GST calculatorfor founders who'd rather build than do tax math.
Add or remove GST in one field, split CGST/SGST or IGST instantly, and see rounded totals the way your invoice will show them.
GST Calculator
Enter amount and select tax slab.
Usually 5 / 12 / 18 / 28. Verify exact rate via HSN/SAC. Max 28% (enable ADV for higher).
GST is added ON TOP of amount
Not legal advice • Verify before filing • Privacy: runs in your browser
Two ways GST shows up on an invoice
Which formula applies depends on whether your quoted price already has tax folded in.
Exclusive — tax added on top
Use this when you're quoting a base fee and adding GST separately.
Base ₹50,000 at 18% → GST ₹9,000 → Total ₹59,000
Inclusive — tax already inside
Use this for MRP-tagged goods or when checking a vendor bill that's 'all-in'.
MRP ₹11,800 at 18% → Base ₹10,000 → GST inside ₹1,800
Common HSN & SAC codes, at a glance
GST rates depend on the HSN code for goods or SAC code for services. Use these as a starting point — always confirm the exact classification for your product or service.
Goods — HSN
- Smartphones & mobiles851718%
- Gold jewellery71133%
- Cotton fabric52085%
- Cement252328%
- LED TVs852818%
Services — SAC
- Freelance / IT services998318%
- Legal services998218% (RCM)
- Advertising services9983618%
- Consulting services9983118%
- Restaurant services99635% / 18%
Not sure which code applies to you? CorpE's compliance team can confirm it while setting up your GST registration →
Who ends up using this calculator
Same tool, different reason to open it — pick the shortcut that matches your invoice.
Freelancers & Consultants
- Add 18% GST on a service fee
- Back out GST from a client payment
- Sanity-check TDS vs GST on an invoice
New companies & startups
- Price a product before GST registration lands
- Check invoice math while onboarding a client
- Plan CGST/SGST vs IGST across states
Retailers & traders
- Convert MRP into taxable value
- Product-wise GST at 5%, 12%, 18%, 28%
- Invoice-ready inclusive/exclusive splits
HR & payroll teams
- Check GST on staffing / EOR service invoices
- Verify vendor bills before approval
- Cross-check contractor payout invoices
Three GST calculations people get wrong
Load any of these patterns into the calculator above and adjust the amount.
Create a GST estimate or quotation after calculation
Use this when you want a client-ready estimate with an accurate GST breakup. (Not a final tax invoice.)
- 1Enter the amount and choose Inclusive or Exclusive.
- 2Select the GST rate (5%, 12%, 18%, 28%) based on HSN/SAC.
- 3Enable Inter-state (IGST) if buyer is in another state.
- 4Add client name and optional note in 'Add Invoice Details'.
- 5Print / Save as PDF using your browser print dialog.
Add these to look professional
- Quotation date + validity (e.g. 7 days)
- Payment terms (advance / due on delivery)
- Scope note (what's included / excluded)
- Delivery timeline / support period
- Your contact + business name
Important: This is a proforma / estimate — not a final tax invoice. Actual invoices require GSTIN, invoice numbering, place of supply, and other statutory fields.
Real-world templates
Base: ₹50,000 → GST: ₹9,000 → Total: ₹59,000
Common mistake:charging GST again on an "all-inclusive" quote.
MRP: ₹1,180 includes GST → Base: ₹1,000 + GST: ₹180
Common mistake:using Exclusive mode on MRP.
How to Calculate GST in India (Formulas)
Add GST, remove GST, and split CGST/SGST or IGST using these standard formulas.
Your Questions Answered
GST calculation questions founders ask most — we'll keep updating these answers.
How do I add GST to an exclusive amount?
+How do I remove GST from an inclusive (MRP) price?
+When should I use CGST/SGST vs IGST?
+What GST rate applies to my product or service?
+How does Section 170 rounding work on invoices?
+Can I use this calculator output for GST filing?
+What's the difference between a quotation and a tax invoice?
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