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GST / Sales Tax Calculator

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Calculate Goods and Services Tax (GST), CGST, SGST, IGST breakdown, reverse GST from gross totals, and invoice tax amounts for business transactions.

100% In-Browser Privacy
Zero Server Uploads

GST Calculation Parameters

Configure base price, tax rate slab, and inclusive/exclusive mode

Final Invoice Amount
5,900.00

Includes 900.00 total GST at 18%

Net Amount
5,000.00
Pre-tax base value
Total GST Tax
900.00
Calculated at 18%
CGST (Central Tax)
450.00
9.0% split
SGST (State Tax)
450.00
9.0% split

Who Is GST / Sales Tax Calculator Built For?

Business owners and freelancers calculating GST amounts for client invoices and tax filings
Accountants computing CGST, SGST, and IGST breakdowns for intra-state and inter-state sales
Shoppers determining pre-tax costs and tax components on retail purchases

Key Benefits & Core Capabilities

Add GST & Remove GST (Reverse Calculation)

Calculate tax to add to a net base price, or reverse-calculate original pre-tax amount and GST paid from gross totals.

CGST & SGST Split Breakdown

Automatically breaks down 5%, 12%, 18%, and 28% tax slabs into equal Central (CGST) and State (SGST) shares.

Standard GST Slabs & Custom Rates

Quick preset buttons for 0%, 5%, 12%, 18%, and 28% GST slabs or custom percentage entry.

100% In-Browser Privacy

Calculate proprietary invoice amounts and accounting taxes with complete local privacy.

Step-by-Step Guide: How to Use GST / Sales Tax Calculator

  1. 1
    Enter AmountInput your base amount in your currency.
  2. 2
    Choose Rate & ModePick standard tax slabs (5%, 12%, 18%, 28%) or custom %, and select GST Inclusive or GST Exclusive.
  3. 3
    View SummarySee original cost, net tax amount, CGST/SGST split, and total invoice amount.

How It Works & Technical Architecture

For inclusive GST (Reverse): Base Price = Total Amount / (1 + GST Rate / 100); GST Amount = Total Amount - Base Price.

For exclusive GST (Forward): GST Amount = Base Price × (GST Rate / 100); Total Amount = Base Price + GST Amount.

For intra-state sales, the GST Amount is split equally (50% CGST + 50% SGST) in client JavaScript.

Practical Use Cases & Applications

B2B Client Invoicing

Calculate exact 18% GST ($180) to add to a $1,000 consulting fee invoice.

Retail Receipt Tax Extraction

Extract pre-tax price ($847.46) and 18% GST ($152.54) from a $1,000 retail bill.

Intra-State vs Inter-State Tax Filings

Calculate equal 9% CGST and 9% SGST allocations for local state tax returns.

E-commerce Product Pricing

Determine gross listing prices that maintain targeted net profit margins after GST.

Supported Formats & Input Options

Amount (Net or Gross)GST Rate (0%, 5%, 12%, 18%, 28%, Custom)Inclusive or Exclusive Mode

Frequently Asked Questions

How is GST calculated on an inclusive price (extracting GST)?

Formula: GST Amount = Total Price - (Total Price / (1 + GST Rate / 100)). For example, for $118 with 18% GST: Base = $100 and GST = $18.

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

CGST (Central) and SGST (State) are applied on sales within the same state (split 50/50). IGST (Integrated) is applied on sales between different states.

Can I enter custom GST percentages?

Yes. You can select standard rate slabs or type any custom tax percentage.

Is my financial data uploaded to any server?

No. All GST calculations execute 100% locally in your browser memory.

Can I copy the invoice tax breakdown with one click?

Yes. Softnag includes one-click copy buttons for net price, GST amount, CGST, SGST, and total gross price.

What is the difference between GST inclusive and exclusive?

GST Exclusive means tax is added on top of the base price. GST Inclusive means the entered price already contains the tax amount.