GST Calculator

About this calculator

This calculator adds or removes Goods and Services Tax from an amount: adding it multiplies the base price by (1 + GST rate), while removing it divides a GST-inclusive price by (1 + GST rate) to recover the pre-tax amount — the same reverse-tax logic used in countries like Australia, New Zealand, India, Canada, and Singapore, each with their own standard GST rate.

Business owners use it to price products correctly and issue GST-compliant invoices, accountants use it to reconcile GST-inclusive receipts back to net sales figures for tax filings, and shoppers use it to check exactly how much tax is baked into a listed price. The calculator handles both directions in one place, since "add GST" and "remove GST" are two different formulas that are easy to mix up.