GST Calculator

About GST Calculator

The GST Calculator by Run It Free is a comprehensive, privacy-first tax calculation toolkit designed for small business owners, freelancers, e-commerce merchants, accountants, and consumers worldwide. Whether you need to prepare a client invoice in India, calculate UK VAT, determine Australian GST, or figure out Input Tax Credit (ITC) set-off liabilities for tax return filing, this tool handles all calculations instantly inside your browser. It supports both calculation directions: adding GST to a base pre-tax price (exclusive calculation) and extracting base amount and tax from a GST-inclusive total (reverse GST calculation). Preset slabs cover official Indian GST rates (3%, 5%, 12%, 18%, 28%) and composition scheme rates (1%, 3%, 5%, 6%), alongside multi-region presets for the UK, Australia, Canada, Singapore, and the UAE. An integrated HSN/SAC code lookup helps you quickly find official tax rates for software development, IT consulting, food & catering, electronics, apparel, pharma, and automotive goods. Additional advanced features include an Input Tax Credit (ITC) Set-Off Estimator, multi-item line invoice billing with discounts, downloadable CSV exports, printable PDF quotes, shareable calculation links, and a full-screen Zen Mode — all running 100% client-side with zero data transmission to external servers.

How to Use GST Calculator

1. Select Tax Region & Mode: Choose your tax region (India GST, UK VAT, Australia GST, etc.) and select whether you want to Add GST (Exclusive), Remove GST (Inclusive), or calculate Input Tax Credit (ITC).
2. Choose Tax Slab or Search HSN Code: Click preset slab buttons (5%, 12%, 18%, 28%), enter a custom rate, select a composition preset, or use the HSN/SAC search bar to find rates for specific goods or services.
3. Enter Amounts, Quantities, & Discounts: Type in single amounts or switch to Multi-Item Mode to add product lines with quantities, unit prices, and discount percentages.
4. Export CSV, Print PDF, or Share Link: Copy summary text, download multi-item line data as CSV, print/save a PDF invoice estimate, or copy a direct shareable URL link.

Key Features

• Add GST & Reverse GST Calculation (Exclusive & Inclusive): Instantly calculate tax amounts starting from a pre-tax base price (Add GST) or extract the original pre-tax value and tax component from a GST-inclusive total (Remove GST).
• Input Tax Credit (ITC) Set-Off Estimator: Determine your net cash tax payable to the government by comparing Output GST collected on sales against Input GST credit paid on business purchases, following official IGST, CGST, and SGST utilization hierarchy rules.
• Built-in HSN / SAC Code Search: Search curated HSN (Harmonized System of Nomenclature) and SAC (Services Accounting Code) entries for software services, electronics, dining, textiles, and pharma to auto-select official GST slabs.
• Global Tax Region Presets: Switch seamlessly between India (GST), United Kingdom (VAT), Australia (GST), Canada (HST/GST), Singapore (GST), and UAE (VAT) with automatic currency symbol and tax slab adjustments.
• Multi-Item Invoice Mode with Line Discounts: Build complete invoice estimates with unlimited line items. Specify item names, quantities, unit prices, line-item discount percentages, and custom tax rates.
• Printable PDF Quotes & CSV Export: Export multi-item invoice tables directly to CSV spreadsheet files or generate styled, printable PDF quotation previews ready for client billing.
• Shareable Calculation Links & Zen Mode: Encode calculation states into direct URLs to share exact tax quotes with clients or switch to distraction-free full-screen Zen Mode.

Benefits

• Eliminate Costly Invoicing & Filing Errors: Using incorrect GST rates or applying tax on an inclusive price instead of base price creates reconciliation errors during GSTR-1 and GSTR-3B filing. This calculator guarantees accurate pre-tax and tax amounts.
• Optimize Input Tax Credit (ITC) Cash Flow: Easily estimate your net cash tax liability versus excess credit carried forward by setting off Output GST against Input GST across IGST, CGST, and SGST.
• Speed Up Quote Preparation & Invoicing: Quickly create multi-item quotes with line discounts, export data to CSV for accounting software (Tally, Zoho, Quickbooks), and generate PDF quotes in seconds.
• Multi-Currency & Global Tax Compliance: Work seamlessly with international clients in the UK, Australia, Canada, Singapore, or the UAE without switching tools.

Supported Formats & Capabilities

• Single-item GST & VAT calculation (Add or Remove tax)
• Input Tax Credit (ITC) set-off calculation (IGST, CGST, SGST)
• Multi-item invoice with line discounts & HSN code lookup
• Printable PDF quotation estimate & CSV spreadsheet export

Common Problems & Solutions

Why is removing GST from an inclusive price different than subtracting the percentage?

GST is calculated on the pre-tax base price, not the inclusive total. If a product costs ₹100 base + 18% GST = ₹118 total, subtracting 18% from ₹118 gives ₹96.76 (wrong). The correct reverse formula is: Base Price = Inclusive Price ÷ 1.18 = ₹100.

How does Input Tax Credit (ITC) set-off work for GST return filing?

Under GST rules, Input Tax Credit (ITC) paid on purchases is set off against Output Tax liability (Sales) in a strict hierarchy: IGST credit is utilized first against IGST, then CGST, then SGST. CGST credit offsets CGST and IGST. SGST credit offsets SGST and IGST (CGST and SGST credit cannot offset each other).

What is the difference between CGST, SGST, and IGST?

For intra-state transactions (buyer and seller in the same state), GST is split equally into Central GST (CGST) and State GST (SGST) — e.g. 18% GST = 9% CGST + 9% SGST. For inter-state transactions or imports, Integrated GST (IGST) applies as a single 18% rate.

How do HSN and SAC codes work in GST billing?

HSN (Harmonized System of Nomenclature) codes classify physical goods, while SAC (Services Accounting Code) codes classify services. Each code specifies the official GST rate (e.g., SAC 998311 for IT software at 18%, HSN 8471 for computers at 18%).

Can composition scheme taxpayers use this calculator?

Yes. The calculator includes quick composition presets (1% for manufacturers/traders, 3% for gold, 5% for restaurants, 6% for service providers) to calculate turnover tax liability without charging GST to buyers.

Pro Tips & Best Practices

• Always verify the exact HSN or SAC code for your product or service in CBIC rate schedules before raising official B2B invoices.
• When quoting round-number final prices to customers (e.g. ₹5,000 all-inclusive), use 'Remove GST' mode to find the exact base price and tax breakdown to display on your invoice.
• Use the 'Share Link' button to send clients an exact pre-filled calculation URL so they can review base prices, discounts, and tax breakdowns directly.
• Export multi-item calculations to CSV to easily import invoice line items into accounting software like Tally, Busy, or Zoho Books.

Privacy & Data Security

All calculations run 100% inside your web browser using client-side JavaScript. No invoice amounts, business revenue numbers, customer names, or financial figures are transmitted to or stored on any server. You can safely use this tool for confidential corporate billing, client quotes, and private business tax estimations.

Frequently Asked Questions

How do I calculate GST on a price?

To add GST: GST Amount = Base Price × (GST Rate ÷ 100). Total Price = Base Price + GST Amount. For example, ₹10,000 at 18% GST yields ₹1,800 GST, making the total ₹11,800.

How do I remove GST from an inclusive price?

To calculate base price from a GST-inclusive amount: Base Price = Inclusive Price ÷ (1 + GST Rate ÷ 100). For 18% GST on ₹11,800: ₹11,800 ÷ 1.18 = ₹10,000 base price and ₹1,800 GST.

What is Input Tax Credit (ITC) in GST?

Input Tax Credit (ITC) is the GST tax paid by a business on purchases of goods or services used for business. ITC can be reduced from the Output GST tax collected on sales to determine the Net Cash Payable to the government.

What are the standard GST slabs in India?

The primary GST tax slabs in India are 0% (essential goods), 3% (gold & jewellery), 5% (basic goods & small restaurants), 12% (processed food & construction), 18% (IT, professional services, manufactured goods), and 28% (automotive & luxury items).

How do I export invoice quotes to PDF or CSV?

In Multi-Item Mode, click 'Export CSV' to download an Excel-compatible spreadsheet or click 'Print / PDF Quote' to generate a formatted printable PDF invoice estimate.

Does this GST calculator support international VAT?

Yes. You can switch tax regions to calculate UK VAT (20%), Australia GST (10%), Canada HST (13%), Singapore GST (9%), or UAE VAT (5%) with native currency formatting.

Is this GST Calculator free with no sign-up?

Yes. The GST Calculator by Run It Free is 100% free, unlimited, requires no registration, and processes all calculations locally in your browser.

Related Finance Utilities