Simple GST Calculator
A fast GST calculator for one-off add or remove tax checks. No account, no history, just the amount, rate, and answer.
Price already includes GST? Remove GST with the Reverse GST Calculator
Calculating for Singapore? Use the Singapore GST calculator (9% + service charge)
In New Zealand? Use the NZ GST calculator (15%, IRD ×3÷23 method)
In Australia? Use the Australian GST calculator (10%, ÷11 method)
GST Calculator Workflow
Input Figure
Input the gross or net value from your invoice into the primary field.
Configure Parameters
Select a region-specific rate and toggle the calculation direction.
Export Breakdown
Verify the results and one-click copy data directly into your accounting software.
Simple GST Calculator for Quick Checks
This page is the quick entry point for GST math. Enter an amount, choose a rate, switch between adding GST and removing GST, and get the answer immediately. If you need saved calculation history or repeated invoice checks, use the professional GST calculator instead.
GST Basics: What Is It?
Goods and Services Tax (GST) is a value-added tax on most goods and services sold for domestic consumption. The concept is straightforward, but calculating it manually leads to errors when switching between inclusive and exclusive prices. A reliable GST calculator keeps your figures correct from day one.
Output Tax and Input Tax for Business
As a business owner you act as a tax collector: you charge GST on sales (Output Tax) and claim back GST on business expenses (Input Tax). The difference is what you pay to or receive from the tax office. Using a calculator ensures these numbers are right and prevents headaches at tax time.
Common GST Calculation Mistakes
The most common error is using the wrong direction. If you start with a net/base price and need to add tax, use the GST Exclusive Calculator — built for B2B quotes, purchase orders, and ex-GST invoicing. If you start with a final price that already includes GST and need to split out the tax, use the GST Inclusive Calculator for receipts and expense claims, or the Reverse GST Calculator when working backwards from a quoted total.
Compliance and Record-Keeping
Many regions require GST registration only after turnover exceeds a limit (e.g. NZ $60,000). Different countries have different rules for what is exempt or zero-rated—always check your local guide. Keep valid tax invoices for every GST claim; for repeat checks and multi-line invoices, use the GST Calculator with Audit History to keep a local trail of how each amount was derived.
Global GST & VAT Rates 2026
| Country | Standard Rate | Tax Type |
|---|---|---|
| New Zealand | 15% | GST |
| Australia | 10% | GST |
| United Kingdom | 20% | VAT |
| Singapore | 9% | GST |
| India (Avg) | 18% | GST |
| Malaysia | 0% | GST |
GST Compliance FAQ
Q1.How does a GST calculator help with business transactions?
A GST calculator helps businesses act as tax collectors. By using a calculator, you can accurately charge GST on sales and claim 'input tax credits' for business expenses.
Q2.Why does the calculation direction matter?
Choosing the wrong mode can lead to a 10-20% difference in your final revenue, depending on rate and amount. This tool ensures profit margins are protected by accurately switching between Inclusive and Exclusive prices.
Q3.Is this tool compatible with global tax systems?
Yes. Whether it's GST, VAT, or Consumption Tax, the mathematical logic remains the same. You can input any percentage rate for your specific region.
Q4.How do I calculate 'Zero-Rating'?
Simply set the rate to 0% for zero-rated goods. This allows businesses to still claim back GST credits while charging no tax to the buyer.
Q5.What are common global tax rates?
Tax rates vary: New Zealand (15%), Australia (10%), UK (20%), and Singapore (9%). Always enter the latest rate for accurate compliance.
Q6.Can this handle exempt vs zero-rated supplies?
While exempt supplies have no GST, zero-rated supplies have 0% GST. This tool helps you distinguish between them to ensure tax-efficient accounting.
Q7.How to use for partial payments?
Simply enter the partial payment amount to determine the immediate tax liability for that specific transaction period.
Q8.How does this protect my financial privacy?
This tool uses a local-only execution model. No data is stored on servers, making it safe for corporate environments.
Recommended Tools
Choose the calculator that matches your calculation direction, workflow, or tax task.
GST Exclusive Calculator
Use the GST Exclusive Calculator to add GST to a net base price for B2B quotes, purchase orders, and invoices. Specialized for ex-GST workflows, not receipts.
GST Inclusive Calculator
Extract the net amount from GST-included receipts, MRP shelf prices, and expense-claim totals. Built for B2C tax-inclusive splits, not B2B ex-GST quotes.
Reverse GST Calculator
Work out GST backwards or remove GST from a total price — free reverse GST calculator covering NZ 15%, AU 10%, UK 20%, India 18%. Avoids subtract-15% errors.
GST Calculator with Audit History
GST calculator with audit history, local storage, and multi-line breakdowns for repeat invoice checks and audit-friendly business workflows. For accountants.
Canada GST/HST Calculator (All 13 Provinces)
Calculate Canadian sales tax for all 13 provinces: GST 5%, HST 13-15%, PST and Quebec QST. Add, remove or reverse tax instantly with official CRA rates.
Quebec GST/QST Reverse Calculator
Reverse or add Quebec sales tax instantly: GST 5% + QST 9.975% calculated in parallel per Revenu Québec rules. Split any total into base, GST and QST.
Singapore GST Calculator (9%)
Add or remove Singapore's 9% GST instantly, with an optional 10% service charge for restaurant bills. Official IRAS rates, history table and bill-split tips.
GST Calculator NZ — Add or Remove 15% GST
Add 15% GST to a price or pull the GST out of a GST-inclusive total with Inland Revenue's ×3÷23 method. Free NZ GST calculator with formulas and examples.
GST Calculator Australia — Add or Remove 10% GST
Add 10% GST to a price or pull the GST out of a GST-inclusive total with the official ÷11 method. Free Australian GST calculator with formulas and examples.