GST Calculator
Enter an amount, pick a GST slab and choose whether the price includes the tax or not — you get the GST amount, the net base and the gross total, with the CGST and SGST halves.
Adding versus removing GST
Quoted prices come in two flavours. A tax-exclusive price is the taxable value — GST sits on top, so a ₹10,000 service at 18% invoices ₹11,800. A tax-inclusive price is what the customer actually pays; the tax is already inside it, so the taxable value is the amount divided by (1 + rate) — ₹11,800 inclusive at 18% means a taxable value of ₹10,000 and ₹1,800 of GST.
Dividing by (1 + rate) is the step people get wrong — subtracting 18% from 11,800 gives ₹9,676, which is not how inclusive pricing works. The calculator does the division whenever you pick the "remove" mode.
The CGST / SGST split
For sales within a state, GST splits evenly: half goes to the central government as CGST and half to the state as SGST. An 18% slab becomes 9% + 9% on the invoice. For inter-state sales the same total is charged as IGST instead — the total never changes, only the label on the line item.
The calculator always shows both halves, so you can copy either layout onto an invoice without re-deriving the numbers.
Common uses
Invoicing. Convert a base rate into a tax-inclusive final price, or back out the taxable value from an all-inclusive quote.
MARGIN checks. Merchants working backwards from an MRP can see exactly how much of the shelf price is tax.
Reconciliation. Verify that an invoice's tax line matches the slab rate the supplier claimed.
Frequently asked questions
Which GST slabs are supported?
The standard slabs — 0.25%, 3%, 5%, 12%, 18% and 28% — are preloaded. Compensation cess and special rates are not included; compute those separately.
How do I remove GST from a tax-inclusive price?
Enter the inclusive amount, pick the rate and switch the mode to "remove". The calculator divides by (1 + rate) rather than subtracting the percentage — that is the correct method.
Why is my CGST shown as half the GST?
For intra-state supplies the tax splits evenly between the centre (CGST) and the state (SGST). Inter-state supplies use IGST for the whole amount instead.
Is the taxable value the same as the net price?
Yes — net, taxable value and base price all refer to the amount before GST.
Does it handle reverse charge or composition scheme?
The arithmetic is the same; only who pays and at what rate differs. Enter the effective rate that applies to your case.
Can I share a specific calculation?
Yes — amount, rate and mode travel in the URL, so a shared link reopens the exact numbers.