GST / VAT Calculator

Add Tax to a Price, or Extract It From a Total

Two situations come up constantly in business:

1. You know the base price. You need the total including tax. → Add Tax mode
2. You know the total (tax-inclusive). You need to separate the base from the tax. → Extract Tax mode

Both are simple arithmetic. The second one trips people up because the instinct to "subtract 18% from the total" gives the wrong answer. This tool handles both correctly.

The Formulas

Adding Tax (Tax-Exclusive):

Tax Amount = Base Price × (Rate ÷ 100)
Total Price = Base Price + Tax Amount

Example — Invoice with 18% GST:

• Base: ₹8,500
• Tax: ₹8,500 × 0.18 = ₹1,530
• Total: ₹10,030

Extracting Tax (Tax-Inclusive):

Base Price = Total ÷ (1 + Rate ÷ 100)
Tax Amount = Total − Base Price

Example — Receipt shows ₹10,030 including 18% GST:

• Base: ₹10,030 ÷ 1.18 = ₹8,500
• Tax: ₹10,030 − ₹8,500 = ₹1,530

The common mistake: Calculating 18% of ₹10,030 gives ₹1,805 — that's 18% of the gross, not the correct tax. The extract formula divides by (1 + rate), giving the true pre-tax base.

Tax Rates Quick Reference

India — GST Slabs:

International VAT Rates:

For any other jurisdiction, use the custom rate field.

Everyday Business Scenarios

Sending an invoice: You charge ₹25,000 for consulting services. GST at 18% must be added. The tool instantly shows the tax amount (₹4,500) and the invoice total (₹29,500) with the correct line-item breakdown.

Reconciling receipts: Your expense receipt shows ₹4,720 including 18% GST. You need the net amount for accounting. The tool extracts: base ₹4,000, tax ₹720.

Comparing prices: One vendor quotes ex-GST, another quotes inclusive. Normalize both to their base price before comparing — the tool extracts the base from the inclusive price in one step.

Cost pricing for retail: You buy goods at ₹1,200 + 12% GST = ₹1,344 per unit. Knowing the land...