GST Calculator

Add GST to a base amount or remove GST from a GST-inclusive price.

How this calculator works

This GST calculator supports two use cases: adding GST to a base amount, or removing GST from a GST-inclusive price to find the original base amount and tax portion.

Formula used

Add GST:
GST Amount = Base × (GST% / 100)
Final Price = Base + GST Amount

Remove GST (when the price already includes GST):
Base = Final / (1 + GST% / 100)
GST Amount = Final − Base

Example calculation

If base is 1000 and GST is 18%, then GST amount is 180 and final price is 1180.

FAQs

  • What does “Remove GST” mean? It treats your input as a GST-inclusive amount and calculates the base and GST split.
  • Can GST be 0%? Yes. In that case GST amount is 0 and base equals final.
  • Does it handle multiple GST slabs? This is a single-rate calculator; enter the GST percentage you need.