Skip to content
Entrovix AI

GST Calculator

Adds GST to a price or extracts it from a GST-inclusive one, splitting the result into CGST and SGST or showing it as IGST.

Runs in your browser — nothing is uploaded

Invoice lines

Add every line at its own slab — the totals and the rate-wise summary follow.

₹
₹

Invoice total

₹1,28,500

₹1,10,000 taxable + ₹18,500 GST

Taxable value
₹1,10,000
CGST (central)
₹9,250
SGST (state)
₹9,250
Invoice total
₹1,28,500

Intra-state: two tax lines, half each

Both parties are in the same state, so each slab splits down the middle — an 18% item shows 9% CGST and 9% SGST as separate lines. One combined "18% GST" line is not a valid tax invoice.
ItemQtySlabTaxableCGST + SGSTTotal
Website design118%₹1,00,000₹9,000 + ₹9,000₹1,18,000
Printed brochures25%₹10,000₹250 + ₹250₹10,500
Need this as an API?
Why use it

Built to be genuinely useful

Both directions

Add tax to a base price, or work backwards from an inclusive total — which is the harder one, and the one people get wrong.

Splits the components

Within a state the tax divides equally into CGST and SGST; across states it is a single IGST. Invoices must show the split, so the calculator does.

Nothing is uploaded

The arithmetic runs in your browser. Salary, marks and tax figures are nobody else's business, and none of it is sent anywhere.

Free, no sign-up

No account, no limit on how many times you run it, and no result held back.

How it works

Three steps

  1. 1

    Enter the amount and choose whether it already includes GST.

  2. 2

    Pick the rate.

  3. 3

    Read the tax, the split and the total.

Working backwards from an inclusive price

Removing GST from an inclusive figure is not the same as taking the percentage off it. At 18%, the tax inside a ₹1,180 total is not ₹212.40 (18% of 1,180) but ₹180 — because the tax was calculated on the base of ₹1,000, not on the total.

The formula is total × rate ÷ (100 + rate). Taking the percentage off the inclusive figure instead overstates the tax by roughly the rate squared, which at 18% is a consistent error of about 3%. On a reconciliation across a quarter that is not a rounding difference.

CGST, SGST and IGST

The split follows the place of supply. A sale within a state divides the tax equally between the centre and the state — 18% becomes 9% CGST and 9% SGST. A sale across state lines is a single 18% IGST, which the centre later apportions.

The total the customer pays is identical either way, so this looks like paperwork, and it is — but it is paperwork that matters. Charging CGST and SGST on an interstate supply, or IGST on a local one, is a filing error that has to be corrected rather than absorbed.

FAQ

Questions people ask

API access

Need GST Calculation in Your App?

Add GST calculation to your website, application or back-office workflow through API access.

Tell us what you are building, how you plan to use it and the volume you expect. We will come back to you with availability, integration details and a quote for your usage.

Related tools

More india tools

Available tools are linked; the rest are in development.

Income Tax CalculatorSalary CalculatorHRA CalculatorEMI CalculatorSIP CalculatorAI WriterAI SummarizerAI ParaphraserAI HumanizerAI Grammar CheckerAI RewriterAI Translator
All India Tools

Need a tool like this for your business?

We build internal tools, dashboards and automation that fit how your team works.

See Our Services