Late GST Penalty Calculator NZ
Estimate Inland Revenue late payment penalties and use of money interest (UOMI) when GST tax is paid after the due date. Enter the unpaid GST amount, the due date, and the payment date to see the 1% initial penalty, the 4% further penalty, and daily UOMI.
This late GST penalty calculator follows IRD published late payment stages and the underpayment UOMI rate of 8.97% a year from 16 January 2026. Late filing of the return is a separate charge. Runs in your browser. No account. Not an IRD website and not tax advice.
Penalty calculation history and PDF
How the late GST penalty calculator works
A late GST return filing penalty calculator and a late GST payment penalty calculator answer different questions. Filing late can trigger a flat late filing fee. Paying the GST after the due date triggers late payment penalties and, separately, use of money interest.
This tool is a GST late filing penalty calculator companion for the payment side: unpaid tax, days late, the 1% and 4% late payment stages, and daily UOMI. It does not replace your myIR statement. IRD’s final figure is what you owe.
The official stages sit on Inland Revenue’s late payment penalties page. Interest rates sit on the UOMI page. For ordinary add or remove GST maths use the homepage GST calculator NZ.
GST late payment penalty: the 1% and 4% stages
IRD says late payment penalties start from the day after the payment due date. For most unpaid GST they are given in two stages that matter for this calculator:
| Stage | When | What IRD charges |
|---|---|---|
| Initial 1% | Day after the payment due date | 1% of the unpaid tax |
| Further 4% | 7th day after the payment due date | 4% of the remaining tax including the 1% penalty already added |
| Monthly 1% | Each month unpaid (some taxes only) | Not charged on GST for return periods ending 31 March 2017 onwards |
That last point matters for a GST late return filing penalty calculator user who also left the tax unpaid. IRD’s guide IR240 confirms the monthly 1% late payment penalty stopped for GST periods ending 31 March 2017 onwards. The initial 1% and further 4% still apply. Confirm the period on your statement.
GST late filing penalty versus late payment penalty
People searching for a gst late filing penalty calculator or a gst penalty for late filing calculator often mix up two IRD charges.
Late filing. If you do not file the GST return on time, IRD may charge a late filing penalty. For GST the amount depends on your accounting basis when the return is due: $50 on the payments basis, and $250 on the invoice or hybrid basis. Details: IRD late filing penalties. IR240 notes you will not get a GST late filing penalty if you filed all GST returns on time for the last 12 months; IRD sends a warning letter instead, and may charge if another return is late within 12 months.
Late payment. If the tax stays unpaid after the due date, the 1% and 4% late payment stages can apply, plus UOMI. File even if you cannot pay. That is IRD’s own advice in IR240. Filing on time avoids the separate late filing fee and shows good faith. Steps for lodging a return: how to file your GST return in myIR. If the return itself was wrong, see how to correct GST return errors.
Use of money interest (UOMI) on unpaid GST
UOMI is separate from the flat late payment penalties. IRD calculates interest daily on overpaid or underpaid tax. It does not compound, and it is not included when IRD calculates the penalty percentages.
From 16 January 2026 the underpayment rate is 8.97% a year and the overpayment rate IRD pays is 2.25% a year. Earlier rates (including 10.91% from 29 August 2023) no longer apply for periods after the change date. Check the table on IRD’s interest on overpayments and underpayments page.
Interest: outstanding balance × daily rate × days overdue
Example: unpaid GST = $10,000.00
One day of underpayment interest ≈ $10,000 × (0.0897 ÷ 365) = about $2.46 per day
IRD charges debit interest on outstanding tax (including penalties) of more than $100. Interest you pay on underpayments is deductible for business purposes. Interest IRD pays you on an overpayment is gross income. This page’s older “interest is not deductible” claim was wrong against current IRD guidance.
Worked example: 10 days late on $12,000
Suppose GST of $12,000 is due and you pay 10 days after the due date. The estimate below uses IRD’s stages and the 8.97% underpayment rate. Your statement may differ after grace periods, remissions, or part payments.
| Item | Working | Amount |
|---|---|---|
| Unpaid tax | Core GST | $12,000.00 |
| Initial 1% | $12,000 × 0.01 | $120.00 |
| Further 4% | ($12,000 + $120) × 0.04 | $484.80 |
| UOMI (illustrative) | Daily interest on tax and penalties across the overdue days | See calculator for your dates |
Paying before day 7 avoids the 4% stage. Paying on day 1 still attracts the 1% if no grace period applies. Save the run in history and export a PDF working paper for your agent. If provisional tax is also late, use the provisional tax calculator for instalment planning, then return here for the GST payment estimate.
Late payment grace period
If it is your first late payment in a 2 year period, IRD may give you a grace period before charging late payment penalties. IRD will tell you if you have a grace period and your new due date. If you do not pay by that new date, IRD charges the penalty from the original due date.
IR240 says the grace period is automatic when you qualify: you have paid all your taxes on time for the last two years, and IRD sends a letter. A grace period suspends penalty charges, but IRD still charges interest. Do not wait for the letter to clear the principal if you can pay.
Instalment arrangements and waiving penalties
If you cannot pay in full, contact IRD early. An instalment arrangement in myIR can stop further late payment penalties from the day it is set up, as long as you keep to it. IRD still charges interest. If you set up the plan on or after the due date, the 1% and 4% stages can still apply. See IR240 and IRD’s instalment guidance.
You can ask IRD to waive a late filing, non electronic filing, or late payment penalty. IRD’s waiving payment penalties page says they may waive for reasonable cause beyond your control, a genuine mistake, a one off situation, or wrong advice from IRD that led to the late action. Finances alone are not a reason to waive. Remission of interest is rare.
Pay the principal when you can, file the return, then send a secure message in myIR if you are asking for a waiver. Keep records for seven years. Broader compliance traps: 10 common GST mistakes in NZ. If IRD reviews your file, start with the IRD audit preparation checklist and GST audits and disputes.
Mistakes that grow a GST debt
1. Not filing because you cannot pay
That can add a late filing penalty on top of late payment charges. File the return, then talk to IRD about payment.
2. Waiting past day 7
The 4% stage applies on the 7th day after the due date on remaining tax including the 1%. Paying earlier can avoid that jump.
3. Using an old UOMI rate
10.91% was the underpayment rate from 29 August 2023. From 16 January 2026 the underpayment rate is 8.97%. Always check IRD’s current table.
4. Ignoring myIR notices
IRD can escalate collection. An instalment arrangement or early contact is cheaper than silence.
Other New Zealand tax calculators on this site
Work out the GST figure before you model penalties with the GST calculator NZ. Build taxable supply information with the GST invoice generator. Border GST uses the GST on imports calculator. Payroll and contractors: PAYE calculator, withholding tax calculator, and FBT calculator. Due date context: GST tax due date calendar 2025/2026. Accounting basis affects late filing amounts: invoice basis vs payments basis.
Late GST penalty calculator: common questions
Answers checked against IRD guidance current at 24 August 2026.
It estimates late payment penalties (1% then 4%) and daily use of money interest on unpaid GST tax between the due date and the payment date. It does not calculate the separate GST late filing fee ($50 or $250 by accounting basis).
From 16 January 2026 the underpayment rate is 8.97% a year. The overpayment rate IRD pays is 2.25%. Confirm on IRD’s UOMI page before you rely on a figure.
No for GST return periods ending 31 March 2017 onwards. IRD still charges the initial 1% and the further 4%. Monthly 1% late payment penalties continue on some other unpaid taxes.
$50 if you are on the payments basis when the return is due, and $250 if you are on the invoice or hybrid basis. That is separate from late payment penalties and UOMI.
If you have paid all taxes on time for the last two years, IRD may give an automatic late payment grace period and will tell you the new due date. Interest can still run. If you miss the new date, penalties are charged from the original due date.
Yes, for late filing, non electronic filing, or late payment in limited cases such as reasonable cause beyond your control, a genuine mistake, or wrong IRD advice. Financial hardship alone is not a waiver reason. Interest remission is rare. Use myIR secure message after you file and pay what you can.
IRD calculates interest daily. Interest does not compound and is not included when calculating the 1% and 4% penalties. Debit interest can apply to outstanding tax including penalties once those penalties are on the account (generally when the balance is more than $100).
IRD says interest you pay on underpayments of tax is deductible for business purposes. Interest IRD pays you on an overpayment is gross income.
Request an instalment arrangement in myIR or contact IRD. Keeping to the arrangement can stop further late payment penalties from the day it starts. Interest usually continues.
Yes. No account. History and PDF export run in your browser. The site may show advertising. We do not upload your unpaid tax amounts for the calculation itself.
What this page is checked against
Last full check: 24 August 2026. GSTCalc.nz is a New Zealand publisher of free tax calculators. We are not Inland Revenue. Ads may fund the site. This is not tax advice.
Arithmetic
1% on unpaid tax after the due date; 4% on remaining tax including the 1% from the 7th day after; UOMI at 8.97% ÷ 365 per day. Final liability follows myIR.
What we are: A free late GST penalty and UOMI estimate tool for New Zealand.
What we are not: A filing service, a waiver decision, or a substitute for IRD’s statement. Complex debt needs a registered tax agent. New operators: new business GST compliance roadmap. Wider system: ultimate guide to GST in New Zealand.
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