Fast GST is a complete GST billing, invoice maker and tax invoice app with the same fast GST calculator you already rely on built in.

Create GST invoices, business bills, tax invoices and professional PDF invoices in seconds. Calculate GST instantly, manage customers and products, export invoices, and share bills directly on WhatsApp or email.

Everything works offline with no login and no monthly fee. Your business data stays on your device.

The app is designed calculator-style and inspired by modern POS billing screens, so daily GST billing feels fast, clean and familiar instead of complicated.

GST BILLING & TAX INVOICE

✔ Create GST invoices, tax invoices, quotations and business bills
✔ Multi-item invoice support with quantity, rate and GST per item
✔ Add discounts and calculate CGST, SGST and IGST automatically
✔ Save customer details for faster repeat billing
✔ Save products with GST rates for quick invoice creation
✔ Add your GSTIN and customer GSTIN for GST-ready invoices
✔ Add logo, signature and business details on invoices
✔ Professional invoice templates for different business styles

GST CALCULATOR

✔ Add GST and remove GST instantly
✔ Reverse GST calculation
✔ Inclusive and exclusive GST calculation
✔ All major GST slabs: 3%, 5%, 12%, 18% and 28%
✔ Automatic CGST, SGST and IGST split
✔ Custom GST rate support
✔ Discount calculator built into GST calculation
✔ Fast calculator-style interface for daily use

INVOICE EXPORT & PAYMENT

✔ Export invoices as clean PDF files
✔ Share invoice as image, PDF or text
✔ WhatsApp-friendly invoice sharing
✔ Thermal invoice and receipt style export
✔ Add UPI QR code for direct payment collection
✔ Print-ready invoice layouts

BUSINESS TOOLS

✔ Customer management system
✔ Product and item catalog with GST rates
✔ Invoice history with status tracking
✔ Multiple business profiles
✔ Business signature support on invoices
✔ Backup and restore your data securely
✔ Google Drive encrypted backup support

FAST, LIGHTWEIGHT & OFFLINE

✔ Works fully offline
✔ No signup required
✔ Lightweight and fast performance
✔ Dark mode support
✔ Smooth modern UI built for daily billing
✔ Designed for phones, retailers and small business use

MADE FOR

Shop owners, retailers, wholesalers, traders, kirana stores, freelancers, GST consultants, accountants, mobile shop owners, service providers and small businesses who want simple GST billing without heavy accounting software.

WHY SMART GST CALCULATOR?

• GST calculator and invoice maker in one app
• Built for fast daily GST billing
• Offline-first experience
• Professional invoice export
• No subscription required to get started
• Easy enough for small businesses and shop counters
• Powerful enough for professional GST invoicing

FAQs

Is Fast GST Calculator free to use?
Yes. You can calculate GST, create invoices and export bills for free with no forced signup.

Does it work offline?
Yes. Smart GST Calculator is built offline-first, so you can create GST bills and invoices even without internet.

Can I create GST invoices with multiple items?
Yes. Add multiple products or services with quantity, rate and GST percentage, and the app calculates totals automatically.

Can I add my business GSTIN and logo?
Yes. Save your business profile once including GSTIN, address, logo, signature and UPI QR and it appears on invoices automatically.

Can customers pay directly from the invoice?
Yes. You can add your UPI QR code so customers can scan and pay directly.

Can I export invoices as PDF?
Yes. Invoices can be exported as PDF, image or shared directly through WhatsApp, email or print.

Does the app support CGST, SGST and IGST?
Yes. The app supports CGST + SGST as well as IGST billing modes.

Can I backup my invoice data?
Yes. You can create encrypted backups and restore them later, including Google Drive backup support.

Download Fast GST today and simplify GST billing, tax invoices and invoice sharing for your business.