Add GST, VAT or sales tax to a price, or remove it from a tax-inclusive price, with stacked state and local rates or India's CGST/SGST split.
By AdminDrafted with AI writing toolsUpdated Checked examples: 6
Adding 8.25% tax to $1,000.00 gives $1,082.50, of which $82.50 is tax.
| Item | Rate | Amount |
|---|---|---|
| Price before tax | — | $1,000.00 |
| Rate 1 | 6.25 % | $62.50 |
| Rate 2 | 2 % | $20.00 |
| Price including tax | — | $1,082.50 |
Each rate is applied to the pre-tax price, not compounded on the other taxes.
Adding tax multiplies the pre-tax price by (1 + rate ÷ 100). Removing tax from a tax-inclusive price divides by the same factor; multiplying the inclusive price by the rate would overstate the tax. When several rates apply, such as a state and a local sales tax, each is charged on the pre-tax price and the amounts are added.
With the defaults, 1,000 at a 6.25% state rate plus a 2% local rate, the Texas maximum combination, carries 82.50 of tax, 1,082.50 in total. Under India's GST, an 18% rate on 1,000 adds 180: 90 of CGST and 90 of SGST for a sale within a state, or 180 of IGST for a sale between states.
The rates are the ones you enter, so check the current rate for the product and the place of sale. US sales tax is set by state and local governments, so two addresses in the same state can pay different rates.
To add tax, multiply the pre-tax price by 1 + rate ÷ 100. To remove tax from a tax-inclusive price, divide by the same factor. At 18% GST, 1,000 becomes 1,000 × 1.18 = 1,180, with 180 of tax, and 1,180 ÷ 1.18 brings it back to 1,000. The same formulas work for any VAT or sales tax rate.
Tax = price × rate ÷ 100, and the total is price + tax:
When several rates apply, such as a state and a local sales tax, each is charged on the pre-tax price and the taxes are added. On 100, a 6.25% state rate and a 2% local rate give 6.25 + 2.00 = 8.25 of tax, 108.25 in total.
Divide the inclusive price by 1 + rate ÷ 100 to get the price before tax; the tax is the difference. In one step, tax = inclusive price × rate ÷ (100 + rate).
Multiplying the inclusive price by the rate overstates the tax, because it taxes the tax as well: 1,180 × 18% = 212.40, not 180.
| Mode | Entered amount | Rate | Before tax | Tax | Including tax |
|---|---|---|---|---|---|
| Add | 1000 | 18% | 1000.00 | 180.00 | 1180.00 |
| Remove | 1180 | 18% | 1000.00 | 180.00 | 1180.00 |
| Add | 1000 | 18% | 1000.00 | 180.00 | 1180.00 |
| Remove | 2360 | 18% | 2000.00 | 360.00 | 2360.00 |
| Add | 1000 | 5% | 1000.00 | 50.00 | 1050.00 |
| Add | 1000 | 40% | 1000.00 | 400.00 | 1400.00 |
| Add | 100 | 8.25% | 100.00 | 8.25 | 108.25 |
| Remove | 120 | 20% | 100.00 | 20.00 | 120.00 |
| Remove | 54.13 | 8.25% | 50.00 | 4.13 | 54.13 |
| Add | 500 | 0% | 500.00 | 0.00 | 500.00 |
| Add | 0 | 18% | 0.00 | 0.00 | 0.00 |
The first and third rows are the same 18% sale within a state and between states: the tax is the same 180, only its split differs. The 8.25% rows combine a 6.25% state rate and a 2% local rate.
On a sale within an Indian state, the GST rate is split equally between central GST (CGST) and state GST (SGST, or UTGST in a union territory). On a sale between states, the whole rate is charged as integrated GST (IGST).
At 18% on 1,000, that is 90 of CGST plus 90 of SGST, or 180 of IGST. Since 22 September 2025 the main GST rates are 5% and 18%, with 40% for specified goods (56th GST Council recommendations). Gold, silver, platinum and jewellery are taxed at 3% (Schedule IV of Notification 9/2025-Integrated Tax (Rate)).
Particular goods and services can still carry other rates or exemptions, so confirm the rate for the item and the date of supply.
Removing 8.25% from 54.13 gives a pre-tax price of 50.0046 and tax of 4.1254, which round to 50.00 and 4.13.
An invoice that rounds the tax on each line can end a cent away from one that taxes the total, so follow the rounding rule your invoice or tax return requires.
For tax on earnings rather than on a price, use the income tax calculator. For a discount or markup before tax, use the discount and markup calculator, and for any other percentage, the percentage calculator.
Checked against: 1000 × 0.18 = 180, split equally between CGST and SGST
Checked against: HMRC VAT fraction for the 20% rate is 1/6: 120 × 1/6 = 20; exact decimal arithmetic 120 / 1.2 = 100
Checked against: 100 × 0.0625 + 100 × 0.02 = 8.25
Checked against: 500 × 0 = 0 by definition
Multiply the pre-tax price by the combined rate. At 8.25%, a 100 purchase carries 8.25 of tax. In Texas that combined rate is the 6.25% state rate plus the maximum 2% of local taxes; California's statewide rate is 7.25% before local additions. Oregon, Montana, New Hampshire, Delaware and Alaska have no general state sales tax, although Alaskan localities may levy one.
Divide the VAT-inclusive price by 1 plus the rate. At the UK standard rate of 20%, 120 ÷ 1.2 = 100, so the VAT is 20, which is also 1/6 of the inclusive price: HMRC's VAT fraction for the 20% rate (VAT Notice 700). The UK's other rates are 5% (reduced) and 0% (zero-rated), and since 1 April 2024 businesses must register once taxable turnover passes £90,000.
Within a state, the GST rate is split equally between central GST (CGST) and state GST (SGST, or UTGST in a union territory); between states, the full rate is charged as integrated GST (IGST). At 18% on 1,000, that is 90 of CGST plus 90 of SGST, or 180 of IGST. Since 22 September 2025 the main GST rates are 5% and 18%, with 40% for specified goods.
Each member state sets its own standard rate, which the VAT Directive (article 97) requires to be at least 15%. At 1 July 2025 the lowest standard rate was Luxembourg's 17% and the highest Hungary's 27%; Finland charges 25.5%, Estonia 24% from 1 July 2025 and Romania 21% from 1 August 2025 (European Parliament research briefing, January 2026).
For planning only. Lenders, tax authorities and markets apply their own rounding, fees and rules; confirm figures with them before you commit.
This calculator includes 6 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.