GST and VAT arithmetic for invoices
This calculator helps with the everyday tax math behind quotes, invoices, receipts, and pricing pages. It can add tax to a net amount, extract tax from a tax-inclusive gross amount, or compare two rates before you send a quote.
The presets include Australia GST, Canada GST/HST, UK VAT, and a manual US sales tax option. You can also override the rate directly for any market.
How to use it
- Enter the amount.
- Choose a GST, HST, VAT, or sales tax preset.
- Pick add, extract, or compare mode.
- Copy the invoice line into the document or email you are preparing.
Important limits
This page calculates the arithmetic for a rate you choose. It does not decide tax registration, exemption, reverse-charge, place-of-supply, or product-specific tax treatment.