What is a GST Calculator (India)?
Indian GST works both directions: quoting a price before tax (add GST) and figuring out the tax hidden inside an inclusive price (remove GST) — the second one is where the mental math goes wrong, because you divide by 1.18, not subtract 18%.
Pick the slab, choose the direction, and read base, tax, total and the CGST/SGST split.
For businesses, the direction of the calculation decides compliance: quotes and invoices to consumers must show GST-inclusive prices under Indian rules, while B2B invoices itemize base and tax so buyers can claim input credit. Getting the reverse calculation wrong (subtracting 18% instead of dividing by 1.18) understates the base and overstates the tax on every line.
How to use the GST Calculator (India)
- Enter the amount.
- Pick the GST rate and whether the amount includes tax.
- Read base, GST and total.
Frequently asked questions
What is input tax credit?
Registered businesses offset GST paid on purchases against GST collected on sales, remitting only the difference — the mechanism that makes GST a value-added tax rather than a cascading one.
When do I need GST registration?
Broadly: turnover above Rs 40L for goods (Rs 20L for services, lower in special-category states), or any interstate B2B supply. Thresholds change — confirm current rules with a CA.
How do I remove GST from an inclusive price?
Divide by (1 + rate/100): ₹1,180 inclusive at 18% → 1180 ÷ 1.18 = ₹1,000 base, ₹180 GST. Subtracting 18% gives the wrong answer.
What are CGST, SGST and IGST?
Within a state, GST splits equally into central (CGST) + state (SGST). Across states, the full rate is charged as IGST.
Which slab applies to my product?
Slabs (0.25–28%) are set per HSN/SAC code — check the GST rate finder on cbic-gst.gov.in or ask your CA.
Is this a substitute for tax advice?
No — it is arithmetic. Classification and compliance questions belong with a professional.