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GST Calculator

Calculate GST (Goods and Services Tax) with Toolspy's professional calculator. Support for inclusive and exclusive GST calculations with multiple tax rates.

GST Calculator
Enter amount and select GST rate to calculate tax
GST Rates
0% (Exempt)
5%
12%
18%
Selected
28%
Quick Tips
Most common GST rates are 5%, 12%, 18%, and 28%
Use inclusive mode when GST is already included in the price
All calculations are done locally for privacy

GST Calculator (India)

Add GST to a base price (exclusive) or extract GST from a total (inclusive). Supports common India GST rates (0%, 5%, 12%, 18%, 28%). Useful for invoices, quotes, and quick checks.

This GST calculator helps you quickly split an amount into base + tax, or add tax on top of a base amount. Pick the correct mode, choose the GST rate, and you’ll get the numbers you can copy into an invoice or quote.

Need to reverse a total that already includes GST? Try the reverse GST calculator.

GST calculator — inclusive and exclusive modes with GST rate selection
Getting started

How to calculate GST

Pick the mode, rate, then enter your amount.

1. Choose inclusive/exclusive

Exclusive adds GST on top. Inclusive extracts GST from the total.

2. Select GST rate

Common slabs: 0%, 5%, 12%, 18%, 28%.

3. Enter amount

Copy the base, GST amount, and total into your invoice or quote.

Modes

Inclusive vs exclusive GST

GST exclusive (add GST)

You have a base price and want the total after GST. The tool calculates tax and grand total.

GST inclusive (remove GST)

You have a total that already includes GST and want the base amount and tax component.

Math

GST formulas

How the base and tax are computed.

If the base amount is \(B\) and GST rate is \(r\) (for example 18% = 0.18):

Tax = B × r, Total = B × (1 + r)

If the total amount \(T\) already includes GST:

Base = T / (1 + r), Tax = T − Base

Heads up

Common pitfalls

Confusing inclusive vs exclusive

If your price already includes GST, use inclusive mode. If GST needs to be added on top, use exclusive mode.

Wrong GST rate

Rates depend on product/service classification. Use the applicable rate for your invoice or quote.

Rounding expectations

Invoices may round paise differently depending on accounting settings. Treat this as a calculator for planning and quick checks.

Place of supply rules

Whether CGST/SGST or IGST applies depends on intra-state vs inter-state supply. Use the splitter tool when you need that breakdown.

Overview

What this tool supports

Feature checklist
A factual summary of what the GST calculator does.
FeatureSupportedNotes
Inclusive and exclusive modes
Yes
Add GST or extract it from a total.
Common India GST rates
Yes
Includes 0%, 5%, 12%, 18%, 28%.
Instant calculation
Yes
Results update from your inputs.
Signup required
No
No account needed.

Frequently Asked Questions

What is the difference between GST inclusive and exclusive?
Which GST rates does the calculator support?
Is this calculation suitable for official filing?
Does the tool store my invoice amounts?
Community

User reviews

No reviews yet. If you used the tool, you can share feedback on our feedback page.

Ready to calculate GST?

Pick inclusive or exclusive mode and get the base + tax split instantly.