Formula
Add tax: gross price = net price × (1 + tax rate ÷ 100); tax amount = gross price − net price. Remove included tax: net price = gross price ÷ (1 + tax rate ÷ 100); tax amount = gross price − net price.
Business
VAT / GST Calculator
Add tax to a net price, remove tax from a gross price, and show the tax amount clearly for receipts, quotes and classroom checks.
Calculator
Working calculator
Live result144.00 gross120.00 net × 1.2000 = 144.00 gross; tax added 24.00
Formula used
Add tax: gross price = net price × (1 + tax rate ÷ 100); tax amount = gross price − net price. Remove included tax: net price = gross price ÷ (1 + tax rate ÷ 100); tax amount = gross price − net price.
This is the method behind the answer, so the result can be checked rather than simply trusted.What-if check
Rate comparison
Compare common rates against the same entered amount. This helps show whether the price was treated as net-before-tax or gross-tax-inclusive before the report is printed.
| Rate | Net | Tax | Gross |
|---|---|---|---|
| 0% | 120.00 | 0.00 | 120.00 |
| 5% | 120.00 | 6.00 | 126.00 |
| 10% | 120.00 | 12.00 | 132.00 |
| 20% | 120.00 | 24.00 | 144.00 |
Visual proof
Net + tax = gross
Mode 0 adds tax to a net amount. The printed report keeps that basis beside the result.
Printable calculation report
Result: 144.00 gross. Assumption: The entered rate is the applicable VAT, GST or sales-tax-style percentage for the item being checked.
- Price amount
- 120
- VAT / GST rate
- 20
- Mode: 0 add tax, 1 remove tax
- 0
- Page/date context
- 2026-05-16 UTC page version
- Page URL
- https://calculationtime.com/calculators/vat-gst-calculator
Worked example
To remove 20% VAT from a gross price of 120, divide 120 by 1.20 to get a 100 net price. The tax amount is 120 − 100 = 20. To add 20% to a 100 net price, multiply 100 by 1.20 to get a 120 gross price.
Professional note
Master’s Tip: keep the tax basis visible on quotes and purchase records. A price that says “120” is not enough for bookkeeping unless the report also says whether 120 was net, gross tax-inclusive, or tax-exempt.
Regional and unit assumptions
Standard or basis: transparent tax-rate arithmetic using the user-entered percentage. No country-specific VAT, GST, exemption, invoice or filing rule is claimed; use the official local tax authority for compliance decisions.
Assumptions and limitations
- The entered rate is the applicable VAT, GST or sales-tax-style percentage for the item being checked.
- Mode 0 treats the entered price as net before tax; mode 1 treats the entered price as gross tax-inclusive.
- Currency symbols, invoice rounding rules, exemptions, reverse charge, import duties and multi-rate baskets are not handled.
- This calculator is an arithmetic aid only, not tax, accounting or compliance advice.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Add tax: gross price = net price × (1 + tax rate ÷ 100); tax amount = gross price − net price. Remove included tax: net price = gross price ÷ (1 + tax rate ÷ 100); tax amount = gross price − net price.
Standard or basis
Standard or basis: transparent tax-rate arithmetic using the user-entered percentage. No country-specific VAT, GST, exemption, invoice or filing rule is claimed; use the official local tax authority for compliance decisions.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Master’s Tip: keep the tax basis visible on quotes and purchase records. A price that says “120” is not enough for bookkeeping unless the report also says whether 120 was net, gross tax-inclusive, or tax-exempt.
Related calculators
Questions
How do I add VAT or GST to a price?
Multiply the net price by 1 plus the tax rate as a decimal. For 20%, multiply by 1.20.
How do I remove VAT or GST from a tax-inclusive price?
Divide the gross price by 1 plus the tax rate as a decimal. The tax amount is the gross price minus that net price.
Is VAT calculated the same as GST?
For this arithmetic calculator, yes: both use the same percentage add-or-remove formula. Legal treatment, exemptions and filing rules still depend on the country and item.
Why is removing 20% tax not the same as subtracting 20%?
Because the 20% tax is based on the net price, not the gross price. A 120 tax-inclusive price at 20% contains 20 tax, not 24.
Can I use this for official tax returns?
Use it only as an arithmetic check. Official records need the correct local rate, invoice basis, exemptions, rounding rules and accounting treatment.
Calculation note
Consumption taxes such as VAT and GST are usually calculated as a percentage of a taxable net value, then shown separately or included in the customer-facing price. The key arithmetic issue is knowing whether the entered amount is before tax or already tax-inclusive.
Adding tax and extracting tax are different operations
Adding tax starts with the net amount and multiplies upward. Extracting included tax starts with the gross amount and divides back to the net amount. Subtracting the tax rate from a gross price gives the wrong answer because the tax percentage was not applied to the gross base.
The rate is only one part of a real tax record
A receipt or quote may need the supplier details, tax registration status, product category, exemption status, invoice date and local rounding rule. This page keeps the arithmetic transparent, but it does not decide whether a transaction is taxable.
Printable records help avoid net-versus-gross confusion
The printed report is designed to show the input amount, rate, mode, formula and result on one page, so a quote note, bookkeeping check or classroom worksheet does not lose the basis of the calculation.
Sources and further readingEuropean Commission: VAT rules and ratesAustralian Taxation Office: GSTNew Zealand Inland Revenue: GST