Sales Tax Calculator (Add or Remove)
Add sales tax/GST to a price, or extract the tax hidden inside a tax-inclusive amount — with the tax amount and the net and gross totals shown.
Sales Tax
GST slabs: 5, 12, 18, 28%
Total (with tax)
₹1,180
Tax ₹180 at 18%
Net Amount
₹1,000
Tax Amount
₹180
Gross Amount
₹1,180
Tax Rate
18%
How It Works
Sales tax (or GST in India) is a percentage added to the price of goods and services, and this calculator works in both directions. In “Add” mode, you enter the pre-tax price and the rate, and it returns the tax amount and the total you pay. In “Remove” mode, you enter a tax-inclusive amount — a bill total that already includes tax — and it extracts the original base price and the tax portion inside it, which is essential for accounting and invoicing. Removing tax is not simply subtracting the percentage: because the tax was added on the smaller base, you divide the gross by (1 + rate) rather than multiplying. For India, enter your applicable GST slab (5%, 12%, 18% or 28%). The calculator shows the net amount, the tax, and the gross total together so the numbers always reconcile.
Formula
Add: Tax = Amount × rate%; Total = Amount + Tax. Remove: Net = Amount ÷ (1 + rate%); Tax = Amount − Net.
Frequently Asked Questions
How do I add sales tax to a price?
Multiply the price by the tax rate to get the tax, then add it. At 18%, a ₹1,000 item has ₹180 tax and a ₹1,180 total. Use “Add Tax” mode.
How do I remove tax from a total?
Divide the tax-inclusive amount by (1 + rate). For 18%, a ₹1,180 total ÷ 1.18 = ₹1,000 base, so the tax was ₹180. Use “Remove Tax” mode — you cannot just subtract 18%.
Why can’t I just subtract the percentage to remove tax?
Because the tax was calculated on the smaller pre-tax base, not the larger total. Subtracting 18% of the gross over-removes. Dividing by 1.18 correctly recovers the base price.
What GST rates apply in India?
The main GST slabs are 5%, 12%, 18% and 28%, depending on the product or service. Enter your applicable slab as the rate. Some items are exempt (0%).
Is this the same as a GST calculator?
The maths is identical — GST is India’s sales tax. This tool adds or removes any flat rate; for the CGST/SGST/IGST split, use our dedicated GST calculator.