Free GST tools for every calculation
Everything runs in your browser — nothing is uploaded, no account needed. Add or remove GST, split it by tax head, build invoice values, preview GSTR-1 and GSTR-3B figures, and plan your input credit. When you're ready, GSTSelf helps you prepare the actual returns.
Most used
GST Calculator
Add GST to any amount at rates from 0.25% to 28%, with CGST/SGST or IGST split.
Reverse GST Calculator
Remove GST from a tax-inclusive amount to find the base value and tax portion.
GST Inclusive Calculator
You know the final price including GST — find out how much of it is tax.
CGST + SGST Calculator
See both halves of intra-state GST together, side by side, in one step.
GST Invoice Generator
Create a professional GST invoice online and download it as a PDF — free, right in your browser.
GST Invoice Calculator
Build an invoice value from quantity, rate, discount and GST — line by line.
GSTR-1 Calculator
Total up your outward supplies into GSTR-1-style figures before filing.
GSTR-3B Calculator
Combine outward tax and ITC to preview your GSTR-3B cash position.
Net GST Payable Calculator
Apply your credits against output tax and see the cash still needed.
GSTR-1 vs GSTR-3B Reconciliation
Compare declared GSTR-1 values against GSTR-3B and flag every mismatch.
HSN/SAC Helper
Search the full code lists to identify the right HSN or SAC.
GSTIN Validator
Check a GSTIN's structure, state code and checksum — offline, instantly.
GST Inclusive Calculator
You know the final price including GST — find out how much of it is tax.
GST Exclusive Calculator
Add GST on top of your base price and get the invoice-ready total.
CGST Calculator
Calculate only the central tax half of intra-state GST on any amount.
SGST Calculator
Calculate only the state tax half of intra-state GST on any amount.
IGST Calculator
Calculate integrated tax at the full slab rate for inter-state supplies.
CGST + SGST Calculator
See both halves of intra-state GST together, side by side, in one step.
GST Split Calculator
Take any GST amount and split it exactly into CGST and SGST halves.
GST Percentage Calculator
Find what share of a tax-inclusive price is actually GST, as a percentage.
GST Invoice Calculator
Build an invoice value from quantity, rate, discount and GST — line by line.
GST Discount Calculator
Apply trade discounts before tax and see why order matters for GST.
GST Invoice Total Calculator
Add up several lines at different slabs into one clean invoice summary.
Credit Note Calculator
Work out the tax reduction when you issue a credit note against a sale.
Debit Note Calculator
Work out the extra tax when you issue a debit note for under-billing.
GST ITC Tools
3 tools
HSN/SAC Tools
2 tools
GSTIN Validator
Check a GSTIN's structure, state code and checksum — offline, instantly.
GST State Code Finder
Every GST state code from 01 Jammu & Kashmir to 97 Other Territory.
GST Rate Calculator
See one amount taxed at every slab from 0% to 28%, side by side.
GST Due Date Helper
Pick a return period and see GSTR-1/GSTR-3B due dates and countdowns.
From estimating to filing
These tools give you numbers. GSTSelf's guided workflows turn them into return-ready data — with your invoices stored only on your device.