Tools
VAT/GST calculator: add or remove tax at any rate
Type an amount and your rate. Choose whether the amount is before tax or already includes it, and the calculator shows the net amount, the tax and the total.
In short
This free VAT/GST calculator from SimpleERP adds tax to a net amount or takes it out of a gross amount, at any rate, exact to the cent. It works for VAT, GST and sales tax alike, rounding as a SimpleERP invoice line does.
How to use it
Three inputs, and the answer updates as you type.
Enter the amount
A price before tax, such as 1000, or a price that already includes tax, such as 1200. No currency symbol is needed.
Enter your tax rate
Any rate from 0 to 100, decimals allowed: 20 for the UK, 5 for the UAE, 7.5 for Nigeria, or your state's combined sales tax rate.
Say whether tax is included
Before tax adds the tax on top. Including tax takes the tax out, which is what you need to read a receipt or a shelf price.
In India, tax splits into central and state parts by place of supply: use the GST calculator (India), which shows that split.
VAT, GST and sales tax: what is the difference?
The arithmetic is the same; who pays it and when is not. The tax is called VAT or GST depending on the country, and works the same way: each business in the chain charges it on its sales and reclaims what it paid on its purchases, so only the final consumer bears it. Sales tax, as in the US, is charged once, at the final sale, and a business buying to resell usually shows an exemption certificate instead of paying it.
- VAT/GST: charged at every stage, reclaimed by registered businesses, paid in full by the consumer.
- Sales tax: charged only on the final sale, at a rate set by the state and often the city or county too.
- Either way, the tax on one line is the amount before tax times the rate.
- Zero-rated and exempt sales are different things in most VAT countries; neither shows tax on the invoice, but they treat your purchases differently.
Which rate should I use?
Most countries have one standard rate and a few reduced rates for food, books, children's clothes or energy. The standard rates below are the ones SimpleERP sets up for each country. Confirm the rate for your own goods with your tax authority before you rely on it, because rates change and reduced rates are many.
| Country | Standard rate | Currency |
|---|---|---|
| United Arab Emirates | 5% | AED |
| United Kingdom | 20% | GBP |
| Australia | 10% | AUD |
| Canada | 5% | CAD |
| Germany | 19% | EUR |
| Ireland | 23% | EUR |
| Netherlands | 21% | EUR |
| New Zealand | 15% | NZD |
| South Africa | 15% | ZAR |
| Kenya | 16% | KES |
| Nigeria | 7.5% | NGN |
| Singapore | 9% | SGD |
| Philippines | 12% | PHP |
| Indonesia | 11% | IDR |
| Saudi Arabia | 15% | SAR |
| Pakistan | 18% | PKR |
| Bangladesh | 15% | BDT |
| Sri Lanka | 18% | LKR |
Do this automatically in SimpleERP
On a SimpleERP invoice you never work tax out by hand. The rate comes from the product, the tax is worked out on each line, and the total includes it.
- Tax rates set up for your country when you sign up, with your standard rate as the default.
- A rate per product, changeable on the line for a one-off sale.
- The tax posts to its own account, so the tax you owe is always one report away.
- Amount in words printed on the invoice, in your currency.
Illustration of invoice INV-2026-0213 to Northside Retail with sales tax 6.25% and the amount in words.
The maths
How it is calculated
Tax is a percentage of the amount before tax. Taking it out of a gross amount uses the same rate, divided differently.
- Adding tax: tax = amount before tax × rate ÷ 100, and total = amount before tax + tax.
- Taking tax out: tax = amount including tax × rate ÷ (100 + rate), and amount before tax = amount including tax − tax.
- At 20%, the tax inside a gross price is 20 ÷ 120, or one sixth. At 5%, it is 5 ÷ 105, or one twenty-first.
- The tax is rounded half up to the cent, or to three decimals when you type the amount with three (dinars and rials), and the amount before tax is whatever is left, so the two always add back to the amount typed.
Example
Worked example
Harbor Supply Co. sells steel racks worth $1,000 before tax.
| Rate | Amount | The amount is | Tax | Before tax | Total |
|---|---|---|---|---|---|
| 20% | $1,000.00 | Before tax | $200.00 | $1,000.00 | $1,200.00 |
| 20% | $1,200.00 | Including tax | $200.00 | $1,000.00 | $1,200.00 |
| 5% | $1,000.00 | Before tax | $50.00 | $1,000.00 | $1,050.00 |
Type 1000 and 20 to see the first line, then switch to Including tax and type 1200 to see the second.
Honest limits
What this calculator does not do
- It does not know your rate: reduced rates, exemptions and US local sales tax rates are yours to enter.
- It works on one amount at one rate; an invoice with several rates is the sum of its lines.
- Reverse charge, exports and cross-border rules are outside this calculator; ask your accountant how they apply to you.
FAQ
Questions, answered
How do I add 20% VAT to a price?
Multiply the price by 1.2. For $1,000 that is $1,200, of which $200 is tax. The calculator does the same and rounds the tax to the cent.
How do I work out the VAT in a price that includes it?
Divide the gross price by 6 when the rate is 20%, or in general multiply it by rate ÷ (100 + rate). For $1,200 at 20% the tax is $200 and the price before tax is $1,000.
Why not just take 20% off the gross price?
Because the tax was 20% of the net price, not of the gross. Taking 20% off $1,200 gives $960, which is $40 too low. The right answer is $1,000.
Does this work for sales tax in the US?
Yes, as long as you enter the combined rate for the place of sale: state, county and city together. Sales tax is usually added on top of a shelf price, so choose Before tax.
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