GST Calculator

Add GST to a base price or remove GST from a total. Supports all Indian GST slabs — 0%, 5%, 12%, 18%, and 28% — with CGST/SGST breakdown. Runs entirely in your browser.

Which calculation do you need?

Add GST when you have a base price. Exclude GST when you have a total and need to find what's inside it.

Add GST

You have a base price (excl. tax). Get the GST amount and the final total.

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Exclude GST

You have a GST-inclusive total. Find the base price and how much of it is tax.

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How to calculate GST

Two steps — pick the direction, enter the amount, done.

01
Choose Add GST or Exclude GST
Add GST: you have a base price and want the GST-inclusive total. Exclude GST: you have a total price and want to find the base amount before tax.
02
Enter the amount and select the GST slab
Type the price and pick the applicable rate — 0%, 5%, 12%, 18%, or 28%. The CGST, SGST, total GST, and final amount appear instantly.

Frequently asked questions

Free, no account needed.

All five standard Indian GST slabs: 0%, 5%, 12%, 18%, and 28%.

For intra-state transactions, GST is split equally between CGST (Central GST) and SGST (State GST). So 18% GST = 9% CGST + 9% SGST. For inter-state transactions, IGST applies at the full rate instead.

Total = base price × (1 + GST rate / 100). A ₹1,000 item at 18% GST: ₹1,000 × 1.18 = ₹1,180.

Base = total / (1 + GST rate / 100). A ₹1,180 total at 18% GST: ₹1,180 / 1.18 = ₹1,000.

Nothing is sent anywhere. Runs in your browser.

Yes, on any modern phone or tablet browser.

Need a full GST invoice?

The Invoice Generator lets you add your business name, client details, line items, and GST — then download a clean PDF. No signup, no watermark.

Open Invoice Generator →

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How to calculate GST

Two steps — pick the direction, enter the amount, done.

Choose Add GST or Exclude GST

Add GST: you have a base price and want the GST-inclusive total. Exclude GST: you have a total price and want to find the base amount before tax.

Enter the amount and select the GST slab

Type the price and pick the applicable rate — 0%, 5%, 12%, 18%, or 28%. The CGST, SGST, total GST, and final amount appear instantly.