New Zealand GST removal separates the GST included in a GST-inclusive price by dividing the gross total by 1 plus the GST rate as a decimal. The output gives the price excluding GST and the GST amount inside the final total. The calculation depends on the current GST rate, taxable supply status, invoice wording, rounding, mixed items, zero-rated supplies, discounts, and whether the displayed price includes GST.
Formula:
GST-exclusive price = GST-inclusive price / 1.15
Then:
GST included = GST-inclusive price - GST-exclusive price
What Does Removing New Zealand GST Mean?
Removing New Zealand GST means working backward from a price that already includes GST. It separates:
| Output | Meaning |
|---|---|
| GST-exclusive price | Price before GST |
| GST included | GST inside the total |
| GST-inclusive price | Final price including GST |
This helps with receipts, invoices, refunds, pricing, and bookkeeping.
New Zealand GST Formula
The New Zealand GST reverse formula answers the query "how do I remove 15% GST from a GST-inclusive price?" Divide by 1.15 to get the GST-exclusive price, then subtract that result from the total to get GST included. Do not take 15% off the final price because GST is 15% of the net price, not 15% of the gross price.
New Zealand Inland Revenue states that GST is 15 percent. For a GST-inclusive price:
GST-exclusive price = Total / 1.15
GST included = Total - GST-exclusive price
The general formula is:
Pre-tax amount = Total / (1 + rate / 100)
At 15 percent:
1 + 15 / 100 = 1.15
3/23 GST Shortcut
The 3/23 shortcut answers the query "what fraction of a New Zealand GST-inclusive price is GST?" At a 15% GST rate, the GST portion of a GST-inclusive price is 3/23 of the total. Use this shortcut when you need only the GST amount. If you also need the GST-exclusive price, subtract that GST amount from the total.
At 15 percent GST, GST included in a GST-inclusive price is 3/23 of the total.
Why:
15 / 115 = 3 / 23
Example:
115.00 x 3 / 23 = 15.00
Then:
115.00 - 15.00 = 100.00
The 3/23 shortcut is useful when you only need the GST portion.
Step-by-Step Calculation
A step-by-step workflow prevents the two most common mistakes: removing GST from a price that does not include GST, and using the wrong country formula. Confirm the amount is New Zealand GST-inclusive, divide by 1.15, subtract to find GST, and check the result forward. This sequence is safer than memorizing only the shortcut.
Use the steps in order when the source document is a receipt, quote, refund, or invoice. The first step protects taxability and price-label intent. The middle steps calculate GST-exclusive amount and GST included. The final check proves that the result can rebuild the original total. If any step fails, stop and inspect the source lines before using the number.
Step 1: Confirm the Price Includes GST
Confirm that the price is New Zealand GST-inclusive before dividing by 1.15. If the amount is GST-exclusive, add GST forward instead. If the amount is zero-rated or exempt, there is no 15 percent GST portion to remove for reverse calculation.
Only reverse GST from a GST-inclusive price. Look for labels such as GST inclusive, incl. GST, a New Zealand tax invoice, or a GST amount shown separately. If the document is GST-exclusive, zero-rated, exempt, or unclear, do not silently remove GST. The formula is only as reliable as the price label.
Only reverse GST from a GST-inclusive price.
Step 2: Divide by 1.15
Divide the GST-inclusive amount by 1.15 to recover the GST-exclusive value. The result is the price before New Zealand GST. Use it as the net amount for the taxable line, then calculate the GST portion by subtracting it from the original gross amount.
Divide the GST-inclusive amount by 1.15 because the final price equals 115% of the GST-exclusive price. Keep extra decimals in the working calculation and round only the final display amount. This protects small receipts and invoices from avoidable one-cent differences.
230.00 / 1.15 = 200.00
Step 3: Subtract to Find GST
Subtract the GST-exclusive amount from the GST-inclusive total to find GST included. As a check, add the GST-exclusive amount and GST amount back together. If the result does not match the original price, review rounding or whether the price really included GST.
Subtract the GST-exclusive amount from the GST-inclusive total to find the GST included. This is clearer than "taking off 15%" because it respects the relationship between gross, net, and GST. If the invoice already shows GST separately, this subtraction is also a useful verification check.
230.00 - 200.00 = 30.00
Step 4: Check Forward
Check forward by multiplying the GST-exclusive amount by 15% and adding it back to the net amount. The forward check catches decimal mistakes, wrong-rate mistakes, and accidental use of the Australian 10% GST formula. If the forward result does not return to the original total, review rounding and source labels.
200.00 x 15 percent = 30.00
200.00 + 30.00 = 230.00
Worked Example: 115.00 GST-Inclusive
| Component | Amount |
|---|---|
| GST-inclusive price | 115.00 |
| Divide by | 1.15 |
| GST-exclusive price | 100.00 |
| GST included | 15.00 |
Worked Example: 575.00 GST-Inclusive
This example answers a common larger-total query. The same 1.15 formula works for receipts, quotes, and invoices when the full amount is taxable and GST-inclusive. If the total combines taxable and zero-rated lines, separate those lines first because the 575.00 total may not be one clean GST-inclusive base.
575.00 / 1.15 = 500.00
575.00 - 500.00 = 75.00
The GST-exclusive price is 500.00 and GST is 75.00.
Small Price and Rounding Example
Small prices are where rounding questions usually appear. A GST-inclusive price like 19.99 does not divide into a neat two-decimal net amount. The right workflow is to calculate with precision, round the displayed GST-exclusive amount to cents, then derive the displayed GST amount from the rounded values or compare with the invoice method.
Suppose the GST-inclusive price is 19.99.
19.99 / 1.15 = 17.3826...
Rounded GST-exclusive price:
17.38
GST included:
19.99 - 17.38 = 2.61
Rounding by line or invoice can shift one cent.
GST-Inclusive vs GST-Exclusive
| Price type | Meaning | Calculation |
|---|---|---|
| GST-inclusive | GST is inside price | Divide by 1.15 |
| GST-exclusive | GST not included yet | Multiply by 1.15 |
| Zero-rated | GST rate is 0 percent | Do not remove 15 percent |
| Exempt | GST not charged | Do not remove GST |
Receipt and Tax Invoice Clues
Look for:
| Clue | Action |
|---|---|
| GST inclusive | Divide by 1.15 |
| GST shown separately | Verify by subtraction |
| Tax invoice | Check GST amount |
| Zero-rated supply | Use 0 percent |
| Mixed items | Separate first |
| Refund | Use original sale evidence |
Reverse GST with Mixed Items
Suppose a receipt total is 172.50:
| Line | Amount |
|---|---|
| Taxable item including GST | 115.00 |
| Zero-rated item | 57.50 |
| Total | 172.50 |
Reverse only the taxable item:
115.00 / 1.15 = 100.00
115.00 - 100.00 = 15.00
The zero-rated item remains 57.50.
Refund Example
A refund should use original sale evidence. This example assumes the refund is GST-inclusive and reverses a taxable supply. If the refund is a goodwill credit, shipping-only credit, zero-rated item refund, or marketplace adjustment, separate the refund reason before removing GST. The refund amount is not automatically the GST base.
Suppose a GST-inclusive refund is 46.00.
46.00 / 1.15 = 40.00
46.00 - 40.00 = 6.00
The refund reverses 40.00 of GST-exclusive value and 6.00 of GST.
Invoice Example
Suppose a New Zealand tax invoice shows a GST-inclusive total of 1,150.00.
GST-exclusive amount:
1,150.00 / 1.15 = 1,000.00
GST:
1,150.00 - 1,000.00 = 150.00
| Invoice field | Amount |
|---|---|
| GST-inclusive total | 1,150.00 |
| GST-exclusive amount | 1,000.00 |
| GST included | 150.00 |
If the invoice already shows GST separately, use the reverse calculation to check it.
Price Tag Example
A price tag example helps users who only know the displayed customer price. If the listed price includes New Zealand GST, divide by 1.15 to find the GST-exclusive price and subtract to find GST. This calculation explains price composition. It does not prove GST registration, invoice validity, or whether the supply should legally have GST.
Suppose a listed price is 34.50 and includes New Zealand GST.
34.50 / 1.15 = 30.00
34.50 - 30.00 = 4.50
The GST-exclusive price is 30.00 and GST is 4.50.
Service Invoice Example
A service invoice uses the same arithmetic when the service is taxable and the total includes New Zealand GST. If the invoice already shows GST separately, use the reverse formula as a check. If the service is zero-rated, exempt, outside scope, or not clearly GST-inclusive, do not apply the 1.15 divisor without source confirmation.
Suppose a service invoice shows a GST-inclusive total of 920.00.
920.00 / 1.15 = 800.00
920.00 - 800.00 = 120.00
The GST-exclusive service fee is 800.00 and GST is 120.00.
Discount Example
A discount example answers whether GST should be removed before or after discount. If the discount reduced the taxable selling price before GST was finalized, reverse GST from the final discounted GST-inclusive price. If the discount is a later credit, reimbursement, or settlement adjustment, inspect the invoice sequence before calculating.
Suppose a product is discounted and the final GST-inclusive price is 92.00.
92.00 / 1.15 = 80.00
92.00 - 80.00 = 12.00
Reverse GST returns the GST-exclusive discounted price, not the original price before discount.
New Zealand GST Quick Table
| GST-inclusive price | GST-exclusive price | GST included |
|---|---|---|
| 11.50 | 10.00 | 1.50 |
| 34.50 | 30.00 | 4.50 |
| 115.00 | 100.00 | 15.00 |
| 230.00 | 200.00 | 30.00 |
| 1,150.00 | 1,000.00 | 150.00 |
Rounding New Zealand GST
New Zealand GST calculations can produce fractional cents because dividing by 1.15 often creates repeating decimals. Keep precision in spreadsheets and round only display values. If your result differs from a tax invoice by one cent, check whether the seller rounded by item, by line, by invoice total, or from a GST amount calculated with the 3/23 shortcut.
GST calculations may not divide evenly into cents.
Example:
19.99 / 1.15 = 17.3826...
Rounded GST-exclusive price is 17.38 and GST is 2.61. If an invoice totals GST by line, a one-cent difference can appear.
New Zealand GST Rate vs GST Share of Total
The GST rate is 15 percent of the GST-exclusive price, but GST is 3/23 of the GST-inclusive total.
| GST-inclusive price | GST share using 3/23 | GST-exclusive price |
|---|---|---|
| 23.00 | 3.00 | 20.00 |
| 115.00 | 15.00 | 100.00 |
| 575.00 | 75.00 | 500.00 |
This is why taking 15 percent off the final price gives the wrong GST amount.
Mini Audit Before Removing GST
Ask:
- Is the price GST-inclusive?
- Is the supply taxable at 15 percent?
- Are zero-rated or exempt lines mixed into the total?
If the receipt mixes different GST treatments, split it before calculating.
For business records, keep the tax invoice or receipt that shows whether the amount was GST-inclusive. The calculation is only as reliable as that source document and its line details.
Decision Matrix
| Situation | Best action |
|---|---|
| Price includes New Zealand GST | Divide by 1.15 |
| Need GST portion only | Use 3/23 shortcut |
| GST shown separately | Verify by subtraction |
| Mixed taxable and zero-rated items | Separate first |
| Zero-rated sale | Use 0 percent |
| Refund | Use original sale evidence |
| Rounding mismatch | Check line rounding |
Operational Checklist
Before removing New Zealand GST, check:
| Check | Why it matters |
|---|---|
| Price includes GST | Confirms reverse calculation is needed |
| 15 percent rate applies | Prevents using another country’s GST |
| Supply is taxable | Zero-rated and exempt supplies differ |
| Mixed lines are separated | Prevents over-removing GST |
| Invoice or receipt is available | Confirms GST treatment |
| Rounding is expected | Explains one-cent differences |
What New Zealand Reverse GST Can and Cannot Prove
| Can prove | Cannot prove |
|---|---|
| GST-exclusive price from a GST-inclusive total | Whether the supply is legally taxable |
| GST amount using 15 percent | Whether the seller applied GST correctly |
| 3/23 GST amount | Whether documentation is sufficient |
| Refund GST split | Whether tax reporting is correct |
Common Mistakes
Common mistakes usually come from confusing rate, share, country, and taxability. New Zealand GST is 15% of the GST-exclusive price, but the GST portion inside a GST-inclusive total is 3/23. The formula should not be used on zero-rated or exempt amounts, and it should not be applied to mixed receipts without separating taxable lines first.
The safest correction is to ask what the number represents before calculating. Is it GST-inclusive, GST-exclusive, zero-rated, exempt, a refund, a discount, or a mixed receipt total? Once the entity is clear, the formula becomes simple. Most wrong answers come from applying the right formula to the wrong entity.
Taking 15 Percent Off the Total
Taking 15% off the GST-inclusive total overstates the GST amount. For 115.00, 15% of the total is 17.25, but the actual GST included is 15.00. Use 3/23 to find the GST portion directly, or divide by 1.15 to find the GST-exclusive amount first.
GST included in 115.00 is 15.00, not 17.25.
Using Australian GST Formula
The Australian GST formula uses 10% and a one-eleventh shortcut. New Zealand GST uses 15% and a 3/23 shortcut. Using the wrong country formula will produce a believable but incorrect net price and GST amount. Confirm jurisdiction before calculating, especially when working with invoices from multiple countries.
Australia uses 10 percent GST. New Zealand GST is 15 percent.
Removing GST from Zero-Rated Items
Zero-rated items do not contain 15% GST to remove, even though they may still be relevant for GST reporting. From a reverse calculation view, the GST amount inside a zero-rated item is zero. If a receipt mixes taxable and zero-rated lines, reverse only the taxable GST-inclusive lines.
Zero-rated items do not contain 15 percent GST.
Ignoring Mixed Receipts
Mixed receipts can contain taxable items, zero-rated items, exempt items, shipping, refunds, or discounts. Reversing the full total by 1.15 can remove GST from amounts that never included GST. Treat each line as an entity with amount, GST treatment, and evidence before calculating the net price.
Separate taxable and zero-rated amounts before reversing.
Confusing 3/23 with the Net Price
The 3/23 shortcut gives the GST amount, not the GST-exclusive price. If the total is 115.00, 3/23 gives 15.00 GST, and the net price is 100.00 after subtraction. In spreadsheets, keep separate columns for GST amount and GST-exclusive value so the shortcut is not used in the wrong field.
3/23 gives the GST amount, not the GST-exclusive price.
Entity Map for New Zealand GST Reverse Calculation
| Entity | Role |
|---|---|
| GST-inclusive price | Starting price |
| GST-exclusive price | Price before GST |
| GST amount | 3/23 of GST-inclusive total |
| Taxable supply | Includes GST |
| Zero-rated supply | 0 percent GST |
| Tax invoice | Evidence of GST treatment |
What This Page Does Not Cover
| Topic | Better page |
|---|---|
| Australian GST | How to Remove Australian GST from a Price |
| General VAT | How to Reverse VAT from a Total |
| GST and QST | How to Reverse GST and QST in Québec |
| Rounding | How to Round Reverse Tax Calculations |
Frequently Asked Questions
How do I remove New Zealand GST from a price?
Divide the GST-inclusive price by 1.15 to find the GST-exclusive price, then subtract that result from the total to find GST included. This works when the amount is taxable and GST-inclusive. If the receipt mixes zero-rated or exempt items, separate those lines before applying the formula.
Divide the GST-inclusive price by 1.15, then subtract the result from the total.
What is GST in 115.00?
If 115.00 includes New Zealand GST at 15 percent, the GST-exclusive price is 100.00 and GST is 15.00.
What fraction of a GST-inclusive price is GST in New Zealand?
GST is 3/23 of a GST-inclusive price when New Zealand GST is 15%. This shortcut gives the GST amount inside the gross total. It does not directly give the GST-exclusive price, so subtract the GST amount from the total if you need the net price.
GST is 3/23 of the GST-inclusive price when the rate is 15 percent.
Can I use 10 percent for New Zealand GST?
No. New Zealand GST is 15%, so the reverse divisor is 1.15 and the GST shortcut is 3/23. The 10% and one-eleventh shortcut belongs to Australian GST. Using 10% on a New Zealand GST-inclusive price will overstate the GST-exclusive price and understate the GST amount.
No. New Zealand GST is 15 percent.
Why does my GST result differ by one cent?
Your result can differ by one cent because the invoice may round by line, by item, by GST component, or by total. Spreadsheet formulas may keep more precision than the receipt display. Check the invoice rounding method before assuming the GST rate is wrong, especially on small totals or mixed-line receipts.
Line rounding or invoice rounding can create small differences.
Sources
These sources support the rate and official GST context, while the formulas on this page come from the arithmetic relationship between GST-exclusive price, GST rate, and GST-inclusive total. Use Inland Revenue for compliance-sensitive questions such as registration, taxable supplies, zero-rated supplies, invoicing, and return treatment. Use this page for reverse calculation and receipt interpretation only.