 June 2026 has no accounts ending in the year to 31 March 2026, so the IRD says there are no assessable profits for 2025/26. If the first accounts had closed on or before 31 March 2026 and shown a profit, profits tax or provisional profits tax would be payable on it.

A new business also waits a while for paperwork. GovHK says a newly registered business generally receives its first profits tax return some 18 months after it starts trading or is incorporated. Until a return arrives, the duty runs the other way: anyone chargeable to tax has to tell the IRD in writing within four months after the end of the basis period, under section 51(2) of the Inland Revenue Ordinance. If you are setting up now, our guide to company registration in Hong Kong puts that first return on the same timeline as incorporation, business registration and the first audit.

The last year. In the IRD's cessation example, a business with accounts to 31 December 2024 that ceases on 28 February 2026 prepares cessation accounts from 1 January 2025 to 28 February 2026 and reports them in the 2025/26 return. That final basis period runs to 14 months. For unincorporated businesses, the IRD asks for written notice of the cessation within one month.

The Hong Kong tax calendar, month by month

The table follows the 2025/26 returns through 2026 and into the payments due in early 2027. The last column shows where each date comes from, because that decides whether it moves.

Which dates are fixed and which are printed on your return

Hong Kong tax dates fall into three groups, and only the first is truly fixed.

Set by law. The year of assessment always runs from 1 April to 31 March. The duty to notify chargeability within four months after the basis period ends also comes from the Inland Revenue Ordinance, which for salaries tax and property tax means 31 July.

Set by IRD practice. The bulk issue of profits tax returns takes place on the first working day of April each year, and the IRD normally issues the employer's return (BIR56A) on the same day, to be filed within one month. Individual returns follow in early May: on 2 May in 2025 and on 4 May in 2026.

Printed on the document. The filing deadline belongs to each return. GovHK says profits tax returns are generally due within one month of issue, and that the compliance date is specified on page 1 of the return. Payment dates work the same way: on a salaries tax demand note, the IRD prints the due dates in red on the first page, together with the deadline for a holdover application.

Electronic filing adds time, but not in the same way for everyone:

• Individuals (BIR60): filing electronically extends the deadline by one month automatically. For 2025/26, that moved 4 June to 4 July 2026, and 4 August to 4 September 2026 for sole proprietors.
• Companies filing voluntarily online: GovHK says the IRD grants a further one-month extension on application, if the profits tax return is then filed through the Business Tax Portal or Tax Representative Portal.
• Large multinational groups: the first phase of mandatory electronic filing started on 1 April 2026. Hong Kong entities of multinational groups within the global minimum tax regime have to file profits tax returns electronically from 2025/26, and those that had notified the IRD of their status before March 2026 receive the extra month automatically.

Block extensions for represented taxpayers

A company or individual with a tax representative files on a different timetable. Each year the Commissioner issues a circular to tax representatives setting out the block extension scheme; the 2025/26 circular was issued on 19 March 2026, and from April 2026 representatives have had to apply for block extensions electronically through the Tax Representative Portal. The scheme covers both profits tax returns and individual returns.

For 2025/26 profits tax returns, GovHK's profits tax page (last revised in July 2026) lists these extended due dates:

Going beyond these dates is hard. GovHK says a further extension is granted only in the most exceptional circumstances, on a written request that explains the delay and includes supporting evidence.

Because block extension dates are only available through a tax representative, they are one practical reason companies appoint one. GovHK says the IRD publishes the circular at the beginning of each year, so the dates for 2026/27 returns should appear in early 2027.

Assessments, provisional tax and payment dates

The IRD assesses tax once the year is over, which is why Hong Kong runs a provisional tax system. As its profits tax guidance puts it, the assessable profits for a year cannot be known until after the year ends, so a provisional charge is raised; when the final assessment is made, the provisional tax already paid is set against it.

Salaries tax. Most employees pay in two instalments. The split is long-standing: a 2013 Legislative Council reply on salaries tax payment arrangements explains that the first instalment is the balance of the previous year's final tax plus 75% of the provisional salaries tax for the current year, and the second instalment is the remaining 25%. The demand note shows the exact amount of each instalment, so that is the figure to rely on.

The IRD's holdover FAQ uses that timing, with a demand note issued on 5 August 2026, and notes that most taxpayers have their first instalment due in January 2027. For a first-time taxpayer, no provisional tax was paid for the year just assessed, so the "balance" in the first instalment is that year's entire tax, on top of most of the next year's provisional tax. That is why a first Hong Kong tax bill can look large.

Profits tax. There is no single payment month for companies. The notice of assessment follows the return, so payment dates vary from company to company, and the notice sets the due dates for any final tax and for provisional tax for the following year. Provisional profits tax can be payable in two instalments.

Paying less provisional tax. A holdover application can reduce provisional tax when income or profits for the year are likely to fall below 90% of the previous year's. For profits tax, the grounds for holding over provisional profits tax also include an objection to the previous year's assessment and a cessation of the business, and an application on the falling-profits ground needs signed draft accounts covering at least eight months. The deadline is 28 days before the payment date or 14 days after the notice was issued, whichever is later.

Missing a date. For individuals, a return filed late can lead to a penalty or prosecution, and to an estimated assessment that leaves out allowances and deductions. Tax paid late attracts a 5% surcharge, then a further 10% on any amount still unpaid six months after the due date.

Budget and Policy Address: when a year's rules change

Two announcements each year can change the tax for a year that has already started or just ended.

The Budget was delivered on 26 February 2025 and on 25 February 2026, and both proposed a one-off reduction for the year of assessment about to end: a 100% reduction capped at HK$1,500 per case for 2024/25, and a 100% reduction capped at HK$3,000 per case for 2025/26, across profits tax, salaries tax and tax under personal assessment.

The reduction is applied in the final assessment, so returns are filed as usual and nobody needs to apply. It does not reduce provisional tax. For 2025/26, the IRD's Budget tax measures page records that the legislation passed on 13 May 2026 and was gazetted on 22 May 2026, and that any final assessment issued before then is reassessed.

The Policy Address comes in the autumn. On 16 September 2026 the Chief Executive proposed higher child allowances for second and subsequent children born on or after that date, taking effect from 2026/27 once legislation passes. For a year of assessment that is already running, the allowances can still change before the return is filed.

Where an accountant or tax advisor fits into the calendar

Once the year-end is set, most of the calendar repeats itself. The dates that need judgement sit at the edges: the first return about 18 months after incorporation, a change of year-end, a cessation, and a provisional tax bill based on a better year than the current one.

For a corporation, the IRD expects audited financial statements with the profits tax return in nearly all cases, so the audit has to be finished before the filing date. For a December 2025 year-end with a tax representative, that meant signed accounts in time for 31 August 2026 on paper, or 2 October 2026 electronically. The audit firm a company picks, and how early it can start, sets the pace for the rest of the calendar, and our guide to choosing a certified public accountant in Hong Kong covers how to check one and what else a company files each year.

A single firm can carry the whole cycle: one of the accounting firms in Hong Kong can keep the books, coordinate the audit and act as tax representative, which brings the block extension dates into play. For computations, offshore profits claims or a holdover on falling profits, profits tax specialists can take the technical side. Individuals with several employers, overseas days or a provisional bill that no longer fits their income can find salaries tax help, and for objections or questions that cut across tax types, see the wider list of tax advisors in Hong Kong.

This guide is general information, not tax or legal advice. Dates and rules change each year; for a specific business or personal situation, speak with a qualified accountant or tax advisor.