Final amount
₹11,800
Price plus GST at 18%.
GST Calculator
Add GST to a price or remove GST from a GST-inclusive price, and see the original amount, GST amount, and final amount instantly.
Under 15 seconds
Updated 22 Aug 2026
12,450people used this
Results dashboard
GST amount
₹1,800
Tax at 18% on the original amount.
Original amount
₹10,000
Taxable value before GST.
Total payable
₹11,800
GST is 15.25% of this GST-inclusive value.
A GST calculator calculates the GST amount and the final price from the amount you enter and the applicable GST rate. Use add mode when your price excludes tax, and remove mode to strip GST out of a GST-inclusive price and recover the taxable value.
Visual breakdown
A visual view of your calculation.
Interactive charts arrive here soon.
Invoice split
Values a GST invoice would show. On an intra-state supply the GST is split equally into CGST and SGST; on an inter-state supply the same total is charged as IGST.
| Line item | Amount |
|---|---|
| Taxable value | ₹10,000 |
| GST at 18% | ₹1,800 |
| CGST (intra-state, half) | ₹900 |
| SGST (intra-state, half) | ₹900 |
| IGST (inter-state, full 18%) | ₹1,800 |
| Invoice total | ₹11,800 |
Smart Insights
Generated from the numbers you entered — no guesswork.
- Adding 18% GST to ₹10,000 makes the invoice ₹11,800.
- GST works out to 15.25% of the GST-inclusive amount and 18% of the taxable value.
- For an intra-state supply, show CGST ₹900 and SGST ₹900 separately on the invoice.
- The rate that actually applies depends on how your goods or services are classified under HSN/SAC and on the rules in force, so confirm the slab before invoicing.
How does the GST Calculator work?
Each step the calculator runs, in plain language.
- 1
What GST is
GST is an indirect tax charged on the supply of goods and services in India. The seller collects it on top of the taxable value and pays it to the government, so it is a pass-through cost rather than part of business income.
- 2
Adding GST
When your price excludes tax, multiply it by the rate to get the GST amount and add the two together. This is the normal direction for quotations and B2B invoices.
- 3
Removing GST (reverse GST)
When a price already includes GST, divide it by (1 + rate ÷ 100) to recover the taxable value. The difference between the two is the GST already embedded in the price.
- 4
CGST, SGST, and IGST
For a supply within one state, the total splits equally into CGST and SGST. For a supply across states or an import, the same total is charged as a single IGST amount.
GST Calculator formula
The exact maths behind every number on this page.
Add GST: GST = A × r ÷ 100 • Final = A + GST | Remove GST: Original = A ÷ (1 + r ÷ 100) • GST = A − Original
- A
- Amount you enter — excluding GST when adding, including GST when removing
- r
- GST rate in percent (0, 5, 12, 18, 28, or a custom rate)
- Original
- Taxable value before GST
- Final
- GST-inclusive amount payable
Reverse calculation never uses A × r ÷ 100 — dividing by (1 + r ÷ 100) is what recovers the taxable value from a GST-inclusive price.
GST Calculator calculation example
A service priced at ₹10,000 before tax, at an 18% GST rate.
- 1Original amount (A)₹10,000
- 2GST at 18%10,000 × 18 ÷ 100 = ₹1,800
- 3Final amount10,000 + 1,800 = ₹11,800
- 4Reverse check11,800 ÷ 1.18 = ₹10,000
- 5Intra-state splitCGST ₹900 + SGST ₹900
The buyer pays ₹11,800, of which ₹1,800 is GST. Switching to 'Remove GST' and entering ₹11,800 at 18% returns the same ₹10,000 taxable value.
Important assumptions
What this calculation includes, and what it leaves out.
- A single GST rate applies to the whole amount you enter. Mixed-rate invoices must be calculated line by line.
- Compensation cess, TCS, TDS under GST, discounts, and rounding rules for invoices are not applied.
- The CGST and SGST split assumes an intra-state supply; an inter-state supply carries the same total as IGST.
- Which slab applies to a product or service depends on its HSN or SAC classification and the notifications in force — confirm the rate before invoicing.
Sources we follow for figures that change
- CBIC GST portal — official notifications, rate schedules, and circulars
- GST Council — rate decisions and press releases after each Council meeting
Benefits
Why people use this calculator before signing a loan.
Correct invoices
Get the taxable value, GST, and total that a compliant invoice needs, with the CGST/SGST split ready.
Works both ways
Add tax to a quotation, or strip tax out of an inclusive retail price using the same calculator.
Any rate, including custom
Standard 0%, 5%, 12%, 18%, and 28% slabs plus a custom rate between 0.1% and 100% for special cases.
What it does not decide
It cannot tell you which slab applies to your product, whether you must register, or how much input tax credit you can claim — those depend on classification and current rules.
Financial tips
Practical guidance to act on your result.
- Always show the taxable value and GST separately — a GST-inclusive lump sum makes input tax credit harder to claim.
- For MRP-based pricing, use 'Remove GST' so your margin is calculated on the taxable value, not the inclusive price.
- Confirm the HSN or SAC code for what you sell; the rate follows the classification, not the invoice format.
- Reconcile the input tax credit you claim with what your suppliers actually filed before each return.
Frequently asked questions
Short, direct answers to the questions we hear most.
Read the thinking behind it
Guides that explain how to use this calculation in a real decision.
Taxes • 5 min read
GST on an invoice: inclusive, exclusive and reverse working
Adding tax to a price and extracting it from a total are different sums. Here is how to get both right.
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Disclaimer
CalPaisa calculators are for general information and planning only. Results are estimates based on the values you enter and standard formulas, and may differ from the figures your bank, employer, or tax authority applies. Nothing here is investment, tax, or legal advice. Please confirm important decisions with a qualified professional. Read our financial disclaimer, learn how CalPaisa works, or tell us about a calculation you think is wrong.