GST Calculator
Calculate GST inclusive and exclusive amounts for India.
Input & results
Input values
Results
Enter values to see instant results.
Calculation History
- Your calculations will appear here.
Recent calculations are saved automatically as you adjust inputs.
For informational purposes only. Consult a CA for official tax filing. Tax data version: FY 2025-26. See our full disclaimer.
What is GST?
GST (Goods and Services Tax) is India's unified indirect tax on supply of goods and services. Businesses and consumers often need to add GST to a base price or extract GST from an inclusive invoice total. This GST Calculator supports standard slabs (0%, 5%, 12%, 18%, 28%) and custom decimal rates for accurate tax breakdowns.
GST (Goods and Services Tax) is India's unified indirect tax on the supply of goods and services. You often need to add GST to a base price or extract it from a tax-inclusive total. This calculator supports the standard slabs (0%, 5%, 12%, 18%, 28%) and custom rates, splitting any amount into base, GST, and total.
Why is it used?
Businesses, freelancers, and consumers all deal with GST. Calculating it accurately ensures correct invoicing, helps verify the tax on bills, and clarifies the pre-tax value hidden in inclusive amounts.
Who should use it?
Freelancers and small businesses preparing quotes, accountants checking line items, and consumers verifying GST on bills.
How it works
- Choose Add GST (tax-exclusive amount) or Remove GST (tax-inclusive total).
- Enter the amount and select a GST rate or type a custom percentage.
- The calculator splits the amount into base, GST component, and total.
- Use Remove GST mode to find the pre-tax value on restaurant bills or invoices.
Formula
Variable definitions
| Variable | Meaning |
|---|---|
| Amount | Base (tax-exclusive) amount |
| Rate | GST rate in percent |
| Total | Tax-inclusive amount |
| Base | Pre-tax value extracted from an inclusive total |
How the formula works
- Choose Add GST (exclusive amount) or Remove GST (inclusive total).
- For Add: GST = Amount × Rate ÷ 100; Total = Amount + GST.
- For Remove: Base = Total ÷ (1 + Rate/100); GST = Total − Base.
- Review the base, GST component, and total.
Example calculation
Add 18% GST to ₹1,000.
| Input | Value |
|---|---|
| Amount | ₹1,000 |
| Rate | 18% |
| Mode | Add GST |
- GST = 1000 × 18 ÷ 100 = ₹180
- Total = 1000 + 180 = ₹1,180
Result
More examples
Remove 18% GST from an inclusive ₹1,180.
| Input | Value |
|---|---|
| Total | ₹1,180 |
| Rate | 18% |
| Mode | Remove |
- Base = 1180 ÷ 1.18 = ₹1,000
- GST = ₹180
Result
Methodology
- Gather Base Amount, Calculation Type, GST Rate, Custom GST Rate (%) from your documents or estimates.
- Enter each value in the matching field; units must match the labels.
- The calculator applies the GST formula and updates results in real time.
- Compare scenarios by changing one input at a time.
Benefits
- Instant GST split for invoices and quotations.
- Works for both exclusive and inclusive pricing modes.
- Custom rate field supports non-standard GST percentages.
- No sign-up — runs privately in your browser.
Use cases
- Freelancers and small businesses preparing GST-inclusive quotes.
- Consumers verifying GST on restaurant or retail bills.
- Accountants quickly checking tax components on line items.
Tips & important notes
- Confirm whether your invoice amount is GST-inclusive or exclusive before choosing the mode.
- IGST applies on inter-state supply; CGST+SGST on intra-state — the math is the same, only labels differ.
- Rounded totals on bills may differ by ₹1 from theoretical calculation.
Common mistakes
- Confusing tax-inclusive and tax-exclusive amounts before choosing a mode.
- Applying the wrong slab rate to a product or service.
- Expecting bill totals to match exactly when rounding is applied.
Related concepts
- CGST, SGST, and IGST components
- Input tax credit
- Inclusive vs exclusive pricing
Good to know