Free New Zealand calculator

GST Return Calculator NZ: Estimate GST Payable or Refundable

Use already-classified, eligible sales and purchase totals for one NZ GST filing period to estimate the net GST position. This is a worksheet, not a filing service.

Calculation sources checked 11 October 2026 · NZD · Estimates only

How does it work?

Estimated net GST equals output GST on standard-rated sales minus eligible input GST on purchases, plus debit GST adjustments minus credit GST adjustments. Accounting basis and claim eligibility determine which transactions belong in the period.

Enter your details

GST accounting basis (controls what you include)

Eligible standard-rated sales total (NZ$)

Sales totals are

Eligible claimable purchases total (NZ$)

Purchase totals are

Additional debit GST adjustments (GST dollars)

Additional credit GST adjustments (GST dollars)

Your estimate

Estimated net GST for the period—

GST on standard-rated sales—

Eligible input GST on purchases—

Additional debit GST adjustments—

Additional credit GST adjustments—

Enter valid figures for an indicative result.

Method and worked New Zealand example

For GST-inclusive eligible amounts, the GST component is total × 3/23. For GST-exclusive amounts, GST is amount × 15%. Then subtract eligible input GST from sales GST, add debit GST adjustments and subtract credit GST adjustments.

Example: $11,500 GST-inclusive standard-rated sales contain $1,500 output GST; $4,600 GST-inclusive fully claimable purchases contain $600 GST; the estimate is $900 payable, before adjustments.

Accounting basis must be applied before you enter aggregated amounts. Under payments basis include amounts received/paid during the period. Under invoice basis, different timing may apply for invoiced sales and purchases; hybrid has its own rules. This tool cannot verify your transactions or record dates.

Assumptions and important limitations

For GST-registered users with correctly classified transactions only. Excludes zero-rated and exempt transaction classification, mixed private/business use adjustments, import GST, bad debts, special supplies, partial payment timing and all other unmodelled return boxes. Check source records and file in myIR; this result is not a submitted or complete GST return.

Official sources (checked 11 October 2026): IRD calculating GST; IRD claiming GST; IRD filing GST.

Frequently asked questions

Can I file my GST return here?

No. Only a planning estimate is produced. Use myIR or supported accounting software to file.

Can I claim GST on every purchase?

No. Claim eligibility depends on taxable activity and proper records; private/exempt purchases are not generally fully claimable.

Why select GST inclusive or exclusive?

The tax component is 3/23 of a GST-inclusive total versus 15% of a GST-exclusive amount.