GST Calculator
Add GST to a price or extract GST from a GST-inclusive amount.
Base Amount
₹1,000
GST (18%)
₹180
Total
₹1,180
CGST ₹90 + SGST ₹90
About the GST Calculator
Add GST to a base price or pull it back out of a tax-inclusive bill — both directions, instantly. This free GST calculator runs entirely in your browser, so your pricing and invoice figures never leave your device. Shop owners use it to build quotations with clean pre-tax amounts, freelancers check what slice of a client payment is actually tax, and buyers see how much GST hides inside an MRP before comparing prices. Pick one of the standard slabs or type a custom rate, enter the amount, and read the base, tax and total together.
How the two directions work
Every GST question runs one of two ways. Adding tax to an exclusive price is plain multiplication: GST = base × rate ÷ 100. An 18% slab on ₹10,000 adds ₹1,800 and bills ₹11,800. Extracting tax from an inclusive figure is where most mistakes happen, because the tax already sits inside the number — you divide rather than subtract. The base equals the amount ÷ (1 + rate ÷ 100), and GST is simply whatever remains. Subtracting 18% directly from an ₹11,800 bill gives ₹9,676, which is wrong by more than ₹300; the true taxable value is ₹10,000. The percentage must apply to the smaller pre-tax figure, never the larger total. For invoicing, the tool also shows the intra-state breakup. A sale within one state splits GST evenly into CGST and SGST — two halves printed as separate lines on the invoice — while a sale across state lines carries the whole amount as IGST instead. The buyer pays identical tax either way; only the paperwork changes.
Picking the right slab
Indian GST runs from nil up to 28%. Fresh produce and unbranded staples sit at zero; rough precious stones carry 0.25%; gold jewellery sits at 3%; most goods and services fall under 5%, 12% or 18%; and luxury items top out at 28%. The four buttons cover the everyday slabs, and the rate box beside them accepts anything — type 3 for gold, 0.25 for rough gems, or a combined effective percentage if your item also attracts cess. One caution bears repeating: classifications move through Council notifications, and near-identical products can land in different slabs depending on brand status, composition or intended use. Check your product's HSN code (goods) or SAC code (services) against the current CBIC schedule rather than copying whatever the shop next door charges.
Pricing mistakes this avoids
The classic shopkeeper error is quoting a tax-inclusive number as if it were exclusive. If your margin works at ₹10,000 net and you say "ten thousand plus GST" when you meant ten thousand including GST, an 18% invoice quietly hands roughly ₹1,525 of your own margin to the department. The mirror trap catches buyers comparing quotes: ₹11,800 charged at 18% and ₹11,800 charged at 12% are not the same offer until the tax is stripped out of both. Discounts deserve care too — apply them to the base price before adding GST, not to the taxed total, otherwise the discount itself distorts the tax arithmetic on your invoice. And remember that MRP labels on packaged goods are printed inclusive of GST, so extracting rather than adding is usually the right move at a shop counter. This page is general education, not tax advice; filings and input credits need your chartered accountant.
Real numbers, start to finish
A design studio in Pune bills a client ₹40,000 for services before tax, charged at the standard 18% slab. In Add GST mode the tool multiplies once and shows the invoice should read ₹47,200, splitting the tax into equal CGST and SGST halves since both parties are in the same state. The next day the studio receives a software subscription bill of ₹11,800 that already includes 18% GST. Switching to Remove GST mode divides instead of subtracting and recovers the real figures underneath.
| Scenario | Base | GST @ 18% | Total |
|---|---|---|---|
| Invoice raised (add): ₹40,000 exclusive | ₹40,000 | ₹7,200 | ₹47,200 |
| Bill received (remove): extract from ₹11,800 | ₹10,000 | ₹1,800 | ₹11,800 |
Both directions at 18% GST
On its own invoice the studio collects ₹7,200 of tax to remit — ₹3,600 CGST plus ₹3,600 SGST. On the incoming bill, only ₹10,000 of the ₹11,800 is genuine cost; the remaining ₹1,800 is tax it can claim back as input credit if registered under GST. Reading both directions correctly stops the studio padding quotations by accident and overstating expenses by exactly the tax inside them.
Video slot: gst-calculator-walkthrough.mp4
Switching between Add and Remove modes while typing a ₹10,000 amount, showing the base, GST and total cards update live along with the CGST/SGST split as each slab button is pressed.
Coming soonHow to Use GST Calculator Online
Follow these simple steps to use GST Calculator securely in your web browser.
- 1
Select Add or Remove GST
Choose Add GST for pre-tax base prices or Remove GST to extract taxable value from a total bill.
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- 2
Enter Amount & Rate
Type the amount and select 5%, 12%, 18%, 28% or enter a custom rate.
02-gst-calculator-enter-amount-rate.png
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- 3
Click to Calculate Split
Click calculate to view base amount, total GST, final amount, and 50/50 CGST and SGST equal split.
03-gst-calculator-click-to-calculate-split.png
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Features & Specifications
Formulas
Exclusive: Base * (r/100) | Inclusive: Total / (1 + r/100)
Currency
Indian Rupee (INR ₹)
Tax Breakup
Equal 50/50 CGST + SGST Calculation
Privacy Status
100% In-Browser Local Processing
100% Free & Private In-Browser Processing
Rupix operates on a zero-upload architecture. All computations, file parsing, and transformations occur locally inside your web browser. No document bytes, sensitive text, or personal data are ever uploaded or transmitted to remote servers.
Why use Rupix GST Calculator?
Inclusive & Exclusive Modes
Adds GST to pre-tax prices or reverses GST from total billed amounts without rounding errors.
CGST and SGST Split
Displays equal 50/50 intra-state tax breakup ready for invoice generation.
Standard Indian Slabs
Preset 5%, 12%, 18%, and 28% buttons plus custom percentage input.