GST + invoicing tools, free.
The same calculators we built into Ketpy Book — extracted, free, and no email capture. Bookmark them; CAs and shop owners use them daily.
Calculators for filers, CAs & shopkeepers.
GST Calculator
Add or remove GST 5/12/18/28%. Auto CGST+SGST or IGST split based on intra/inter-state supply.
HSN / SAC Finder
Search 8 lakh+ HSN/SAC codes by keyword. Get the right GST rate + chapter heading instantly.
GST Late-Fee Calculator
Compute late filing fees + 18% interest for GSTR-1 / 3B / 9 / 4. Auto-applies the per-Act cap.
Generate documents — no account.
Free Invoice Generator
GST-compliant invoice in 60 seconds. Multi-rate line items, signature block, branded PDF — no signup.
e-Invoice JSON Generator
Build an IRP Schema 1.1 JSON from a simple form. Download or copy — ready for upload to einvoice1.gst.gov.in.
Business Loan EMI Calculator
Plan a working-capital, equipment-finance or MSME term loan. EMI, total interest, full amortisation schedule.
Real outputs, no demo wall.
{
"Version": "1.1",
"TranDtls": { "TaxSch": "GST", "SupTyp": "B2B" },
"DocDtls": { "Typ": "INV", "No": "INV-2026-001" },
"SellerDtls": { "Gstin": "27ABCDE1234F1Z5" },
"ItemList": [{ "HsnCd": "8504", "GstRt": 18 }]
}Useful tools shouldn't cost an email.
No email capture
We don't ask for your address before showing the result. Bookmark, share, do whatever.
No ads
Truly free. The "premium" version is the full Ketpy Book product — and it costs ₹499/year, not ₹0 with ads.
India-specific
Built for our GST law, our PIN codes, our state codes — not a US calculator with a ₹ symbol slapped on.
Tested in production
These are extracted from the same code Ketpy Book runs on 2,400+ tenants.
Coming next.
Want one of these prioritised? Drop us a line →
Outgrowing the free tools?
Run your whole business on Ketpy Book — Lite from ₹499/year, Pro from ₹1,499/year. Lite from ₹499/year, Pro from ₹1,199/year. One-click 30-day refund.