Late-payment interest on Vietnamese taxes: how it accrues and how to plan tax payments around cash flow

In Vietnam, tax that is paid after its deadline attracts late-payment interest, calculated per day on the amount paid late, from the day after the deadline until the day before the tax is paid. The rate has long been 0.03% per day; check the rate in force before calculating. The payment deadline is generally the same as the filing deadline under the Law on Tax Administration (Law 38/2019/QH14), so a return filed on time but paid a week late still costs interest. Late-payment interest is separate from administrative penalties, which depend on the breach and are set in the penalty regulations.

For most foreign-invested companies late-payment interest is not about inability to pay. It comes from timing and process: a payment made to the wrong code, an amended return that reaches back to an earlier deadline, a provisional CIT shortfall discovered at finalisation, or a payment scheduled for the deadline day that the bank processes the next morning. This guide covers where interest comes from and how treasury and tax teams can plan so that it does not arise.

How the interest is calculated

The mechanics are simple, which is why the cost is easy to underestimate:

• Base: the amount of tax paid late, not the whole return.
• Period: from the day after the payment deadline to the day before payment, counted in calendar days, including weekends and holidays.
• Rate: 0.03% per day under the rules that have applied for years; confirm the current rate.

Hypothetical example. Suppose a company pays VND 800 million of VAT 20 days late. At 0.03% per day, interest is 800,000,000 × 0.03% × 20 = VND 4.8 million. Over a year of repeated small delays across several taxes, this adds up. And in the ordinary course late-payment interest is not a deductible expense for CIT, so its real cost is higher than the amount paid.

Five ways interest arises without anyone deciding to pay late

1. Paying on the deadline day through a slow channel. The tax is treated as paid when the payment is recorded, and a transfer initiated late on the last day may not be. Pay a few working days early.
2. Wrong payment details. Each payment carries the tax type and related codes. A payment made to the wrong code sits against the wrong obligation while the right one shows as unpaid. Fixing it takes a request to the tax office, and interest may run meanwhile.
3. Amended returns. When a company corrects an earlier return and the correction increases tax, the additional tax is late from the original deadline, not from the date of the amendment. Interest on a correction for a period two years ago can be significant.
4. Provisional CIT shortfall. If quarterly provisional payments fall short of the final liability by more than the permitted margin, interest runs on the shortfall from a provisional-payment date, not from 31 March. Check the margin and the start date in the current rules.
5. Audit findings. Additional tax assessed after a tax audit or inspection carries interest from the original deadline, which is why unresolved positions from earlier years become more expensive every month.

Putting tax into the treasury forecast

Tax payments are among the most predictable outflows a company has, yet they are often missing from the cash forecast until the week they fall due. A workable approach:

Where the Vietnamese company depends on funding from the parent, the lead time matters: capital or loan drawdowns need registration and bank processing, and foreign exchange conversion takes time. A tax payment that depends on money arriving from abroad the day before the deadline is a late payment waiting to happen.

A monthly payment routine that prevents most interest

1. Day 1 to 5: update the tax lines in the cash forecast from invoices issued and received and from payroll.
2. Day 10 to 12: prepare returns; the preparer calculates the amount payable for each obligation.
3. Day 13 to 15: reviewer checks the return and the payment details — tax type and codes — against last month's accepted payment for the same obligation.
4. Day 15 to 17: treasury releases payment, leaving working days before the 20th for bank processing.
5. By the 20th: return submitted; confirmation that the e-tax account shows the payment against the right obligation.
6. Last week of the month: reconcile the e-tax account with the ledger for all obligations and raise any difference with the tax office.

Quarterly filers run the same routine in the first month of each quarter. The point is not the exact days but the order: calculate, check the payment details, pay early, confirm in the tax account, reconcile.

Amending returns without making it worse

Voluntary correction is the right thing to do when a company finds an error, and it is treated more favourably than an error found by the tax authority. But the interest clock started at the original deadline, so the sooner the correction and the payment, the lower the cost.

• Correct and pay together. File the supplementary return and pay the additional tax, with the interest calculated on it, at the same time.
• Do not wait for year end to correct monthly VAT errors found in March. Each month of waiting adds interest.
• Keep the working showing how the error was found and calculated. It helps if the tax office asks, and it helps the next accountant avoid the same error.

Where the correction reduces tax, the company has overpaid; see below.

Overpayments, offsets and refunds

Companies also end up with money on the wrong side: tax paid twice, paid to the wrong code, or overpaid after a correction. An overpayment does not automatically cancel an underpayment of a different tax. Depending on the case and the current rules, the company can ask for the overpaid amount to be offset against other obligations or refunded. Until that happens, the underpaid item can still accrue interest.

The fix is routine reconciliation: once a month, compare what the company believes it has paid with what the e-tax account shows as paid and as outstanding, obligation by obligation. Resolve differences with the managing tax office promptly. A small unresolved difference that sits for a year is how companies discover, during a tax audit, that interest has been accruing on something they thought was paid.

Extensions: what exists and what does not

There are two kinds of relief from payment deadlines, and neither is automatic.

• Case-by-case extension under the Law on Tax Administration, for specific situations such as serious losses from force majeure. It requires an application with evidence and a decision from the tax authority.
• Policy extensions issued by the government in some years for certain taxes and certain groups of taxpayers, to support businesses in difficult periods. Whether one applies to a given period, which taxes it covers and what must be filed to use it all depend on the specific decree for that period.

We do not list current policy extensions here because they change from year to year. Check with your adviser whether one is in force for the period you are paying, and whether your company must submit a request to benefit. An extension that required a request is not available to a company that simply paid late.

Where to check what you owe

• Your company's e-tax account — payments recorded, obligations outstanding and interest the system has calculated. Check it monthly, not only at year end.
• The mobile tax app — a read-only view useful for finance directors and legal representatives who need to see the position quickly.
• Your bank's payment confirmations — matched to the e-tax account, not only to the ledger.
• Your managing tax office — to correct misallocated payments or request offsets. Since 1 July 2025 the tax administration has three tiers: the central Tax Department, provincial and city tax offices and grassroots tax offices.

Unpaid tax that remains overdue can move into enforcement, and the Law on Tax Administration attaches consequences to the company and, in some situations, to its legal representative. Keeping the account reconciled monthly is the simplest way to make sure that never begins by accident.