Tax Pooling Savings Calculator NZ
Enter your tax shortfall, original due date and a provider quote. The calculator compares that quote with IRD's published UOMI rates over the same days.
The amount that was not paid by the original due date.
Add any fixed setup, transfer or administration fee in the quote.
The 6.5% default is illustrative. Replace it with the annual rate in your current written quote.
Estimated saving
$48.9598 days compared
Estimated IRD UOMI
$722.52Published daily underpayment rates
Estimated pooling cost
$673.56Quoted rate plus entered fee
Estimate only. It compares UOMI with a simple annual provider rate and fixed fee. It does not include late-payment penalties, changing balances, provider-specific compounding, or confirm that IRD will accept the transfer for your tax type and timing.
What the comparison means
Tax pooling intermediaries hold tax payments in an account at Inland Revenue. When an eligible transfer is made to your account, IRD can treat it as paid on the date the pooled funds originally entered the account. That backdating is what can remove UOMI on a provisional-tax shortfall.
This calculator does not assume a market rate. Enter the annual rate and every fixed fee from your provider's current quote. IRD UOMI comes from the central published-rate table and is split automatically when the selected period crosses a rate change.
Start with the provisional tax calculator if you still need to work out the instalment, or the terminal tax calculator if you are estimating the final balance.
Check eligibility before relying on the saving
Common use
Buying backdated income tax to cover an eligible provisional-tax or terminal-tax shortfall. An approved intermediary must make the transfer and IRD's timing rules must be met.
Restricted uses
Regular GST is generally excluded. PAYE is limited to reassessment or adjustment situations. Other taxes, amended assessments and late transfers have specific windows.
Read IRD's rules for using tax-pooling funds, then confirm the exact tax type, date and amount with an IRD-registered intermediary or your tax adviser.
Frequently asked questions
How does tax pooling reduce use-of-money interest?
An IRD-registered tax pooling intermediary can transfer a payment held in its pool to your tax account with an effective date on or before the original due date. If the transfer qualifies and covers the shortfall, this can remove the corresponding backdated UOMI.
What rate does this calculator use for IRD UOMI?
It uses IRD's published daily rates for every day in the period, including changes within the selected dates. The current underpayment rate is 8.97% from 16 January 2026.
Can I use tax pooling for GST or PAYE?
Regular GST payments cannot generally be made using purchased tax-pooling funds. PAYE can only be covered in limited reassessment or adjustment circumstances. Confirm the tax type and transfer window with an IRD-registered intermediary.
Does the result guarantee the provider quote will be cheaper?
No. The estimate uses the annual rate and fixed fee you enter. Provider pricing, eligibility, compounding and transfer terms vary, so compare the result with a written current quote.
Does IRD charge UOMI on every shortfall?
IRD says debit interest applies where the outstanding tax balance, including penalties, is more than $100. Safe-harbour rules can also remove UOMI for some provisional taxpayers.
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