Entrovix AI

GST Calculator & Invoice Builder

Build a whole invoice rather than converting one number — several lines, each on its own slab, split correctly into CGST and SGST or IGST, with a rate-wise summary in the shape GSTR-1 wants.

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
Why use it

Built to be genuinely useful

Multi-line invoices

A 5% item and an 18% service on the same invoice, totalled properly. Real invoices are not one amount at one rate.

Correct tax split

CGST + SGST within a state, IGST across one. Getting it wrong blocks the buyer's input credit.

Rate-wise summary

Grouped by slab, the shape a GSTR-1 return is filed in, downloadable as CSV.

Both directions

Add GST or extract it from an inclusive figure — the usual source of invoice errors.

How it works

Three steps

  1. 1

    Add a line for each item or service, with its own amount, quantity and slab.

  2. 2

    Say whether the supply is inter-state and whether your amounts already include GST.

  3. 3

    Read the totals, the tax split and the rate-wise summary.

Real invoices are not one amount at one rate

A design retainer at 18% and printed brochures at 5% go on the same invoice, and somebody has to total them and split the tax correctly. Every GST calculator online takes a single amount and a single rate, which means that person is doing it by hand in a spreadsheet.

This one takes as many lines as you need, each with its own slab and quantity, and produces both the invoice totals and the rate-wise breakdown — the grouping GSTR-1 asks for, which is otherwise a separate manual step at filing time.

Inclusive or exclusive — get this right

Adding 18% to ₹1,000 gives ₹1,180. But extracting 18% GST from ₹1,180 does not mean subtracting 18% of ₹1,180 — that gives ₹967.60, which is wrong. You divide by 1.18 to get back to ₹1,000.

This asymmetry is behind a large share of invoice mistakes. The calculator asks which case you are in rather than guessing, and applies it consistently across every line.

CGST, SGST and IGST — and why the split matters

For supply within a state, GST splits evenly into CGST (central) and SGST (state): 18% becomes 9% plus 9%, shown as two separate lines. For supply between states, the whole amount is a single IGST line instead.

The total tax is identical either way, so it is tempting to treat the split as bookkeeping. It is not. An invoice carrying the wrong split — or a single combined 'GST' line — is not a valid tax invoice, and the buyer's input credit claim fails on it. That is the consequence people are actually trying to avoid, and it is why the toggle is the first control on the page.

FAQ

Questions people ask

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