GST Calculator: Inclusive & Exclusive GST
Free GST calculator for India: add or remove GST at the new 5%, 18% and 40% slabs (or old 12%/28%) and get the CGST, SGST and IGST breakup instantly.
Tax Breakdown
Final Payable Amount
₹0
Compliance Guide
Inter-state
Use IGST when billing a client outside your registered state.
Local
Use CGST + SGST when both parties are in the same state.
Rounding
Invoices are typically rounded to the nearest whole rupee.
About this tool
Calculate Indian GST at the 5%, 18% and 40% slabs in force since 22 September 2025 — or the older 12% and 28% rates for earlier invoices — adding tax to a base price or extracting it from an inclusive one, with the base, tax, and total broken out clearly. Shopkeepers, freelancers, and bill-checkers all get the arithmetic the invoice depends on.
How to Calculate GST
- 1
Enter your amount and select the applicable GST rate — 5%, 18% or 40% for most goods and services since 22 September 2025, 0% for exempt items, or 12% and 28% for invoices dated before then.
- 2
Choose the direction: exclusive (add GST to a base price) or inclusive (extract the GST already inside a total).
- 3
Read the full breakdown — base amount, GST amount, and final price — ready for your invoice or verification.
Why Calculate GST with Wrklyst
- Billing Figures Stay Private
- The computation is local browser math — your pricing and invoice amounts aren't transmitted anywhere.
- Inclusive Math Done Right
- Extracting GST from an inclusive price is the step people get wrong (it isn't 18% of the total); the correct back-calculation is built in.
- Invoice-Ready Breakdown
- Base, tax, and total presented separately — exactly the three lines a GST invoice needs.
GST Practice Tips
- Quote prices to businesses as base + GST, to consumers as inclusive — matching each audience's expectation.
- Verify restaurant and retail bills occasionally: extract the GST and check the rate applied is the right slab.
- Invoice line items with different slabs must be calculated separately, not averaged.
- Keep the breakdown from every calculation — the base/tax split is what your GST return needs.
Frequently asked questions
How do I know which GST slab applies?
Rates are set per category by the GST Council. Since 22 September 2025 most goods and services fall into two slabs — 5% for essentials and everyday items, 18% for most other goods and services (the most common rate for services) — with 40% for certain luxury and sin goods and 0% for exempt items. The old 12% and 28% slabs were folded into these. Check your item's HSN/SAC code classification for certainty, as categories do get revised.
Why isn't extracting GST just taking 18% off the total?
Because the tax was computed on the base, not the total. From an 1,180 inclusive price at 18%, the GST is 180 — which is 18% of the 1,000 base but only ~15.25% of the total. The correct extraction divides by 1.18; taking 18% of the total overstates the tax every time.
What are CGST, SGST, and IGST on my bill?
The same tax, split by geography: intra-state sales divide the rate equally between central (CGST) and state (SGST) halves — an 18% charge shows as 9% + 9% — while inter-state sales carry the full rate as IGST. Your total is identical either way; only the government-side allocation differs.
Do freelancers need to charge GST?
Registration is generally required above ₹20 lakh annual turnover for services (₹10 lakh in special-category states), after which you charge GST — typically 18% for services — issue GST invoices, and can claim input credits. Below threshold, registration is optional but sometimes worthwhile for B2B clients who expect GST invoices.