# GST, VAT and sales tax calculator

> 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.

操作できるページ：https://www.calcopenly.com/ja/finance/gst-vat-sales-tax-calculator
分野：お金の計算機

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.

## 入力

- **I want to** (選択肢：Add tax, Remove tax)
- **Amount**: The price before tax when adding tax; the price including tax when removing it
- **Tax type** (選択肢：Sales tax or VAT, India GST)
- **Tax rates (%)**: Separate several rates with commas (for example state 6.25 and local 2); each applies to the pre-tax price. UK VAT is 20, EU standard rates run 17–27.
- **GST rate**: Slabs from 22 September 2025: 5% and 18%, 40% for specified goods, 3% for gold
- **Supply** (選択肢：Within a state (CGST + SGST), Between states (IGST))

## 結果

- Tax amount — 主な結果
- Price before tax
- Price including tax
- Combined rate
- CGST
- SGST / UTGST
- IGST

## 計算式

$$
\text{Add: } G = N\Big(1 + \tfrac{\sum r_i}{100}\Big) \qquad \text{Remove: } N = \frac{G}{1 + \sum r_i / 100}
$$

## 計算例

### Add 18% GST within a state

- I want to: Add tax
- Amount: 1000
- Tax type: India GST
- GST rate: 18%
- Supply: Within a state (CGST + SGST)
- **Tax amount: 180.00**
- **CGST: 90.00**
- **SGST / UTGST: 90.00**
- **Price including tax: 1,180.00**
- 照合元：Python decimal: 1000 × 0.18 = 180, split equally between CGST and SGST

### Remove 20% VAT from 120

- I want to: Remove tax
- Amount: 120
- Tax type: Sales tax or VAT
- Tax rates (%): 20
- **Price before tax: 100.00**
- **Tax amount: 20.00**
- 照合元：HMRC VAT fraction for the 20% rate is 1/6: 120 × 1/6 = 20; Python decimal 120 / 1.2 = 100

### State 6.25% plus local 2% on 100

- I want to: Add tax
- Amount: 100
- Tax type: Sales tax or VAT
- Tax rates (%): 6.25, 2
- **Tax amount: 8.25**
- **Price including tax: 108.25**
- **Combined rate: 8.25%**
- 照合元：Python decimal: 100 × 0.0625 + 100 × 0.02 = 8.25

### Zero rate

- I want to: Add tax
- Amount: 500
- Tax type: Sales tax or VAT
- Tax rates (%): 0
- **Tax amount: 0.00**
- **Price including tax: 500.00**
- 照合元：500 × 0 = 0 by definition

### Remove 18% IGST from 2360

- I want to: Remove tax
- Amount: 2360
- Tax type: India GST
- GST rate: 18%
- Supply: Between states (IGST)
- **Price before tax: 2,000.00**
- **IGST: 360.00**
- 照合元：Python decimal: 2360 / 1.18 = 2000; 2360 − 2000 = 360

### Remove stacked 8.25% from 54.13

- I want to: Remove tax
- Amount: 54.13
- Tax type: Sales tax or VAT
- Tax rates (%): 6.25, 2
- **Price before tax: 50.00**
- **Tax amount: 4.13**
- 照合元：Python decimal: 54.13 / 1.0825 = 50.0046…; tax 4.1254…

## よくある質問

### How do you calculate sales tax?

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.

### How do you remove VAT from a price?

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.

### How is GST split into CGST, SGST and IGST?

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.

### What are the VAT rates in the EU?

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).

### 「GST, VAT and sales tax calculator」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：6。 例えば、「Add 18% GST within a state」はPython decimal: 1000 × 0.18 = 180, split equally between CGST and SGSTと照合しています。

### この計算方法の出典は何ですか？

GOV.UK — VAT rates; PIB — Recommendations of the 56th GST Council meeting (rates from 22 September 2025); CBIC — GST concept and status (CGST, SGST/UTGST, IGST).

## 出典

- [GOV.UK — VAT rates](https://www.gov.uk/vat-rates)
- [PIB — Recommendations of the 56th GST Council meeting (rates from 22 September 2025)](https://www.pib.gov.in/PressReleasePage.aspx?PRID=2163555)
- [CBIC — GST concept and status (CGST, SGST/UTGST, IGST)](https://cbic-gst.gov.in/)

_計画の参考用です。金融機関、税務当局、市場は独自の丸め方、手数料、規則を適用します。契約などの前に該当機関へ金額を確認してください。_