Free · no sign-up · works on your phone
Free GST tools for small businesses
Work out GST, check a customer’s GSTIN, find an HSN code, make a GST invoice and keep track of return dates and late fees. Every tool runs in your browser, uses the GST rates in force since 22 September 2025 and links to the official source.
All tools
GST calculator
Free GST calculator: add GST to a price or remove it from an inclusive amount, with the CGST + SGST or IGST split and the new 5%, 18% and 40% rates.
Open toolGSTIN validator
Check any GSTIN instantly: 15-character format, state code, PAN and the check digit, decoded on your phone. Catch typing mistakes before you bill a customer.
Open toolHSN code finder
Search HSN and SAC codes for common goods and services by name or number, with GST rates checked against the schedule in force since 22 Sept 2025. Free.
Open toolGST invoice generator
Make a GST tax invoice online for free: seller, buyer, HSN, CGST/SGST or IGST worked out, amount in words. Print or save as PDF. Quotations and challans too.
Open toolMargin calculator
Work out profit margin, markup and selling price from your cost, with or without GST. See the price to quote and the profit you keep on every unit sold.
Open toolGST late fee calculator
Calculate the late fee and 18% interest for filing GSTR-3B, GSTR-1, GSTR-4 or GSTR-9 late, with the turnover-based caps currently notified. Free and instant.
Open toolGST due dates
GST return due dates for this month and the next two: GSTR-1, GSTR-3B (monthly and QRMP), IFF, PMT-06, CMP-08, GSTR-4 and GSTR-9, filtered for how you file.
Open toolInvoice and document formats
Printable samples with the fields GST rules ask for, each one ready to fill in our invoice generator.
Want all of this done on every bill?
Invoiqo works out GST, saves HSN codes and customers, and keeps your invoices and payments in one place. The Free plan never expires.