Add tax to a net price, remove tax from a gross price, and show the tax amount clearly for receipts, quotes and classroom checks.
Live math canvas
At 20% VAT/GST, 120.00 entered as net price gives net 120.00, tax 24.00, and gross 144.00.
Formula applied
CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.
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.Your live breakdown
These values come from the controls above and update when the calculator changes.
Resulting answer
Mode: net price. Net 120.00; tax 24.00 at 20%; gross 144.00.
Assumptions used
Set mode to 0 for net-to-gross or 1 for gross-to-net. Confirm the local tax rate before using the result in records.
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.
Printable record
These rows are ready for a report, worksheet, quote note or audit trail.
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.
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.
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.
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.
Methodology & Accuracy
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.
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: 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: 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.
Multiply the net price by 1 plus the tax rate as a decimal. For 20%, multiply by 1.20.
Divide the gross price by 1 plus the tax rate as a decimal. The tax amount is the gross price minus that net price.
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.
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.
Use it only as an arithmetic check. Official records need the correct local rate, invoice basis, exemptions, rounding rules and accounting treatment.
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 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.
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.
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.